Right, hoping to try and find an answer to this.

Car: My94 WRX Wagon. BPM Twindump Downpipe into Apexi N1 center and backbox. Thus it's decatted.

After fitting the downpipe I'm getting what I believe is overboost. here's what happens.

If I plant the old foot to the floor then boost gauge jumps up to 0.9 bar, then it immediatly drops down to around 0.5 bar, then back up to 0.9, then down to 0.5 then back up, then it stays up.

Is this over boost? if not then what is it?

A few people have said that the ECU could be detecting Det and retarding the ignition, thus causing the problem. could this be true? (I'm running purley on optimax)

I seem to recall that fitting a 3mm (wrong size?) restrictor *somewhere* will fix it, is this true? if so then what size restrictior, and exactly where do you fit it.

Is this an easy/cheap thing to fix?

It's a tad annyoing, plus I want to RR the car and this overboost will muck up the info from the dyno (or am I wrong?)

thanks for any info or help

 

Sounds like overboost quite classic description. Changing restrictor sorts it but I could only tell you how on MY99/00 the earlier ones are different.

 

Thanks john, at least I know it's overboost now!