Spark table pretty low after head swap & higher compression...

[osuhog]

I had to remove a bunch of timing from my stock tables after my head swap. Just wondering if this looks okay to everybody & if I need to worry about anything else at play here.

I had a lot of KR around the .52/2200 area, so I had to remove a bunch of timing there. Most of that is right as I punch it to WOT from a dig.

I also had quite a bit in the .88/4000 region, also at WOT & mostly after the 1-2 & 2-3 shifts. Those areas of KR tapered off as my RPM's went higher, so I'm still able to run 25-27 at 6000-6400 RPM's with no KR. I also smoothed up all the areas around the KR accordingly.

I figured right at 11:1 compression with my heads & cam, & unfortunately all we have around here is 91 octane (no ethanol), so no 93 to try out.

Stock fuel pump & SVO red top injectors tuned with the Greg Banish tables. I haven't hooked up a gauge to check fuel pressure, but my injector duty cycle never goes above 78% or so & I'm running 12.95 AFR at WOT.

I've never heard any pings or knocks at all coming from the engine, but I do occasionally hear something banging underneath the car at WOT. Exhaust or suspension or something, just not sure what & haven't been able to track it down. But, I also heard this when I was cam only & never had these KR issues then. That said, I just now got tires that can actually hook from a dig. I was just spinning my run-flats when I was cam only, so that might not be much of a comparison.

Anyway, I don't have a lot of experience here & was just looking for some more opinions.

[eficalibrator]

Higher compression should require less timing to hit MBT (or the knock limit), so you're on the right path. You are discovering one of the signs of a more efficient engine.

BTW, what's with the hole in the timing map around 0.76g/cyl and 4800rpm? If you really only need 12 degrees here, chances are that adding load is not going to make it want to tolerate 18 degrees at 0.80g/cyl. Remember, timing generally goes down as loading goes up and the resulting tables should be smooth and progressive.

Check your fueling at 2200/.52g/cyl and make sure you're not going lean (or rich) on tip-in. You might be using spark to cover for a fueling issue. Go back and check those points in steady state and make sure the VE surface is right on the money there.

[osuhog]

Great, thanks so much for the suggestions Greg. Something I probably should have mentioned. I've actually been fine-tuning my MAF in these logs with the KR, so my tune was OLMAF. I figured I'd knock out any KR & perfect the MAF at the same time.

So, I just went back to my regular CL tune & drove around at lunch today. Seems that my CL tune never even hits those single digit timing cells at WOT from a dig. So, in turn, I don't see nearly as much KR, even with some higher timing values in my CL tune.

As far as that dip you mentioned, I was getting some KR in those cells right after the 1-2 & 2-3 shifts, so i had to remove quite a bit of timing there. I'll try to smooth things in that area a little better.

I'm gonna have to do some more logging & see what I can figure out over the next few days after my CL revelation.

Thanks again, I'll report back with any new findings!

[Higgs Boson]

Yep, I have to run quite a bit less timing than stock in some places with my 408. 10.92 SCR and 8.7 DCR.... timing map looks like this: