Twin Turbo 400 Buildup- '89 Iroc-Z
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Car: 91 rs
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
arent other fall backs of superchargers that they can only make as much max boost as high as you rev... example being that turbos can make more boost bc supercharger max boost is directly rated to max RPM. except for the option of smaller pullies. a good thing about superchargers tho is less weight (turbo has lots of plumbing), less heat (doesnt always need an intercooler depending on boost etc) but they make less power and take power from the engine to operate.
is there any issues with running a MAF with a turbo or dual turbos? seems that most ppl switch to the 730 ecm and speed density
is there any issues with running a MAF with a turbo or dual turbos? seems that most ppl switch to the 730 ecm and speed density
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From: NYC / Jersey
Car: 1990 Trans Am GTA
Engine: Turbo 305 w/MS2
Transmission: 700R4
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Originally Posted by customblackbird
arent other fall backs of superchargers that they can only make as much max boost as high as you rev... example being that turbos can make more boost bc supercharger max boost is directly rated to max RPM. except for the option of smaller pullies. a good thing about superchargers tho is less weight (turbo has lots of plumbing), less heat (doesnt always need an intercooler depending on boost etc) but they make less power and take power from the engine to operate....
http://www.musclemustangfastfords.co...all/index.html
Originally Posted by customblackbird
is there any issues with running a MAF with a turbo or dual turbos? seems that most ppl switch to the 730 ecm and speed density....
http://www.youtube.com/watch?v=hPKzLU3r-1E
Last edited by Street Lethal; Oct 7, 2009 at 04:19 PM.
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From: Benzie, MI
Car: 91 rs
Engine: Blow through 383, 10 psi, xr288hr
Transmission: Manual th350 ATI 3000
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
I saw that article over a year ago and no one I talked to ever heard of using a wastegate. I think its pretty cool, but the cost of upgrading the head, changing to a cog drive, and worrying about the crank snout breaking are enough make turbo much more appealing, not to mention turbo does make more power at the same boost level.
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From: NYC / Jersey
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
How can a turbo make more boost at the same boost level w/out knowing which turbo and which supercharger is being used in comparison though? 15-psi is 15-psi, with the only difference of course being the smaller unit cannot keep up at higher RPM's, and will eventually run out of steam. If we compare an F3R procharger against a T88 turbo, there is simply no comparison, the F3R procharger owns it. But if we're talking a P1SC, then yes, the T-88 turbo will destroy it. Too many variables....
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Car: 89 Iroc-z
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
All i know is turbos sound soo much better than blowers.
I gotta fix my exhaust as its not properly supported. Clamp came loose and the muffler is hanging low. Gotta push back up and tack it up into place, fab a hanger perhaps and then reclamp it.
Somehow my trans temperature sender in the pan broke in half...no wonder my tranny gauge aint working. Must have scrapped it on something but i have no idea how i hit something that low at that spot, and yet nothing else below the car hit anything.
uploaded a new tune and was gonna sneak it out tonight but need to fix other issues first. Gotta get some welding wire, i'm all out
I gotta fix my exhaust as its not properly supported. Clamp came loose and the muffler is hanging low. Gotta push back up and tack it up into place, fab a hanger perhaps and then reclamp it.
Somehow my trans temperature sender in the pan broke in half...no wonder my tranny gauge aint working. Must have scrapped it on something but i have no idea how i hit something that low at that spot, and yet nothing else below the car hit anything.
uploaded a new tune and was gonna sneak it out tonight but need to fix other issues first. Gotta get some welding wire, i'm all out
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Car: 91 rs
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Transmission: Manual th350 ATI 3000
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Whenever I have seen supercharger vs turbo dyno graphs with the same peak boost, the turbo makes more power from boosting point to finish and a lot more torque earlier also.
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Car: 89 Iroc-z
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
yeah on my setup the tune is working pretty good now. Got the battery voltage table setup so it runs these injectors well when the volts start to go south. Secured the alternator feed wire so that it doesnt wiggle loose now. Going to try a few things today, abit more idle tuning and then trying to get a heavy throttle pass above 4000 rpm. It was cutting out up there so i figured it was lean.
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Car: 89 Iroc-z
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
redid my VE map for above 70-80KPA to 180KPA to make it look right. values when graphed did not represent what i thought a VE curve should look like. Zero'd out the boost multiplier table and added that percentage into the VE map.
Its getting there. Hit 6psi my first run with it and 60% throttle. Got to 6000 rpm so no longer breaking up at 4000. IT was a lean spot there so the new VE map helped alot. Few more runs and on my last run tonight I hit 9.7 psi, which aint good since I have 6-7 psi springs in the gates. Its still lean, in the high 13's to 1 at WOT.
I was only there for a little bit and the car just BLEW the tires apart. My nitrous 383 didnt do it like this but was capable of breaking tires loose at 40mph rolls when it was cold out. Its chilly today but according to my logs i was doing about 50 when i got into boost and tires spun to 80mph. Car felt amazing even tho its not tuned.
I can tell i have exhaust leaks and another issue with bank to bank balance, as my driver side turbo was glowing red hot and i saw flames out the down pipe, so something caught fire there. Needs richened up alot
Its getting there. Hit 6psi my first run with it and 60% throttle. Got to 6000 rpm so no longer breaking up at 4000. IT was a lean spot there so the new VE map helped alot. Few more runs and on my last run tonight I hit 9.7 psi, which aint good since I have 6-7 psi springs in the gates. Its still lean, in the high 13's to 1 at WOT.
I was only there for a little bit and the car just BLEW the tires apart. My nitrous 383 didnt do it like this but was capable of breaking tires loose at 40mph rolls when it was cold out. Its chilly today but according to my logs i was doing about 50 when i got into boost and tires spun to 80mph. Car felt amazing even tho its not tuned.
I can tell i have exhaust leaks and another issue with bank to bank balance, as my driver side turbo was glowing red hot and i saw flames out the down pipe, so something caught fire there. Needs richened up alot
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Good to hear that you are making progress. I guess now you have to beat old man winter in order to keep working on the car. 
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Orr89.... Good talking with you the other night on Sy/Ty chat... Good folks over there to help.
Keep us posted.. Glad your over 4000rpm.. Sweet!
I know you explained it with running out of steam but it's the amount of volume a turbo puts out that really makes the difference.
A TA49 at 15psi is totally different than a 70mm turbo at 15psi.
It's like saying your going to use 16gauge wire to your starter to turn the car over because it reads 12volts. The amount of energy in a 2 gauge wire (volume) is totally different than a 16gauge wire (volume) even though they read the same 12volts at the end.
