As documented elsewhere in these pages, my 89Carlsson, at ~153k miles I fitted bleed valve, nothing else, and adjusted it over several runs so as to give the peak boost allowed by the electronics. Performance improvement was amazing. Details if you want, just ask and I'll bore you to death.
ps. Total cost = £15, time = 1 hour including mopre and more enjoyable road tests!
I tell you what I did have done..I took my carlsson to trent saab..its a 1990 9k with low mileage about 62k Trent Saab did a good service on it but found a few bits and bobs that needed sorting out cost me over £700 Glen their tech was excellent nice people to deal with....But my tweaking money was gone..the car on the drive back home (preston)was really smooth and I got very good Mpg..but in all honestly the car felt slower..and was not boosting as well..So the week after I took the car to motorsport developments in Blackpool...wow...they burnt me a chip...new wastegate act...manual boost valve...changed my new Abbott dump valve (for sale if anybody needs one)..3 months on the car really flys 60 120mph not much can hold on to it...need a abbott exhaust now...thinking of have a local shop make me a system up in s/s..still saving up
Porker the dump valves total cost was £138.06, If you give me your email I forward a copy of the invoice and a picture if you want, it is blue in colour and was on the car for about 1000 miles you can have it for £50 if you want it