spool up time

[eclipx]

after the inital bolt ons and gagues, whats the best way to shorten up(err, i guess it would be shorten down) spool up time on a gsx?

 

[madmax]

exhaust,exhaust, exhaust. the faster you can get exhaust gases out of your engine, the quicker your turbo will spool.

 

[eXploitedGST]

mad max is right. one of the biggest things u can do to help your turbo is freeup unneeded backpressure in the exhaust pipes after the turbo. get a bigger downpipe. free flo convertor. and a nice muffler maybe a apexi dunk

 

[eclipx]

thanks. my dsm is stock now, i was gonna do the boost gague/intake/BOV first, and then either rims or exhuast.. do you suggest getting the exhuast first?

 

[eXploitedGST]

id probably get the boost gauge first to know what your running. then exhaust.

 

[eclipx]

is 2.5" piping enough, or is 3" too much? which is ideal. i know ima mod more, but i dont know how much, as long as the car lasts(85Kmiles) ima mod it.

 

[eXploitedGST]

the bigger the better.. im gonna run 3" with turbo u dont need backpressure in the pipes. its all made at the turbo turbines.

 

[EclipsingU]

Yep tell him to boost creep his engine to the melting point.

If you go to a full 3 in turbo back exhaust then you'll need to port your o2 housing and turbo to 7 cm. Port the exhaust manifold collector to 7cm as well.

Worry about the boost gauge when you're ready to up your boost pressure.

Right now you need to open your intake path, 3 in cat-back exhaust and then install a boost gauge.

Install a boost controller and up your boost to 15psi. Re-wire your fuel pump and do your port work mentioned above. Then do the 3in dp and high flow cat.

Thats the safest way and is generally agreed on by top tuners. Some move this mod up or down, but it is a generally good build order.

EDIT: On the question of if 2.5 in is enough or 3 in is to much. You have to ask yourself where you plan to go with your car. If you're wanting high hp and low 1/4 ets then 3in is the way to go. If you just want a quick daily street driver with decent reliablity and high 12 sec + 1/4 mile times then stay with the 2.5.

 

[Black95GSX]

I'd suggest getting an upgraded BOV before an exhaust... more bang for the buck IMO.

Here's my personal fav. order of mods:
Intake
bov/uip
boost gauge
full exhaust
boost controller
egt gauge



and as far as boost creep... that is not going to be an issue with a T25. Your not going to be able to hold 15psi till redline anyways, so why worry? If you get a 14b/16g or bigger, then yes you will need to port your o2 housing to prevent creep. But at the same time, get a 34mm flapper on the wastegate and you wont' have to worry about creep.
My old 16g didnt' creep once, even when I ran it w/o an exhaust.

 

[Kevin Jewer]

Originally posted by EclipsingU
If you go to a full 3 in turbo back exhaust then you'll need to port your o2 housing and turbo to 7 cm. Port the exhaust manifold collector to 7cm as well.

None of those things affect creep. Porting the O2 only helps after porting the flapper gole itself. To show the extreme end of it, I installed an external dump O2 housing (VP stainless) on an otherwise stock turbo and creep was still at 22 psi, didnt move at all. And thats with ZERO wastegate runner restriction. Porting the manifold and turbine inlet to 7cm will not affect creep at all, just overall flow through the turbo. The best thing you can do is open up the hole and the exit area in the turbine housing and just port match the O2 to it. That got my creep from 22-24 psi to 15. A little more work and its down to 10. I run 18 psi daily anyway so it doesnt matter, but I have done this on dozens of DSMs and the pattern is always the same, and the creep is fairly predictable for a given type of porting. Just keep in mind that the stronger the car runs the more it creeps Just wanted to clarify a bit...

 

[rick]

i am getting a 3inch no cat exhaust on a virtually stock motor. should i worry about creep? and if so, do i need any special skills to port my O2 housing,, or can i just buy the dremel and a carbide tip and do it at home. if i can do it myself, what would be a good rule of thumb? how much should i takre out? sorry bout the questions, but i gotta know, i aint got money to just buy new motors after i blow this one

 

[Quacylla]

You will creep and creep bad. Go have a look at www.vfaq.com for the larger wastegate door mod.

 

[Kevin Jewer]

Yes. Also take a good look at how to open up the wastegate exit area. Tom does a great job explaining it. That got my creep from 22 to 16-17 all by itself. The hole got it down the rest of the way, but not as much of a change.

 

[GST4U2NV]

we made 370whp with a 2.5 turbo back, so 3 isn't always what its cracked up to be, just keep that in mind