I have a greddy kit on my integra, 450cc injectors, high flow cat and apexi ws2 exhaust.

the exhaust is still pretty new, i only had it for like 2k miles or so before i decided to go turbo.

i need to get my car retuned cause it kills a lot of gas, so im wondering if i should upgrade the exhaust before i get it retuned.
is it a big difference to upgrade to a larger downpipe( most likely spoolin performance 2.5?) and 3" exhaust?

i figure itll be almost a grand for a new exhaust system, thats kind of a lot of money. im not too aggressive a driver but do like to have some power. the car currently feels like it chokes, like it doesnt kick too hard. itll spool up fast to like 7psi but the cars not really going anywhere. im wondering if thats because my exhaust is too small or im just expecting too much out of a greddy kit.

 

also do i lose mpg going to a larger exhaust?

 

nobody?

 

Depends on what power goals you have, thats what I tell our customers. If your not looking for a lot of power, the WS will be fine. If your looking to push every last bit of horsepower out of your setup, upgrade then.

 

it may feel like its choking b/c the greddy kits come with small turbos right? like t25's and whatnot. thats nothing more than a stock turbo off alot of slow cars

 

I would say upgrade your exhaust. I upgraded my stock exhaust to a 2,5 inch, and it's a lot different. I'm making a lot more top end power. This is on a 2 liter Accord with 14b turbo in a Prelude chassis.

 

Just curious, what size is the stock greddy downpipe? Also isnt the WS2 a little bigger then 2.5" ?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 007EG &raquo;</TD></TR><TR><TD CLASS="quote">Just curious, what size is the stock greddy downpipe? Also isnt the WS2 a little bigger then 2.5" ?</TD></TR></TABLE>

No, I believe the Apexi WS2 is 2.36" ID, please correct me if I'm wrong.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blackcherry &raquo;</TD></TR><TR><TD CLASS="quote">it may feel like its choking b/c the greddy kits come with small turbos right? like t25's and whatnot. thats nothing more than a stock turbo off alot of slow cars</TD></TR></TABLE>

meh. it's a t25 flange on the turbine housing to the manifold, but not all their turbos are small. i maded 303 whp @ 12psi on a stock gsr and 18g turbo.

 

yeah i just checked and the greddys i think did come with 18g it was the turbo specialties that had one with a HUGE t25. . .not

 

im not looking for worlds of power, but if its a pretty worthwhile difference, ill spring for the upgrade

 

it certainly won't hurt.

 

If I were you I'd turn the boost up and match that with a Spoolin 3" downpipe and full 3" exhaust.. you will be happy you did

 

i want to keep my ac so i think that rules out 3" downpipe. ive got a stock block gsr so i dont really want to turn up the boost, want to avoid headaches as much as possible

 

Do give you an idea, my sedan had a s-trim t3/t04b & 3" dp/exhaust/no cat, and my coupe had a 50trim T3 & 3" dp/stock cat/stock exhaust. They both spooled at the same RPM, but my sedan used about 35% more fuel (same AFR's/PSI). The turbo difference should have made it only 10% fuel difference (31lb/min vs 35 lb/min, same turbines), and spooled a few hundred RPM apart.

I'd say just turn up the boost. A 60mm exhaust (2.36") will obviously hurt spool/upper rpm, since the 3" has &gt;61% more volume. Its also going to be much louder unless you use a 3" WS2 baffled muffler.

I'd suggest pulling the axle-back section off if you want an idea of what a straight-through 3" exhaust will sound like. To some, its too much.

 

so a larger exhaust will kill more gas?

ive been talkin to spoolin/redzone and am looking into a 3" dp(after elbow) and 3" exhaust.


if i just changed the dp and exhaust but kept my ws2 muffler, will that be a big hinder?

 

technically means it makes more power

 

im looking for maybe 230-250WHP. none of my friends have cars with modified engines so im not sure what that amount of hp feels like, im just shooting for that because its the average of what a stock block gsr w/ greddy turbo kit does on 7ish psi?

also if upgrading the exhaust only gives me like maybe 20hp difference i can live without the upgrade


Modified by so simple at 3:25 PM 1/9/2008

 

The higher up with the power you go, the bigger the gains you will see from the larger exhaust. Per say, at the 250whp level, you may gain 15-20whp from the exhaust change, while if you were aiming for the 400whp level you may gain 50-60whp+. Now my numbers are off, but you get the idea.

And on the gas mileage side of it. My old bone stock b18b, running 275whp daily, 550 injectors and full 3'' exhaust gave me typically around 30-35mpg highway. Not really boosting all the time, but not being a baby either. Around town in the mid to high 20's and in boost quite a bit. So i dont think the exhaust is any different on better or worse gas mileage

 

I put down 267 hp and 220ftlbs on a 2inch greddy downpipe to a 2.36 apexi N1 exhaust ending with a 2.5 es oval. All tuned on Neptune by tony1. I plan on doing a 2.5 downpipe to a 3 inch high flow/ 3 inch piping and 3 inch magnaflow, Hopefully ill gain more

 

i just did a compression test for the first time, 210/200 straight across which is good i believe.

i think my turbo seals are bad though because i am losing some oil and my charge pipes are a little oily, now i dont know if i should fix the seal or get the exhaust,

i suppose if i get the exhaust i could just feed the motor a little oil here and there when it gets low