Help, I either need new engine or new knowledge!

[mr.prick]

Well, has this been a constant issue or a recent one?
What do your spark plugs look like?
Do you know if Ethanol is in the gas you buy?

[kwhiteside]

Well, has this been a constant issue or a recent one?
What do your spark plugs look like?
Do you know if Ethanol is in the gas you buy?

After started tuning after getting this car. I first logged it at road atlanta when high spark was flat line 25 and there was bad knock all over the place. As I've learned to tune, I drop the spark down to where I'm at now. Last week I went back to a track (Roebling Raod) where I know my car was much much faster down the straight and have concluded that my safe 19.5 degree timing causes the slower car. Yet I still have some knock as you see. Short answer, YES.

I would be very interesting to see if the knock happens on a dyno now that I have actual following commanded and the LTFTRIMS within -5 to 2 range.

Been a year since I've done the plugs. When they did the compression check they said they looked like new and didn't replace them even though I had a new set for them to use. I'll be looking at them again soon and if I go to the trouble of pulling them out, I replace them!

There is a slight chance I go to Road Atlanta this weekend. If I do, I would change the plugs, change PE to richer. These two things should have some effect. What about my ECT. Should I be tweaking my thermostat to get that temp down to the 190's.

I use 93 gas. Usually shell or chevron stations by the tracks. Quicktrip at home.

[mr.prick]

Looking at your log that KR is pretty high and
even tho LTFTs are positive during PE, AFR is a little lean.
IDC was about 90% BTW, bumping up fuel will make it higher.
If you can increase FP you might be able to lower IDC a little.
I have heard that certain crank pulleys can cause KR.

You can drop the fan temps instead of changing the tstat.
I would:
richen PE AFR, lower the PE TPS% & turn of DFCO.
Kudos for using serial WBO2.

[WeathermanShawn]

Ken, if you look at my tune you will see a safe way to reduce the amount of KR, and how quickly it will decay.

I.E., instead of 4+ degrees of knock that last 15 seconds, you can safely lower it 25-50%, and make the KR go away quicker. It is a common technique. In effect you are not 'desensitizing' the Knock Sensors, you are just manipulating the tune to manage brief amounts of KR.

As long as you remember your settings, it is an acceptable way to manage KR. Obviously, you should pursue all the other suggestions.

[joecar]

Ken,

Most of your knock seem to be at about 4500 rpm (less than 5000 rpm)...

So try this (also): increase spark timing in the regions above 5000 or 5500 rpm... see 1st pic.

Also note: in the KR waveform when you see a "sawtooth" pattern (i.e. a spike followed by one or more spikes while the 1st/previous spike was decaying) then it most likely is real knock... see other pics.

Edited.

[kwhiteside]

Also note: in the KR waveform when you see a "sawtooth" pattern (i.e. a spike followed by one or more spikes while the 1st/previous spike was decaying) then it most likely is real knock... see other pics.

I do see a rise during the decay in the pic. Not a bunch and when I look through the whole log, 8 out of 10 just simply decay away. So tell me, those occasional teeth make you feel it is real knock?

[WeathermanShawn]

Ken, I usually get more worried about KR as I start hitting 100% Throttle. What is interesting about yours is that you are getting it a lot of times at values much less than WOT.

Are you sure nothing is banging around when you accelerate. Like a few others have noted, exhaust pipes and crank pulleys can make a metallic sound..and you get one big bang of KR, then nothing else.

I would say several portions of your log look like repeated KR due to the sawtooth nature, but a few you had one massive KR event, then even as you accelerated (and KR was decaying) you got none.

I still will stick with the following. If you can find 98 octane gas, fill it up with it and try your run. Or if you lower your timing and it goes away..probably KR.

I realize if you do that you will have little to no performance spark advance. Perhaps you have some false knock, with a little 'real' KR from time to time. Unfortunately, you might have to try those half-dozen techniques to eliminate the source.

[kwhiteside]

Looking at your log that KR is pretty high and
even tho LTFTs are positive during PE, AFR is a little lean.
IDC was about 90% BTW, bumping up fuel will make it higher.
If you can increase FP you might be able to lower IDC a little.
I have heard that certain crank pulleys can cause KR.

You can drop the fan temps instead of changing the tstat.
I would:
richen PE AFR, lower the PE TPS% & turn of DFCO.
Kudos for using serial WBO2.

Fan level1 comes on at 190 and full fan at 195. This means my fans are on full force the whole time I'm at the track. From research, fans are irrelevent at the track, since you always going over 100 anyway, natural airflow is more then fan flow. My take on this piece of the equation is to get higher flow back to the radiator by using one or both of the Evans
180degree high flow thermostat
High Flow water pump
I'm thinking the thermo is a no brainer, but it wont happen by the weekend.

DFCO -- Why turn this off at the track? Are you just trying to keep more fuel in the system during decel, thinking that when I go full throttle I might avoid a lean spike (encouraging knock)? Keep in mind that road racing is different than drag strip. There is no dropping the hammer down EVER. Everything is smooth. When you slide through a turn exactly at the point where traction is about to give way, you cannot punch the gas. Guaranteed spin if you do that.

Injector Duty Cycle -- I see that when I knock, I'm around 60% and when at 140mph I'm at about 88% of my injectors. Now the way I understand this is that even though I'm not at 100%, the closer I get to that number, the better chance of some little fuel sputter which would cause a lean. When the knock happens however, 60% shouldn't be a problem should it?

BTW, thank you very much for working with me and taking the time to look at my tune. Prick, Joe, Shawn

[kwhiteside]

Ken,

Most of your knock seem to be at about 4500 rpm (less than 5000 rpm)...

So try this (also): increase spark timing in the regions above 5000 or 5000 rpm... see 1st pic.

I'm trying this, makes total sense. I see that happening too.

Just so you know where my mind is. When you come out of a turn you drop down to maybe 3k and need lots of torque to get up to the 5k range. It's very important. So important that if I cant resolve it, I will start throwing money at the engine. I have to fix it. Welcome to my obsession

[mr.prick]

When my IDC got to 95% AFR was rich.

I turned off DFCO in CL because it made re-engaging
the clutch a little rough between gears.