I'm getting really low boost at WOT in my 89 turbo II. I remember it boosted to around 0.5 kg/cm before, which is just over 7 psi. However, now it barely hits half of that...around 3.5 psi at WOT throughout the entire rev range in second gear and even going full throttle into 3rd, it still doesnt go above that.

The boost gauge i'm using is an aftermarket hks gauge using its own sender and vacuum line, so readings shouldn't be a problem.

I searched before, but there could be a myriad of problems. I'm still running the stock exhaust with all cats and nearly 132k on it. Could it be clogged and severely affecting my exhaust flow?

I'd love to get this car boosting correctly, especially with the scca slush season coming up. My car is severely handicapped without boost in my class.

 

1. stock cat is clogged
2. vacuum leak

check both. does your idle fluctuate at all ? any smoke out the exhaust?

 

No smoke out of the exhaust. Idle is pretty much rock steady at 750 or so.

Could it also be the wastegate being stuck open or the wastegate actuator?

 

Hmmm.

Just did a little testing on the way home today. I can get very close to full boost in the higher gears. Maybe going 70mph in 4th gear can yield 90% of full boost or so (i'd say around 0.4kg/cm2).

Seems like it's a problem with the wastegate...maybe the C Clip?