OMG - you can search the net AND cut 'n paste? WOW! I am so impressed :lala: :lala: I've already read that

BTW - tell us about your car and your experience with 'Ram-Air'. Put-up or shutup.

Tim

 

btw, tell me about your experience with comparing 'Ram-Air' to a cold air intake. Put-up or shutup.


physics.

yes i copied and pasted the first popup from a google search. want more proof? do the phycics. the science, the math, whatever.

"ram air" = cold air AND "ram air" !> "cold air"


thanks for playing. have a nice day.

 

Dude (that is your screenname isn't it?) - you are soooo clueless it is rediculous. Can you not read what you pasted and clearly see the differences? Must I point everything out to you?

For once - sit back, read, and be open minded instead of HAVING to argue. There are CLEARLY some differences between what you copied/pasted and the real world scenario we are talking about here. Stop being so argumentative and keep an open mind. That author was addressing a particular situation.

Did you NOT read my previous post?! OMG - just read and let some thoughts sink in before you post. I REPEAT - I have direct 1/4 mile track results that show the SAME TEMPERATURE of incoming air .... but with a 1mph and 0.1 gain in the 1/4 via using the Ram-Air Myth. Back to back testing - same track, same weather, 1/2 hour apart.

Tim

 

Yeah thank you, that's what I thought. I just learned how to do area of circles so I could figure out compression ratios.
So you think GM used a 48mm because that's all they had that would fit?

 

No GM used a 48MM because it's what works best for a street application motor. GM designs motors that work anywhere in the world, at any elevation, in a miriad of weather conditions and still perform well. Then we come along and decide we know better!!!

 

while i agree with using the smallest possible TB that flows enough for the motor, using the argument that "GM knows best" is pretty weak.

id get more indepth with the flow vs restriction vs TPS resolution vs how much air it flows with how far you push down the pedal driveability....

 

About the STUPID 502ci 48mm TB argument's.......

Simply put, GM did that for COST SAVING PURPOSES. GM never made a bigger twin blade TPI style throttle body, bigger than a twin 48mm. They do offer bigger throttle bodies in the form of single blade TB's designed for different GM applications (Ex... the LS-1 and Ram-jet 350 which uses a LS-1 TB). Yes, you could use a LS-1 throttle body on a ram-jet 502, but this would require an adapter plate which GM did NOT want to spend the money on for time and materials / engineering. They also did NOT want to spend the money on time/materials/engineering to develope a bigger twin blade throttle body.

So it comes down to money. They used what they had laying arround that would work. There is a ton of aftermarket Throttle bodies for cheap and Chevrolet would not be even close to competitive on price if GM did make a bigger TB.

Will a twin 48mm work to feed that 502? Of course it will. GM engineered it to work with it due to cost.

Will that beast of a motor benefit from haveing a bigger Throttle body? You're damn right it would!

 

It's not that "GM knows best", it's that when they design vehicles they design them to work in various conditions and still perform. Possibly a 48 MM TB gives the best overall performance, emmisions and fuel economy.

The GMPP division is in the business of selling performace parts, right?
So it would stand to reason if there was a performance benefit from installing a larger TB on their performance engine that they would, no?

GM has any size TB available to them, they design the freakin things to their needs, so if they put a 48 MM their must be a reason for it.

I'm not exactly onboard with the theory that GM knows nothing. These guys are top engineers designing cars from the ground up. Maybe considerations go to emmisions and fuel economy as well, but an efficient engine that makes good clean power is what I want as well.

I took my 89 GTA that rans 15@89MPH and was getting 20-22 MPG and got it to run 13.7@100MPH and get 25 MPG. My engine is running more efficiently, creating less pollution and making more overall power than before.

Will I see an increase going to a 52MM TB, probably, but will I have the same mileage, low emmisions, and efficient running engine as before? Maybe not. More air means more fuel which means you better hope that your combustion can burn it as complete as possible. Higher compression would help to burn more of the air/fuel mixture but alas adding a larger TB doesn't affect your static compression.

All I said from the beginning is that over TBing is not necessarily a good idea.