You have a grasp on this I know.. but it helps explain it for others that don't.
I've been running 17-18psi on 93oct for the last few years. No knock retard ... No alky/meth injection. I've not pushed it any harder but really don't need to at this point.
It's dependable and fun. I run it with a 1/2 tank of gas and 18psi in the drag radials.
Pretty much the way you'd catch me on the street.
~Scott
Keep us posted.. Glad your over 4000rpm.. Sweet!
15-psi is 15-psi,
A TA49 at 15psi is totally different than a 70mm turbo at 15psi.
It's like saying your going to use 16gauge wire to your starter to turn the car over because it reads 12volts. The amount of energy in a 2 gauge wire (volume) is totally different than a 16gauge wire (volume) even though they read the same 12volts at the end.
You have a grasp on this I know.. but it helps explain it for others that don't.
I've been running 17-18psi on 93oct for the last few years. No knock retard ... No alky/meth injection. I've not pushed it any harder but really don't need to at this point.
It's dependable and fun. I run it with a 1/2 tank of gas and 18psi in the drag radials.
Pretty much the way you'd catch me on the street.
~Scott
Joined: Jul 2003
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From: NYC / Jersey
Car: 1990 Trans Am GTA
Engine: Turbo 305 w/MS2
Transmission: 700R4
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Originally Posted by UR50SLO
I know you explained it with running out of steam but it's the amount of volume a turbo puts out that really makes the difference. A TA49 at 15psi is totally different than a 70mm turbo at 15psi....
Last edited by Street Lethal; Oct 15, 2009 at 12:55 PM.
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From: Benzie, MI
Car: 91 rs
Engine: Blow through 383, 10 psi, xr288hr
Transmission: Manual th350 ATI 3000
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
15 psi is 15 psi, but how hot is the air? Intake manifold air density is what makes the difference.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Originally Posted by Batass
15 psi is 15 psi, but how hot is the air? Intake manifold air density is what makes the difference....
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
If you use the same exact engine for comparison, lets say for arguments sake, the smaller turbo makes 15-psi at 3000-RPM @ WOT. Now, remove that turbo, and install a T76 on the very same engine. The T76 will make more than 15-psi @ 3000-RPM, but that isn't what I'm saying
I you take a TA49 that you have set at 15psi total boost on the wastegate.
Then replace it with a 76gtq with 15psi total boost set on the wastegate your telling me that that exact same car will not go any faster.... Lol Ok.
I run a larger turbo on my car so I don't need to run as much boost and it keeps my IAT's low.
I found this on another site... I think it explains it pretty well
(By Duckstu)
It would seem that being as boost pressure is measured INSIDE the intake,...and after the throttle body,..that 20 psi is 20 psi, is 20 psi. But it's not.
2 reasons why.
1. The smaller the turbo,..the harder it has to work to stuff the same amount of air through the compressor housing. The blades are turning faster to do the same job, and are cutting into the air more often,..and the air is being squeezed harder to get it through the small scroll of the compressor side. All this adds up to more heat in the intake air.
More heat in the intake air means the air will be less dense. And as we all know,...you can be at 600 feet above sea-level on a hot day and the car is sluggish,..and on the same piece of road on a cold day and the car is fast. Same air pressure,...but different air densities because of the temperature of the air.
Reason 2. What really counts is the total mass of the air being moved through the engine (see reason 1). If you had a really restrictive exhaust manifold,...not all of the combusted air could get out of the cylinders during the exhaust stroke. Some of it would be left in the cylinder.
Then durring the intake stroke,...the cylinder would injest less new air because some of the space would already be used up by exhaust gases left behind from the last combustion event. You can see what happens next. If the cylinder is injesting less air on the intake stroke,..it acts like a smaller engine,... and less new air delivered by the turbo will be required to maintain the 20 psi. As the engine gets bigger, (or the engine evacuates the exhaust more effectively) the more volume of air the turbo will be required to deliver to maintain boost pressure. Taken to the extreme,...picture a 1/2" diameter exhaust pipe. How much power would your car make? Even at 20 psi of boost, it would probably be under 80 whp.
I.e., ask yourself why headers make an engine more powerfull? Same intake air pressure. It's because they cause the cylinders to have more room for the next intake charge.
The hot-side of turbo acts as a restrictive header. The smaller the housing is,...or the more resistance the turbine wheel exibits (because it is working harder to turn the compressor wheel super fast), the more combustion gasses will be left in the cylinder. A big turbo that can easilly flow air through the compressor side will not require as much resistance to be put into the hot-side wheel (turbine) and the housing itself will also flow better. A double whammy in either direction.
Bottom line,...the bigger turbo will not restrict the exhaust as much,...it can flow air through the comprssor side easier and therefore inject less heat into the air,...and both of these will cause the turbo to have to flow more molecules of oxygen and nitrogen through the engine in order to get back up to the same boost pressure as the smaller turbo ran.
More volume of denser air means more molecules of air total,...and more air total means more stuff to expand,...and more oxygen and fuel to expand it with. All of which means more power.
So bottom line,...the 20 psi from the smaller turbo is 20 psi of hotter and less dense air,.....and the engine is taking smaller gulps of this less dense air at each cylinder filling.
2 reasons why.
1. The smaller the turbo,..the harder it has to work to stuff the same amount of air through the compressor housing. The blades are turning faster to do the same job, and are cutting into the air more often,..and the air is being squeezed harder to get it through the small scroll of the compressor side. All this adds up to more heat in the intake air.
More heat in the intake air means the air will be less dense. And as we all know,...you can be at 600 feet above sea-level on a hot day and the car is sluggish,..and on the same piece of road on a cold day and the car is fast. Same air pressure,...but different air densities because of the temperature of the air.
Reason 2. What really counts is the total mass of the air being moved through the engine (see reason 1). If you had a really restrictive exhaust manifold,...not all of the combusted air could get out of the cylinders during the exhaust stroke. Some of it would be left in the cylinder.
Then durring the intake stroke,...the cylinder would injest less new air because some of the space would already be used up by exhaust gases left behind from the last combustion event. You can see what happens next. If the cylinder is injesting less air on the intake stroke,..it acts like a smaller engine,... and less new air delivered by the turbo will be required to maintain the 20 psi. As the engine gets bigger, (or the engine evacuates the exhaust more effectively) the more volume of air the turbo will be required to deliver to maintain boost pressure. Taken to the extreme,...picture a 1/2" diameter exhaust pipe. How much power would your car make? Even at 20 psi of boost, it would probably be under 80 whp.
I.e., ask yourself why headers make an engine more powerfull? Same intake air pressure. It's because they cause the cylinders to have more room for the next intake charge.
