i picked up an S5 turbo for my 88 and will be doing a few other upgrades. Will the stock S4 computer suffice or will I need to grab an S5 computer as well?

 

S4 computer will run it just fine. You will have a non-running S4 if you plug in an S5 ecu.

 

While it's out, you ought to port both wastegate ports. It can't hurt.

FC3S Pro: Kouki Turbo Wastegate Porting

 

Hope you grabbed a matching manifold!

 

i did. I'm going to be sending the turbo out to be rebuilt and upgraded (http://gpopshop.com/). once i have it back i will be pairing it with an rtek stage one and racing beat rev T2 exhaust system.

 

Im running a stock rebuilt s4 tii with the s5 turbo. The wastegate is fine on mine. Im running 3inch rev downpipe with a mix of rb and kniggtsports parts. As well as intake. Ive got no creeping issues. 7.5lbs all day. The s4 was creeping to 12 on me with the waategate ported to the max of the flapper door

 

just out of curiosity, have you ever dynoed this kind of setup?

 

pretty sure you will need the s5 oil drain line as well...it is different than the s4.

 

^ You can bolt the S4 oil drain to it.



I fully understand that the S5 wastegate ports are superior to the S4 wastegate port. I'm just saying if the turbo is out, why not port the wastegate passages? It's simple, and will put your mind at ease.

 

250 - s5 turbo, haltech, fuel, exhast.

Never ported the wg, only problem I had was with it cracking open in 3rd -5th above 5500rpm. It goes from 11-12psi down to 6psi. I would guess you could get closer to 300 if you put a spring on it to help hold it shut.

 

Hmm.... that's interesting. I ported my S5 turbo, shaved the back of the flapper, and verified the wastegate is actuating. I STILL get massive boost creep. I have a 3" downpipe (brand unknown, I bought it used) mated to a 3" resonator (I made it out of a fart can lol) then branches off to 2x 2.125" pipes going to a pair of Pacesetter mufflers (hey, I like the look, ok). I fabricated the whole exhaust myself.

I guess I'm either really good at building exhaust, or I'm terrible at porting wastegates

 

I get zero boost creep with my S5 hybrid, and it was the same when I had the turbine housing on a stock turbo (3" intake, 2.5" DP). The runners are ported out to 23mm and 26mm (stock is 18mm and 23mm IIRC), and the backplate has had 1/8" of material removed from the inside to allow the door to open further & more volume to pass through.

Yep. The oil drain line just needs to match the front cover on the engine.

 

Have yet to dyno. Im guessing around 200-220. all i kno is i can hang with my friends 05 procharged gt mustang on his 12lb pulley till top of 3rd. I also have my boost taper down to 5.5 after 6.2k. ssuming boost controller would help that.

 

Uhhhhhhhhhhhhhh i mean v6 procharged. I dont kno my mustangs. Smh.

 

Boost controller will not help it stay shut. The exhaust is pushing harder than what your wg actuator can hold back.

 

Mazda sized the stock turbo for response, so the stock compressor just barely provides enough air at redline. You need a bigger compressor if you want to hold higher boost all the way to redline.