That's all my point is, and unless you can show me how a 350 spinning 6000 rpm at 100% VE requires more than the calculated 608 CFM then I still beleive that overall performance would be better with a 52MM TB that flows 750 CFM versus a 58 MM that flows 1000 CFM

 

Okay this makes sense to me. Otherwise it wouldn't seem make sense using the same TB on a 305 and a 502.

 

GMPP is a division of GM that IS performance oriented. That division isn't as concerned with gas mileage / emissions as you would think. Example...... the ramjet 502 wasn't designed for any specific vehicle and putting this motor in any given vehicle would not be emissions legal as this motor did not come factory installed into any GM vehicle.

So the reason why this crate "performance" motor did not come with a bigger throttle body is COST ! Period. They used parts that were already produced to still make good power and to also save as much money in cost to produce to maximize profit on each unit sold.

 

Sounds pretty stout to me....and they didn't seem to cut corners on the whole engine, except for the TB according to you!

If GM felt it needed a larger TB they could have easily used one from Holley, Edelbrock or any other manufacturer and sold it as a GMPP part, as they do with lots of other parts they sell, i.e. the 1.6 roller rockers I just bought are Cranes sold as a GMPP.

Cutting costs is a lazy excuse when we don't dig deeper to see why GM or any other car manufacturer does things.

 

im not picking sides or anything, but i am going to pick apart what you just said...... i think we agree with the TB size, but for diff reasons


if that were true, it would be a compermise... and we want best peak performance, nothing else.

they dont have any size avail to them... they need to use a production one for cost reasons, plus GM is a rather large corp... because of that, they arnt all ways allowed to make the "best" or most efficent decision. we really dont know whats avail to them

its not a all or nothing thing. they can know alot and still choose whats best for their app.... IE what they can put on the engine to sell the most of them with the largest profit margin that still makes good enough power for people to buy.



whoa. thats a lil mishmash there... if you went a little oversize on the TB it would make zero diff. the computer would get a smaller TPS signal for the amount of fuel it sees.... but also the MAP sensor would see the air, add the fuel and you dont have to worry about mixture, compression or anything like that.
the largest effect it would have would be the "pump shot" that it needs to add when it sees the blades flick open... for the same amount of TPS movement the blade is allowing more air thru... so it needs to give a shot of more fuel.... a small change can probly be automaticly compensated for... a larger one would have to have a chip burnt....

lets pretend we put that mono blade one on a stock 350.
the larger prob here is the fact that the TPS sees only, say 50% TPS, yet the car has as much air as it can suck already.. meaning 50% =75% =100%. that also means that you have do drive under 50% throttle to cruise... the throttle is much more sensitive, without giving any real benifit. a slight bump of the accel now would be like a push with the stock tb.
as long as the TB is not the primary restriction(ie its the stuff behind the throttlebody thats keeping the motor from getting more air) a larger TB will not flow any more air.

all it will do is make the accel more sencitive.. not a good thing for racing or street driving. you're only human.. if you have 5" of travel to work with, you can do slight changes easily. if you have 2" to work with the slight changes are much harder to do.





i agree that while you should have one slightly larger then ideal (JIC) you shouldnt have it HUGE. it would just make driving it harder without giving more power.

 

Poncho, it's not a "lazy excuse".......it IS the reason!

 

