since the other places to discuss it were inappropriate, here it is.
lets take a look at their faq, and put it up against the wall of basic thermo, fluid dynamic principles, shall we?
heat is energy. heat in a closed system won't make volume, it'll make pressure... a means of storing energy.
volume between the cylinder head and the turbo is somewhat fixed... that makes it a variable that isn't. so an increase in temperature will cause a corresponding increase in pressure. either way, its energy.
conservation of mass applies here. The mass flow rate is equal to the density times the velocity times the flow area.
if we hold mass flow rate as constant and flow area constant, we see that velocity is inversely proportional to density.
conservation of momentum also applies.
also, for isentropic flow, change in pressure is equal to change in density times the speed of sound squared.
so if velocity goes up, pressure goes down... not up.
aren't we still in the exhaust, where's this extra "volume" coming from?
mass flow. also, see nozzle physics above
trucks are 1+ feet in the air. plenty of ambient air around it. A car is much lower. In most sports cars, you'd have that pipe near the exhaust tunnel. The airflow it will recieve will be the heat wash off of the radiator, engine, and exhaust. its warm down there.
heat exchange rate is largely dependent on temperature difference between the various media. you'd need the air outside the pipe to be meaningfully cooler than the air inside the pipe. you'd also need good contact between most of the air in the pipe and the pipe, which generally means small fins and a lot of surface area. you then need similar radiative area.
their best numbers (which are probably the ones they'd post) will be with cold pipes. heat absorbtion with aluminum pipes is one thing. dumping that heat back out is another. ideally, IC efficency should be measured not as a peak.
they are probably heavily reliant on building heat in the exhaust to make that side of things work, but also heavily reliant on not building heat in the charge pipe. you might see how those are against each other.
is that a "well, it could be worse" answer? 10 feet of pipe is 10 feet of pipe.
at a given pressure, the greater the flow the greater the loss per foot of pipe.
numbers are good. numbers are even better when they have the right information attached to them for them to actually mean something.
Using the right units would probably be helpful too.
turbos being hot and the gasses being hot are *slightly* different concepts. As per the links i provided, the turbine is driven by energy. change in total energy across the turbine tells you what energy has gone into turning the turbine. less heat means less energy available to turn it.
NO! airflow doesn't do it. you can't run a steam turbine on the same mass flow of lukewarm water. ENERGY spins the turbine.
methanol burning cars and diesel trucks have similar peak EGT ranges. they also usually have "small" turbos for their displacement. both are generally fairly slow to come on boost still, especially given their usual power goals. methanol race cars end up running a lot of boost and size most of the turbo bits around that (or the rules). diesels shouldn't be directly compared as they are a very different beast. for a diesel, boost doesn't make power, it makes safety. they can make the power without the boost in most cases, just not for very long before something goes boom.
i know they've seen the PV=nRT equation before. They even tried using it. someone should explain to them how it works. honestly, them not getting this right is depressing. V is the volume... of the VESSEL.
The heat doesn't cause the "air molecules" to seperate, it causes them to move faster. temperature is a measure of internal energy. the exhaust manifold is a relatively fixed volume, so if we're going to assume that we can apply the ideal gas laws, we can assume that the increase in temp will be an increase in pressure. (or that a decrease in temp will have a corresponding decrease in pressure.)
again, an example of complete misunderstanding.
yes, heat energy is lost. mass flow is the same. mass flow rate is the same.
you are driving the turbine with cooler air, and thus less energy.
go tell a power plant engineer to use cooler steam to drive his turbines because cooler is better.
the volume isn't bigger when the exhaust system is shorter.
saying that there is less backpressure caused by the smaller housing with the cooler gasses is very misleading as well.
highlighting compromises that shouldn't be made.
again more misunderstanding and BS. engine temp and EGT are VERY unrelated. chances are that an STS or any other rearmount will have significantly more lag while the car (and exhaust) isn't up to temp though. probably a "other turbo cars are like that too" smoke and mirrors attempt at saving face when some customers call and complain.
is there a "sized correctly" on an improperly placed turbo?
generalities....
they don't understand flow through a nozzle well either.
bigger pipes pre turbo increases the volume and surface area. that'd hurt even worse.
so once all of the exhaust is glowing hot (as to minimize heat loss) its good to go. before that, good luck getting it to do anything...
on a *not 14 feet from the engine* turbocharger, there is no waiting for your exhaust to heat up.
they use very small housings. we get it. doesn't mean it won't work up front. it'd spool markedly faster closer to the engine.
i think there are a lot of issues at play here. one is understanding of physics. the other is expectations and experience. if you've never been in a responsive vehicle, you don't realize how unresponsive something else may be.
i will say that it is one thing to discuss details of turbine energy collection and something else entirely to get it completely wrong. especially the basic physics side of things.
innovation implies something new. there's nothing "new" about doing something the wrong way. in general, you *try* to place the turbine as close to the energy source as possible. there are often compromises that must be made that force you to put it slightly farther than you may otherwise like. taking that and intentionally putting it as far from the energy source as possible isn't "innovative" so much as unintelligent.
it'd be like walking up to the plate in baseball and thinking "everyone else here is trying to hit that white ball they throw at you... but i'm going to be different.i'll not hit it and see what happens." if you stand there and don't swing, and they walk you, does that mean its a good approach and a "proven" technique?
numbers themselves can be made to be decent. especially for one pull on a dyno. we've always known that peak numbers mean nothing. we also know that a dyno can't tell you how responsive an engine may or may not be. transitions, drivability, and responsiveness are the bits most in question here.
the efficency of the system isn't in question as we know that will be bad.
