Exhaust. The truth.

[AFaceInTheCrowd]

check it out. i've only been on this board for about a month, so if this has been posted already, SRY!!!

http://www.nsxprime.com/FAQ/Miscellaneous/exhausttheory.htm

thats the article by overboost. it dispells all the myths about exhaust.

 

[perfworks]

"""A lot of the time, you'll hear someone talking about how much hotter the exhaust system on a turbo car gets than a naturally aspirated car. Well, if you are catching my drift so far, you'll know that this is a bunch of BS. The temperature of exhaust gas is controlled by air/fuel mixture, spark, and cam timing. Not the turbo hanging off the exhaust manifold."""
this is one of his quotes in the end.

for the most part he is on target with his theory . this last one is where he loses me.this should be worded differently because every set up is different.
a stock manifold and cat , etc would apply here and compare to a turbocharged set up in regards to heat. but there are certainly instances when the turbo becomes such a restriction that temps increase way beyond N/A temps on any manifold.
never mind the fact that on the inlet tubine side of the turbo at a given RPM will always be hotter than at the pressure differential of the downpipe.

 

[perfworks]

try this too
http://www.burnsstainless.com/TechArticles/Theory/theory.html

 

[AFaceInTheCrowd]

wow, thats pretty interesting too. i was thinking about putting a cherry bomb glasspack on my MSP, but then i said "NAH".

 

[perfworks]

good thing you didnt

 

[AFaceInTheCrowd]

don't those sound beefy tho? thats the kinda sound i want. exhaust notes that i like: greddy evo, magna flow and other deep rumbly exhaust. not the wet fart sounds.

 

[perfworks]

magna flow has a nice sound
i dont really like the glass pack sound though

 

[REMillers]

What truth? I'll finish reading it but so far nothing there that doesn't make natural sense.
Course after seeing many modded cars by owners, I guess some people just don't take the time to learn about engines and their car.

 

[perfworks]

true

 

[dmitrik4]

but there are certainly instances when the turbo becomes such a restriction that temps increase way beyond N/A temps on any manifold.
never mind the fact that on the inlet tubine side of the turbo at a given RPM will always be hotter than at the pressure differential of the downpipe.

true. but what i think he was trying to say is that gases after a turbo will almost always be cooler than gases at the same spot in an N/A car. the reason is that the gases have to do work to spin the turbine wheel, and lose energy in the process. the N/A gases just have to move...similar to what happens in the power turbine end of a gas turbine engine. the gas flow is always cooler after it turns the turbine wheel(s).

on the other hand, he didn't seem to mention that the turbo'd car's exhaust system is probably moving a lot more air than the N/A. i think that most of the stuff you find on the internet needs to be taken with a grain of salt unless the author includes some calcs or other objective data...

 

[perfworks]

well said!

 

[I-Am-Chris]

true. but what i think he was trying to say is that gases after a turbo will almost always be cooler than gases at the same spot in an N/A car. the reason is that the gases have to do work to spin the turbine wheel, and lose energy in the process. the N/A gases just have to move...similar to what happens in the power turbine end of a gas turbine engine. the gas flow is always cooler after it turns the turbine wheel(s).

on the other hand, he didn't seem to mention that the turbo'd car's exhaust system is probably moving a lot more air than the N/A. i think that most of the stuff you find on the internet needs to be taken with a grain of salt unless the author includes some calcs or other objective data...

one word FRICTION

 

[perfworks]

true. but what i think he was trying to say is that gases after a turbo will almost always be cooler than gases at the same spot in an N/A car. the reason is that the gases have to do work to spin the turbine wheel, and lose energy in the process. the N/A gases just have to move...similar to what happens in the power turbine end of a gas turbine engine. the gas flow is always cooler after it turns the turbine wheel(s).

on the other hand, he didn't seem to mention that the turbo'd car's exhaust system is probably moving a lot more air than the N/A. i think that most of the stuff you find on the internet needs to be taken with a grain of salt unless the author includes some calcs or other objective data...

also,
i think you understand that the turbine does not spin just because of the flow in the exhaust. there is alot more to it then that. the velocity created build pressure that creates more heat. its the heat we are interested in. the turbine impeller will spin because the velocity yes but also because of the pressure differential on the outlet side. the larger the pressure differential the faster the spool up (of course in theory) and there fore increased manifold temps.

 

[AFaceInTheCrowd]

so, is heat good? according to that article (overboost), heat is important to moveing exhaust gas.

 

[perfworks]

it helps in velocity for quick exit of gases into the atmosphere.
heat helps in the exhaust manifold to a certain extent for a turbo because it is the expansion of those gases that push against the turbine wheel to compree the air on the other half of the shaft.
again anything to an extreme is no good. its how you control it that gives you the performance you desire.

 

[AFaceInTheCrowd]

and the light shines...

 

[LinuxRacr]

(hmm) Page won't load for me?:wtf:

 

[perfworks]

try again today

 

[dmitrik4]

one word FRICTION

one word: HUH?