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I'll try making the changes you recommended. I was considering that all along but wanted to see if other people agreed to go ahead and try adding more timing.
Idk how s3's act vs s1's. I know my car took more timing going from stock cams to s2's on pump gas. On E85, it didn't really care either way. Also consider that the bigger cams are "louder" and you could simply be getting some phantom knock due to increased valvetrain noise. Unfortunately with E85, you can't simply dump in some race gas and see if it goes away to prove its just phantom knock like you can with pump gas.
Have you altered the knock sensor filtering settings at all? What are you seeing for knock voltage? Is the car pulling any timing when you are seeing the knock counts in the log?
The fact that you lost power by pulling timing, and that you're on E85, makes me think you're getting some phantom knock from the bigger cams.
Just remember to only add 1 degree, maybe 2 degrees at a time, and make sure you see power increase to correspond with it..
I'm 24 and 24 for mid and high knock multiplier. I haven't been logging knock voltage but will log it this time. The car does pull timing when knocking. Eventually the knock goes away and the timing jumps back up to match my map.
I was picking up noticeable gains adding timing with no difference in knock sum.
There is no apparent pattern in knock voltage and knock sum. Just under 4500 RPM I was no knock and .95 knock voltage and next data point was 4700 voltage .76 with 2 counts of knock. Voltage climbs a little and it still drops to 1 count and goes away after. A little further in RPM range I even see it hit over 2.0 and no knock sum registered.
Think it's just false knock after the S3 cams and Kiggly springs and retainers?
If this is actually knock indicating detonation I should be it be able to continue to gain power by increasing boost or timing right?
If so what should I try increasing my knock multiplier to? I'm 24 mid and high right now. Should I assume E85 won't knock at high 11s AFR and increase it until I eliminate the knock before I try to tune on 93?
Graph of knock sum and knock voltage.
Last edited by ridenrunwv; Aug 19, 2015 at 09:50 AM.
To me, it sounds false if you're adding timing and gaining power while getting the same knock counts, and the knock isn't there on every pull. Keep in mind knock voltage always goes up with RPM, the engine simply makes more noise.
Do you have a dyno in your area? Sometimes road tuning can generate false knock, and putting it on a dyno can help eliminate it.
I do not have easy access to a dyno. The graph I posted above is knock sum graphed with knock voltage. You can see that sometimes the voltage will drop and a knock sum is recorded for some reason.
Being able to add timing and make more power makes me think it's false knock. It makes it more so because you're not getting it on every run. If you're happy with the power level, I would run it, even if its 1-2 counts of real knock every now and then, its not the end of the world. On my tune, Aaron has it setup to flash the check engine light when it knocks, but it doesn't flash until the car sees 8 counts of knock. Granted, my car doesn't knock. But it gives you an idea of what a pro tuner has to determined to be acceptable. When I get home, I'll post a log to show you my knock voltage/afr/rpm/boost. I don't think Aaron would want me posting the timing column though
I had a good idea about what the timing should be but the knock in that RPM range is really getting me. It's pulling timing when it detects knock so it messes with my tune even if it is false knock.
I was still gaining power at this timing. No more knock than before.
With how much timing you added, I would definitely say its false. Maybe one fo the tuner guys on here can chime in, or send them a PM. JohnBradley is Aaron at English racing, and then you have TSComp..
I'm going to try turning up the knock multiplier even more I guess. When I eliminate the knock I will lower the timing back down some and try to add it back with more consistent logs just to make sure I'm not passing MBT. It would be a lot more consistent and easier to check for gains if I didn't have the ECU pulling timing sometimes and not pulling it other times. If anyone reads this and thinks it's a bad idea to increase knock multiplier to over 24 please let me know.
Aug 18, 2015, 04:03 PM
