Im going to be porting my wastegate soon (just got another s4 turbo)....however a few threads, have raised my concern in my cars reliability. I have an 88 TII, stock turbo. 2.5" full exhaust, no emissions, FCD, 6 puck clutch, New atkins rebuild, new stock injectors. New stock fuel pump (walboro in the mail, should be here tomorrow). Also have a check valve/bov installed. The exhaust is single out the passenger side, no cats, no silencer in the muffler. (loud as hell, i dont like it, ill fix it when i have cash) anywho, my car boosts 5psi no problem, actually, it will pull 8psi, or 10psi, will creep to 11psi or 12, but its as if it were hitting fuel cut at that point, so i usually keep my boosting to 8psi when i want to get into it. Car will not boost to redline, which I understand is typical. Reason for turbo replacement, is that the turbo on the car right now has bad seals, high mileage, and shaft play out the ****, smoking, etc.

Am I hurting the motor, or running the risk of damage with the car running the way it is now? Should the car be boosting as much as it is, or is it creeping that much? I am going to port the wastegate on the other s4 turbo I have so it will be comparable to NZconvertible's porting technique. I am also installing the fuel pump as soon as it gets here tomorrow or saturday morning. With the fuel pump installed, and the current modifications, will it be safe to push the car to 8-10psi without the possability of engine damage? I just want to make sure I'm not leaning the car out and killing it, I havent had any problem with detonation, and it seems the car is running rich as hell at this point. Any suggestions, concerns? I just don't want to damage the car, I can't afford to....

 

It's possible the "as if fuel cut" at 11PSI is fuel leanout and/or detonation.

Yes - porting the waste gate is a must.
Just try not to "test" it until you get the fuel mods all done.

It sounds like you know what to do.

 

yea, at around 11psi, it wants to die. It bogs, and wants to stall out, makes an ungodly noise. So I was figuring it was leaning out due to the stock fuel pump not being able to support the fuel demands. I've done it maybe twice, on accident. I'll check the compression just in case while I'm installing the walboro. The car also has the TB mod and a ported TB. Once the fuel pump is installed I'll feel a lot safer boosting the car over 7psi. I havent had any problems or issues over 8-10psi, car handles it well. It backfires on deceleration, sounds like its just in the muffler though, or out the tailpipe. Could this be caused by the check valve/bov? I really need to get a good BOV in there as well. I think thats about it....thanks!!

 

also, what kind of vacum should my car pull at idle. here are the current modifications to the car. its pulling like 10 at idle, and 20 when the car is driven but not under any throttle.
the car has a atkins rebuild in it, has about 13k on it at the present time. oil was just changed about 200 miles ago.

removed -
acv
egr
aws
bac
airpump
split air pipe
main cat
precat
cold start assist
thermowax
rats nest

- mods -
2.5" dp
2.5" midpipe
2.5" cat back
ebay muffler
tb mod
ported tb
fcd
corksport ss oil cooler lines
ACT 6 puck clutch

- electrical -
apexi autotimer
panasonic headunit
autometer boost gauge