just wondering what power levels they are good up to. i realize there are gains to be made with a 3" regardless of boost levels but when does the 2.5" really start restricting power?


Modified by rextec at 6:37 PM 12/18/2006

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rextec &raquo;</TD></TR><TR><TD CLASS="quote">just wondering what power levels they are good up to. i realize there are gains to be made with a 3" regardless of boost levels but when does the 2.5" really start restricting power?


Modified by rextec at 6:37 PM 12/18/2006</TD></TR></TABLE>

I made 400whp on my last car, with an Inline pro 2.5" production downpipe, 2.25" test pipe, and 60mm greddy b-pipe, with an Oval ES muffler.

 

u can make 400+ but the 3inch will help u spool faster.

 

wow 400whp is pretty good! any others out there?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by s2kdre &raquo;</TD></TR><TR><TD CLASS="quote">u can make 400+ but the 3inch will help u spool faster.</TD></TR></TABLE>

hmmm..... im new to turbos so im just curious... would the 3 in actually help u to spool faster. The reason i ask is b/c the smaller exhaust would create more back pressure, and then I WOULD THINK that the extra backpresure would help u to spool faster in the lower rpm range, where as the larger exhaust would free up more power in the upper rpms.

im just curious because i know this is huge in the all motor world: what is the best amount of back pressure and how high can u rev the engine before the exhaust limits it. so if someone could please just clarify this for me, thanx.

P.S. not trying to thread jack

 

yea back pressure is bad in the tubo world.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by advert &raquo;</TD></TR><TR><TD CLASS="quote">yea back pressure is bad in the tubo world. </TD></TR></TABLE>

cool thanx for clarifying that for me. i just knew that on a NA motor a small amount of backpressure is good during low rpms because it helps to force the piston back down, however in the higher rpms backpressure is not good at all on a NA motor.

after i posted the question i started thinking and i realized that the turbo should make up for the need for any back pressure.

https://honda-tech.com/zerothread?id=1829015

^^^this is the thread that got me thinking about the whole back pressure thing^^^

 

18psi/pumpgas/t367/ls-vtec

3inch downpipe/ stainless/ v band'd/3-2.5 reducer @ the crossmember, then 2.5 to aeroturbine muffler.

 

red x on what i assume is a dyno graph

 

back pressure is always a bad thing!!!

in allmotor world flow is very important, a bigger then necesairy diameter will hurt flow and thus power.

in FI world, any form of restriction is bad. that's why open downpipe is good, the bigger the diameter the easyer the spool, flow after turbine is not very important, as long as it's as unrestricted as possible