what exhaust should a 2.3L 6000rpms cam ed and ported motor use.

to get an idea of the air flow, my stock t3 .42/.48 ars loses boost from about 4000 on @ 10psi.

any ideas?

 

3" should work fine. You could be a balla and step up to 3.5" or the new 4" bandwagon

 

o yea, your turbo is probably the cause of the boost drop off.

 

.48ar on a 2.3l..... yea, thats causing the boost drop

 

why is the .48ar exh causing the boost drop?

i thought the compressor side had more to do with it?

 

kinda sorta. a turbine housing that small causes a lot of backpressure, which hinders the engines ability to breath.. ive got a .63a/r turbine housing for a t3 if you want it. stage 1 wheel, ford 5-bolt pattern. it will help you hold boost longer and higer in the rev range.

 

bump for a good seller if your considering it

 

how much?

 

back to topic.

wouldn't a 3" exh decrease my torque compared to a 2.5" exh?

but which one would flow topend and still give good torque?

 

the 3" would be best. it would allow your turbo to breath better, allowing more top end flow, it would help you hold boost a little longer in the rev range because your turbo can breath better

 

i think i will go with 2.5" so i can maintain good low end torque and still continue with my top end with the turbo.

 

when ur boosted the bigger the better. Go 3, ****, go 4" i doubt you'll loose anything

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DARKON &raquo;</TD></TR><TR><TD CLASS="quote">i think i will go with 2.5" so i can maintain good low end torque and still continue with my top end with the turbo.</TD></TR></TABLE> a turbo in itself is already too much backpressure, technically you will gain more low-end with bigger exhaust because your turbo will spool up faster. and for the record backpressure has nothing to do with low-end, exhaust gas velocity does

 

how does exhaust gas velocity relate to low-end?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DARKON &raquo;</TD></TR><TR><TD CLASS="quote">how does exhaust gas velocity relate to low-end?</TD></TR></TABLE>

Smaller tube means higher exhaust velocity at lower engine speeds. There is an optimal velocity for scavenging effects, a smaller exhaust speeds up the flow to optimal earlier in the rev range, so you end up with more torque at the low end. The backpressure is a side effect; if you want the gas to speed up, you have to force it through the tubes so you end up with falloff on the topend due to backpressure.

The best would be an exhaust that changes diameter with the engine rpm... ha.

 

yay for exhaust theory... 8D

so a smaller tube will help turbo spool faster?

but a larger tube will help sustain the power on high rpms.?

 

nope, the theory he is talking about is great for atmospheric engines but in the words Corky Bell (author of "Maximum Boost") "The best turbo exhaust, is no exhaust". If there is very high pressure in the turbo manifold, and very low pressure on the exhaust side (low backpressure) the turbo will spool up easily, this is because gas flows from high pressure to low pressure by law. If there is lots of backpressure, it will choke the engine, and spool up and response will suffer because the manifold pressure will not try to force itself through the turbo as easily, and the engine will have to waste potential horsepower on pumping the air through the small/restrictive exhaust. Bigger is better with a Turbo