eg6hatch

I have a 1997 Supercharged Integra GSR, Jackson Racing, and i have a apexi world sport 2 on it now, and i have a feeling i could be alot more open with soemthing else, what do you guys think, apexi n1, or what? thanks

Also the world sport is 2 1/4" i think, what size piping should i get, 2 1/2" or 3", it is a supercharged gsr, dc 4-2-1 header, injen intake, and a couple more bolt ons.

beepy

Exhaust size is much less important on a SC app than a turbo. Just follow a simple formula.

Take the amount of boost you plan to make, convert that to absolute atmospheres. Now multiply that value by the displacement of your engine. That will give you a very rough estimate of the exhaust airflow requirements.

For example, say you have a 1.8 liter with 14.7 PSI of boost. That is 2 atmospheres absolute, so your engine will act similarly to a 3.6 liter engine. Now what size of exhaust does a 3.6l need? I would say about 2.25" is plenty, and any more you would lose lowend torque.

eg6hatch

ok, so if i run 8 psi, on a 1.8, what size would i need, so if i buy the 2.36" n1, would i lose low end

Tad

ok whats absolute atmospheres...

beepy

There are gauge atmospheres, as in, "I made 1 bar of boost". Then there are absolute atmospheres, as in, "I have a 3-bar MAP sensor".

In a perfect world, if you make a bar of boost, you have 2 bar of pressure in the engine, which will be twice as many moles of air if at the same temperature. (This is a conservative estimate, in reality there will be less than 2x the moles of air)

In a perfect world again, if you have twice as many moles of air, you would need twice as much fuel, and you would have twice as much exhaust. Thus the conservative estimate is to treat the engine as having twice the displacement.

Tad

so what you're saying is that if your running 1bar of boost then you can
treat it as if your engine has twice the displacement?

Muckman

iTrader: (2)

Its easy, just get a 3".

beepy

Yes, but only for a supercharger application, and again it's a rough estimate. 3" on a 1.8 liter with 1bar of boost is way overkill. My 5.7 liter, 385 ft-lb Camaro engine only had a single 3" exhaust.

eg6hatch

so would a apexi n1 at 2.36" be ok?

Tad

perfect imo

i'm running a kinda stepped setup,
stock header.. 2.25 ITR bpipe, then 2.5" axleback..

I think its good? hehe..

eg6hatch

so will 2.36" on my car be ok, apexi n1 that is?

Muckman

iTrader: (2)

Im pretty sure all Apex piping is 2.36" (60mm). Sure it'll be ok. Not the best, but ok.

eg6hatch

ok, then what would be the best exhaust for my car?

eg6hatch

SO should i buy the n1, or another exhaust

Muckman

iTrader: (2)

3" > 2.5" > Apexi WS/N1 2.36"

beepy

Don't get stuck with "the bigger the better" here. If anything, exhaust scavenging is MORE important with a supercharger than N/A.

Muckman

iTrader: (2)

Right. no bigger than 3" then

Tad

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by beepy &raquo;</TD></TR><TR><TD CLASS="quote">Don't get stuck with "the bigger the better" here. If anything, exhaust scavenging is MORE important with a supercharger than N/A.</TD></TR></TABLE>

what do you mean by exhaust scavenging?

eg6hatch

I just want to know whetehr i should buy the apexi n1 in 2.36", or get something else