Hey guys, I have a stock turbo with an adjustable wastegate actuator recently installed. Stock downpipe and stock intercooler. I've been tuning the car and on pump gas I've been limited to 15-16psi with no knock (ambient temps in the high 80's), but when I first go to WOT and the turbo spools the boost will spike to around 19-20 psi and then settle back to 15-16. Once it settles it does not creep back up. Is this normal or am I overlooking something? I had it turned up to 20 psi a few weeks ago on 100 octane and did not notice boost ever showing above 20. Now that I've had to decrease the boost again I've noticed this.
Check and replace vacuum hoses to the wastegate, compressor hosing and boost solenoid on the passenger side valve cover. Dry rotted or cracked hoses seep pressure and cause issues.
Are you sure there is no knock at the 19/20# mark retarding the timing? Try adding the 100 octane again and see if it goes away after vac. inspection.
No knock at all when I had 100 octane in the tank and 20# boost. I only noticed the boost spike when set to 15-16 on pump gas. It only spikes when the turbo first spools. DP is stock with cat delete and flowmaster catback. I definitely need to replace the vacuum hoses, they are dry rotted.
I've been planning to buy the silicone vacuum line kit from gbodyparts, guess I need to move that to the top of my shopping list! http://www.gbodyparts.com/product_info.php?products_id=66&osCsid=44571be351b6d9d5b66f9d97fd701795