The hot-side of turbo acts as a restrictive header. The smaller the housing is,...or the more resistance the turbine wheel exibits (because it is working harder to turn the compressor wheel super fast), the more combustion gasses will be left in the cylinder. A big turbo that can easilly flow air through the compressor side will not require as much resistance to be put into the hot-side wheel (turbine) and the housing itself will also flow better. A double whammy in either direction.
Bottom line,...the bigger turbo will not restrict the exhaust as much,...it can flow air through the comprssor side easier and therefore inject less heat into the air,...and both of these will cause the turbo to have to flow more molecules of oxygen and nitrogen through the engine in order to get back up to the same boost pressure as the smaller turbo ran.
More volume of denser air means more molecules of air total,...and more air total means more stuff to expand,...and more oxygen and fuel to expand it with. All of which means more power.
So bottom line,...the 20 psi from the smaller turbo is 20 psi of hotter and less dense air,.....and the engine is taking smaller gulps of this less dense air at each cylinder filling.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Originally Posted by UR50SLO
So... exactly what is it that your saying Lol?
Again, nothing changes the fact that 15-psi is still 15-psi. I mean, do I have to get Eric Marshall and Bob Bailey here for you to understand this? Bigger compressor wheels flow more air, so at a given (the same) RPM, the bigger turbo will always flow more, because psi will be more than the smaller turbo can dish out at the very same RPM level. By the way, you don't just slap on a larger turbo and run in the nine's on the very same setup as the small one, you need larger injectors, larger wastegate, not to mention larger stall, because it will lag, not to mention tune. Speaking of which, the last time I checked, replacing a small turbo with a much larger one, in respect to tuning, the cells most looked at, and changed, are up high in the grid, for a reason, because that is where the additional boost becomes a factor....
Your argument is that a larger turbo can squeeze more air through a two inch intake valve during 1 through 15-psi, when the stock turbo is already at full volume during that time. Full volume, meaning, you CAN'T get more air into the combustion chamber. You will need to prove that you can get more air in with factual proof, because that is impossible. The benefits of the larger turbo over the smaller one is that it takes less resistance (meaning, you can run a gigantic intercooler, you can run ported heads, bigger cam, and 4" intake), and make the same amount of boost the smaller one would need to WITH resistance, because the larger turbo obviously flows more air to begin with. Not to mention, the larger turbo lasting longer up top. So explain yourself, show me how a larger turbo can squeeze more air than a stock turbo into a stock engine, up until 15-psi, when the stock turbo has already filled up the volume.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
The very fact that you cannot decipher what I'm saying tells me everything.
They say a picure is worth a thousand words well....
Yours:
Mine:
Bring your car out to Drag Week next year it's quite a Challange for us Morons
who don't understand anything.. I'm suprised we can still remember how to walk
and chew gum!
You'll be walking all over us with your understanding of 15psi .... whew I'm stupid!
Sorry to mess up your thread Or89..
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
The very fact that you cannot decipher what I'm saying tells me everything. If your going to cap it at 15-psi on the very same engine, the larger turbo will have to be capped earlier on in the RPM because it flows more air ON AVERAGE because of it's impeller speed, not to mention the wastegate needing to be bigger, so what is so hard to understand about that? During 1 through 15-psi, one can only squeeze so much air through a two inch (if that) intake valve, so how exactly can a larger turbo get more air through that valve when the smaller one is already at full volume up until that point lmao....?
Again, nothing changes the fact that 15-psi is still 15-psi. I mean, do I have to get Eric Marshall and Bob Bailey here for you to understand this? Bigger compressor wheels flow more air, so at a given (the same) RPM, the bigger turbo will always flow more, because psi will be more than the smaller turbo can dish out at the very same RPM level. By the way, you don't just slap on a larger turbo and run in the nine's on the very same setup as the small one, you need larger injectors, larger wastegate, not to mention larger stall, because it will lag, not to mention tune. Speaking of which, the last time I checked, replacing a small turbo with a much larger one, in respect to tuning, the cells most looked at, and changed, are up high in the grid, for a reason, because that is where the additional boost becomes a factor....
Your argument is that a larger turbo can squeeze more air through a two inch intake valve during 1 through 15-psi, when the stock turbo is already at full volume during that time. Full volume, meaning, you CAN'T get more air into the combustion chamber. You will need to prove that you can get more air in with factual proof, because that is impossible. The benefits of the larger turbo over the smaller one is that it takes less resistance (meaning, you can run a gigantic intercooler, you can run ported heads, bigger cam, and 4" intake), and make the same amount of boost the smaller one would need to WITH resistance, because the larger turbo obviously flows more air to begin with. Not to mention, the larger turbo lasting longer up top. So explain yourself, show me how a larger turbo can squeeze more air than a stock turbo into a stock engine, up until 15-psi, when the stock turbo has already filled up the volume.
Again, nothing changes the fact that 15-psi is still 15-psi. I mean, do I have to get Eric Marshall and Bob Bailey here for you to understand this? Bigger compressor wheels flow more air, so at a given (the same) RPM, the bigger turbo will always flow more, because psi will be more than the smaller turbo can dish out at the very same RPM level. By the way, you don't just slap on a larger turbo and run in the nine's on the very same setup as the small one, you need larger injectors, larger wastegate, not to mention larger stall, because it will lag, not to mention tune. Speaking of which, the last time I checked, replacing a small turbo with a much larger one, in respect to tuning, the cells most looked at, and changed, are up high in the grid, for a reason, because that is where the additional boost becomes a factor....
Your argument is that a larger turbo can squeeze more air through a two inch intake valve during 1 through 15-psi, when the stock turbo is already at full volume during that time. Full volume, meaning, you CAN'T get more air into the combustion chamber. You will need to prove that you can get more air in with factual proof, because that is impossible. The benefits of the larger turbo over the smaller one is that it takes less resistance (meaning, you can run a gigantic intercooler, you can run ported heads, bigger cam, and 4" intake), and make the same amount of boost the smaller one would need to WITH resistance, because the larger turbo obviously flows more air to begin with. Not to mention, the larger turbo lasting longer up top. So explain yourself, show me how a larger turbo can squeeze more air than a stock turbo into a stock engine, up until 15-psi, when the stock turbo has already filled up the volume.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Originally Posted by UR50SLO
....
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
I work for a turbomachinery company as a compressor application engineer... smaller diameter wheels have to spin faster than larger ones to get the same pressure rise. Thats a given.
If you hold compressor wheel speed constant, and also hold flow constant, the larger diameter wheel will make more pressure output.
