Different '424' pcm's

[vlad01]

sort of, there is an ignore count table. Its like a threshold level adjustment for each rpm 400 rpm or something like that.

I don't find it very effective as it doesn't fix the cause, which is the knock filtering hasn't got any smarts. Just a basic band pass filter and digital counter if I recall correctly.

The problem I found is it triggers easy as with normal engine noise and doesn't trigger much at all on real knock, I have proven and proven again on the dyno with knock headphones that its a complete useless and nuance system.

Only real way is to use knock ears (sensor, signal processing and headphones) to listen for knock when tuning and accommodate a bit of safety margin in the tune and you won't have to deal with sporadic power loss or damage to the engine. Its what good tuning is all about

[nutbag355]

Yeah fair enough, as I mentioned in an earlier reply I don't want it from using while tuning, only to be used as a fail safe in the event of a bad batch of fuel or fuel component failure and yeah knock ears are the go indeed. The engine I've built to go In the car is for a boosted application so it would have been nice to have the knock filter/strategy in place in the event something should go wrong fuel wise.

I wonder if there is a way to adapt an LS knock plate and sensors to a 304/355 block and write a code to suit it........

[vlad01]

Festy did did make programmable knock filter that worked awesome as but then stopped due to supply issue of one of the components and hasn't sorted an alternative since, thats my understanding anyway.

[Holden202T]

the other alternative is to change the knock retard settings, so it doesn't remove as much timing, and then at least you can see if its triggering and use it more as a reference....

[nutbag355]

Not much point doing that if it picks up false knock from valve train noise or exhaust pulse. Might have to sent festy a pm to see if he has found another way to get them to work.

[antus]

Or run a completely external knock detection system. Jenko posted a link a couple of weeks back to a really bright looking one with LEDS but I dont know if the product works or not (or how well). It sounds like an aftermarket system to be used as a warning would suit your needs. If you are worried about being able to pull timing on bad fuel then you could use the power/econ function of 11p to have a second copy of the timetable in econ which is a flat 5 degree reduction of a copy/paste of the main spark map. Then if you detect big knock from bad fuel you can choose econ and know you have some safety. To be fair if the fuel is real bad you can probably hear it by ear, so just implementing the second spark map might be a sufficient tool to have.

FWIW the knock detection works 'OK' on a tight original engine. It just doesnt fair so well on a noisy engine, because of its age and wear and tear or because of modifications.

[nutbag355]

I'll be running bouser e85 so I might just be better off running a flex fuel sensor with a ethanol content display screen and just setup the hi and low octane tables with the appropriate spark maps on a switch then At least I'll be able to control the onset of knock before it can occure.
Or better yet , is there a way to have the flex sensor hooked up to do the switching automatically????
Maybe run a fuel pressure sensor with an alarm for if a pump fails.

Plenty of ways to skin a cat as they say