Exhuast work on remote mount turbo worth it?

[grandkodiak]

Does it do any good to have headers and mandrel ypipe with hiflows with a turbo over stock parts?

[Red91vette]

With a remote mount, it doesn't hurt to have LT's if you already have them, but don't go out and buy them. Don't have any cats, one day the inside will break up and there goes your expensive turbo. If you have stock manifolds, just get a catless y pipe and go from there to the turbo. Are you planning on buying an STS system or build your own?

[Zakar]

if you are looking at spending the 6g's on the sts system you could have a custom kid fabbed and done right.. and that would eliminate the lag of a 15 foot charge pipe

[stonebreaker]

LT's won't help on a forced induction setup because the exhaust pressures involved far exceed any tuning effects of the headers.

As far as the lag time of a 15 ft charge pipe, I'd like to suggest to Zakar that he calculate the time needed to pressurize it. I think he'll find it's a lot shorter than he thinks.

[Zakar]

it all adds up, you will lose throttle response aswell.


i think the STS intercooler is pretty cool... i wonder how well it works

[grandkodiak]

"The intake tube, which runs up the driver's side of the car, displaces an internal volume that closely matches most front-mounted turbo systems installed with intercoolers. In simpler terms, a large compressor (the turbo) fills a small volume (the intake tube) in about 0.05 seconds with the STS Turbo system, resulting in very minimal lag. " -GM

[Zakar]

however there IS still going to be a measureable lag difference between the 2..

plus the STS system probably doesnt spool as soon as a frontmount setup.

[Zakar]

are you serious?? you dont think with a front mount single setup both banks flow through the turbo??

and obviously when sizing your turbos for a dual setup you are going to downsize the exaust side..

the STS turbo system is good for the ease of installation, that is it.. it holds no advantages over frontmount systems.. this is FACT

exaust temp and velocity is very important to spool.. both of which you lose a considerable amount of with the sts kit..

[stonebreaker]

are you serious?? you dont think with a front mount single setup both banks flow through the turbo??

and obviously when sizing your turbos for a dual setup you are going to downsize the exaust side..

the STS turbo system is good for the ease of installation, that is it.. it holds no advantages over frontmount systems.. this is FACT

exaust temp and velocity is very important to spool.. both of which you lose a considerable amount of with the sts kit..

Not true. Kinetic energy equals 1/2 mass x velocity squared. Temp doesn't enter into the calculation. While the VOLUME of the exhaust gasses gets smaller as the exhaust gasses cool, the MASS remains the same. The velocity can be reclaimed by maiking hte A/R raito smaller on the STS turbine scroll.

[grandkodiak]

missed the point somewhere i guess

[Zakar]

so you are saying temperature has nothing to do with spool?

[enginjoe]

This subject has been beat to death a hundred times, but just to recap...

A rear mounted turbo can be made to spool as quick as a front mounted turbo or it can make the same peak power, but not both. You have to reduce A/R to get spool time down on a rear mounted system, but it chokes off sooner, hence lower power. Or you can go the other way, like I did and go for more power and get a little more lag.

If you want to talk energy equations, you have to do it right. Exhaust contains two types of energy; kinetic and thermal. What makes it hard is that the two are related and are generally governed by the equation pressure*volume = mass * gas constant * Temp (PV=mRT). If you re-arange the equation you get m=PV/RT. Since mass and R are constant, as temperature goes down you have to reduce either pressure, volume or both (in this case both).

So, as the gas comes out of the cylinder it has its max temperature and velocity. It loses a slight amount of speed due to the exhaust gas becoming more dense (taking up less space due to cooling) and frictional type effects, but these are probably small enough to be negligible. As it makes its way to the rear of the vehicle it loses heat which causes a loss in temperature (touch exhaust and see if you want to see heat transfer work). As the gas loses heat it lowers its temp along with its pressure and volume to conserve mass. It is important to note that the massflow is essentially constant in this closed system. What drives a turbine to accelerate is pressure and effective area upon which it acts. The gas at the rear of the car has less pressure and therefore causes the turbine to spin up slower. Thus the necessity for smaller A/R to make up the difference.

Once you have spin-up accomplished, power to run the compressor side is essentially from the inertia of the gas flowing through the turbine and power levels will approach those of a front mount.

BTW, I have a rear mount system and I am a rocket scientist by trade.

[daveb91]

missed the point somewhere i guess

Are you reading your own thread wondering how your question turned into this?

[grandkodiak]

lol

[grandkodiak]

happens to all my post actually... dunno what it is