Depending on how much pressure rise your trying to get out of the wheel, this usually leads to the smaller machine being slightly less efficient than larger one given similar conditions. When looking at the compressor map, if your working smaller turbo harder as in spinning it faster to get certain pressure rise/ratio, your gonna be off its peak efficiency. Its gonna heat the air charge more. Stepping up to larger wheel to slow down the compressor side will move the operating point closer to peak efficiency, so it can compress a given amount of air to a given pressure without adding alot of extra unnecessary heat. That depends on shape of the map tho.
You'd have to be operating the smaller wheel faster and more towards choke to get same pressure rise and flow as a larger wheel thats running slower, more towards middle of the operating range. So in that sense, the larger wheel is more efficient and should heat up the air charge less. Not always the case i guess, it depends on the final efficiency. In my industry i have seen smaller wheels at faster speeds create same pressure rise at a given flow and result in same or slightly less outlet temps than larger slower moving wheels. Just depends on the efficiency curve of the wheel.
But my industry is on a MUCH LARGER scale than turbocharger wheels so it may be more dramatic of a difference in size on the smaller level
If you hold compressor wheel speed constant, and also hold flow constant, the larger diameter wheel will make more pressure output.
Depending on how much pressure rise your trying to get out of the wheel, this usually leads to the smaller machine being slightly less efficient than larger one given similar conditions. When looking at the compressor map, if your working smaller turbo harder as in spinning it faster to get certain pressure rise/ratio, your gonna be off its peak efficiency. Its gonna heat the air charge more. Stepping up to larger wheel to slow down the compressor side will move the operating point closer to peak efficiency, so it can compress a given amount of air to a given pressure without adding alot of extra unnecessary heat. That depends on shape of the map tho.
You'd have to be operating the smaller wheel faster and more towards choke to get same pressure rise and flow as a larger wheel thats running slower, more towards middle of the operating range. So in that sense, the larger wheel is more efficient and should heat up the air charge less. Not always the case i guess, it depends on the final efficiency. In my industry i have seen smaller wheels at faster speeds create same pressure rise at a given flow and result in same or slightly less outlet temps than larger slower moving wheels. Just depends on the efficiency curve of the wheel.
But my industry is on a MUCH LARGER scale than turbocharger wheels so it may be more dramatic of a difference in size on the smaller level
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Originally Posted by ???
holy s.h.i.t! I'm pretty much speechless after reading that.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Originally Posted by Orr89RocZ
But my industry is on a MUCH LARGER scale than turbocharger wheels so it may be more dramatic of a difference in size on the smaller level....
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
I don't have to strap a 88mm turbo on ... my 76GTQ is actually too large for my current combo. I'd be better served by a 71DBB. I just can't afford it.
Almost everything on my car was used from TurboBuick.com. I got deals on the parts I used and then fabricated everything else from scratch. Alot of hard work and time and it paid off.
You need to walk away from links to OTHER peoples cars and Video's of other peoples cars and do actual "WORK" on yours. Then you can come on here and tell eveyone how much you know and have accomplished with all your "Knowledge"
Prove me wrong.. don't get mad.. Get focused and build somthing!
We are here on this and other boards to help one another and discuss ideas.
I looked through your posts on your topic's and others before I posted.
15psi will be 15psi but the Air will be cooler and denser leaving the tuner the ability to
tune in more timing or boost before detonation on the larger turbo every time.
Everyone has their own way of reaching their goals... That's what makes sharing information helpfull... Let's keep it on the "Helpfull" tone from here out.
Again.. sorry Or89.
Thanks for your above input.
~Scott
Almost everything on my car was used from TurboBuick.com. I got deals on the parts I used and then fabricated everything else from scratch. Alot of hard work and time and it paid off.
You need to walk away from links to OTHER peoples cars and Video's of other peoples cars and do actual "WORK" on yours. Then you can come on here and tell eveyone how much you know and have accomplished with all your "Knowledge"
Prove me wrong.. don't get mad.. Get focused and build somthing!
We are here on this and other boards to help one another and discuss ideas.
I looked through your posts on your topic's and others before I posted.
15psi will be 15psi but the Air will be cooler and denser leaving the tuner the ability to
tune in more timing or boost before detonation on the larger turbo every time.
Everyone has their own way of reaching their goals... That's what makes sharing information helpfull... Let's keep it on the "Helpfull" tone from here out.
Again.. sorry Or89.
Thanks for your above input.
~Scott
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
the only way my post could have been more of a waste is if I tried to help you understand why you're wrong.
but what the hell, quick and simple. the larger turbo builds the boost while heating the air less. less heat = more o2 in a givin cfm of air flow. as in your valve example. so yes, the same cfm may be going past your valve at 15psi with either, but the cooler charge from the larger turbo will make more power because it has more o2.
and it doesn't matter how big your intercooler is, or what meth your running, cooler temps out of the turbo = cooler temps out of your intercooler/meth kit.
now this is a total waste of a post since you will make up some backassward way to dissagree with me.
but what the hell, quick and simple. the larger turbo builds the boost while heating the air less. less heat = more o2 in a givin cfm of air flow. as in your valve example. so yes, the same cfm may be going past your valve at 15psi with either, but the cooler charge from the larger turbo will make more power because it has more o2.
and it doesn't matter how big your intercooler is, or what meth your running, cooler temps out of the turbo = cooler temps out of your intercooler/meth kit.
now this is a total waste of a post since you will make up some backassward way to dissagree with me.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Scott, I'll be the grown up here, and will end this right now, because this is something we shouldn't even be arguing about. I'm just going to ask you a couple of questions, then maybe you'll understand why I keep saying 15-psi is 15-psi, regardless of turbo size. Do you agree that it takes x amount of air to create 15-psi, and only x amount of air? Do you agree that @ 15-psi, an engine doubles its cubic inch displacement because of that specific amount of air? Now, since I'm sure you agree with those two statements, if a larger turbo stuffed more air in (again, I'm NOT saying that it doesn't flow more at that RPM, only that it's not getting that potential flow in because the cylinder is already max filled by the small turbo), and if x amount of air makes 15-psi, then where is that extra air? If that exrtra air happened to get in at 15-psi, then it would no longer be considered 15-psi, it would be higher. Do you see what I'm saying yet? At 15-psi, both turbo's are equal, because both are capable of filling the small cylinder from 0 vacuum, to 15-psi....
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Originally Posted by ???
the larger turbo builds the boost while heating the air less....