While ram air may never result in positive pressure at vehicle speeds, it can get you closer, or in otherwords, move it closer to zero vacuum. I am big into sportbikes (I drag a GSXR1340) and used to have a 97 ZX7R Kawasaki as an everyday bike. The ZX7's incorporate ram air as most bikes do, nowadays. I always believed it seemed to pull harder on the interstate (over 80mph or so). I remember a very good article in one of my bike mags, which I can't find now, testing the different ram air setups on all of the ram air bikes. Right off the top I will say that none of the bikes went to a positive pressure, but a few came close (ZX7 and GSXR750). It was very evident that ram air, if well designed, does create more power. All of our intakes create a vacuum while in operation. If we have a well designed ram air setup, we can reduce this vacuum as our speed increases. Obviously nothing is going to be noticed at normal operating speeds, but I think most of us spend some time at the track. I trap over 106mph, and if ram air is somewhat effective over 80mph, I would see a reduction in vacuum for 26mph or so starting before the 1/8 mile mark. The gain at normal operating speeds would come from the cooler outside air afforded by the ram air intakes. So you tell me, for a few dollars and a little labor, wouldn't you like to enjoy the twin benefits of a ram air system? This whole argument is of the started topic, but it raises some valid points. The problem with the practical physics article is that people like you and me have personally witnessed the positive effects of ram air. Traxion picked up a mile per hour and a 1/10, which equate to approximately a 10 horsepower gain. My ZX7R could stay with 900's on the interstate which would otherwise kill me at lower speeds even though we ran the same overall gearing and had close to the same weights with me usually even being heavier!

The topic on hand is what throttle body to purchase. I know that a 52mm will feed roughly 450 to 460 horsepower (TPIS advertisement) but my motor should be close to 500 when all is said and done(I have around 420 right now). I have prom tuning left, could use a better exhaust system, and obviously a throttle body and more. This is all a moot point in the next year or two when I purchase my ProCharger setup which will be the 12psi system, at which point I will be expecting 700+ hp. In the meantime I would like to get as much naturally aspirated hp as I can. Thank you all for participating in this thread.

 

exactly. a straighter intake trac or one with less restriction (and less turns) will make more power. not debating that.

im just saying that you arnt gaining any pressure.


and the reason your bike and most others have a thru frame straight shot like that isnt because of ram air.... its packaging reasons... its the only way to get a straight clean shot of air into the bike.... looks cool too..

athough i always thought the kawas thin lil scoop up front looked like it had its mouth partway open, or somthing... i donno, kinda freaky in a coo way...

 

random slightly offtopic question..... on your drag bike, you still run the stock lil rubber boots that go from the frame intake hole to the engine? ive had some people tell me that on modded motors they suck shut some..... i dont buy it, since i think suzuki would have caught that, but wachoo think?

 

My ZX7R had the twin side ram inlets like the old SRAD GSXR750's and not the ****ty thin ones like the ZX6 and ZX9. My GSXR1340 does not use the stock airbox because they are restrictive and I use Mikuni RS40mm flatslide carbs with K&N individual filters and couldn't use the airbox if I wanted to. My original tubes were hard plastic anyhow, so you'd have to have some pretty serious vacuum to collapse them, lol! My gixxer is a 92 750 frame and bodywork and there was no ram air back then on bikes, just fresh air intakes.

 

hehe k...


im more of a yamaha/ honda/ducati/buell guy myself....... but mostly because of the area i live in, not the bikes themself...

 

To thoes who think that they know more then GM, please post a pic of your ME degreese along with your masters in any type of automotive engineering along with ID to prove its you. Please, GM engineers did a lot more R&D then your "seat of the pants" dynos. The 48 was a comprimise for the street. 48 is fine for X amount of flow, and really the choise is do you want to blow 300 on a 52 or 58 or save it for something else that will benifit you greater, like a torque converter, headers, etc. A TB isnt gunna increase you HP or et's any better then say new gears and a TC, or exhaust so why blow 300 if you dont need to? If a 48 can supply enuff cfm's for a 350hp motor, and there being only minimal increase in hp, why bother? If you dont need to spend he money on a new tb that will increase hp by a slim margin, why? Now FI set ups or motors with larger cubes pushing or sucking more air in want more air, and a 52 or 58 would be a good idea as now there is a larger demand for air, F/I set ups for sure.

Ram air is part myth, part very true. It has been proven that a cowl hood will indroduce more colder air at the base of the windshield then a ram air hood would. Im sure Ram Air helps sell the Trans Ams cause look how well they sell!! oh wait....(in all actuality, ram air WS6's did sell very well as did most LS1 models)
Ram air cant be totaly a myth and totaly disregarded as engineers from numerious companies have used a ram air set up(all of the big 3 did it) and it doesnt ram air into your car, but increases cold air intake a lot more then sucking up hot engine air.

