Hi - I am having a problem with boost pressure fluctuating over 4krpm. The car starts to pull hard from 3200 rpm in high gears, I hit about 18psi on a T63 at 3800, as soon as I hit 4000 rpm I get a quiet chchchch noise and see the boost gauge fluctuating......
Before this, I was out tearing it up one night last year, lots of 4th gear pulls, no problems, then it suddenly started doing this quiet chchch noise and lost all top end power. There is basically nothing at the top end at all, it doesnt missfire, just chchchch. The car has been tuned quite conservatively, 288rwhp@8psi, 414rwhp@18psi, I am looking to add timing and power when I sort this problem.
Motor compression is spot on.
It doesnt matter whether Im at low boost over 4000rpm or at high boost, there is no issue below this engine speed. For example, I could be at say 18psi at 3800, ease of the throttle before 4000 so Im only boosting 10psi and still chchch.
I have had the car running A1 with this turbo with no surge, so Im pretty sure its not compressor surge, it seems to be RPM dependant.
I have changed the plugs from copper to platinum, then to iridium, changed coil pack, ignitor box, wires, changed BOV. Turbo had alot of damage from a bearing failure 17,000 miles ago which I replaced yesteday. I really thought this was the problem but no joy.
Hope someone can help! :icon_bigg
Before this, I was out tearing it up one night last year, lots of 4th gear pulls, no problems, then it suddenly started doing this quiet chchch noise and lost all top end power. There is basically nothing at the top end at all, it doesnt missfire, just chchchch. The car has been tuned quite conservatively, 288rwhp@8psi, 414rwhp@18psi, I am looking to add timing and power when I sort this problem.
Motor compression is spot on.
It doesnt matter whether Im at low boost over 4000rpm or at high boost, there is no issue below this engine speed. For example, I could be at say 18psi at 3800, ease of the throttle before 4000 so Im only boosting 10psi and still chchch.
I have had the car running A1 with this turbo with no surge, so Im pretty sure its not compressor surge, it seems to be RPM dependant.
I have changed the plugs from copper to platinum, then to iridium, changed coil pack, ignitor box, wires, changed BOV. Turbo had alot of damage from a bearing failure 17,000 miles ago which I replaced yesteday. I really thought this was the problem but no joy.
Hope someone can help! :icon_bigg