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Scott, I'll be the grown up here, and will end this right now, because this is something we shouldn't even be arguing about. I'm just going to ask you a couple of questions, then maybe you'll understand why I keep saying 15-psi is 15-psi, regardless of turbo size. Do you agree that it takes x amount of air to create 15-psi, and only x amount of air? Do you agree that @ 15-psi, an engine doubles its cubic inch displacement because of that specific amount of air? Now, since I'm sure you agree with those two statements, if a larger turbo stuffed more air in (again, I'm NOT saying that it doesn't flow more at that RPM, only that it's not getting that potential flow in because the cylinder is already max filled by the small turbo), and if x amount of air makes 15-psi, then where is that extra air? If that exrtra air happened to get in at 15-psi, then it would no longer be considered 15-psi, it would be higher. Do you see what I'm saying yet? At 15-psi, both turbo's are equal, because both are capable of filling the small cylinder from 0 vacuum, to 15-psi....
However, "street" you are wrong... I know why you are thinking your not, but you are. 15psi IS 15psi IF the temps and relative humidity are the same for both volumes of air. However you can make 15psi with different AMOUNTS of air if you use different densities, by either altering temperature or relative humidity (from here on we will drop RH because it really is a small part of density). Simply speaking the AMOUNT of air going thru an engine is what determines its power output, not the pressure. Can we agree on this?
If so, I can clearly explain it to you. Take a balloon(#1) and blow it up to 2 feet in diameter then tie it off (no air can go in or out). To expand the rubber surface on the balloon to 2 feet takes a certain pressure (call it Xpsi).
Now given the same type of balloon(#2), and blow it up to 1 feet in diameter and then tie it off... then put it over a hot stove. The balloon(#2) will begin to expand due to the heat... if you remove the balloon(#2) from the stove when it expands to 2 feet in diameter, balloon(#2) will have the exact same pressure(Xpsi) BUT will contain a less AMOUNT of air than balloon(#1).
The same reason sealed CO2 containers can explode when heated... they are sealed so no air can go in or out, but they get heated so there PSI increases till they explode.
Greater the AMOUNT of air = greater explosion (Horse power)
Not, greater the PSI
Does that make sense?
Last edited by BirdsOnly; Oct 15, 2009 at 06:13 PM.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
.... your talking about variables though, are you saying that a larger turbo on said LC2 will supply denser air when it can't even spool? Intake temps can be lowered w/alky, regarldess of turbo size, that is not what I'm saying, I'm speaking in general, not to mention only up til 15-psi. BTW, that's it, no more on this subject as this is Justin's thread.
Last edited by Street Lethal; Oct 15, 2009 at 06:32 PM.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
.... your talking about variables though, are you saying that a larger turbo on said LC2 will supply denser air when it can't even spool? Intake temps can be lowered w/alky, regarldess of turbo size, that is not what I'm saying, I'm speaking in general, not to mention only up til 15-psi. BTW, that's it, no more on this subject as this is Justin's thread.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Talk about getting off subject... I came here to see if Orr got his $58 nonsense sorted out.
Read quote below and you'll figure out why you just smacked your head.
In other words, contrary to what you said above about RH and temp effects, when it measures "X" psi in balloon one and "X" psi in balloon two (lets just call "X" 15psi for kicks) then the psi as you said is the "exact same". The reason for this is because... follow along class... any device used for measuring PSI does just that, measures PSI. It does not measure air density, temperature, humidity, or anything else. It measures air pressure and thats it. So 15psi IS 15psi, no matter where you measure it or on what car for that matter. You guys talking about differences in turbos and volumes of air are involving other properties of air that are totally relevant to power output, but totally irrelevant to the fact that an air pressure gauge does not measure or understand any of that. So happens a lot of people dont as well but thats another subject and unfortunately has nothing to do with Orr's tuning! 
I dont agree. The guy I quoted above explained why it can take x, y, or z amount of air to get to the same psi reading. psi is only part of the puzzle.
Read quote below and you'll figure out why you just smacked your head.
I dont agree. The guy I quoted above explained why it can take x, y, or z amount of air to get to the same psi reading. psi is only part of the puzzle.
Last edited by madmax; Oct 16, 2009 at 12:35 AM.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
rob a larger turbo moves more volume of air,
how do u think my car makes more power with the 60-1 turbo over the t3/t4 turbo while running less boost.
uve worked with me on my car and seen the differences hell u even drove it with both diff turbos on it
how do u think my car makes more power with the 60-1 turbo over the t3/t4 turbo while running less boost.
uve worked with me on my car and seen the differences hell u even drove it with both diff turbos on it
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
even mild boost like 8lbs?So looks like Orr has the $59 version and some 80 lb injectors working right? Cool. Do you have the LC1 tied into your data stream as well?
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
I think the problem here is that its being more complicated than it really is. I'm not exactly sure what someone means when they say 15 psi is 15 psi. 15 pounds per square inch is exactly that but one 15 psi isn't moving the same amount of air as another 15 psi.
You can have 15 psi of cold air and 15 psi of hot air. Everyone knows which one will make more power and it can be very substantial. Efficient=less work to produce same airflow.
Maybe what is getting confused is that psi does not reflect air density. 20 psi of hot air can contain the same amount of air as 10 psi of cool air.
When I hit 9 psi from my supercharger at 4500rpms and it stays at 9 psi to 6500 the extra CFM being moved is negated by the drop in density. A larger volume of air is being moved, but less actual air.
Does this mean that my engine is seeing the exact same amount of air at 4500 and 6500? I wonder if the torque curve would be near flat in this range? Well, I suppose the blower is harder to turn, so the engine is losing power there.
I know this is off topic, but I think this is some very important stuff and I would appreciate someone evaluating my thoughts here.
Another thing to throw out there-water injection. I have been told that without making any adjustments to the motor, injecting water won't increase power. The idea is that while it cools the air, increasing density, it occupies space and lowers actual airflow.
I inject pure alcohol and my peak boost didn't change from prior, but I make a hell of a lot more power.
You can have 15 psi of cold air and 15 psi of hot air. Everyone knows which one will make more power and it can be very substantial. Efficient=less work to produce same airflow.
Maybe what is getting confused is that psi does not reflect air density. 20 psi of hot air can contain the same amount of air as 10 psi of cool air.
When I hit 9 psi from my supercharger at 4500rpms and it stays at 9 psi to 6500 the extra CFM being moved is negated by the drop in density. A larger volume of air is being moved, but less actual air.
Does this mean that my engine is seeing the exact same amount of air at 4500 and 6500? I wonder if the torque curve would be near flat in this range? Well, I suppose the blower is harder to turn, so the engine is losing power there.
I know this is off topic, but I think this is some very important stuff and I would appreciate someone evaluating my thoughts here.
Another thing to throw out there-water injection. I have been told that without making any adjustments to the motor, injecting water won't increase power. The idea is that while it cools the air, increasing density, it occupies space and lowers actual airflow.
I inject pure alcohol and my peak boost didn't change from prior, but I make a hell of a lot more power.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Talk about getting off subject... I came here to see if Orr got his $58 nonsense sorted out.
Read quote below and you'll figure out why you just smacked your head.
In other words, contrary to what you said above about RH and temp effects, when it measures "X" psi in balloon one and "X" psi in balloon two (lets just call "X" 15psi for kicks) then the psi as you said is the "exact same". The reason for this is because... follow along class... any device used for measuring PSI does just that, measures PSI. It does not measure air density, temperature, humidity, or anything else. It measures air pressure and thats it. So 15psi IS 15psi, no matter where you measure it or on what car for that matter. You guys talking about differences in turbos and volumes of air are involving other properties of air that are totally relevant to power output, but totally irrelevant to the fact that an air pressure gauge does not measure or understand any of that. So happens a lot of people dont as well but thats another subject and unfortunately has nothing to do with Orr's tuning!
I dont agree. The guy I quoted above explained why it can take x, y, or z amount of air to get to the same psi reading. psi is only part of the puzzle.
Read quote below and you'll figure out why you just smacked your head.
In other words, contrary to what you said above about RH and temp effects, when it measures "X" psi in balloon one and "X" psi in balloon two (lets just call "X" 15psi for kicks) then the psi as you said is the "exact same". The reason for this is because... follow along class... any device used for measuring PSI does just that, measures PSI. It does not measure air density, temperature, humidity, or anything else. It measures air pressure and thats it. So 15psi IS 15psi, no matter where you measure it or on what car for that matter. You guys talking about differences in turbos and volumes of air are involving other properties of air that are totally relevant to power output, but totally irrelevant to the fact that an air pressure gauge does not measure or understand any of that. So happens a lot of people dont as well but thats another subject and unfortunately has nothing to do with Orr's tuning!
I dont agree. The guy I quoted above explained why it can take x, y, or z amount of air to get to the same psi reading. psi is only part of the puzzle.
I think what "speed" ment by "15psi is 15psi".... is that if you take an engine and put a 50mm turbo on it and spool it to 15psi at 5000RPM you will get the same horsepower as if you took that same engine and put a 80mm turbo on it and dial it in to get 15psi at 5000RPM. What "speed" is doing wrong is he is confusing Density with Pressure.... increase in pressure does not always mean increase in density.
AMOUNT of air does not equal PRESSURE
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Oh I agree with you that volume is separate from pressure, but could really care less if you think you are "right" or not because you're a meteorologist.
You are not right saying that "15psi IS 15psi IF the temps and relative humidity are the same for both volumes of air." because as you later explained in your own post, you can have 15psi with different temperatures.
You are not right saying that "15psi IS 15psi IF the temps and relative humidity are the same for both volumes of air." because as you later explained in your own post, you can have 15psi with different temperatures.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
rob a larger turbo moves more volume of air,
how do u think my car makes more power with the 60-1 turbo over the t3/t4 turbo while running less boost.
uve worked with me on my car and seen the differences hell u even drove it with both diff turbos on it
how do u think my car makes more power with the 60-1 turbo over the t3/t4 turbo while running less boost.
uve worked with me on my car and seen the differences hell u even drove it with both diff turbos on it
Another thing to throw out there-water injection. I have been told that without making any adjustments to the motor, injecting water won't increase power. The idea is that while it cools the air, increasing density, it occupies space and lowers actual airflow.
I inject pure alcohol and my peak boost didn't change from prior, but I make a hell of a lot more power.
I inject pure alcohol and my peak boost didn't change from prior, but I make a hell of a lot more power.
The water injection is a good detonation supressor... but it's not going to drop the inlet temps like alky/meth. Water will not increase the octane like alky/meth.
So some guys use a mix of water/alky/meth or just streight alky/meth.
The Total AFR seen by your O2 will need to be slightly richer with alky/meth.
I normally target 11.4-11.7AFR at WOT where with alky/meth you are going to make a bit more power at the 10.8-9range.
I have a Alky kit sitting at the shop.. It was given to me but I still can't bring my self to put it on. Alot of guys have great luck with it. The theory behind it is solid.
The only way I'll install it next year is if I can put a safty on there somehow to where if that pump does not come on and I'm over 18psi it'll shut the car down.
I can proably run 24-28lbs with alky/meth on 93oct pump gas but I know
I'd take out the head gaskets if the alky/meth doesn't spray. That's my only reason
for not installing it. Maby this winter I'll play with some safty precautions and install it.
I've been through the Small block Nitrous stuff..years ago... awsome when it works right but when there's a problem.. your picking up engine parts.
Reliability is first...
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Originally Posted by project89
rob a larger turbo moves more volume of air....
Ed Brewer holds the record for the fastest STOCK TTA running alky w/27-psi: 11.37 @ 117....
Strap a larger turbo on that exact setup and it will ANNIHILATE those times at 27-psi....
.... now;
A STOCK TTA set at 15-psi will only be able to muster a high 12 with a good launch, low 13 w/out....
Throw a larger turbo with the SAME psi cap of 15, and you WILL NOT GO ANY FASTER THAN THAT, period!
Again, I know larger turbo's flow more air, that is not what I'm saying....
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
So looks like Orr has the $59 version and some 80 lb injectors working right? Cool. Do you have the LC1 tied into your data stream as well?
Car seems to do the surgy idle when in park and with hot coolant. While in drive it calms down and when driving stop and go, its not an issue at all from my last drive. Cold start is fine and stable but rpms are up just abit more than I want to see.
I dont want to spend much more time tweaking idle...this car wasnt made for idling
I'm hoping to hit the track next saturday as it looks this saturday is rained out. Plus i stil have some tuning to do. Hope to see what it will do at 10psi but I want to try a 15psi race gas setup to, to hopefully get a 9 second pass this year.LC1 is tied into the computer. Seems to work pretty good. I like this feature. Log all the important stuff in tunerpro rt, and can easily read whats goin on in real time on the screen if needed. I have a analog style air fuel gauge as well mounted by the cigarette lighter area.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Yep so far so good. Drivability is great. I had idle working pretty good, may need to tweak a few things but now my IAC sensor is acting up and causing some surging of the idle. IAC counts are alot higher for some reason than when i had the car running good. Its been raining here so i havent had a chance to get the car out and play with it again. I'm trying to figure out if there is something wrong with using LS1 sensors with TPI ecm/code 59 which used older different sensors. If thats the case, i'll have to get a new intake elbow made and use my old holley 58mm that i still have but I like the round throttle body stuff.
