stock internal b16a2 vibrant header 4-1 2.5" collector 2.25" resenator no cat, and mugen twin loop muffler. would i see better gains with the 2.25" piping ir a 2.5"?

p.s. cams will come in the near future, S2s2 cams with a pnp and 3 angle valve job comin soon

 

I would go ahead and open it up with the 2.5" you shouldn't loose out since you will have more air flowing in....

 

almost forgot aem cai and skunk 2 intake mani on the other end already installed

 

i would go 2.5 thats what I plan on running...

 

ok cool

 

2.25" is just fine... no need for monster exhaust, and remember you want some back pressure...

 

ok so goin from a 2.5 inch collector to a 2.25 cat delete and 2.25 inch piping would have enough backpressure for the stock a/f ratios?

 

yeah im going to be running 2.5 on my SOHC turbo setup...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by riceburnerryan &raquo;</TD></TR><TR><TD CLASS="quote">yeah im going to be running 2.5 on my SOHC turbo setup...</TD></TR></TABLE>


well that's a bit different bro... i ran 3" all the way on my turbo sohc setup... he's running i/h/e on a b16 lol... 2.5" is fine dude, no need to be a monster when it comes to exhaust, infact smaller diameters over the years have shown better numbers on N/A motors, do a lil search ull see... once u got forced induction, than of course more flow is better but on an n/a b16 i wouldnt go bigger than 2.25"... IMO anyways...

 

yeah but he is running a small collector and that should give him enough back pressure to run 2.5??

 

Azztin, i got a 4-1 vibrant header with a 2.5 inch collector that will soon be on the car so if i went to 2.5 i wouldnt have the backpressure...unless i kept my cat and didnt replacit it with a resonated cat delete pipe

ok good yeh i have spent the last hour researching 2.25 vs 2.5 n/a and backpressure theory, i believe im gonna stick with the 2.25" now


Modified by capthappy8p at 9:38 PM 6/18/2008

 

2 and 1/4 is fine. You won't notice more power from 2.5 inch exhaust on your motor/setup.

I didn't read past your original post so if someone disagrees with me -- that's nice, I don't care.

 

What'ts the point of having a 2.5" collector and then trying to cram the exhaust wave down to a 2.25" pipe?

Backpressure is the enemy...do some reading and figure out how exhaust systems really work.

 

google dude. 2.25 is best. everybody has an opinion. it is your job to see which will work for you. 2.25 is the way to go.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1CaMw0nDeR &raquo;</TD></TR><TR><TD CLASS="quote">remember you want some back pressure...</TD></TR></TABLE>
Not unless you're trying to quiet the car down.

Also, an exhaust that is too big will result in more backpressure.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ddd4114 &raquo;</TD></TR><TR><TD CLASS="quote">
Not unless you're trying to quiet the car down.

Also, an exhaust that is too big will result in more backpressure.</TD></TR></TABLE>

Exactly bro, that's why I told him I wouldn't go so big... The bigger he goes the more backpressure he's gonna have and that's not always a good thing, but some backpressure is gonna be needed regardless...

Bottom line is a 2.25" exhaust would probably be your best bet on an I/H/E B16... Unless you like bogging out and love hearing that all famous shotgun backfire haha...

 

Well it really depends on what you want. Larger exhaust will shift the power curve higher in the RPM range. If it gets too large (&gt;2.5") than a little 1.6 liter motor will never be able to flow enough to fill it up, and you will lose power because your engine is working to increase the pressure in a large volume (the exhaust).

Smaller exhaust will maintain high velocity in the exhaust and help "suck" the exhaust out of your engine. This makes for good drivability around town, and is also the reason why stock exhausts are small. I would say no more than 2" for a daily driver.

2.25" will help shift the power band high enough that you may gain a few more horsepower close to redline, but you will lose a whole lot of torque at the mid and especially at low RPM. So its up to you if 3hp more at 6-8k RPM is worth 3hp less at 1-5k RPM.

 

If it's just gonna be a b16 with i/h/e I would stick with 2.25"

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1CaMw0nDeR &raquo;</TD></TR><TR><TD CLASS="quote">some backpressure is gonna be needed regardless... </TD></TR></TABLE>
It depends. If he's worried about noise or emissions, then a little backpressure can be beneficial. However, in a performance application, backpressure is never desirable in any quantity.

 

I run a 2.5 inch on my i/h/e b16 - I do run pretty rich and it isn't loud at all pretty quiet actually. I think it is more preference and brand/design as well as muffler/resonator/cat setup.

There are tons of factors you have to look at not just the size of the piping.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ddd4114 &raquo;</TD></TR><TR><TD CLASS="quote">
It depends. If he's worried about noise or emissions, then a little backpressure can be beneficial. However, in a performance application, backpressure is never desirable in any quantity.</TD></TR></TABLE>

LoL that's what im saying bro... I think you're just reading my post's wrong, i'm telling him that backpressure is going to be there regardless of what he does, but to much is not good... And as far as to little goes, he's not even going to have that issue if he runs a 2.25" exhaust thats a whole 1/2" bigger than stock exhaust diameter for most of our cars "civics especially" so that 2.25" exhaust would give him the most beneficial outcome rather than going to a thicker diameter where he's gonna incur more issues and possible power-loss...

And as far as performance goes, its a B16 with I/H/E dude not like he's toppin the charts or anything, if he was coming at us with a fully built b16 turbo, than yeah this discussion would be taking a completely different route, but as for the base he is standing on right now, 2.25" would be the best bet for him IMO... I don't expect everyone else to agree, but from personal experience that's just what I would go with, nothing bigger...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1CaMw0nDeR &raquo;</TD></TR><TR><TD CLASS="quote">LoL that's what im saying bro... I think you're just reading my post's wrong, i'm telling him that backpressure is going to be there regardless of what he does, but to much is not good... </TD></TR></TABLE>
Sorry, I was basing my responses off of these:
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1CaMw0nDeR &raquo;</TD></TR><TR><TD CLASS="quote">remember you want some back pressure...</TD></TR></TABLE>
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1CaMw0nDeR &raquo;</TD></TR><TR><TD CLASS="quote">some backpressure is gonna be needed regardless...</TD></TR></TABLE>

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ddd4114 &raquo;</TD></TR><TR><TD CLASS="quote">
Sorry, I was basing my responses off of these:

</TD></TR></TABLE>

naa it's cool man, i understood where you were gettin your responses from but I was just not being persistent enough on what i really was trying to get across... i was just laying those facts out to the OP so he understood that backpressure was gonna be around regardless, he just wasn't going to want to go with to much ie: bigger exhaust, and since he wasn't going to a smaller than OEM diameter than low backpressure wasn't even an issue, but i do understand where ur comin from that's why i just tried to elaborate a little more clear... no worries