i've always built carbed cars. have ripped out plenty of third gen computers. i just purchased a mint 86 camaro with a 305 tpi only 100k miles. i already upgraded the ignition and the exhaust. now the 305 wont be staying im going to use it to see if the tpi is worth keeping over a carb. itll either be nitrous or a procharger. my question here is which one will best cure the lack of top end on these cars. i will eventually upgrade to a superram setup new heads and cam that can be transferred to the bigger motor. i like the torque that these cars make and from what ive read as far as n/a goes torque is plenty easy to make. so any advice will be appreciated to get this tpi project going and hopefully make me like them.

 

Neither will create more top end. The TPI intake is designed to make power under 5000 rpm. Superram will cause it to make more power above 5000 rpm and will perform much better.

But nitrous and procharger will make that car much stronger in its current rpm power band with TPI.

Procharger will have the power there all the time. Nitrous will only have power when you have the bottle filled up and turned on and at WOT at rpms above 3000-3500. Nitrous runs out and then you have to keep getting it filled up at 40-50 bucks a 10 lb bottle. Gets old quick, thats why i decided to boost my motor.

 

thanks for the tips. btw pics of twin turbo buildup is nuts nice work. i intend on building a 383 or a 400 ill build my usual long block. just have to figure out my tpi setup. is there any other overall system or a mix of parts that will flow better than the super ram. ive built a few 1000 hp procharged carb motors, and i would like to get the most out of a tpi i can get. ill be running an f1r procharger and an intercooler. id like to run the motor to 6500-7000.

 

As for for price. I've got a total of $800 into my nitrous setup, plus $45 for bottle refill. I don't use nitrous that much, I'm on my second bottle, the first one lasted for a year. Still runs cheaper than a $4000 supercharger.

 

You'll be way better off with nitrous, way less stress on the engine over time, incase it's your street car also. Forced induction and nitrous all work to do the same thing, more oxygen in the engine. Yet the supercharger is constantly taking a certain amount of power from your engine, while nitrous is a 100% power gain. The choice is up to you, a cheaper system that puts way less stress on your engine, or an expensive one that always robs horsepower to make power, and has shift lag.

 

I'll have to disagree with "way less stress on the engine over time". The majority of ProCharger's fastest racers switched from nitrous to supercharger because they were tired of breaking pistons.

 

You've gotta understand these are professional racers with serious non-street legal cars that are sometimes putting down 2,000 horsepower. Pistons break no matter what with that kind of power, it's expected, plus they don't use a 2 stage kit. The nitrous just kicks in all at once. Superchargers and nitrous both work to do the same exact thing, get more oxygen in the cylinder, would you rather have an actual power adder, or something that's technically an engine parasite, by robbing horsepower from the serpentine system?

 

Actually, they run 3, 4, & 5 stage nitrous systems flowing enough nitrous to provide an extra 1000+hp. They could never put everything they got to the ground right out of the hole even with there chassis cars and pro builders working on it. They ramp the power in though multiple nitrous stages and very complex clutch work.

As far as whats easier on the engine depends on the engine itself and the amount of nitrous you plan to run through it. An engine built for nitrous use should not have any ill effects on the engine itself, up to a certain point. It has however, been proven that procharger and turbo combos are in fact easier on parts, both engine & driveline. But that's at extreme HP levels. Normal street cars will not run enough nitrous or boost to worry about these extreme conditions.

That said, any engine not built for the power adder your running is a grenade waiting to explode. Just depends on how greedy the owner gets and what precautions are taken to avoid problems.

For normal street cars, it really just depends on if you want the power to be there all the time or if you prefer the stealth of nitrous.

 

I'm a little biased. I'd rather have the blower. Blowers and turbos DO create parasitic loss, but I wouldn't call them a parasite. When your making 1,500 - 3,000 RWHP BECAUSE OF the blower, it's hardly a "parasite". Same goes for lower horsepower street cars for that matter.

 

the HP loss isn't that great that your gonna lose 100 horse i mean come on it's just spinning off the crank

 

I've just always liked turbos and or nitrous, they're way better for the three honks and smash on the gas racing on highways and what not. I rode in my buddy's cobra and after 140-150 if he didn't shift as fast as possible, under a half second, he'd lose boost.

