Just bought a 98 UK car with a nice set of mods and a manual boost adjuster under the bonnet. Currently the boost gauge is reading 15psi at max boost, the turbo is standard, what I would like to know is what is a "safe" level of boost with a standard turbo?
Brief description of main mods:

• Prodrive performance pack
• HKS unequal length headers
• GGR full exhaust
• Pipercross induction kit

Any help or advice would be much appreciated.
Ta!

 

If its still got the td04 turbo then you should be fine at 1.1bar upto 1.2bar but you may get fuel cut around 1.15 1.20bar
You wouldnt want to be doing more than that with td04
Do you have a Knocklink or Lambdalink fitted for monitoring ?

 

That's a good question.......no idea.....how can I find out?
Only got the car on Tuesday and still haven't managed to figure it all out. This is my first scooby and I don't know much about them.
The bills and history look like the guy knew what he was doing (no expense spared) and it runs as sweet as a nut except for the bluddy irritating clutch judder (new exedy clutch fitted 3k miles ago with lightened std flywheel).

 

On the MY01+ WRX's 16.5 psi is considered the max safe boost level for the TD04 13T. Anything more than that is pushing the turbo past is efficency range. Not too sure about the classic scoobs but I would think it would be about the same.
Can your scoob handle it? Depends on the age, mileage, injectors, fuel system, rings and a leak down test couldnt hurt. Do you have a way to check your EGT's and 02 readings? If not, invest in some good gauges and a compression/leak down test before you crank up the boost on an older car. Some may think I am too cautious but tests are cheaper than a new engine!
Just FYI my '02 WRX with 40k miles has never run more than 17psi and makes 295.7hp w/ just 15.2 psi.

 

You can run at least 1.5 bar (22 PSI) on a TD04 with the right ignition timing. Goes quite well too. Exact compressor map is not available, but a smaller one shows 74% compressor efficiency. The key is not to overdo it too high up the rev range... drop it back to 1 bar at 6000 RPM. You end up with a flat power curve from about 4000 RPM and a very fast car on the road. Needs a custom map to do properly though.