hey guys i've been told that at about 10 lbs i'll get spikes without portinig the wastegate.... is it necesary or is it just a rumor?

 

I've seen it work great on S5 turbos when using an electronic boost controller.

 

I would Deffinatly Port the S4 wastegate. I dunno about S5, but porting cant hurt it. ALWAYS better safe than sorry man.

 

uhh, so if i hit 10psi on my S4 turbo (not ported) i'll get boost spike? are you sure you aren't talking about boost creep?

 

I'm not sure what you are talking about. if you are running 10psi with the stock wastegate that is fine. the problem is adding an exhuast will put you to 10 psi. and there is no way to lower it.

 

i have an s5 turbo.... btw. but i have an 87 TII

 

I'm not sure people understand what a wastegate does. Porting your wastegate will not cause boost spike or boost creep and it will not make you run at 10psi. The wastegate vents excess exhaust gas, porting it makes it bigger there for allowing you to vent more gas. I think a search of the forum on the purpose and function of the wastegate might be in order.

 

Is he asking if he would get boost creep running at 10 psi with the stock S4 wastegate...??????

 

Not sure. I ran 10-11psi on stock S4 turbo with no boost creep whatsoever.

 

I ran 10-11 on my stock turbo on my S5 with no problem.

 

with my Profec-B i ran 10 psi on my S5, No problem. If you have other bolt ons you will notice that the stock turbo will have some difficulty maintaining that pressure at high RPM's in the upper gears. Especially if your turbo has high miles and is stock. porting the waste gate allows better control of the boost curve (rise).

 

I have 88 tii, get 10psi in 1st, 9 psi in 2nd, 13 psi in 3rd. Only major mod I have is a 2.5 inch exhaust from turbo to muff. I also removed egr. That's it. I get no boost creep or spikes what so ever.

 

The more boost you run the less you need a wastegate. So, you won't get any spiking.