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to a point yes Posted by jak [Email]  (#195) [Profile/Gallery]
(more from jak) on Tue, 7 Jun 2005 09:32:56
In Reply to: soo...., tom, Tue, 7 Jun 2005 08:09:27 Members do not see ads below this line. - Help Keep This Site Online - Signup |
I was thinking about what chris said & yes on a dyno for a pull or few the cat being the biggest restriction in the exhaust, replacing the OE cat with a better flowing unit may yield the biger #s over the cat back but overall you are better able to get rid of more heat with a biger cat back so pre ignition will be reduced for sure with biger pipe cat back & this will allow an APC or trionic system to maintain higher boost levels with more stability & for a longer duration
I think if you go too big that you can get poping & stuff & I remember brad saying something about reasonably sized pipe keeping exhaust velocity up to help scavenging which sounds valid so 3 inch is I think a good choice
friggin WRX boys put on like 3,5 & 4 inch pipe
your WG is gona be able to dump exhaust around the turbine more effectiveley with less backpressure so when the ECU comands to dump boost because of pre ignition or whatever it can do so loose even more heat more effectiveley & recover more quickly
as RPMs increase a smaller cat back is gona have more trouble getting rid of heat & backpressure will increase with RPMs which makes it harder to get rid of the heat when the engine realy need to because its usualy working harder higher in the RPMs
also when you think about pipe diameter & flow think about lenth too so like a 2.5 inch pipe might be great if its short but a good lenth of it will have more trouble flowing then a shorter lenth
frank stromqvist who I definatly respect as a tuner sugjests using only 3 inch pipe never a 3 inch DP with smaller catback
so thats my 50 cents on the matter
take care
JAK
, Tue, 7 Jun 2005 06:23:20, Wed, 8 Jun 2005 07:22:57, Tue, 7 Jun 2005 05:53:58, Tue, 7 Jun 2005 09:32:56 <-- Viewing This Message, Tue, 7 Jun 2005 19:29:42
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