antman89iroc

I am getting a lot (-10*) of knock retard but primarily in first gear. It occurs above 5000 rpm at the top of first gear but does not happen in 2nd or 3rd. This is at WOT running up through the gears. I get KR with only 30* SA in first but can run 36* SA in 2-4th. Probably doesn't have anything to due with EBL specifically and maybe more of an engine or trans issue.
I have turned down the KR attack rate and have pulled over 6 degrees in first only but it is still there. I am wondering if something else may be causing it. Possibly the fast rate of RPM rise in first or even related to the transmission somehow. Looking for ideas.

RBob

iTrader: (1)

Tire spin.

RBob.

antman89iroc

Interesting comment RBob. When it happens at the track data logs aren't showing definite tire spin. Could be happening but this is with slicks.

Why would tire spin cause KR? Is it because of the acceleration rate? Could this be happening regardless of spin? That or transmission making a "detonation like" sound only in first. Any other thoughts?

RBob

iTrader: (1)

Any sudden change in background noise will trigger knock being reported. The knock filter has two basic methods of knock detection. A large amount of noise in a particular area of frequency.

Or a sudden change in the frequency of the noise.

RBob.

antman89iroc

What about rocker noise? I have noticed them getting louder (roller rockers) lately even after re-adjustment. Odd it only seems to occur in 1st gear and high rpm (5k+).

I haven't seen significant indication on plugs but I can't say there is no knock. Otherwise I would mute or zero out the KR. Just hate to eliminate KR just in case.


I just remembered I recently installed a twin disc clutch with solid hubs. I have noticed some gear rattle at lower rpms and moderate loads. I wonder if the lack of dampening could be sending a signal back up from the trans?

RBob

iTrader: (1)

Hard to say, although they would be just as noisy gear independent.

I once tried to put a 5 speed trans into 6th, now that created a ton of knock retard.

RBob.

antman89iroc

I bet! You got me thinking. I don't have my tuning computer in front of me right now but I remember seeing some KR (or counts) at low map values at around the same RPMs. Running up through the gears there is a ton of counts that come in around 5000 in first and just roll up. I currently have my attack rate very low and still get a lot of retard. Maybe I could raise the KR threshold MPH to the top of first gear and see what happens. Any other ideas on how to isolate true knock from other noise?

RBob

iTrader: (1)

And it was a regular normal shift, zing for a split second. It registered a lot of counts & retard. Back in the day I regularly shifted with the go-pedal on the floor. I wonder how much knock that would have created. Them Muncies didn't like that so I stopped doing that so I didn't have to swap them on a regular basis...

Unfortunately this won't work. I looked into it earlier today. I knew that either the RPM or the MPH threshold being exceeded would allow knock retard. But I wasn't sure how the code was written regarding the RPM threshold. Looking at it, once the RPM is at (or over) 3187.5 then retard will be allowed.

Going to put this on the code changes list, as being able to do this would be handy.

RBob.

antman89iroc

Thanks for the insight. I'm running a TKO 600 trans and it seems to take a beating but isn't a smooth gear box.

I'm going to look into options including pulling 1st gear SA way back (20*) to see if the KR is still there. I believe I can dumb it down but am reluctant to do so. Another point I noticed is the 1st gear SA is worse at the track on slicks than on the street spinning. But it is there in both cases.

Let me know if any updates become available. Thanks you always take time to help. I still think the EBL is a great upgrade from the 165 I was running. Sooo much more capability.

antman89iroc

Thanks for the insight. I'm running a TKO 600 trans and it seems to take a beating but isn't a silky-smooth gear box.

I'm going to look into options including pulling 1st gear SA way back (20*) to see if the KR is still there. I believe I can dumb it down but am reluctant to do so. Another point I noticed is the 1st gear KR is worse at the track with slicks than on street tires with some spin. It is there in both cases though.

Let me know if any updates become available. Thanks you always take time to help. I still think the EBL is a great upgrade from the 165 I was running. Sooo much more capability.

antman89iroc

If anyone wants to take a look, here's a log from a run showing what I am experiencing. Run begins a 3:00.