Only Boosting to 0.5Bar? Help!
 

I have just fitted a decat downpipe on my 95 classic which only other mods are polar performance chip, straight through exhaust, into an ac invo 4inch box and forge dump valve. The car was running fine on my little test drive but then took it on the motorway and was stll good for the first few bolts of acceleration. Then i dont know if i hit the fuel cut 1st or if it touched flat line but the exhaust then backfired which sounded nice by the way because it was normaly quiter :D. But then when i came back on to accelerate to dump and i noticed the dump wasn't as loud. I then noticed i was only boosting to 0.5bar instead 1.2bar... I have tried looking for leaks around the d/v etc but no luck i have noticed i have a slight blow on the downpipe where it meets the centrepipe which i will sort now but didnt think that would affect it...

Can anyone help? just my luck whenever i decide to add something to my car it always bites back :cry:

It sounds like you hit boost cut.

The PP chip's max boost is 1.1bar and the cut is 1.2bar. You've probably overboosted and ECU/chip has gone into 'limp-home' mode, hence only 0.5bar. You sure you fitted the downpipe onto the back of the turbo okay? Any leaks here will invariably cause overboosting. You really need to check all the pipes/unions of the boost control system and the exhaust system.

If you do an ECU reset, you'll prob get it out of limp-home mode, but something must have caused it in the first place, so unless rectified, will no doubt happen again...

See here for good advice/troubleshooting: Frequently Asked Questions

Well said that man