So I have the racing beat turboback exhaust with the 3" downpipe to the 2.25" piping, with a ported turbo wastegate on a 1989 Turbo II. I was having a bit of fun on the freeway today, and managed to hit around 11psi in 3rd gear. I've never seen it boost that high before, and now I'm a little scared that I'll blow my motor up. It was pretty cold out today, maybe mid 30s, so I was wondering if this may account for the increased boost I saw?

In any case, I'm wondering what I can do to increase the amount of fuel going to my motor to compensate for the increased boost. I already have an FD fuel pump, but that might not be enough to compensate. What can I do on an S5 to increase the fuel? I assume that larger injectors can be used, as well as a stand alone fuel controller. What would be the best route to go? Car is primarily used for autocross.

 

get a safc or a full standalone and a wideband

 

If your only mods are the exhaust and wastegate then you should be fine. A piggy back is never a bad idea but a full stand alone is overkill here.

And you should get a FCD if you don't have one.

 

You said you mainly use the car for autocross. I don't know how your autocross is set up, but here they class cars according to SCCA classifications. If your organization does this, then you have to consider what class your car will fall into for competition when you change the injectors, ECU or add a piggy back device.

 

Yeah, I have a FCD already

Project84: I run in the SF Region in SCCA. I already run in BSP, so I'm assuming that the injectors are legal to run, along with the piggyback. In any case, I'll look into it.

 

Don't change your injectors without adding a piggy back or standalone.

I'd say get a wideband and see how rich/lean the car is running. The cold weather won't make more boost but it will help prevent detonation. If the car is on the lean side, a good FPR (riseing rate) might be all you need to get it running a little more rich.

 

I use a 12volt 5th injector from an old Saab turbo.

I use a Hobbs/Honeywell pressure switch.

I only had to tap the exsiting fuel line. The 12 volt injector comes with a banjo bolt.

It handles an extra 3 psi over stock.

I have seen others use 2 of them.