[Diy_efi] Knock Detection using GM ESC Module

[Ken Richardson]

We recently had one of our race engines fail due to a lean condition. It
basically detonated itself to death, melted 4 pistons until one finally let
go. The engine ran fine on the dyno and in testing so we think it was a fuel
restriction that caused it. We couldn't find anything so we're going to
richen the carb up and add some octane boost to the fuel to be on the safe
side.

I picked up a GM ESC module from an early 90's GMC truck, 5.7L. Our race
engine is a 350cid GM smallblock bored 0.060 oversized. I'm going to use the
ESC module with a power transistor to drive a warning light on the dash of
the car. I haven't experimented with this before, it looks like it should
work. Lightly tapping on the block with a hammer flashes the light. Will the
ESC module/sensor consistently detect detonation at higher RPMs, in the
range of 3800 to 5800rpm? This is the RPM range we run the engine. Will the
larger cylinder diameter throw the sensor tuning off enough that it won't be
reliable?

We want to limit our chances of burning any more pistons. We got lucky this
time, no damage to the block, although the heads needed to be rebuilt due to
the aluminum buildup. It gets expensive not to mention working our buts off
to get ready for the next race.

Opinions??

Thanks
Ken R.



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