Originally Posted by posidon42
Ok ok, thanks for the level headed feedback guys. I am going out of town on business for a month so I will have some time to figure out what I need to do to fix this problem. As I said before, I was just 'thinking' about it. Of course, when I told my wife I was thinking about it, that is when she finally authorized the turbo kit. You are right though, I am probably jumping the gun a bit and should just focus on getting this fixed.
I think you will find debugging your current setup will be much more time and cost affective than a v8. I personally would like a v8 as well, but I love the turbo and won't change this car. If anything I'll get a v8 in addition to this one.
The fact that you aren't making boost until high up in the range suggests that you have one of the following problems:
1) A boost leak. One of your intake pipes is probably leaking. Easy way to find the leak is to put a PVC cap into the ends of your piping at the turbo and TB. In one of these caps thread in an air line fitting and hook up a regulated air supply @ approximately the level of boost you run. If there is no leak, inspect the two couplers at the turbo and TB ends, and call it good. This is probably the number 1 cause of low/late boost.
2) WG is failing open. This is usually caused by improper arm tension or a worn/weak spring. If you can open the wastegate by hand without significant difficulty while the actuator and arm are attached then this is most likely the culprit. Retension the arm much tighter and/or replace the actuator.
Your overboost problem is likely caused by:
1) Inadequate downpipe flow from the wastegate port. This can be solved by enlarging/smoothing the tubing from the wastegate exit to the rest of the downpipe.
2) Electronic boost control not tuned properly (if it's electronic)
3) Faulty wastegate actuator. This can be tested by hooking up regulated air to the actuator and creeping the pressure up. determine what pressure (if any) causes the wastegate to fully open and go from there.
My guess would be that you are experiencing a combination of boost leak and wastegate failing closed. Once the airflow from the turbo exceeds that of the leak in the plumbing your boost shoots up. Either the wastegate is not responding fast enough or is not responding at all.