 

Not 100 horsepower, but 50 horsepower on most street cars making about 12+ PSI. I'm just not fond of anything that has to TAKE power to make it, that's not exactly a power adder in my opinion.

 

So then you're not fond of turbos either then? Please don't tell me you're one of those people that think turbos are "free power".

 

Turbo suffers from no "parasitic loss" being it uses the engines waste... (exhaust)
But as mentioned, using 25 hp off the crank to creat 200 with an SC? Everything has it's price... Try craming a turbo in our tight engine bay which already has heating issues without a glowing turbo & manifold in there...

I have a Procharger in the Closiet... so yes, $4k + investment... still need some injectos, install and tune... and probably an engine rebuild before I bolt it on... so this supercharger is much mroe than $4k... I'm starging to like the idea of a less expensive nitrous system

Raf

 

Sorry, but that is incorrect. Put simply, the turbo creates backpressure which robs horsepower.

 

Understood...
You can either rob some power from your exhaust creating back pressure for your turbo, or other power from your crank for the super charger, or rob your wallet each time you wanna fill up the NOS bottle...

But you'de have to fill that bottle up tons of times to get the cost to what a supercharger / turbo setup would be... Unless your a custom fab person with mad skills, that would off set the cost some...

Raf

 

Turbos are free power, except of course the price of the turbo setup, how would something that uses exhaust gasses, which has about the same backpressure as a stock muffler, take power? Oh yeah luvofjah, check out the STS rear mount turbo, It has next to nothing for backpressure since the turbo IS the muffler. It replaces it.

 

A sc is a nice unit for boast since its basicall a bolt on. But you have to factor the cost and parastitic loss, wich means an engine making 500 rwhp (a relatively easy number to hit with any quality power adder) Will acctually have to make 50 to 100 more hp to overcome the loss from the sc. Thats all that extra stress and not to mension fuel it takes to get a good net hp. A good nitrous system to reach the same goal is gonna be thousands less but there will always be that one time where a forth gen or mustang pull up next to you and wanna play but you ain't got no spray. Its a give and take. Usually if you have the money to spend go with boast. If your pockets aren't so deep go with spray. I love a 20 punch on the street with about a 150 shot. But again nothing pull like 20 psi on the big end of the track.

 

Finally someone who understands the downside of superchargers, and realize the gain isn't always worth the loss with a street engine.

 

Turbos ARE NOT free power. Only in a perfect world or very ideal conditions would a turbo ever create less of a restriction than a muffler. Saying that your using exhaust gasses that are going to be wasted anyways is as stupid as saying blowers don't take any extra power to turn because the crank is spinning already anyways. (Which obviously isn't true.)

 

Are you seriously trying to argue this point with me? Check out an STS rear mount turbo, the turbo Is the muffler. As I mentioned in the post you quoted. Sure, engine bay mounted turbos running full exhausts even with cats will have tons of back pressure. But an STS or an engine bay mount running open headers? Nah.

 

Well, Yes and no. A turbo system does create more back pressure between the engine and turbo than is usually found in a simular na engine. The question is does that mean there's a loss of power anywhere. Lets look at a blower style engine for a second. Its obvious the blower makes more power for the engine, but it takes a lot of power to drive the belt. The engine is having to make more power at the crank than is used through the drivetrain. I think, most people think, a turbo motors' added back pressure means the engine is unable to move as much air out as quickly as a na motor so the turbo takes power to run. No. For a split second before a turbo starts to make boast it is operating like i previously said. But as soon as the intake goes under pressure it is going to make much more power and create much more exaust gasses than it could of without the turbo. There is no point ( that i can see) where the turbo creates a draw from the engine like what we see in the blower motor. In a sense it is "free" power because there is no wasted energy. If you can point out some oversight of mine please let me know, I only want to shed some light on a subject I have studied a lot about in the hopes to eventually build an appropriate system for my own car.

 

Yep yep, I wish more people understood turbos.

