PFC in a R33 GTR - Knock Level's ?

[cameron]

Hey Guys,

In the R33 GTR with an FC is it normal for the knock level's to hit 100+ ?

This only happens after you have just finished accelerating hard and have just backed off the throttle.

Its running 14psi of boost which is controlled via the H/C.

Jun

[pnblight]

no mate that sounds like pinging under full throddle , factory system warns you normally around 60 knocks i think from memory and most people like to keep dowm toward 20 to 30 i believe

[cameron]

Its fine under acceleration but after you lift you'r foot from the accelerator it jumps upto 100 knock.

[mutex]

I'd be interested to know as well, I have a R34 GTT and after periods of WOT when I back off the accelerator knock can spike momentarily.

I presumed it was because it's going from a high load row to light load row in fc map, and consequently heaps of advance is added in a short period of time. ie. going from 18 deg -> 35 deg, also light load has less fuel being injected. If the head or some component within is still hot maybe this could cause detonation?

I have been in this boat, and replaced my factory plugs with cooler versions and this decreased knock a tad, but cleaning up my map (going to another tuner) had the biggest impact.

Mark.

[Targa Tom]

We run ours fairly rich on a trailing throttle... helps cool turbo and I would guess stops similar problems to what you are having.

Helps with the flames too... Which can't be bad LOL

TT

[cameron]

mutex,

This may be the problem as its not tuned.

Targa Tom,

Good idea after long periods of boosting to cool cylinder's down also.

Jun