If you want to put in a 52 or 58mm tb in your lil 305 then go ahead and blow the cash, but if your not pushing more then 350hp at the crank, there is no real true need for one. As for the ram jet 502, they put that on there for more of a streetable engine. Just cause its a crate motor doesnt mean you cant mod it for more performance.

 

1 mph and 1/10th sounds like a good way to spend $200 bucks. If you look in classifieds or on ebay, you can find 52mm or 58mm tb's for the same price. I got mine used for $170. I don't regret it one bit. I agree that $300 is a bit much for the gains, but if you are wanting max performance and you are big into racing, then 1/10th is definately money well spent.

 

PLus they look cool !

 

Thanks for all the input, but the throttle body is gonna have to wait... I got my intake off today so I could replace my lifters and install a rev kit because I launched a plunger at the track last week. It turns out that I broke my lifter in half as well and put a nice big groove in one of my lobes. No more hydraulic rollers for me. I talked to both Crane and Comp tonight about their recommended solid rollers for my car. I hope to have all my new parts early next week.

 

Uh so which one is it? Do they have any size available to them or do we really not know whats avaliable to them.

And also your saying a small corporation would be more able to make the "best" design? This is probobly because they would have the best people working for them right? Cause im sure GM just hires thier engineeres right off the street.

My input on the ramjet would be this. Yes, the 52 mm might make mroe power. But I would assume this.

Ramjet 502 costs ~ $8700
Ramjet 502 makes ~ 500 HP
58 MM TB Costs (for GM) ~ $200

So the 58 MM TB would add on ~ 2.3 % more cost to the crate engine. If the TB made 20 more HP (on a 500 HP engine remember) that would be %4 more power.

Now, GM engineers surly know how much power a bigger TB would add . Seems to me that if it made this much power for such a little (comparitive) cost, they would have included it with the crate engine.

Conclusion- Either the TB would cost more to implement . OR it just wouldent make that much power.

 

89TransAm.....great points...I agree

 

both. they arnt mutually exclucive.


i think its safe to assume that they have to pull from their parts bin. that limits it to GM throttle bodys.


now for all we know, the intake design was made before 96.... that would be before the LS1 style throttle body.... or whatever reason... we dont know.

dont be stupid.
just because a engineer comes up with a great idea, doesnt mean GM is going to listen to him.
hell he could walk right up to the guy in charge and say hey, this exact throttlebody will be perfect.. its XXX side... and the boss just has to say... well throttlebody XX is close enough.

its not the "engineeres" fault. THEY DONT MAKE THE DESISIONS.

now if a small company that can make 100% perfect for the app custom parts came along, and was run by a engineer, given the proper financial backing, im sure he could do a better job then GM.

GMs goal isnt to provide peak horsepower for the strip anyway.

**** whatever desicion GM made. do the math yourself. this isnt a stock app anyway.

 

THE REAL QUESTION IS:




where on this chart falls the stock throttle body, and where is the larger ones in question?



this is what it all comes down to. peroid.

 

and the best way to get a answer to that question is to:


find out what the motor needs..

find out what they flow.



the other solution is to do as someone else suggested, and swap TBs on the dyno... you would have to do several runs and avg them however since the dyno will vary...


and a chassis dyno is NOT accurate enough to tell a 2 or 3 hp diff between runs.

 

Come on, man, are you kidding? You think they're the same?? First of all you have eight intake runners, eight head ports and two throttle body openings, so tell me why they're the same.

Look, the original poster is running a STEALTHRAM, not some form of tpi. Yeah, velocity and the correctly sized tb IS important when running TPI and when velocity is an issure, I'm not arguing this. When you actually have a REAL intake, lol, like the MR or STRam, you can throw all that velocity and low end tq bs out the window. When running these intakes all that velocity stuff is going to be determined by the CYLINDER HEADS. Gixxer is running a REALLY BIG CAM, a good HIGH FLOWING intake, and good cylinder heads. There is not near the "charging effect" w/ this setup as some tq-heavy tpi setup, lol again. It all depends on where gixxer wants to rev. If it's close to 7k then he NEEDs the 58mm tb. You guys act like a 350 can't flow enough to nescitate a bigger TB. Tell that to race car driver who shift at 8k+.
I don't know the math, and I'm too lazy to look it up, but to take a 350 to 7,000rpms may require quite a bit of cfm.


