Exhaust Question
- Thread starter Racebred
- Start date
Re: Exhaust Question
Why don't you check this link out... was posted earlier by Whisky Tango... quite interesting article on exhaust design... Cheers!
http://www.cobbtuning.com/tech/exhaustdesign/
gabey said:
Why don't you check this link out... was posted earlier by Whisky Tango... quite interesting article on exhaust design... Cheers!
http://www.cobbtuning.com/tech/exhaustdesign/
Gabey, whats your project if I might ask? Not quite sure what would determine if the exhaust is free flow or semi free flow. In fact, I am not very sure if there is such a classification of semi free flow.
In general, aftermarket exhausts try to improve the flow by trying to move the exhaust gases out of the car as fast as possible. As such, they need to provide for a larger diameter for the internal piping, and secondly, use packing which will not cause turbulence for the exhaust gases trying to get out.
In general, aftermarket exhausts try to improve the flow by trying to move the exhaust gases out of the car as fast as possible. As such, they need to provide for a larger diameter for the internal piping, and secondly, use packing which will not cause turbulence for the exhaust gases trying to get out.
Also, at the end of the day, having a single or double tip for the exhaust is inconsequencial to the flow of the exhaust unless the single tip is the size of a pin hole and the twin tips the size of sewerage pipes...
I would suppose the only way to measure the flow of the exhaust would be to hook up the exhaust to flow machine and measure the volume that moves through the exhaust over a specific period of time.
Only by having a quantitative comparison of flow can you determine if the exhaust is more free flowing or not.
I would suppose the only way to measure the flow of the exhaust would be to hook up the exhaust to flow machine and measure the volume that moves through the exhaust over a specific period of time.
Only by having a quantitative comparison of flow can you determine if the exhaust is more free flowing or not.
Re: Exhaust Question
I believe the industry generally accepted terms of freeflow vs non-freeflow refer respectively to mufflers that do not change the direction of the exhaust gases via baffles and/or perforations (often a bunch of 90 degree turns to get it one full turn to exit the rear), and systems that let the gasses make a single pass without significant change in direction.
You can hollow out your stock muffler and it will definitely be free-er flowing but by industry standards it is still the same type of system it was before the change - unless of course you punch through existing baffles (in the case of stock being non-freeflow) or if you add baffles (in the case stock being freeflow).
gabey said:
I believe the industry generally accepted terms of freeflow vs non-freeflow refer respectively to mufflers that do not change the direction of the exhaust gases via baffles and/or perforations (often a bunch of 90 degree turns to get it one full turn to exit the rear), and systems that let the gasses make a single pass without significant change in direction.
You can hollow out your stock muffler and it will definitely be free-er flowing but by industry standards it is still the same type of system it was before the change - unless of course you punch through existing baffles (in the case of stock being non-freeflow) or if you add baffles (in the case stock being freeflow).
Trigger
Well-Known Member
Guys this links provide pretty good tips!
http://www.dinancars.com/whitepapersFile.asp?ID=3
http://www.dinancars.com/whitepapersFile.asp?ID=3
Brothers,
I just installed the AC Schnitzer exhaust on my z4 and the sound is absolutely gorgeous....too bad, you cant really hear the radio or CD anymore.....but who needs them anyway when you've got an awesome exhaust note which plays according to how heavy is your right foot?? Right?
I just installed the AC Schnitzer exhaust on my z4 and the sound is absolutely gorgeous....too bad, you cant really hear the radio or CD anymore.....but who needs them anyway when you've got an awesome exhaust note which plays according to how heavy is your right foot?? Right?
The Mixmaster
Well-Known Member
Dude
Yeah, I agree. My Z3 has got the AC Schnitzer exhaust too.
You should add a GruppeM and then you will have gorgeous sound coming not only from the back but also from the fornt! Kekeke
Yeah, I agree. My Z3 has got the AC Schnitzer exhaust too.
You should add a GruppeM and then you will have gorgeous sound coming not only from the back but also from the fornt! Kekeke
gabey
Well-Known Member
MRacer77 said:
Dinan says:
"I’m fairly certain that many of you have been exposed to a “bench racing legend” that would have you believe that increased backpressure will improve low rpm power and that low backpressure will increase high rpm output. Nothing could be further from the truth. An exhaust system is sized for maximum flow at wide-open-throttle and peak rpm. All exhaust systems are “oversized” for lower engine speeds (rpm), as backpressure is so insignificant that it can’t even be measured. Less back-pressure always results in more power at higher rpm, with no negative effect on lower engine speed performance. The amount of power that can be extracted from an engine at a given rpm as a result of exhaust design is really limited by the exhaust manifold or header. After the header, less backpressure is always better."
Using this principle, does that mean our stock exhaust is good enough since it is already "oversized"? So what does the aftermarket exhaust makers put inside their exhaust that makes theirs "better" than stock? I can think of bigger piping, probably straight through without any baffles but is performance really markedly improved? I am contemplating "operating" my stock exhaust to take a look inside but a reputable exhaust guy told me he has never done it before! I supposed I have to persuade him but do you think it would be worth it?
Depends on what your aim or what you want to achieve at the end of the day... After market exhausts, I think, differ as they use different materials to deaden the sound. These materials more often then not will cause less turbulence for the exhaust gases enabling them to move faster out the exhaust.
