ok . i have 87 turbo II with Atkins rebulit motor (3000miles) with 3in dp,exhaust. and looking to get a turbo XS manual boost conrtoller and push to 8 psi....
and is it possilbe to push 8psi with out any fuel upgrade?? if not how much boost i should push ???

 

Err.. 8psi should be fine since fuel cut is at what about 8.5psi?

But you have to watch out for boost creep.. have you gotten your wastegate ported?

 

no. i will do that soon as i get boost controller

 

so my fuel will cut off around 8 psi with stock ecu??

 

Yup. Lots of posts and websites on FCD's (Fuel Cut defenders)... do a search you'll find how to make them yourself or where to buy them. And, you have an S4. First thing you should do for that poor turbo is port the wastegate.

 

where is the wastegate located at(sorry stupid ?, but i dont have a turbo 2 yet and id like to do this. also how much at a reg. machine shop...my dads a machinist but he lives 3 hours away)

 

so is it not good for my turbo right?
but is it rebulit turbo help??? cause i have rebuilt turbo also

 

When you remove the turbo, there is a 1/2" thick cast iron plate that the DP bolted to. Under there is the wastegate. All you have to do is make the hole bigger. You might have to take the turbine housing off to keep metal from getting to the bushings inside. There is no way of knowing if the rebuilt turbo has a ported wastegate or not without looking. Measure the ID of the hole. I think the stock ones are like 5/8" abouts.
Boosting to 8 won't hurt the turbo. I've heard they're good up to like 16 or so. I'm quite surprised that you aren't hitting fuel cut. All I have is an intake and gutted cat and I'm all over fuel cut. You may already have a ported wastegate.

 

also, it's not a matter of how much boost you run that determines whether or not it is safe. it's how much horsepower you have. The stock fuel system can only support so much hp. You can have 16psi if you want, as long as you don't go over 250hp.

 

so how much boost stock fuel system can handle???

 

ive read from ppl having 10psi with no problems...save up some money and buy a walbro 255lph fuel pump....if ur planning on going higher get larger injectors...but ppl with 10 psi on stock injectors and pump say they have no problems...just get teh fcd

 

thank you all

 

What other mods are on your car? The stock fuel cut on a s4 Turbo 2 is 7.5 psi. The first thing I did when I got my completely stock T2 was install a boost gauge. I then found out I was hitting fuel cut @ 7.5 psi because my exhaust was so rusted out.

8 psi would be fine without any fuel UPGRADES. just make sure you fuel system is operating at is stock potential.

 

Wrong way around. Do not install a boost conroller until the wastegate is ported (preferably with a bigger flap too) and you have no boost creep.

 

I just got a boost gauge. My car never goes past 5 psi. I own a stock s4.

Thanks

Carlos

 

ok.. my mods are rebulit atkins motor S4 block but they built it with an S5 rear housing,rebuilt turbo, ngk spark, ngk spark plug wire, 3in dp, 3in mp, K&N drop top filter, rotary performance exhaust , mazdatrix motor mounts,stock injectors from RC Engineering... i think thats all right now but lare greddy boost gauge and boost controller!!
but is S4 stock fuel cut on 7.5? i thought was 8.6?

 

I would get an aftermarket boost gauge first before any other mod. Your stock one may be reading inaccurately.

 

but is S4 stock fuel cut on 7.5? i thought was 8.6? [/B][/QUOTE]

 

i guess 8.6 is S5 fuel cut. i was wondering why i'm cutting around 7.5. i though my guage was off. ha oh well, learn something everyday. the first thing i bought for my car was the walbro 255. i have like new injectors and a rewire now. i think 12psi is nearing the 250hp limit on stock fuel system. RC said not to go over like 255 with my stock injectors. going by that, i'm going to get 720's soon for the secondaries just to be safe when i do my exhaust.

 

i aslo learn someting everyday to.. my rx7 and english (i been USA for almost 4 years ha ha.. im trying my best to type)
ok how hard to take stock injectors off ??

 

8.6psi is fuel cut on all models.

 

Easy. Pull off the intercooler and throttle body and you've got access to the fuel rails pretty much right there. I'd recommend you get a factory service manual from mazdatrix for the exact diagrams of everything ... very helpful for almost any mod you want to do.

 

thank you... i know it was around 8 psi

 

My experience with 3" downpipe, fuel cut defenser:

1) waste gate MUST be ported to eliminate boost creep.

2) do not exceed 10 psi EVER with stock fuel system, but even that is not really safe. Above 8.5 psi you should be adding fuel.

3) porting as shown in the attached photo is good enough to hold the boost below 10 psi except on cold days. Only the small hole is enlarged, and the flap has been relieved to allow it to open a bit more. The hole needs to be enlarged concentric with the flap, not with the original hole. This maintains a uniform sealing surface.

4) beware of cold days, or fuel tank below 1/4 when driving aggressively, and 5th gear (where creep is worst).

5) at the first sign of knocking, back off and change your plugs. Expect plug life of 1500 to 2000 miles.

6) my stock pump was good for 60 psi, which should be good enough for 10 psi boost. To be safe install a 255 lph pump if you install a rising rate fuel pressure regulator.

 

hmmm...
how do you attach a photo?