What is the ideal size of exhaust system(dyno proven) for 220whp N/A setup. I see that most of the peoples run 2.5 inch piping but some are running 3 inch like the thermal. Since I have a header-tech header that has a 3 inch collectors, I was maybe thinking of going with a 3 inch piping with a 22 resonator, instead of going with a 2.5 cat back. What is the best application, Ill be making around 220whp tuned with hondata

Either way im going custom with a magnaflow wide open muffler either 2.5 or 3 with a 22 resonator

So 3 or 2.5 inch??
thanks

 

2.5

 

Mandrel-Bent 2.5" should do the job.

 

Why don't you talk to John at hytech. He custom builds headers and exausts for...

 

thanks

I took the optional 2.5 inch extension, thus ill be able to use a 2.5 exhaust

 

Awww man. You should of tested both. I would like to see the effects of a 3" on a set-up like that vs. a standard exhaust.

 

I could still test them, the extension on the header is removable thus I still have the 3 collectors. If I can find a 3 exhaust, i will dyno both

 

3" ..

 

i was told by one of the header tech guys, dont remember his name right now, that i should run a 3" exhaust with my setup, and im aiming around 225 WHP...but at the same time i was told that 2.5 was better by lawrence at dynospot. so i dont know, im gonna talk to both of em further and make a choice.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by -Racer X- &raquo;</TD></TR><TR><TD CLASS="quote">i was told by one of the header tech guys, dont remember his name right now, that i should run a 3" exhaust with my setup, and im aiming around 225 WHP...but at the same time i was told that 2.5 was better by lawrence at dynospot. so i dont know, im gonna talk to both of em further and make a choice.</TD></TR></TABLE>

Im also aiming at 220-225whp

Someone has more info?

Enzo, john, dave??

 

yea 3" is more for FI
2.5" should be well enough cuz if u get a 3" u might not have enough back pressure

 

Well we can sit here and B.S. about it all we want.......but who's see plots to prove?

 

I don't have plots to prove...but on the track my 2.5" (even) all the way through produced better times at 240+whp. The Hytech is a fluent 2.5 from header collection, exit, all the way til it exits the muffler. From my own experience 2.5" worked the best until i slapped a megaphone on the end of the header open exhaust. the Megaphone I was using from Hytech knocked an additional 1/10th off my ET over a completely open header.

My opinion is to stick with the 2.5" over the possible 3" backpressure..

 

thanks lip

Ill go with a 2.5 full cat back with a magnaflow wide open 2.5 exhaust.

 

2 3/4 from collector to cat (which is all the way at the first turn on my crx) then 3in from the cat back. Untunned

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Tbone &raquo;</TD></TR><TR><TD CLASS="quote">2 3/4 from collector to cat (which is all the way at the first turn on my crx) then 3in from the cat back. Untunned
</TD></TR></TABLE>

Can you give detail on your setup, also did you dybo tuned with a smaller exhaust before?

 

I only dynoed that setup.
91 crx hf
dpr head
toda b's
89mm stroke
84mm bore
4.8cc je pistons
smsp header
hondata

motor was a mess 8-9% leakdown and leaky sleeves.
I was just playing with the fuel curve , it was lean as hell. My 370 cc injs were at over 75% duty
I was stupid and didnt raise my fuel pressure enough.

 

I've seen people make power on big na setups by switching to 3"...

Personally im aiming for 230whp, and im going to be using a stock civic dx exhaust system.

.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
and a 3" QTEC... lol

 

people should not really say, 3" or 2.5" unless you have direct experience either way. Dont spread something around you cant back up with factual data, there is enough b.s. opinion floating around

look about 2/3 down the page
https://honda-tech.com/zero...age=6

 

yea thats the word i was looking for velocity. well back pressure was "thought" to be good to keep the fuel in, but now we know we don't need it, because it pushes unusuable air back in and keeps freshair from coming in. but yea u should get a 2.5

 

who on this board actually had experiences with both.

Im not shure but I think Christian ran a thermal 3 and switched for a hytech 2.5, there must be a logical reason

 

hytech isnt designed for pure performance. john wanted to make it quite as well

it would be very difficult to run a 3" with the way the twin loop muffler is setup