 

Are you kidding me? That's how you're going to validate your arguement? I've been on this board for years and have done a lot of research. I also work in the forced induction industry. So no, I'm not trying to argue with you, but I am trying to correct some of the misinformation you keep putting on this forum. Your arguement is hardly an arguement at all. You haven't validated anything. Just because STS replaces the muffler, doesn't mean it is the same restriction as a muffler.

5.0 Eater, you obviously have a better understanding of how this works. The turbo actually creates MORE back pressure when it spools. The only way I can think to try to explain this would be to measure the backpressure before and after the turbo. The backpressure before the turbo will be signifcantly higher. Another example. Force air into the engine using a turbo spooled by it's own exhaust. Do the same test using boost created from a seperate source. The engine boosted by the seperate source will yield more horsepower. Why? Because the engine isn't robbed of horsepower used to create the boost. A turbo spooled by exhaust from the same engine, IS NOT free power. Now am I saying that a blower IS? Absolutely not.

 

camaro1eclipse - sorry your thread got hijacked.

 

Even though I love this site, I couldn't care less if you've been here for a millenia. So are you saying a supercharged engine will yield more horsepower, at similar boost levels? That's the only other source of boost I'm thinking of. Well if so, that's complete non sense. That TINY bit of back pressure that turbos do create, help in a sense, they create flatter torque curves. But let's get back to real life, people making huge amounts of power with the STS turbos are running straight pipes, that would create a pathetic amount of back pressure, like I said, next to nothing.

 

I have read through this post and I see it has some extremely simplified explanations of how turbo/superchargers work. IrocZ, you really need to look into how an air compressor works and how much HP is required to compress air no matter what the energy source is.

Also, I do run turbochargers and do all the math involved in sizing them along with the EFI tuning. You will find that your "TINY" exh. BP can be "A HUGE AMOUNT" depending on the turbo exhaust wheel and A/R REGARDLESS of the pipe feeding it.
You are spreading a lot of mis-information in this thread. I recommend you research air compressing in general and also turbine exhaust wheel flow and turbine characteristics. Take a look at the flow maps published by Garrett for starters. Also, search the web for air compressor calculators and see how much HP is required for compressing xxx CFM of air.

The actual compressing of air is what causes the large HP drag, not the belt and pulleys. If you would like to talk about real math eqns and where the loss is then please do so, but just going off about 'so and so says in thier book', or 'STS says so', or whatever is mis-information. STS publishes LARGE amounts of untrue info. to push their product. Not that the product is bad, it is just they twist info. to make it always in favor of a rear mount.

 

"STS Turbos" are just brand name manufacturer turbos put at the rear of a car. STS is known because they figured out how to publish large quantities of bad information and get people to believe it. STS has also had the help of car manufacturers making smaller engine compartments. In late model cars there is often only room to put the turbo under the car. Fact is, heat(energy) and volume is what makes the turbine wheel spin. Using a rear mount, some of the energy is lost in the pipe feeding the turbo. Thus, a smaller turbine is used than would normally be used. This makes the unit spool at the same RPM a FMT would. It also creates more exh. BP at the top end and limits peak HP.

Be it a front mount or rear mount, the larger the turbine then the higher peak HP is available as long as the max. flow rate of the turbine is maintained.

 

First of all, my point in pointing out how long I've been on this site is that I know not to spread misinformation if I don't know what I'm talking about.

I AM NOT saying a supercharged engine will yield more horsepower. If that's all you got from that explanation, you need to go back and carefully re-read it.

 

junkcltr - Thank You!

 

Wheres my popcorn. This is interesting. Haha

 

Do you honestly understand the point of an STS turbo, junkcltr? I really don't think so. Sure the exhaust gasses lose heat and a small amount of energy while traveling through the exhaust, but isn't a heat loss what we want? Look at what you just said.

 

Junkcltr, it seems like you're talking more about engine bay mounted turbos, which I am not. The STS' are a LOT smaller and spin up to between 140,000-150,000 rpm. Now we can all relate this to riding a bicycle. When you're in a low gear on let's say a 15 speed mountain bike, you'll find your legs are spinning extremely fast, but you're not going fast. That's how these turbos are. They spin extremely fast yet most produce a little over 6 psi for the basic universal kit. Sure they produce a lot of back pressure by spinning at them speeds, but does that require a lot of power to pressurize air to about 6 PSI? No. Heck, I heard on a Mythbusters episode, that humans can urinate at over 1 PSI.

 

I understand all types of air compression. Yes, including a RMT (STS in your case). All turbos work on the same principle no matter where you mount them. They work optimally with as much heat flowing through them. Heat is energy and that is what drives the turbine which compresses air on the other side.

A RMT turbine is undersized compared to a FMT turbine because of the typical heat loss. If good material is used for the feed pipe like Inconel, Stainless, or thick mild steel then the turbine can be sized as normal.

 

I am talking about both types of turbo mounting locations and supercharger differences. No, the STS units are not a lot smaller. Yes, all turbos spin over 100K rpm at max speed. Look at any compressor map to determine what the actual RPM is. Turbo/superchargers have nothing to do with pedal bikes or myth busters. If you would like to talk about Physics and math eqns then you can better understand how they work and how to chose the proper unit for the given application.

Here is the deal. A typical engine losses 1/3 HP to heat, 1/3 to the exhaust, and 1/3 to the crank. A supercharger uses a bit of the crank 1/3 HP. A turbo uses some of the crank HP because it cause exh BP to spin the unit. It also uses some of the 1/3 HP in the exh. heat. Therefore, it has a slight advantage over the super because it uses some of the 1/3 HP of exh heat. Which if you look at dyno charts using is 5-20% of the exh. HP. That is, that 5-20% is not lost at the crank.

Look at an air compressor in a garage. The larger the pump, the larger the motor driving it REGARDLESS of the v-belt size. The actual compressing of the air requires the HP, NOT the v-belt eating HP.

 

Yes and no. For a V8 engine it does require a lot of HP to compress to 6PSIg. As volume increases for a constant PSI, the HP requirement goes up. Google air compressor HP and you can play with calculators to see how much HP you need to compress xxx CFM to yy PSIg.

 

Whoa man, I was using bicycles and mythbusters for a nice little comparisson and example, no need to get your panties in a knot over it. Hm, maybe I'll check out them calculators.

 

I think she was wearing a thong when that was written. Check out the calculators. From the sounds of it you are going to be in for a big surprise.

 

How about the heat that comes out of each blower and the blower efficiencies(spelling). A Roots type blower is about 45% efficient, that's why they run great on alcohol or nitro. You put a Roots blower on gas and it's garbage. Turbo's and Centrifugals are around 75% effecient and create much lower outlet temps, thus they work great on gas. Plus you put in a good intercooler and wha la, great power.

 

I just want to make an observation from what you said here to suport my understanding. If engines really lose hp the way you stated than i think you are missing a small point. It is obvious turbos are spun from exaust gasses, so the hp they use doesn't matter since we only uttilize the crank hp through the drive train. In a na car we don't use heat energy or exaust energy to get us through the traps so if we can simply use turbos to take that wasted energy and make additional crank hp its a win win. In my view its better to harness wasted energy and turn it to useable energy than to take useable energy and make more that way, right. And to settle the dispute fmt is much better than rmt. Rmt is a last resort. Thanks.

 

With the supercharger all the energy to compress the incoming air is pulled from the crank 1/3 HP (the HP to spin the driveline).

The turbocharger is more complicated because of the exhaust wheel size and A/R dependency. Choosing a perfect exh. wheel and A/R turbine would give a 1:1 exh BP to intake BP (boost). Assuming that has been chosen then the loss of the crank HP is minimized. That is the engine has the least exh BP possible. More exh BP means that crank HP is being lost. The 1/3 HP energy lost to the exhaust heat is used to drive the turbine wheel so there is a gain there. Suppose the turbine uses 10% of the exhaust heat to spin the turbine, then that means 10% more crank HP is gained.

To get the magical 1:1 exh BP to intake BP (boost) means that a rather large exh. wheel and turbine A/R is required. That usually means late spool, but gives max. peak HP. For example, on my junk stock 305ci TPI engine in a 4x4 truck I chose twin T3 .48 A/R stock exh. wheel turbines. Boost comes in at 1700 RPM, but my exh. BP to intake BP is 2.5:1. At 10PSI of boost I have 25 PSI of exh BP before the turbine. That high exh BP is causing inefficient airflow through the engine and it loses crank HP. Since it is a truck and I desire low RPM torque the high RPM HP loss is fine. I also measured the exh BP after the turbo to find it is always less than 1 PSI. I run two large Dynomax mufflers that flow way more than the HP the engine produces.

The magical 1:1 difference means that the engine is zero pressure differential across it. It "looks" like it is N/A and makes peak HP. A typical street engine with a "this one will work" turbine will have a 2:1 or higher ratio. An undersized exh wheel and turbine is used to make the turbo spool at low rpm which will create more exh BP than intake pressure. That will cause the inefficiency and lose crank HP. It is like putting a "bad" exhaust on an N/A engine. HP is lost at the crank due to the exh. BP.

This is the reason the technology today uses variable vanes in the turbine. A large exh wheel is used and the A/R varies greatly. The goal is to make a small A/R at low airflow rates to build boost and open the vanes at high airflow rates to decrease exh. BP.

Most people focus so much on the air compressor maps when in fact the turbine is as important or more important.

 

Yes. I normally don't even think about Roots blower because to me it is outdated useless technology. I would never put a Roots on anything. Using the centrifugal wheel and housing is the only way to go. I know you already know this, but I mention it for others reading along. Using the 75% efficient wheel means that a higher compression ratio can be used for a given fuel because the incoming air is cooler than the 45% efficient wheel. Which translates to more HP at the crank.

Out of curiousity, what is the diameter wheel, trim, and compressor A/R in the Procharger you run?

 

The biggest they make, it's 7.2.

 

I am guessing you mean a 7.2" inducer which is 183mm. That is big. I would think that at your HP you run almost in the center of the map at peak efficiency. Dumb question, but do you log all the CFM, IAT temp, intake PSI and compare to the comp. map?

 

Yes and no. We measure temp after I.C., KPaskels, TPS, RPM, Air/fuel and some others. We run a long distance and the more sensors we use the less time we have to record. We have not compaired compressor mapping, we only go off of dyno numbers. We are on a conservative tune, we could up the timing and lean it out some to get more power, but we don't need the extra power yet, plus running five miles can be hard on motors especially if we need to back it up in the morning.

 

The 7.2" is actually his exducer. I'm not sure exactly which version of the F3R he has, but the inducer is somewhere between 131mm and 139mm.

 

We have the 139.

 

im not a expert in this topic, but i am a guy with a great understanding in physics and calculous. also ive been reading a lot of turbo posts since im interested in a turbo setup. i agree with junkcltr when he alked about STS turbos. it is all about the pressure between the manifold and the turbo.

lets have a container of 5 liters. lets have a container of 1 liter. if we try to compress (have pressure) on both of them at 6psi, the 5 liters one will take more kinetic energy. why? its Newtons law!!

if u see sts turbos, the lengh of tube between the manifold and the actual turbo on the back is bigger in length, so u get more volume. which means, u will need more gases(which creates preassure) to boost a turbo at 6PSI than a normal setup with a turbo with same caracteristics. from what i have seen, the sts turbo has a "late boost". but correct me if im wrong

 

It comes down to heat loss causing a slower spool. It is energy that spins the turbine. With a short piece of pipe there is less heat loss. Putting the turbo at the end of a long pipe will have a large amount of heat loss and less energy to spin the turbine so STS puts a smaller turbine on to compensate. If the pipe was done in stainless steel, coated, and wrapped then it would spool like an engine mount setup. Putting a smaller turbine to get the spool quick means that it is a bigger restriction at high RPM and causes more exhaust back pressure which yields less peak HP.

A properly done rear mount could in theory make as much HP and spool as quick as a front mount. Most rear mount setups are not designed to be optimal because just a good setup makes much more HP than no turbo at all.

 

I've watched many videos of STS turbocharged cars, they do take maybe a half second longer to spool to full boost, due to the piping to the intake running the length of the car, but that lower boost reduces heat which makes for very reliable and fast street cars, some STS Vettes are pushing 1,000+ horsepower, with nearly flat torque curves. That heat reduction due to it being a rear mount out weighs that added time to spool in my opinion. Just my .