Originally Posted by
scottmeister
Mate it shouldn't be pinging at 9psi. Do not reduce the compression unless you want a dog of an engine to drive. Is it pinging under full boost - and if so, at what RPM? Do you have a wideband - how is the fuelling at this boost? The 4.5s like a funny ignition timing curve, they like full advance by 2500 rpm, then you need to pull timing from then through to about 3500 rpm before adding it in again. I have run 17 psi though the TB45 on 98 with no worries, around 12-14 degrees @ 4000 rpm, AFRs around 11.5. Nowadays I just run 15 psi on E85, needs a bit more timing and makes great power :-)