Car seems to do the surgy idle when in park and with hot coolant. While in drive it calms down and when driving stop and go, its not an issue at all from my last drive. Cold start is fine and stable but rpms are up just abit more than I want to see.
Car seems to do the surgy idle when in park and with hot coolant. While in drive it calms down and when driving stop and go, its not an issue at all from my last drive. Cold start is fine and stable but rpms are up just abit more than I want to see.
Where is the AFR at idle? Timing?... and does the timing jump up/down alot at idle when it's surging/hunting?
Any way you could send me over either a log at idle.... your xdf and BIN file? All I've
got to look through is Our Typhoon setup.
Hope the rain holds off if your ready to do some track testing!
~Scott
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
timing stays locked at idle due to the code commanding it. I got about 24 degrees timing at idle. I was at 21 but i bumped it up some and it seemed to like it.
Air fuel i was in the mid 14's to 1 but when it hunts its going high 13's to low/mid 16's and rpms jump up and down. My IAC was locked at like 149 counts i think from my last log... Before this problem it was running like 11 counts and moving around... So something with the IAC not working is hurting this idle. Need to investigate.
When i get home i'll look to get one of my logs over to you...maybe do a new idle log and play with the IAC wiring.
Got my new front skinnies yesterday..will get them mounted tonight/tomorrow so i'll have them for next week hopefully for some racing Sucks i dont have C5 brakes done yet...17" front runners on stock brakes for the loss
Air fuel i was in the mid 14's to 1 but when it hunts its going high 13's to low/mid 16's and rpms jump up and down. My IAC was locked at like 149 counts i think from my last log... Before this problem it was running like 11 counts and moving around... So something with the IAC not working is hurting this idle. Need to investigate.
When i get home i'll look to get one of my logs over to you...maybe do a new idle log and play with the IAC wiring.
Got my new front skinnies yesterday..will get them mounted tonight/tomorrow so i'll have them for next week hopefully for some racing
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Oh I agree with you that volume is separate from pressure, but could really care less if you think you are "right" or not because you're a meteorologist.
You are not right saying that "15psi IS 15psi IF the temps and relative humidity are the same for both volumes of air." because as you later explained in your own post, you can have 15psi with different temperatures.
You are not right saying that "15psi IS 15psi IF the temps and relative humidity are the same for both volumes of air." because as you later explained in your own post, you can have 15psi with different temperatures.
"15psi IS 15psi IF the temps and relative humidity are the same for both volumes of air"
^^^^ Whether you like it or not, this statement is correct
"you can have 15psi with different temperatures"
^^^^ Whether you like it or not, this statement is also correct
When I say "15psi is 15psi", I mean the situation when 2 different size turbos produce the same hp on the same engine while both making 15psi. When "15psi is not 15psi" is when 2 different size turbos produce 15psi on the same engine BUT make different hp, (due to different temperature outputs of each turbo)
Soooooo, again, where the hell am I wrong?
Last edited by BirdsOnly; Oct 16, 2009 at 12:19 PM.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Here's your own quote
Take a balloon(#1) and blow it up to 2 feet in diameter then tie it off (no air can go in or out). To expand the rubber surface on the balloon to 2 feet takes a certain pressure (call it Xpsi).
Now given the same type of balloon(#2), and blow it up to 1 feet in diameter and then tie it off... then put it over a hot stove. The balloon(#2) will begin to expand due to the heat... if you remove the balloon(#2) from the stove when it expands to 2 feet in diameter, balloon(#2) will have the exact same pressure(Xpsi) BUT will contain a less AMOUNT of air than balloon(#1).
Now given the same type of balloon(#2), and blow it up to 1 feet in diameter and then tie it off... then put it over a hot stove. The balloon(#2) will begin to expand due to the heat... if you remove the balloon(#2) from the stove when it expands to 2 feet in diameter, balloon(#2) will have the exact same pressure(Xpsi) BUT will contain a less AMOUNT of air than balloon(#1).
*sigh*
can lead em to water but cant make em drink.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
When I say "15psi is 15psi", I mean the situation when 2 different size turbos produce the same hp on the same engine while both making 15psi. When "15psi is not 15psi" is when 2 different size turbos produce 15psi on the same engine BUT make different hp, (due to different temperature outputs of each turbo)
HP is can be described as lbs/min of airflow. You can convert it to estimated lbs/min by knowing target air fuel ratio and your brake specific fuel consumption factor. General rule is 10hp per lb/min.
Basic turbo boost math will show that if you lower your inlet temperature of air, you can make the same hp level at a lower pressure (boost). Pressure is just a measure of gas in a set volume. So it makes sense that cooler denser charge will shrink volume and thus exert less pressure in the system, resulting in less actual BOOST pressure on your gauge. Yet same hp can be made because that denser charge is still providing same weight flow.
So if you got 15psi of hot air in a pipe and 15psi of cold air in a pipe, there will be a BIG difference in hp because there is a big difference in actual air flow in the system. There wil be more weight flow in lbs/min with 15psi of colder air meaning more hp is made.
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
No it isn't, you even said so yourself.
Here's your own quote
So to summarize, you have a different n and different T but identical p. So while you have 15psi and 15psi you have temp NOT the same for both volumes of air.
*sigh*
can lead em to water but cant make em drink.
Here's your own quote
So to summarize, you have a different n and different T but identical p. So while you have 15psi and 15psi you have temp NOT the same for both volumes of air.
*sigh*
can lead em to water but cant make em drink.
15psi=15psi if the temps and volume are the same for both indentical engines! PV=nRT, R=constant, P=15psi(for both), T=same for both, and V=same for both(identical engine, intake, etc)... therefore n=THE SAME FOR BOTH!!!!!!
In my balloon example, balloon(#1)(larger/more efficent turbo engine) will have a lower T, but still identical P, V, and R... THUS it must have a higher n! n=amount of air=more horsepower!
When I made the balloon example I PURPOSELY made the TEMPS DIFFERENT to show "speed" how identical pressures in a constant volume can create different AMOUNTS of air(read horsepower)! I did not contradict myself anywhere... I purposely showed a situation when in terms of engine horsepower two identical engines being boosted to 15psi each, with different turbos can make different power due to differing AMOUNTS of air. How the F*ck do you not get that?
a=engine with efficent turbo
b=engine with "too small a turbo"
P(a)=P(b)=15psi
V(a)=V(b)=volume of intake
R=Constant
T(a)<T(b)
Using PV=nRT and T(a)<T(b), n(a) MUST be greater than n(b)
n=amount of air, n(a) has more air!
Please, please tell me I am wrong.... please.
Last edited by BirdsOnly; Oct 16, 2009 at 04:04 PM.
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From: Long Island
Car: Motorcycle
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Whats funny is that for a given mass flow of air in lbs per min, a cooler air flow charge will actually have less volume flow in CFM. Volumeflow in cfm = mass flow in lbs/min * specific volume (which is just inverse of density so as temp changes density changes). Cooler charge increases density which decreases specific volume and thus decreases CFM.
HP is can be described as lbs/min of airflow. You can convert it to estimated lbs/min by knowing target air fuel ratio and your brake specific fuel consumption factor. General rule is 10hp per lb/min.
Basic turbo boost math will show that if you lower your inlet temperature of air, you can make the same hp level at a lower pressure (boost). Pressure is just a measure of gas in a set volume. So it makes sense that cooler denser charge will shrink volume and thus exert less pressure in the system, resulting in less actual BOOST pressure on your gauge. Yet same hp can be made because that denser charge is still providing same weight flow.
So if you got 15psi of hot air in a pipe and 15psi of cold air in a pipe, there will be a BIG difference in hp because there is a big difference in actual air flow in the system. There wil be more weight flow in lbs/min with 15psi of colder air meaning more hp is made.
HP is can be described as lbs/min of airflow. You can convert it to estimated lbs/min by knowing target air fuel ratio and your brake specific fuel consumption factor. General rule is 10hp per lb/min.
Basic turbo boost math will show that if you lower your inlet temperature of air, you can make the same hp level at a lower pressure (boost). Pressure is just a measure of gas in a set volume. So it makes sense that cooler denser charge will shrink volume and thus exert less pressure in the system, resulting in less actual BOOST pressure on your gauge. Yet same hp can be made because that denser charge is still providing same weight flow.
So if you got 15psi of hot air in a pipe and 15psi of cold air in a pipe, there will be a BIG difference in hp because there is a big difference in actual air flow in the system. There wil be more weight flow in lbs/min with 15psi of colder air meaning more hp is made.
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
LMAO! It takes MORE exhaust to spin the larger turbo in a 1.71 / 1.50 application, did you even read what we're talking about here, a "stock LC2". This is ignorance at its best, throwing in words without understanding the argument. Your user ID suits you well, you have no answers whatsoever, only questions....
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Re: Twin Turbo 400 Buildup- '89 Iroc-Z
I am not misunderstanding you, when you said 15 psi is 15 psi only when temperature and rh is the same you are dead wrong. You even say so yourself with your balloon example, I dont know how many more times I have to point that out until you get it. Honestly if you really believe everything you said is true, you are just as lost as speed lethal is.
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Yep so far so good. Drivability is great. I had idle working pretty good, may need to tweak a few things but now my IAC sensor is acting up and causing some surging of the idle. IAC counts are alot higher for some reason than when i had the car running good. Its been raining here so i havent had a chance to get the car out and play with it again. I'm trying to figure out if there is something wrong with using LS1 sensors with TPI ecm/code 59 which used older different sensors. If thats the case, i'll have to get a new intake elbow made and use my old holley 58mm that i still have but I like the round throttle body stuff.
Car seems to do the surgy idle when in park and with hot coolant. While in drive it calms down and when driving stop and go, its not an issue at all from my last drive. Cold start is fine and stable but rpms are up just abit more than I want to see.
I dont want to spend much more time tweaking idle...this car wasnt made for idling I'm hoping to hit the track next saturday as it looks this saturday is rained out. Plus i stil have some tuning to do. Hope to see what it will do at 10psi but I want to try a 15psi race gas setup to, to hopefully get a 9 second pass this year.
LC1 is tied into the computer. Seems to work pretty good. I like this feature. Log all the important stuff in tunerpro rt, and can easily read whats goin on in real time on the screen if needed. I have a analog style air fuel gauge as well mounted by the cigarette lighter area.
Car seems to do the surgy idle when in park and with hot coolant. While in drive it calms down and when driving stop and go, its not an issue at all from my last drive. Cold start is fine and stable but rpms are up just abit more than I want to see.
I dont want to spend much more time tweaking idle...this car wasnt made for idling
I'm hoping to hit the track next saturday as it looks this saturday is rained out. Plus i stil have some tuning to do. Hope to see what it will do at 10psi but I want to try a 15psi race gas setup to, to hopefully get a 9 second pass this year.LC1 is tied into the computer. Seems to work pretty good. I like this feature. Log all the important stuff in tunerpro rt, and can easily read whats goin on in real time on the screen if needed. I have a analog style air fuel gauge as well mounted by the cigarette lighter area.
Thread Starter
Joined: Sep 2003
Posts: 25,895
Likes: 429
From: Pittsburgh PA
Car: 89 Iroc-z
Engine: 555 BBC Turbo
Transmission: TH400
Axle/Gears: MWC 9” 3.00
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
Still raining here, not gonna beable to tune this thing tonight. Tomorrow its suppose to stop by afternoon i hope. Sunday suppose to clear up, i should get some runs in and mess with the IAC stuff
Junior Member
Joined: May 2006
Posts: 54
Likes: 0
From: Long Island
Car: Motorcycle
Re: Twin Turbo 400 Buildup- '89 Iroc-Z
I am not misunderstanding you, when you said 15 psi is 15 psi only when temperature and rh is the same you are dead wrong. You even say so yourself with your balloon example, I dont know how many more times I have to point that out until you get it. Honestly if you really believe everything you said is true, you are just as lost as speed lethal is.
Again!
What "speed" ment by "15psi is 15psi" is that... if two identical engines are running different sized turbos or twins vs single, BUT are both boosting to 15psi nothing else matters, they will have the same horsepower. That is NOT the case! What I am saying is that the only time 15psi on one setup is equal to 15psi on another set up, is when air temp, humidity, etc are the same!
"15psi is 15psi" = a figure of speech! Not to be taken literally! Kinda like saying "not all 15psi are created equal". Because as I know, literally, 15psi is always 15psi, just like 1lbs = 1lbs and 5mph is 5mph.
Maybe your brain can understand this... what I am getting at is that not all 15psi are created equal like "speed" thinks. He was not taking into account air temp, humidity, etc. When talking about engines, the only time you can simply say "15psi is 15psi" is when intake temps and humidity are the same for both engines... otherwise it is not as simple as saying 15psi is 15psi.
I appologize if my "lax" explination caused confusion. I was writing this how I would talk if I were explaining this to you in person and not as if I were writing a scientific explanation.
Last edited by BirdsOnly; Oct 16, 2009 at 06:17 PM.