I am running MS for fuel only right now. Once I get my fuel map set up better I am going to add spark control. But my question is right now if I start to knock the ECU will retard the timing, once MS controls spark nothing will happen if knock occurs. Is anyone using a knock sensor or just listening for it and pretty much hoping it doesn't happen. I saw a circuit before and some said they built it on here but never posted whether it actually worked or not.
#3976, "RE: MegaSquirt and knock sensor" In response to Reply # 0
i can't be sure but u think the stock ecu will only pull so much timing. my car runs the same 16-17 deg. on 7psi as it does on 15psi. i think thats the limit so it will only help so much. if you don't detonate now then just setup a similar timing curve on the ms unless you run huge boost.
#3979, "RE: MegaSquirt and knock sensor" In response to Reply # 2
The stock ECU doesn't pull much timing at all when it sees knock. I've maybe seen a max of like 3 or 4 degrees at most. The matter of fact about these engines is that they were never designed to see boost, or power levels that would require a whole lot of knock induced timing retard. The 420a by design(esp the head/combustion chamber) is very knock retardant, even when using crap 87 octane fuel. This is why minimal timing advance is used at WOT. They assume 87 octane fuel, and of course being naturally aspirated, these engines just dont knock much, if any at all being NA.
There are some methods to monitor knock, but the best i've come across is using your ears. Search for "det cans". You can easily make your own, and work better than any electronic form of knock detection. Another thing you can do that works very well, is to wire up a mic input to the knock sensor, and listen through headphones. For example, wire to the knock sensor output wire, into a laptop mic input, then listen to the sensor through the headphone output. Detonation sounds are very distinct, and sound like loud splats.
The MS has knock inputs, but to trust the sensor and MS to read real knock, is too uncertain IMO.
13.5 @108 MPH-2.2 60ft(stupid FWD!) S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential fuel injection) My webpage: http://eclipsed4evr.home.comcast.net -1998 Mitsubishi Eclipse RS-T- "Toy" -1992 Plymouth Laser Turbo AWD(SOLD) -2000 Honda CR-V(daily)
#3980, "RE: MegaSquirt and knock sensor" In response to Reply # 3
Thanks for the good info. I have seen the det cans and that was my second plan if the knock sensor did not work out.
So how do I go about setting up a spark table? I have my fuel table set up pretty well just needs to be leaned out in boost but the spark table seems to be a little more complicated. Is there a basic spark table that I can use that is close to the stock table?
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