IeatV8s

Have a 88 T2 with a full RB exhaust setup, and I am curious to know if a s5 turbo swap will fix the boost creep problem instead of having to port the wastegate on the s4 turbo?

darkwaveboi

you'd have to take off the turbo either way...might as well port it and save yourself the money.

IeatV8s

but isn't the s5 turbos a better turbo over all?

eViLRotor

iTrader: (2)

Its the same turbo.
The difference is that S5's don't have the twin-scroll actuator and have a double flap wastegate...

IeatV8s

so if i get a s5 turbo, will it have to be ported?

eViLRotor

iTrader: (2)

Not necessarily, the dual flapper wastegate is a lot better...it'll help reduce creep for sure.

IeatV8s

ok well somebody told me with the exhaust setup im running, a s5 turbo is the better way to go.

Scott 89t2

I don't know what you are hitting now but with the S5 turbo and RB exhuast and stock intake I was hitting 9psi. and with a K&N cone around 11.

I would think you are hitting 12-15 with the S4??

it's better but it's still not perfect.

scathcart

well, your stock S4 wastegate is 12 mm.

The stock wastegate on an S5 is 19mm and 24.5 mm, which can easily be ported (and backcut) to 25 mm and 30mm respectively.

You will not creep with this set-up (ported S5 wastegate).

nonameo

port out your S4 wastegate and weld a new flapper on from an exhaust valve.

scathcart

Still won't flow as much as a ported S5 wastegate.
Work it out:
32mm, or 25mm+30mm.
The two smaller holes have a larger volume.

HeffBoost

I'll second that. The only thing I have to add is that since you've got the turbo off either way, down the road you'll be greatful for the S5 porting.

scathcart

ALso, backcut the ports, and do a slight flycut into the backing plate so the flapper door can open a little wider.

IeatV8s

I am getting the s5 turbo for my car. I don't plan on running a lot more boost then what the car runs now. I just noticed once that my boost spiked to 14lbs. of course that's with a autometer boost gauge, but I'd rather be safe then sorry. That's why I'm installing the s5 turbo.