I'm not ready yet anyway so I'll put this on the back burner. I really want to see what these supercharger kits do once they come available. I'd much rather go that route if they are not terribly pricey...guess we'll have to wait and see.

So Brazil mentioned earlier on in this post about hitting at 3500 RPM's, now he is saying 3.2-3.4... Can someone please help me here?:

I drove just across the border to Michigan and back to my hometown on Saturday. It was probably about 400 miles round trip. I had the cruise set right around 3300 RPMs... Even if the turbo that Brazil is talking about doesn't reach full boost until 3500 I would still be getting a good amount of boost at 3300 correct? And if so, when I am cruising down the highway and not even getting on it, I would be "hurting" the longevity of my engine?

Someone please correct me if I am wrong here? Thanks.

This statement could not be more inaccurate. Heat = energy, which increases pressure. If you remember the equation from high school chemistry, pV = nRT i.e. increased Temperature increases pressure which is forced through the turbine blades. Heat is critically important to a turbo working correctly, which is why people wrap headers, downpipes and turbos to keep heat within the exhaust system. It's also why cars that have the turbos close to the heads spool faster.

If this were the "way to go FI," you would see car manufacturers, especially at the high end, using it. Instead, you see them placing turbos as close as practical to the heads.

Ive had a couple of turbo cars and lived in the forums for those cars and I never heard about heat being what caused more power. It was always air flow in and out causing the turbines to spin. The wrapping of things was to keep the heat away from the engine, thus the intakes so cooler air went into the intake mannifold. Heat is actually bad in turbo cars as when you get too much heat from the turbo and the engine temp gets so hot that at some point you will not net any gains from a bigger turbo cuz the heat is causing so much heat soak and reducing power. Just what Ive learned from having a couple of turbo cars but I could be wrong.

Just a side not too, would having a diverter valve that dumps the excess air back into the intake instead of venting it help with the lag of having the turbos far away?

That is not completely true.

While heat does play a factor in turbo function, it's not the most crucial dynamic. The cone effect, whereby velocity increases inside the turbo housing, is much more vital than the slight heat loss caused by moving the turbo system to the rear of the vehicle.

Turbos start producing boost only above a certain exhaust mass flow rate (depending on the size of the turbo) which is determined by the engine displacement, rpm, and throttle opening. Without an appropriate exhaust gas flow, they logically cannot force air into the engine. The point at full throttle in which the mass flow in the exhaust is strong enough to force air into the engine is known as the boost threshold rpm. Engineers have, in some cases, been able to reduce the boost threshold rpm to idle speed to allow for instant response. Both lag and threshold characteristics can be acquired through the use of a compressor map and a mathematical equation.

Outside of operating temperatures, heat is a car's worst enemy.

Oh this post was a quote, lol.

Lol, you're going to be heavily disappointed. I suggest you give STS a call on what turbo (or turbos) you should use in a REAR mount setup.

A rear mount turbo on a traditional turbo set up (in the front like your Evo) will be incredibly inefficient. And a traditional turbo(YOUR GT37!!!) on a rear mount setup will cause lag like you've never imagined. In other words, the maps are different with the traditional and remote(rear) mount setup. This is the reason (or one of them) why you hear people complain about lag with these setups. They custom build them with the wrong type of turbos. I suggest you STOP and do some more homework before you go under the knife. I should have mentioned this earlier.

So sell that turbo and purchase one of theirs since their housings are custom made for that. Call STS for pricing on their turbos. They have many different sizes for different levels of power.

Issues are being conflated here.

First off, heat is the only source of power in an engine. That's why we burn gas under pressure--to create heat. More heat, or more accurately, more delta-Temp, always equals more power. This is consistent with your observation that, given a combustion temperature, a colder intake temperature will result in more power, because there is a greater delta-T. Likewise, given an intake temperature, hotter combustion temperature will create more power, because, again, there is a greater delta-T.

If we had the materials to do it, we would run engines absolutely as hot as we could make them, and by that I mean create the highest combustion temperatures possible. However, heat soak into ancillary parts of the engine, wear, cooling required to avoid materials failure (including oil breakdown, melting metal, etc), and other considerations require that we have to balance heat production with reliability. Thus, we have to limit heat generation for practical reasons.

As for turbos, certainly air flowing through the turbo makes them run and, by implication, more airflow through a turbine will spin it faster. That's not wrong, but it's missing an important point. Hot air is more energetic than cool air. When a molecule of extremely hot air hits a turbine blade it imparts more energy on it than the same molecule of cool air. Thus, the equation PV = nRT informs us that higher T => higher P, and where P (pressure) is a corollary for force applied to the surface of a turbine blade, higher T = more force applied to the turbine blades. Thus, a turbo will perform better if hotter air is running through it. However, for the same reasons as mentioned with engines (namely materials considerations and inability to restrain the heat to just the turbine area), heat has to be managed. If we could run turbos hotter without reliability issues and heat soak, we would. Hotter air through the turbo, where that heat doesn't negatively affect other parts of the system like intake temp, means more power.

Again, just look at the designs of cars. Productions cars, supercars, and race cars all try to put turbos as close to the engine as possible so the air flowing through them is as hot (and thus energetic) as possible.