How it is is relative. Get me some proof about all your theories and make me a believer that gixxer's car doesn't need a 58mm tb.

 

Sorry for not getting back for so long, but assuming the intake track is not being restricted the larger area of the blades is what will let a bigger tb feed an engine better.

Guys this thread is becoming rediculous, search tb and you'll get much better posts about this subject. I've read all of them over the years, and I can say that this one has got just down-right stupid in places. Go ahead do a search you'll get 2k posts at least. I'm not trying to steer people away, I see nothing wrong with a good tb discussion, I just think that more of the "vets" have posted on this subject previously. And I know that some of them are knowledgable way beyond my capabilities.

 

Hey, hey, hey.....EASY on the big fat junky TPI intake comments!

j/k


Actually, with the right base, runners, and some decent porting from base to plenum, you can make the LTR style TPI intakes flow pretty decent!

But, on the TB size issue, I do believe port matching the throttle bores on the plenum to match the throttle body's bores is essential. If you are going to run a 58mm TB, then port the plenum to match. If you dont, then I can see where you may lose a little power due to turbulance of air hitting the walls of the smaller bores behind the Throttle body. Other than that, I still dont believe that the 58mm is too big for a 350.

But, we all know what opinions are like..............

 

That's the problem....too lazy, don't know the math and assumptions of what engines need

It's 706 CFM at 100% Volumetric Efficiency which is rare on a street engine...typically around 85% which would only need 603 CFM for a 350 at 7000 RPM

Seeing as a 48MM flows 660 CFM and a 52 MM flows 750 CFM it stands to reason that a 350 revving 7000 RPM would require a 50 MM TB, so a 52 MM would work well for that engine....

See I do know the math, and I usually do my research before advancing my statements. Most guys on here are bench racers and just go off the old theory bigger is better.

Oh and by the way the reason GM puts a 48 MM TB on the RamJet 502 is because a 454@6000 RPM with 85% VE requires 670 CFM, well within the capabilities of the 48 MM TB, it's not for saving money.

 

Oh and another thing....

Aftermarket companies sell larger TB to the public for 1 simple reason. Why would anyone buy a aftermarket 48MM TB when there stock 48MM works fine?

And then after you've bought that 52 MM they need to upgrade to the 58MM for an another sale....it's all about marketing

 

Then explain why the ram-jet 502 made more power with a 58mm throttle body over the 48mm. I forget where I saw the engine dyno on it, but it made a decent gain with the 58mm. I'll search for it when I have time and I'll post the link if I can find it again.

 

A 502 Ramjet is 502 cubes not 454. At 85% VE the 502 requires 741 cfm @ 6000 rpm. That's wet flow, which assumes that fuel molecules are mixed with the air, taking up a portion of the volume.

 

My mistake....sorry for that.No other changes were done? I'd like to see that chart...and know exactly what was done. Also how much more power?

 

I'm looking for the page that showed pics of that motor on an engine dyno and results it made from changing throttle body and other bolt-ons. If I can find it again, I'll post it. It showed pics and all.

RickTPI- Since I didnt see a MAF, I assume you are speed density with the Holley stuff, right? Do you have any pics of where and how you mounted your MAP sensor? It looks nice! Let me know!

 

See....and other bolt-ons.....how conclusive will that be?

 

Yes it's SD. The MAP is in the upper left corner, mounted on a bracket with the coil, fuel pump & ECU relays. Thanks.

 

Thanks for the math. What's a 383 flow at 7,000rmp, anyway? Since they don't make a 50mm tb, I guess a 52mm tb would be the option. But if you're going to get a 52mm why not a 58mm? What if this guy wants to gun a 383 or 406 in the future? Why bother having to switch to a new tb in the future? Of course all these q's are relating to your math equ. But you know what, that little math formula doesn't figure in to account for things like throttle response and other variables in air density etc.

