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Location:
Melbourne
Registered:
June 2002
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Exhaust size
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Sat, 08 November 2003 15:05
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Hi Guys,
Do you reckon a good 2.5" mandrel exhaust is good enough for a 200Kw@rear wheel turbo car?
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Location:
Melbourne
Registered:
October 2003
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Re: Exhaust size
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Sat, 08 November 2003 20:10
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depends on the engine. But if its going to be a smaller displacement I'd be going 2.75" or even 3"
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Location:
Adelaide
Registered:
May 2002
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Re: Exhaust size
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Sun, 09 November 2003 01:57
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Generally the best exhaust for a turbo car is none at all, failing that, the biggest one you can stuff under the car.
Dont listen to anyone who uses the words 'need backpressure'.
However, for a smaller engine usually a properly muffled single 3inch system can be the best compromise between performance and noise
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: Exhaust size
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Sun, 09 November 2003 06:45
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the best system for a turbo car or streetable power is a huge dump pipe (4", possibly 5 if the turbo is massive) - and shrink this toa 3" system just before your cat. 3" hi flow cat. then either keep the 3" after that, or go down to a 2.5". (the difference between 2.5" and 3" end section on a 250rwkw car I know of was 5 kw)
by the time the exhaust is thru the cat, it will have cooled enough not to require anywhere near the initial diameter.
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Location:
Sydney
Registered:
September 2003
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Re: Exhaust size
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Sun, 09 November 2003 08:03
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Just wondering on the same topic, what size exhaust i should be looking at for my TA22, just running stock 1600 2T engine, planning on getting some extractors. just seen variations of 2" and 2 1/4" any help would be appreciated, thanks
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: Exhaust size
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Sun, 09 November 2003 09:28
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you're running a stock 1.6L engine with about 110bhp - 2" will be plenty 
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Location:
Brisbane
Registered:
May 2002
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Re: Exhaust size
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Sun, 09 November 2003 13:13
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110hp is a bit optimistic actually!
Stock exhaust size is likely more than enough. A decent set of extractors will help a bit, but beyond that, don't bother unless you're after a nicer exhaust note.
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Location:
hobart
Registered:
July 2003
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Re: Exhaust size
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Mon, 10 November 2003 12:12
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does a gze need backpressure???????
ino ive read the post above, just thought id ask.....
would the car go better with no cat????? or , hiflow, would be better then standard
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Location:
Sydney
Registered:
June 2002
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Re: Exhaust size
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Mon, 10 November 2003 13:04
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dont you lose power in the low rev range from lack of exhaust back pressure?
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: Exhaust size
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Mon, 10 November 2003 13:34
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the comment re back pressure was only for turbo cars, which as stated work best with a piece of 4" tubing off the turbo out the side of the car
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Exhaust size
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Mon, 10 November 2003 16:51
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| strober wrote on Tue, 11 November 2003 00:04 |
dont you lose power in the low rev range from lack of exhaust back pressure?
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if you have a cam with large overlap, then back pressure will help stop the fresh charge from blowing out the exhaust// but it's a pretty poor way to go about it.. choosign a better cam to begin with might help..
i think this urban myth probably started with good ol V8 boys, who, after choosing race spec cams, found that they got more torque in the lower rev range with a smaller exhaust.. of course if they could rev past 5000, they'd probably have found where the motor came 'on cam'
problem of backpressure helping a long overlap cam, is that by the time it is on-cam, the exhuats wil be terribly restrictive...
chhose a cam correctly and you don't need backpressure (except for reducing noise)
Cya, Stewart
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