I've got a standard (apart from a Power Engineering centre cat, the down pipe one failed and next job is to replace it so the new centre one went in) STi3 wagon and have been noticing that the boost is variable. Not on a moment to moment basis but day to day or week to week but it will have changed at a discrete point of time though.

Normally max boost is about 1.15bar (the needle hovers around there anyway) with steady build up to about 0.8/0.9 and then a rapid increase, at the moment there is a steady build upto about 0.9 and no big hit afterwards (the best bit!). In first and second it's still balistic whatever boost level, and I don't get chance to look at the guage! It's run on Optimax and NF and hasn't had a recent reset but during that time has run at both boos levels. I'm confused and also dont't think that the downpipe cat is disintigrating and restricting gas flow as its not rattling at all.

Any thoughts or suggestions appreciated.

madmoog

 

i'll bump this to the top as it could help me as well,i seem to suffer the same thing on my my01,as i dont have boost gauges i cant tell what the boost is varying on but i do find that sometimes it even affects second gear as well,is it possible the boost pressure can leak from somewhere??

 

I know that some of the guru's on here will be able to have a good stab at this problem if they read it so bttt. thanks

 

Please, someone. This is like note being noticed on the road in my invisible car