VG30TT/LS1 (corvette) swap

[Pop N Wood]

Texas A&M huh? Explains a lot Guess we have officially high jacked this thread.

 

A physicist looks at this problem and sees the energy released by combustion as the ultimate source of energy. An engineer starts with the gasses being accelerated through the turbine nozzles and works his way backwards. Most gear heads have gone onto a different thread by now

 

What I am saying is an abbreviated version of your wording here:

 

You want the heat back in the cylinders' date=' not for the heat itself, but for the pressure increase it generates on that discrete volume. If you could add pressure without adding the heat, then that would be ideal. But because of the whole PV=nRT, we can't.

.[/quote']

 

The original question is whether suffering heat loss before the turbo stage is desirable or not. PV/T says no. Keep that energy in the exhaust stream for as long as possible and expend it all in the turbine stage if you can.

 

O ringing the heads, ceramic coated pistons and down pipes, iron vs. aluminum heads, avoiding cross over pipes, even ceramic turbos. All ways of managing exhaust energy and effectively dealing with the increased pressures/temperatures. Putting a turbo where the cat mounts goes against all those principles. But if that “remote mounted turbo†provides sufficient boost, then don’t worry about the loss in efficiency and enjoy the other benefits.

[Guest Slack00]

Hahha...yeah...true enough.

 

Well, according to the equations, you could theoretically increase the work rate by increasing the mass flow rate by, yes, you got it, cooling the gas. Just like an intercooler does. In reality I don't know just how constant the volume/density is...those equations, of course, are idealizations; it is assumed that the flow is isentropic ...But I have a very strong feeling, judging by the lack of noise about that idea, that increasing the pressure/heat is the more simple and more effective solution.

 

Anyway, back on the subject of remote mounted turbos, the loss of power available in the exhaust gas stream is simply related to the heat/pressure loss associated with that length of exhaust pipe (ie, head loss). My 'engineering instinct' tells me that it drops sharply as it leaves the exhaust manifold, but that it loses heat at a slower rate as you near the exit of the tailpipe, because heat transfer works a lot like the whole pressure differential stuff: A higher rate at a higher differential, and a slower rate at a lower differential. A hyperbolic curve, if you will. Certainly, losses exist, but I can't say to what degree; I dunno if it even matters.

 

However, when the website was featuring the advantage of the turbo being cooler, I was thinking more along the lines of external effects: away from high underhood temps and stagnant air, closer to high flow, high pressure, low temp, turbulent air underneath the car. I assumed that advantage of this external cooling to the reliability of the turbo was bigger than the disadvantage associated with the head loss (and performance loss) from the length of pipes. I suppose that is a matter of opinion.

 

But you are right, probably not the best method for an extreme turbo setup.

[Ferd/289]

IMO, one important thing to remember to answer this question is that a turbo changes 'velocity energy' into 'pressure energy' which creates heat. The turbo as I understand it, has only one job.

Stands to reason, cooler denser air is the job of 'a' cooling system (not the turbo) whether its intercooler method, intracooler method, water injection, or whatever. Believe me, everything has been tried to cool Turbo air pressure heat generation. A good book in the HPBOoks Turbocharges by Hugh Macinnes.

Ferd