Stock ZR1 KR, extended log included

[InfraRedline]

Oh I've been talking to you on corvetteforum? I'm Lights ZR1 on there.

Safe tune AND 30whp gain? That's the dream. Perhaps my Attack Blue filter should go back in? It hasn't gotten any better with factory, and that filter has dyno proven gains.

I've seen 28.5 degrees of timing and I've also seen it start KRing at 20. And I've seen it peg at 26.5 with no KR, but in the summer.

By a little KR you mean as long as you had the pedal down? My log shows some weird behavior. Mine happens until I let off, 2-7 degrees, spikes somewhere between 3-4k, sometimes it increases in increments at certain RPMs sometimes, and tapers off to the redline. If my understanding of the narrowband voltage is correct, 940~ mW is like 10 AFR. Stupid rich. I can get a wideband, I really wonder if it's possible to replace the factory narrowbands somehow. My Fiat had a factory wideband!

If you think this will help that would be awesome. I always thought some of the tables looked insanely strange.

There's a guy on this forum by the name "marcoturbo", 2012 ZR1 in Germany, his stock log also showed 5* KR peak, he said he took like 3% fuel away in PE and some MAF calibration, next log no KR. However the ambient jumped from 58 to 72 degrees F

I do see my LTFT sit at -0.8 or -3.0 on both banks pretty consistently in that log. Sometimes at 0.0 at WOT, but it seems to change.



That's incredible. They are insanely pig rich, wow. I wish you were around here, I would LOVE to safe tune this car and put this nightmare behind me.

This car was a high school dream. Came out in late 2007, I saw it at the 2008 NY Auto Show. Knew I'd probably never own one, but it happened in 2021. It's been a steady stream of stupid issues and life, with some periods of peace. Dumb, I know, I just like doing things right. Sorry for the sob story, LOL!!

If either of you guys could tweak some things, that would be most appreciated, I am not comfortable doing it myself. I'll have to get credits to tune the modules too I suppose. I think this car needs 2.

Yes sir but it was a while ago in my progress thread. I'm 1SLO2OH on there. But I remember we went back and forth a little bit about the factory ignition timing and the knock you were seeing. My car was only stock for about a month of my ownership, and I only logged it for two baseline dyno pulls, but the first pull saw 2* and then it decayed and the next pull saw just over 1* in the same spot. I've attached the log file of my stock tune below just for comparison.

Stock 537whp.hpl

After those pulls I cleaned up the tune a little bit and then about a week later I put injectors in it and tuned it on E85, and then did the ported blower and bolt ons a few weeks after that.

[SPG1]

Yes sir but it was a while ago in my progress thread. I'm 1SLO2OH on there. But I remember we went back and forth a little bit about the factory ignition timing and the knock you were seeing. My car was only stock for about a month of my ownership, and I only logged it for two baseline dyno pulls, but the first pull saw 2* and then it decayed and the next pull saw just over 1* in the same spot. I've attached the log file of my stock tune below just for comparison.

Stock 537whp.hpl

After those pulls I cleaned up the tune a little bit and then about a week later I put injectors in it and tuned it on E85, and then did the ported blower and bolt ons a few weeks after that.

That's a great log thank you.

Look at the huge difference, your ambient air temp is 82 degrees. When I have those temps, my issue is almost entirely gone. Right now the ambients are in the 50s here. That's when they are the worst, give or take a few.

Your cylinder airmass also is .1 lower, I suspect because of the warmer thinner air.

[Alvin]

It's funny you mention that. Not to long ago a guy questioned a tune someone paid for because the tuner pulled timing in colder air. Myself and another professional tuner said that we agreed with doing that. This is another real world proof. Albeit anecdotal but anyway.

[SPG1]

It's funny you mention that. Not to long ago a guy questioned a tune someone paid for because the tuner pulled timing in colder air. Myself and another professional tuner said that we agreed with doing that. This is another real world proof. Albeit anecdotal but anyway.

So then GM optimized these cars for 93/94 and warmer weather, which matches up to the conditions they did their Nurburgring runs and Papenburg top speed runs in.

No wonder why nobody drives their cars in the cold

I got ahold of Race Proven Motorsports in Delaware, roughly $1250 for a dyno tune and NGK plugs to match. About what I was expecting, the weather is just too cold for these tires for a bit though.

[JayRolla]

It's funny you mention that. Not to long ago a guy questioned a tune someone paid for because the tuner pulled timing in colder air. Myself and another professional tuner said that we agreed with doing that. This is another real world proof. Albeit anecdotal but anyway.

Ha, that might have been me. It was a magnuson can tune if I remember right, not a paid tuner.

[SPG1]

Ha, that might have been me. It was a magnuson can tune if I remember right, not a paid tuner.

It's funny you mention that. Not to long ago a guy questioned a tune someone paid for because the tuner pulled timing in colder air. Myself and another professional tuner said that we agreed with doing that. This is another real world proof. Albeit anecdotal but anyway.

