vlad01 wrote: Fri Jul 18, 2025 6:25 am
Can't real answer that one, I've never tuned anything newer than the 424 and 808, basically I've not touched the MAF based stuff, they do run a different knock filter and system as are said to be much better at telling real know from false and shouldn't aggressively pull so much timing for no reason. Also worth pointing out that the ecotec is also much much more prone to real knock than the Buick and is also many times more susceptible to damage from it since they have open chambers, thinner and brittle pistons and the ring lands are much further up and weaker, ring gaps probably are involved as well.
I wouldn't risk anything unless you know what you are doing with the eco since I have seen many shatter pistons from simple things like a weak fuel pump on a stock ecotec, one guy killed 3 engines in a row within 10min of each being driven. All 3 shattered the pistons from knock, culprit was the dodgy walbro pump the guy installed thinking it was a good idea over the stock pump, obviously backfired big time.
I've seen other issues like this when people have upped the timing bit too much, but it seems that the knock system is only good for saving the engine in all default and stock forms and can't save it from a big problem.
I would only play with them if I had proper knock ears, a good set of long tube headers to reduce the knock threshold and just tread carefully.
These engines aren't very tolerance of knock unlike the older Buicks which just don't seem to give a damn what you do to them. Ecotec is built very different to any Buick that was built before and is more similar to an LS in it's architecture than the original Buicks. Incidentally the LS is also said to be prone to knock, at least the LS1 as they both shared similarities and design goals and were designed at the same time. Emissions and weight savings where the main focus.
Also worth mentioning that their cam with it's super wide LSA is likely a big contributor to their knock tendency as well, so upgrading the cam to one that is much tighter on the LSA really helps to get the performance out of them and also reduce the risk for knock and improve tolerance to minor tuning mistakes.
Maybe The1 can answer what the knock system is like in terms of it's selectivity from real to false knock. The older MAP ECUs sucked in this regard, hence why I just made sure the tune has a safety margin and I just turn the knock control off, but as I mentioned the Buick is tolerant of knock, so if I get some on the occasion I have not seen anything bad from it, and the reason I still get knock occasionally is that the MAP ECUs don't have a air temp spark offset function unlike the newer MAF ECUs, so there are rare conditions that the safety margin doesn't protect against knock, but there are some ways to fudge that with a tiny performance loss that is insignificant. Or you can just run 98 and never have knock period.
They are a really simple motor that are super strong with the worst knock detection.
500+ out of a L36 is not uncommon, have seen them go 600+, L67 have been 700+ numerous times with ease. If you aren't throwing a tonne of comp at it and or ignition the crap out of, they will live forever.
Always turn knock control off and tune without it.
If you don't know the motor or what you are doing it isn't for you.
Better yet, have a set of knock ears.
All the backyarders will have a whinge at my comment and say "theirs is fine"... put it on a dyno or 1/4 mile and you can see just how junk it is if not done right.
Maf based stuff is super simple to understand and tune as well if you disassociate any correllation and take it as raw data... aka "rpm vs x" dont think of it as 0-100kpa, 0-300kpa etc etc