A remote system, while easier to install and probably perfectly functional, will not outperform a properly designed turbo system where the turbo sits near the engine. Too much heat (i.e. energy) is lost in transit to the remote location. You may think that is crazy, but consider this example. At idle, the average EGT on my STi at the headers was 850 degrees F, but by the time it left the exhaust pipe, maybe a second later, it was not hot enough to burn my skin. Heat, and thus energy, is convected away from the exhaust system rapidly as it follows the exhaust path, and the expansion of the exhaust stream in the lower pressure of the exhaust tract also rapidly cools it (back to PV = nRT). Thus, a turbo that sits where the muffler is will have access to far less energy from the exhaust stream than one mounted near the engine and will not be as efficient. Since turbos fundamentally work by recapturing energy in the form of heat, it makes sense to put them as close to that source as possible.

But to reiterate, I'm not saying that a remote system won't work, or that you can't make power with one, I'm just saying that those who would claim they are as efficient, or work as well as a properly designed system, are just trying to sell you something.

Oh my. I will not sit here and attempt to school you at all, lol. But what you said is correct but that's why there's specific compressor maps for remote mounted turbos. PLEASE correct me if I'm wrong but I believe your comparison between remote mounted kits and traditional mounted kits is with the use of a traditional front mount turbo. I don't think you can use a traditional front mount turbo as a controlled variable for your comparison. It cannot remain constant because a remote mount kit is not made for that front-specific turbo. I don't think a comparison can be achieved. Can't compare air volume because the compressor maps and such are different. Can't compare who hits full boost first at a certain RPM because there's too many variables in between, no? I'm confused. :(

Although, any inefficiency is a potential for gain. And lag is a lack of potential. But were not trying to reach obscene power numbers. Just ~5-600whp, lol.

Holy hell, I just realized something. The STS is a different approach to achieve a certain air pressure. It's not meant to "be better" than traditional turbo set ups. But rather just a different, less expensive route to get where you want to be. Because they can make different size turbos to reach almost any power level that the front mount set up can reach.

Interesting things, these epiphanies are. LMAO! Bah, college education, I need moar of it, lol.

Or more common sense, lol.

Well now Im all confused about turbos, cuz I thought it was all about the air flow thru them to get them spinning and the use of an IC was to cool the air going in the intake to get more dense air to allow more fuel which then gets ignited to make the power. Heat was just a by product of the spinning blades and caused heat soak which takes away power. So you are saying that hotter air makes the blades spin faster than colder air? If so I can see your point on the heat thing, then you just need to cool it down before it hits the engine.

Now as far as lag goes, doesnt the size of the turbo determine that? My turbos were small and boost came on around 2500 rpms with no lag. Also they used diverter valves to dump unused air back into the intake to help stop lag and maintain boost. So once the long piping is filled with air in the STS and if they used a DV would there still be alot of lag? I really think the GV in my 2 cars helped keep boost up.

Here is a little info from a site I found:

The exhaust gasses from the engine are directed to the turbine wheel, which takes the enthalpy (energy) of the exhaust and converts that energy into rotating energy. This motion rotates a shaft that both the compressor wheel and the turbine wheel are attached to. This spinning motion spins the compressor wheel, which then compresses the air from the intake air above atmospheric pressure, greatly increasing the volumetric efficiency beyond that of naturally-aspirated engines. The exhaust gasses either hit the turbine wheel, or are directed around the turbine wheel by wastegate. Exhaust gas directed through the wastegate is not used to spin the shaft assembly. This is done to limit the amount of power available to drive the compressor wheel, which is used to limit the boost level of the turbo.

A turbocharger is an exhaust gas driven Supercharger.

Turbo Lag is the delayed response of the engine that is due to the compressor coming up to a speed where boost levels are attained.

Now that is what I always thougt of with turbos. The heat thing might be true in that hotter air can generate more energy and the exhaust gas is hot but I think as far as turbos go I think the flow of air out the exhaust is more important and a better intake flow, which is why most turbo cars increase their exhaust size. But again Im no expert, I just go by what I have learned from having a couple of turbo cars and the forums and searches.

So the only thing I can see being a bad thing about the STS is if the extra piping does cause lag or not.

still g3 intake or injen cai
 

Wich du u think would be considered better to be faster still g3 intakes or injen cai's?

Meh...A little confusing...

Well yes.. Turbo lag has a loooot of reasons for happening though. But your idea of how a remote mount kit works is a little off. Turbo kits in general push a LOT of air to the point that they need wastegates because of the amount of air. So, think more of a high velocity pump pushing air through a small diameter tube. Even simpler, imagine yourself blowing bubbles in a cup of water with an average sized straw. Quick. Do it with a longer straw and there's hardly any difference. Do it with a wider diameter straw and you'll experience some lag. Make it even wider and you'll have problems. Now when it's wide and short, the lag is tolerable (front mount kit). But when the straw is wide and long? Oh boy.

Anyway, it takes .05 seconds for the air from the turbo to reach the intake manifold on their kits. But you have to use the correct mapped turbos that they make or get one custom made just like theirs. And use the suggested charge pipng diameters. :happydance:

There is my retarded explanation.

Make a thread or do a search to find out.