Gixxer, get the 58mm tb, it matches the ports on your intake and you'll be better off in the future.

1bad, sorry about any remark I made about tpi, I got a little carried away.

 

659cfm Wet
For other calculations try here:
http://www.prestage.com/Car+Math/Eng...s/default.aspx

 

Rick you beat me to it.


All of a sudden the math is not enough.....your the one that said the math would show that he needed crazy CFMs....now that the math doesn't work in your favour....scrap it and go by gut feeling....

This whole post makes me laugh. It's filled with guys that from what I can tell never actually race their cars. Not everyone but some of you.

 

It was listed somewhat individually. The throttle body was one of the first mods and gains were listed per mod.

It's been awhile since I've seen it, I'm still looking for it.............

 

Too small of a throttle body and you will choke off the engine.

Too big of a throttle body, then you will hurt the velocity, the manifold pressure and the vaccum on the cylinders will hurt the tuning effect of the "Tuned Port Intake".

The right size for the horsepower you are making will keep the right velocity of intake air coming in. The only reason you may see an increase in throttle repsonse with a 58mm over a 52mm on a LTR, stock head and mild cam motor is the initial vaccum of the cylinders pulling a huge plug of air that has an almost "supercharging" effect when heading through the runner into the cylinder head.

Any more air coming in than the engine needs will actually hurt performance because screws up the flow and velocity that the Tuned Port intake is designed to create. It can mess up the resonance of the air bouncing back off the intake valve creating the plug because the postive pressure coming in from the throttle body is reduced because of the size of the opening and the other cylinders need for air. The plenum needs an amount of pressurizing to work properly. When increase the throttle opening too big, the manifold pressure can drop.

Now, this is all relative to the mods done to the motor. A 58mm on a stock everything motor will surely kill power. Even a 52mm on a stock 305TPI will hurt power.

 

noone has said anything new since i posted the little chart above.


everything is speculation until you measure what the engine needs, and what they provide.





nothing will surely kill anything...
and where did you get this too big crap?!



at WOT there should be no vac... for all intents and purposes, if i could take off the thottle body at WOT, it would be the exact same......... if the throttle body isnt a restriction already.




you guys are either saying bull**** or talking in circles.



we


dont


know





no one has measured it.


noone we know of has done back to back repeatable dyno tests




it is all speculation





PEROID.




until someone has some form of actual PROOF then i dont see the point of another reply.

 

Follow this link:

http://www.mycar.net/mafb/events/1010mirdyno.cfm

Scroll down to the "Before and After"

2.6RWHP increase from 48 to 52mm TB, not much, but an increase.

What's interesting to note (not on topic with this thread) was 1.6 RR's gave the guy 11+ RWHP

Anyway, 2.6RWHP could be dyno error, but I don't think 11+RWHP is error.

I'm sure the 'net is full of before and after runs, I just searched Google with '52mm TB dyno" and a zillion hits came up, just clicked on the first one.

 

Dude, quit making yourself look silly with your post. We all know math is perfect on paper, but your goofy little forumla is far from perfect, when you consider every factor involved in an ICE when talking hp. Alright, I'm done discuss'n w/ you rookies, you can even get the last word in Poncho, I know how much it means to you. As for racing cars, mine has trapped 118mph. Have you? Didn't think so.

This thread is dead...dying....dead.

 

I was ignoring this post since Thursday, mainly due to the fact that I got bored of argueing with people who can't understand simple things, but since you offering up the last word here it is:

I have trapped 108 MPH with my previous car. But what does that mean? What does trapping 118 mean for that matter. Your car might be capable of 122 in someone elses hands and mine 105!

Having a fast car means squat, making a car outperform what it should for what it has, that says alot. Maybe you've done that with your car, how the he11 would I know.

The whole point of this post is for what TB size this guy needs, and you have offered no proof that he needs a 58 MM.

I on the other hand have used "fuzzy" math to show that a 52 MM is the proper size TB for a 350. Take it or leave it, I really don't give a chit

:lala: