Author Topic: Increase in Exhaust Diameter will bhp increase ?  (Read 8562 times)

Offline Ricco_04

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Increase in Exhaust Diameter will bhp increase ?
« Reply #30 on: February 16, 2009, 08:20:27 PM »
Simple question then compared to whats above!

If car was run at 1bar on 3" exhaust, would you see a power increase with 4" exhaust but still run at 1bar?

(Thinking Turbo 13b)

kiwiracer

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Increase in Exhaust Diameter will bhp increase ?
« Reply #31 on: February 17, 2009, 12:30:47 AM »
amazing load of info,albeit its all internet sucked :) and heresay :Laugh,nobody on this forum has actually proved anything by putting up dyno graphs on mods they say works and does not :2Rolleyes,nobody here has proved the gain or loss by plumbing in the screamer pipe into the main system,or increasing the the down pipe to 5" and leaving the screamer pipe to vent to atmosphere,its all proven by via the rolling road.all \'facts\' here are heresay and not backed up by physical evidence :),does i ncreasing the size diameter make the system louder or softer ?..........:bandit intersesting to know

kiwiracer

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Increase in Exhaust Diameter will bhp increase ?
« Reply #32 on: February 17, 2009, 12:34:10 AM »
Quote from: Ricco_04;585001
Simple question then compared to whats above!
 
If car was run at 1bar on 3" exhaust, would you see a power increase with 4" exhaust but still run at 1bar?
 
(Thinking Turbo 13b)

if you got good auxillaries and sombody who knows hoe to map the caron a rolling road :Talking1

Offline PGiljevic

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Increase in Exhaust Diameter will bhp increase ?
« Reply #33 on: October 01, 2010, 03:40:24 AM »
Bumping this good thread :cheers
 
 
3.5" exhaust has been good enough for ~450rwkw 600+rwhp *dynodynamics* (not one hit wonder but repeated many times). SMB mufflers.
 
I will find an extract from a Garrett Engineer who wrote up a fantastic few paragraphs in relation to turbo cars and what effect down stream turbine pressure has on all up system pressure (when considering turbine expansion ratio). *over anyones head yet?*
 
In a nut shell the larger turbo/turbine you run the less effected it is to exhaust back pressure (post turbo) as the turbine expansion ratio to flow the said given amount of gas is LESS :Typing So drain pipe "I ran over a dust bind Honda exhaust" is only really needed on a small turbo working its ring hole out! as its at a very high expansion ratio to make the power you need/want to have.
 
I use a 3.5" diameter system on my own car, with a catalytic convertor, and middle muffler and a big rear muffler and plumbe back exhaust. Turbine outlet pressure is 4psi range at 7500rpm and honest 440bhp output. Exhaust manifold pressure is around 17.5psi and inlet boost pressure is 18psi (better than the fammed 1:1 pressure relationship people strive for), car is whisper quiet too for a Rotary Turbo at this power level. The catalyst imparts over 2.5psi to this post turbine pressure level, without that you could run 700+bhp worth of air flow through the system and still stay at 1:1 pressure with the right sized turbine (housing and wheel).
 
Exhausts dont need to be as large nor loud as some people think to make good power :3gears-rh
"Can\'t be defeated!, don\'t know the word!, shoulder to shoulder!, we\'ll fight the world!, we can\'t be beaten!!!"

Offline mx1311

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Increase in Exhaust Diameter will bhp increase ?
« Reply #34 on: October 01, 2010, 08:40:31 AM »
Quote from: RICE RACING;719020
Bumping this good thread :cheers
 
 
3.5" exhaust has been good enough for ~450rwkw 600+rwhp *dynodynamics* (not one hit wonder but repeated many times). SMB mufflers.
 
I will find an extract from a Garrett Engineer who wrote up a fantastic few paragraphs in relation to turbo cars and what effect down stream turbine pressure has on all up system pressure (when considering turbine expansion ratio). *over anyones head yet?*
 
In a nut shell the larger turbo/turbine you run the less effected it is to exhaust back pressure (post turbo) as the turbine expansion ratio to flow the said given amount of gas is LESS :Typing So drain pipe "I ran over a dust bind Honda exhaust" is only really needed on a small turbo working its ring hole out! as its at a very high expansion ratio to make the power you need/want to have.
 
I use a 3.5" diameter system on my own car, with a catalytic convertor, and middle muffler and a big rear muffler and plumbe back exhaust. Turbine outlet pressure is 4psi range at 7500rpm and honest 440bhp output. Exhaust manifold pressure is around 17.5psi and inlet boost pressure is 18psi (better than the fammed 1:1 pressure relationship people strive for), car is whisper quiet too for a Rotary Turbo at this power level. The catalyst imparts over 2.5psi to this post turbine pressure level, without that you could run 700+bhp worth of air flow through the system and still stay at 1:1 pressure with the right sized turbine (housing and wheel).
 
Exhausts dont need to be as large nor loud as some people think to make good power :3gears-rh


glad to see proper real world info on here finally :wave

regards

c

adrianglock

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Increase in Exhaust Diameter will bhp increase ?
« Reply #35 on: January 07, 2011, 06:11:22 AM »
they said it\'s gonna generate and give some power, I agree