Upgrading exhaust/need new safc for gs4
06-19-09, 06:58 PM
#31
Lexus Champion
hey all, i have some similar questions, (mostly for jbrady and rock alex), I have an sc'd gs4 with no third resonator/ cat and 3" pipes back from that to some large top speed cans. I'll be getting the S&S headers as soon as I can find some(rather not pay retail) and I was wondering if I should leave the cats/ colector area alone or change them to 3" is the s%S headers 3"? don't mean to thread jack, this hould get answered quick i hope
I am guessing you have a centrifugal supercharger like a Vortech, Paxton or Procharger. What is your peak boost? Have you dyno tuned the combination?
What stock exhaust parts do you have left? Sounds like you had the center pipe cut off the Y and a 3" welded on? The stock Y section from the cats back could be upgraded with your supercharged car. That said centrifugal SCs don't start making boost until 2500-3500rpm depending on setup. So a larger system will make off boost throttle response not as crisp. You need cats to pass inspection in most Texas counties so you probably want to keep those. The stock cat outlets are 2" ID. Going with 2.25" to 3" Y pipe may be a good choice for you. I actually have a Y pipe just that size.
The S&S headers will help a bunch.
Here is the Y pipe that I have.
06-19-09, 08:33 PM
#32
Lead Lap
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I'm in west tx san angelo, they don't do a tailpipe or ObdII test hear, just check the brakes and the light/ tire etc, it hilarious , this sc is supposedly good to 20psi, and I won't need more or even close to that, I want to get a pully setup that allows the vortech sc to reach full boost at like 3000 or so and then have a BLV valve set to whatever level of boost I want. then I could have all that boost all the way to WOT
I also will get the S&S headers and may do something about those cats. I checked that lik for the solenoid already too, jeff says he has one and can put it in/ rebuild/ upgrade my tranny at a later date.
I also will get the S&S headers and may do something about those cats. I checked that lik for the solenoid already too, jeff says he has one and can put it in/ rebuild/ upgrade my tranny at a later date.
Last edited by gs400 civi; 06-22-09 at 06:08 AM.
06-21-09, 10:48 PM
#33
I'm in west tx san angelo, this sc is supposedly good to 20psi, and I won't need more or even close to that, I want to get a pully setup that allows the vortech sc to reach full boost at like 3000 or so and then have a BLV valve set to whatever level of boost I want. then I could have all that boost all the way to WOT I also will get the S&S headers and may do something about those cats. I checked that lik for the solenoid already too, jeff says he has one and can put it in/ rebuild/ upgrade my tranny at a later date.
I also will get the S&S headers and may do something about those cats. I checked that lik for the solenoid already too, jeff says he has one and can put it in/ rebuild/ upgrade my tranny at a later date.
06-22-09, 08:00 PM
#35
unless you plan on upgrading rods/pistons/headgaskets/fuel system/tranny/fuel managment, i would not worry about upgrading from V2, its a nice little blower i'm sure people can point you in the right direction but i would think 8-10psi on stock motored 400 would be max i would run. SHould put you right around 400rwhp
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