Exhaust Poll

chii370 · 10-16-2013, 10:08 PM

Ive seen plenty of cars ive had buddies build that fell into the DERP BIGGER MEANS BETTER retard mindset and went from 2.5 to 3 or even bigger. And then gained absolutely nothing on the dyno. There IS a point when its too much. and FI 370's arent exactly a popular choice as we all know, so metric a55tons of options are not available, nor have they been around for 10+ years for tuner experience. So its hard to say what that limit really is. But yeah, im sure at 8000 RPM with a tt setup pushing tons of HP WOULD benifit, but at any other time, it doesnt, especially NA cars. its not just about flow restriction, i wish people would get that **** out of their heads. its about FLOW VELOCITY. you can have MORE, LESS RESTRICTED exhaust through a 2.5 on a motor than a 3!!! OMG HOW you ask. well, allow me to give you a physics lesson. Exhaust comes out in pulses, not a constant stream of air. ahead of the pulse is a high pressure zone, behind is a low pressure zone. each pulse "pulls" the pulse behind it through the pipe. Now if you have pipes that are too big, the pulse will esentially use too much "energy" and start to slow down and instead curl in an outward motion toward the pipe walls. this does 2 things. causes turbulence, and causes a possitive pressure against pressure still exiting the engine, which can raise the pressure directly outside the exhaust valves. If this happens you can be robbed of power by less exhaust exiting the cylinders so less new air and fuel can enter or maf will be incorrect, and more effort to "push" the exhaust out the pipe. this also causes the infamous "rasp" everyone talks about. its NOT a noise the engine makes. Its caused by a drop in exhaust velocity somewhere along the pipe, which creates turbulence. this breaks up the nice individual exhaust tone "puffs" you hear and exits the back in a nasty sounding wheezing noise. havent you made the corrolation between setups that rasp, and the fact that MOST of them are the LEAST restrictive? or have LTH? or HFC or cat deletes? its not simply a "sound the engine makes" EVERY CAR can make that sound. start watching vids for aftermarket exhausts on other cars on youtube. like a tiberon or something. one setup will sound great, and the next will rasp like hell.

Chuck33079 · 10-16-2013, 10:18 PM

Quote:

Originally Posted by chii370

Ive seen plenty of cars ive had buddies build that fell into the DERP BIGGER MEANS BETTER retard mindset and went from 2.5 to 3 or even bigger. And then gained absolutely nothing on the dyno. There IS a point when its too much. and FI 370's arent exactly a popular choice as we all know, so metric a55tons of options are not available, nor have they been around for 10+ years for tuner experience. So its hard to say what that limit really is. But yeah, im sure at 8000 RPM with a tt setup pushing tons of HP WOULD benifit, but at any other time, it doesnt, especially NA cars. its not just about flow restriction, i wish people would get that **** out of their heads. its about FLOW VELOCITY. you can have MORE, LESS RESTRICTED exhaust through a 2.5 on a motor than a 3!!! OMG HOW you ask. well, allow me to give you a physics lesson. Exhaust comes out in pulses, not a constant stream of air. ahead of the pulse is a high pressure zone, behind is a low pressure zone. each pulse "pulls" the pulse behind it through the pipe. Now if you have pipes that are too big, the pulse will esentially use too much "energy" and start to slow down and instead curl in an outward motion toward the pipe walls. this does 2 things. causes turbulence, and causes a possitive pressure against pressure still exiting the engine, which can raise the pressure directly outside the exhaust valves. If this happens you can be robbed of power by less exhaust exiting the cylinders so less new air and fuel can enter or maf will be incorrect, and more effort to "push" the exhaust out the pipe. this also causes the infamous "rasp" everyone talks about. its NOT a noise the engine makes. Its caused by a drop in exhaust velocity somewhere along the pipe, which creates turbulence. this breaks up the nice individual exhaust tone "puffs" you hear and exits the back in a nasty sounding wheezing noise. havent you made the corrolation between setups that rasp, and the fact that MOST of them are the LEAST restrictive? or have LTH? or HFC or cat deletes? its not simply a "sound the engine makes" EVERY CAR can make that sound. start watching vids for aftermarket exhausts on other cars on youtube. like a tiberon or something. one setup will sound great, and the next will rasp like hell.

I was simply addressing the statement you made about FI cars in your previous post. You're correct in your point on NA and supercharged motors. Once you stuff a turbo in the exhaust path, the pulses no longer work like you described. With a turbo, you want the largest pressure differential pre/post turbo possible to keep velocity up. The turbo itself is plenty of restriction, even if appropriately sized. That's why you see drag cars just running a dump tube out the side of the car. That's also beyond the scope of this thread since the vast majority of people looking for a Z34 exhaust are keeping it NA.

synolimit · 10-16-2013, 10:36 PM

Quote:

Originally Posted by chii370

Ive seen plenty of cars ive had buddies build that fell into the DERP BIGGER MEANS BETTER retard mindset and went from 2.5 to 3 or even bigger. And then gained absolutely nothing on the dyno. There IS a point when its too much. and FI 370's arent exactly a popular choice as we all know, so metric a55tons of options are not available, nor have they been around for 10+ years for tuner experience. So its hard to say what that limit really is. But yeah, im sure at 8000 RPM with a tt setup pushing tons of HP WOULD benifit, but at any other time, it doesnt, especially NA cars. its not just about flow restriction, i wish people would get that **** out of their heads. its about FLOW VELOCITY. you can have MORE, LESS RESTRICTED exhaust through a 2.5 on a motor than a 3!!! OMG HOW you ask. well, allow me to give you a physics lesson. Exhaust comes out in pulses, not a constant stream of air. ahead of the pulse is a high pressure zone, behind is a low pressure zone. each pulse "pulls" the pulse behind it through the pipe. Now if you have pipes that are too big, the pulse will esentially use too much "energy" and start to slow down and instead curl in an outward motion toward the pipe walls. this does 2 things. causes turbulence, and causes a possitive pressure against pressure still exiting the engine, which can raise the pressure directly outside the exhaust valves. If this happens you can be robbed of power by less exhaust exiting the cylinders so less new air and fuel can enter or maf will be incorrect, and more effort to "push" the exhaust out the pipe. this also causes the infamous "rasp" everyone talks about. its NOT a noise the engine makes. Its caused by a drop in exhaust velocity somewhere along the pipe, which creates turbulence. this breaks up the nice individual exhaust tone "puffs" you hear and exits the back in a nasty sounding wheezing noise. havent you made the corrolation between setups that rasp, and the fact that MOST of them are the LEAST restrictive? or have LTH? or HFC or cat deletes? its not simply a "sound the engine makes" EVERY CAR can make that sound. start watching vids for aftermarket exhausts on other cars on youtube. like a tiberon or something. one setup will sound great, and the next will rasp like hell.

You read Tonys post too.

chii370 · 10-16-2013, 10:41 PM

lol I dont know people here by name, and dont know a tony.... but maybe? :P No, I just like reading and watching things on the physics behind mechanical equipment. sometimes I get terminology mixed a bit sometimes, but sometimes its nice to know WHY or WHATS causing a specific quote "phenomena" as its been said which usually has a pretty simple explanation. just get sick of people talkin about putting giant exhausts on with HCF, and headers and all this other **** and they dont even know WHY, they just do it because its the general consensus that it makes car go vroom vroom faster. Im happy with my 6 million ton ARK DTS with zero drone, zero rasp, zero hiss, real exhaust tone. and PROBABLY zero gains on a dyno and couldnt care less. goal was to make the car not sound like a toyota prius, goal accomplished. and all of the physics knowledge played a part in proper choice. diameter of pipe, mid pipe style, how restrictive is it, what shape, how long are the pipes, what are they made of, how is it welded, how is it bent, hows the muffler packed and sectioned. ALL THAT **** MATTERS in its exhaust scavenging, flow velocity, sound, everything. leave the engineering to us ENGINEERS.

View Poll Results: Which exhaust do you have or recommend I get???
Stillen	34	14.29%
FI	108	45.38%
ARK	31	13.03%
Berk	30	12.61%
Invidia	35	14.71%
Voters: 238. You may not vote on this poll

10-16-2013, 10:41 PM	#4 (permalink)
chii370 Track Member Join Date: Jul 2010 Location: . Posts: 642 Drives: . Rep Power: 17	lol I dont know people here by name, and dont know a tony.... but maybe? :P No, I just like reading and watching things on the physics behind mechanical equipment. sometimes I get terminology mixed a bit sometimes, but sometimes its nice to know WHY or WHATS causing a specific quote "phenomena" as its been said which usually has a pretty simple explanation. just get sick of people talkin about putting giant exhausts on with HCF, and headers and all this other ** and they dont even know WHY, they just do it because its the general consensus that it makes car go vroom vroom faster. Im happy with my 6 million ton ARK DTS with zero drone, zero rasp, zero hiss, real exhaust tone. and PROBABLY zero gains on a dyno and couldnt care less. goal was to make the car not sound like a toyota prius, goal accomplished. and all of the physics knowledge played a part in proper choice. diameter of pipe, mid pipe style, how restrictive is it, what shape, how long are the pipes, what are they made of, how is it welded, how is it bent, hows the muffler packed and sectioned. ALL THAT ** MATTERS in its exhaust scavenging, flow velocity, sound, everything. leave the engineering to us ENGINEERS. Last edited by chii370; 10-16-2013 at 10:45 PM.

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10-16-2013, 10:08 PM	#1 (permalink)
chii370 Track Member Join Date: Jul 2010 Location: . Posts: 642 Drives: . Rep Power: 17	Ive seen plenty of cars ive had buddies build that fell into the DERP BIGGER MEANS BETTER retard mindset and went from 2.5 to 3 or even bigger. And then gained absolutely nothing on the dyno. There IS a point when its too much. and FI 370's arent exactly a popular choice as we all know, so metric a55tons of options are not available, nor have they been around for 10+ years for tuner experience. So its hard to say what that limit really is. But yeah, im sure at 8000 RPM with a tt setup pushing tons of HP WOULD benifit, but at any other time, it doesnt, especially NA cars. its not just about flow restriction, i wish people would get that **** out of their heads. its about FLOW VELOCITY. you can have MORE, LESS RESTRICTED exhaust through a 2.5 on a motor than a 3!!! OMG HOW you ask. well, allow me to give you a physics lesson. Exhaust comes out in pulses, not a constant stream of air. ahead of the pulse is a high pressure zone, behind is a low pressure zone. each pulse "pulls" the pulse behind it through the pipe. Now if you have pipes that are too big, the pulse will esentially use too much "energy" and start to slow down and instead curl in an outward motion toward the pipe walls. this does 2 things. causes turbulence, and causes a possitive pressure against pressure still exiting the engine, which can raise the pressure directly outside the exhaust valves. If this happens you can be robbed of power by less exhaust exiting the cylinders so less new air and fuel can enter or maf will be incorrect, and more effort to "push" the exhaust out the pipe. this also causes the infamous "rasp" everyone talks about. its NOT a noise the engine makes. Its caused by a drop in exhaust velocity somewhere along the pipe, which creates turbulence. this breaks up the nice individual exhaust tone "puffs" you hear and exits the back in a nasty sounding wheezing noise. havent you made the corrolation between setups that rasp, and the fact that MOST of them are the LEAST restrictive? or have LTH? or HFC or cat deletes? its not simply a "sound the engine makes" EVERY CAR can make that sound. start watching vids for aftermarket exhausts on other cars on youtube. like a tiberon or something. one setup will sound great, and the next will rasp like hell.