I was road tuning my tarmac rally car last night and can't work out why it's knocking at peak torque.
The engine is stock except for 9:1 CP's, Hypergear highflow, 740cc injectors, Blitz front mount and splitfires. As the engine reaches peak torque approx 3700 rpm it starts to knock, so I keep pulling timing out at that point in the map. The mixture is fine pretty solid around .81 lambda, but I'm down to 2 degrees timing in the middle of the map to stop it rattling and it's still not great.
The CRIP and timing are fine at idle, I can't really fault the system when it's idling and I can't believe 2 degrees is right.
My bet is on a dodgy cam angle sensor, any other thoughts? The CAS is wired directly to the Motec in a shielded cable, not the factory wiring. Is there some sort of weird setup in the factory ignition wiring that can alter the timing (unlikely).
I'll post a picture of the timing map when get to the office later on.
The engine is stock except for 9:1 CP's, Hypergear highflow, 740cc injectors, Blitz front mount and splitfires. As the engine reaches peak torque approx 3700 rpm it starts to knock, so I keep pulling timing out at that point in the map. The mixture is fine pretty solid around .81 lambda, but I'm down to 2 degrees timing in the middle of the map to stop it rattling and it's still not great.
The CRIP and timing are fine at idle, I can't really fault the system when it's idling and I can't believe 2 degrees is right.
My bet is on a dodgy cam angle sensor, any other thoughts? The CAS is wired directly to the Motec in a shielded cable, not the factory wiring. Is there some sort of weird setup in the factory ignition wiring that can alter the timing (unlikely).
I'll post a picture of the timing map when get to the office later on.
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