It makes complete sense, colder air is denser, bigger bangs, too much fuel on top of cold making it run richer too.

[JayRolla]

It makes complete sense, colder air is denser, bigger bangs, too much fuel on top of cold making it run richer too.

I was questioning it because it was pulling timing at cold water temps, NOT IAT's. I know GM stock tunes will add tons of timing in high load at cold ECT's. But it made sense because it was a SC on top of an NA high compression engine and if someone decided to get on it when the engine was cold it may have too much timing. I usually just zero all these modifiers out so I can control the timing via the timing map and know what's happening. I only keep the high temp stuff active for safety of course.

[SPG1]

I was questioning it because it was pulling timing at cold water temps, NOT IAT's. I know GM stock tunes will add tons of timing in high load at cold ECT's. But it made sense because it was a SC on top of an NA high compression engine and if someone decided to get on it when the engine was cold it may have too much timing. I usually just zero all these modifiers out so I can control the timing via the timing map and know what's happening. I only keep the high temp stuff active for safety of course.

Ah gotcha!

[biholliday]

Im not sure on a boosted engine but on a NA just adding a can of Octanium booster per 10 gals of 91 octane completely wiped out any knock that was showing in the scanner for me. Actually was able to add timing to the whole table 4 degrees with no knock. As seen on Race Proven Motorsports channel about a year ago.

[SPG1]

Im not sure on a boosted engine but on a NA just adding a can of Octanium booster per 10 gals of 91 octane completely wiped out any knock that was showing in the scanner for me. Actually was able to add timing to the whole table 4 degrees with no knock. As seen on Race Proven Motorsports channel about a year ago.

It's the same situation as the C7s. The owners manual says to run 100 above 86 degrees or something for the Z06, and for the ZR1 all the time for best performance, while for the C6 ZR1 it just says 93 or higher. The timing is on the bleeding edge.

[JayRolla]

It's the same situation as the C7s. The owners manual says to run 100 above 86 degrees or something for the Z06, and for the ZR1 all the time for best performance, while for the C6 ZR1 it just says 93 or higher. The timing is on the bleeding edge.

I wouldn't call it bleeding edge. It's tuned for performance. Anyone that tunes a car to zero detonation all the time on 93 octane is literally detuning the car below what the factory does. Seeing detonation is normal, especially when boosted and on hot days.

[SPG1]

I wouldn't call it bleeding edge. It's tuned for performance. Anyone that tunes a car to zero detonation all the time on 93 octane is literally detuning the car below what the factory does. Seeing detonation is normal, especially when boosted and on hot days.

I’ve got the opposite problem, detonation on cold days. In the summer I see none or very little usually.

[edcmat-l1]

I’ve got the opposite problem, detonation on cold days. In the summer I see none or very little usually.

Best thing you can do is leave it alone and let it do its thing.

[SPG1]

Best thing you can do is leave it alone and let it do its thing.

There’s no benefit to tuning it? They remove timing, optimize fuel and other stuff since it’s pig 10:1 rich, among other things. Surely it can’t make it worse. It doesn’t feel right to drive it like this.

[edcmat-l1]

There’s no benefit to tuning it?

I didn't say that.

Surely it can’t make it worse.

Famous last words.

It doesn’t feel right to drive it like this.

Why? If you weren't logging it, how would you even know?

[JayRolla]

I’ve got the opposite problem, detonation on cold days. In the summer I see none or very little usually.

You need some e85 in that thing. LOL.

[SPG1]

You need some e85 in that thing. LOL.

LOL I know. Would be great. No E85 here. 3 places in the entire state, none close. 94 is all I got.

[JayRolla]

LOL I know. Would be great. No E85 here. 3 places in the entire state, none close. 94 is all I got.

Meth injection!!

[SPG1]

Meth injection!!

Cool as a cucumber!

I’ve noticed the KR is directly related to hitting PE regardless of throttle. No PE = No KR. Probably needs timing taken down to 24 max as somebody said and maybe 2-3% removed out of power enrichment.

[edcmat-l1]

I’ve noticed the KR is directly related to hitting PE regardless of throttle. No PE = No KR. Probably needs timing taken down to 24 max as somebody said and maybe 2-3% removed out of power enrichment.

Why would you do that?

Pretty much across the board, regardless of model, engine, fuel etc. every damn thing has some amount of knock retard. It means the system is functioning as it should. To tune for zero knock retard is to either detune the engine or deaden the knock sensors to the point of not working. Either one is counterproductive. Knock retard is not a bad thing. In most cases, especially bone stock vehicles, the best thing to do is leave it alone.

The proper way to approach this would be to figure out why it has KR and if you should even do anything about it.

First thing would be to zero out the burst knock. If the KR goes away you know that's it. If it doesn't there are methods to figure out whether it's real knock or not. But even if it is, the system is doing its job.