Stock ZR1 KR, extended log included

[SPG1]

My 19,700~ mile 2010 ZR1 shows me KR almost everytime I step on the gas over a certain amount, basically it seems anything in or near boost. New battery, just reset fuel trims and the ECU. Battery was also disconnected for a week while I waited for a new hold down. The log included does show little to no knock learn factor, so maybe its torque management? No PID for that sadly. No burst knock shown. It's all total KR or KR.

I logged absolutely everything I could think of, there's a ton of pulls in this log, half throttle, full throttle, you name it. Could the numbers be slightly inflated since this is the first time the car has had electricity to it in several days? Not sure. But this has been happening it seems whenever I pay attention to it. Log and tune included. The tune is confirmed stock, or so I'm told. Weirdly, in the summer months, this issue seems to vanish. Weird. Makes me think it is torque management, since cold air equals bigger bangs especially with forced induction.

Only mods are reinforced DMS OEM bricks and a ZZP solid isolator coupler. Plugs and wires (Firecore50) were changed roughly 2 years ago, didn't seem to help.

I am running Sunoco 94 octane. This first started on Mobil 93 octane. No difference between them, but I run 94 for the extra knock protection. The manual also says 93 or higher. I do not burn a drop of oil. It's still roughly around the max line on the dipstick, just as it was in the spring.

My last thread was a waste of everybody's time since I didn't have the data ready and I profusely appologize for that. I believe a dyno tune would fix this. It appears it's running rich, as expected.

[Alvin]

Get a wideband on it to verify AFR. but the narrow bands indicate a decent mix for a supercharged car.

Out side of that.. start taking timing away in affected areas in the main spark table.

Torque management will not show up as knock retard.

[SPG1]

Get a wideband on it to verify AFR. but the narrow bands indicate a decent mix for a supercharged car.

Out side of that.. start taking timing away in affected areas in the main spark table.

Torque management will not show up as knock retard.

Will do, I may have somebody look at it, not super confident touching the tune on my own.

Speaking of the wideband, I was wondering if it was possible to replace the narrowbands with widebands if you tune, I’m guessing not though, probably needs to be in addition.

Anyhow, is there anything concerning in the log? If you notice on the big pull, when I hit 4th the knock seems to stop. This has been driving me crazy. If I do this exact thing in the summer, it’s nonexistent 95% of the time.

[abc]

Do these things really want that much timing near peak torque? 28 degrees has to be excessive at 4500 rpm, on pump gas, isn't it?

The IAT spark adder seems excessive during the cooler weather you are experiencing. That would be one of the reasons you see the issue in cooler weather compared to the summer, warmer weather.

[SPG1]

Do these things really want that much timing near peak torque? 28 degrees has to be excessive at 4500 rpm, on pump gas, isn't it?

The IAT spark adder seems excessive during the cooler weather you are experiencing. That would be one of the reasons you see the issue in cooler weather compared to the summer, warmer weather.

I found that extremely odd as well, but yes, it asks for a lot of timing. In the summer I’ve seen it request 26.5 degrees, sometimes even as high as 28.5. If there’s any KR, it’s usually small amounts. Same timing in the winter, KR. I am on 94 octane pump gas from Sunoco. I first discovered the issue in early 2023 before Spring on 93 octane, I had recently installed an Attack Blue dry nano air filter and thought that was the cause, considering how sensitive these cars are to smooth airflow over the MAF. Went back to factory, no change. I live in a coolish climate (NJ) and we are at sea level. I did see the knock learn factor was all over the place.

[gtstorey]

Have you confirmed that the tune is stock?

[SPG1]

Have you confirmed that the tune is stock?

A couple of others checked some of the tables with me. We didn't see anything obvious, but I grabbed the two other stock 2010 ZR1 files off HPT repository. I don't know if this car was ever touched. I just hope I haven't done damage.

[abc]

I first discovered the issue in early 2023

Have you ever looked for it before early 2023? Is it possible it's always behaved this way? I assume when they tune these cars to leave the factory it's in a very controlled environment and if you get close to the original variables of the controlled environment, the car will perform at it's best. Anything else and the tune is set up to pull timing to protect itself.

[SPG1]

Have you ever looked for it before early 2023? Is it possible it's always behaved this way? I assume when they tune these cars to leave the factory it's in a very controlled environment and if you get close to the original variables of the controlled environment, the car will perform at it's best. Anything else and the tune is set up to pull timing to protect itself.

No sadly, that’s about when I both added KR to Dashlogic and added the attack blue filter. Wish I looked beforehand. I had Dashlogic for a while before that for IAT1 and 2, never thought about even needing the knock PID. Added it to fill up my HUD arrangement.

[abc]

never thought about even needing the knock PID. Added it to fill up my HUD arrangement.

Well that explains it as far as I'm concerned. I'm pretty sure the pro's will chime in and say what you are seeing is normal with these cars. I would probably look into the IAT spark adder section, burst knock section, main spark tables, dial them back in your "problem areas" and forget about it. You could also consult an experienced pro and let them work their magic, then forget about it.

There is so much compromise with the factory street driven cars, you end up with what you have. That's also part of the reason for the market that HPT's is in. HPT's gives us the ability to remove some of the compromise in area's you feel the desire to do so to customize your personal vehicle. What works for you or what you like may be worlds different from what works for/or the next guy likes. The OEM is obligated to make a product that is the best it can be for the most customers, meet government regulations, and live long enough that it's customers will be repeat customers.

Remember the OEM's have endless resources compared to the biggest Hotrod/custom/race shops you can dream of. They have the resources (including the brain power) to build whatever you could dream up, but who is gonna buy it and will they sell enough to stay in business?

[SPG1]

Well that explains it as far as I'm concerned. I'm pretty sure the pro's will chime in and say what you are seeing is normal with these cars. I would probably look into the IAT spark adder section, burst knock section, main spark tables, dial them back in your "problem areas" and forget about it. You could also consult an experienced pro and let them work their magic, then forget about it.

There is so much compromise with the factory street driven cars, you end up with what you have. That's also part of the reason for the market that HPT's is in. HPT's gives us the ability to remove some of the compromise in area's you feel the desire to do so to customize your personal vehicle. What works for you or what you like may be worlds different from what works for/or the next guy likes. The OEM is obligated to make a product that is the best it can be for the most customers, meet government regulations, and live long enough that it's customers will be repeat customers.

Remember the OEM's have endless resources compared to the biggest Hotrod/custom/race shops you can dream of. They have the resources (including the brain power) to build whatever you could dream up, but who is gonna buy it and will they sell enough to stay in business?

Absolutely, the plan was to have somebody dyno tune it on 94 with that filter and call it a day. I’m not after max attack, just don’t want it knocking. I know OEMs have to compensate for terrible fuel and conditions.

[abc]

It' may not be knocking. Have you looked into the burst knock? Maybe one of the pro's will step in, but I believe there is a chance it's not knocking and the PCM is being proactive based on the formulas for burst knock that are attempting to predict knock before it happens.

For what you want, it doesn't have to go to a dyno and in reality, this issue (if you want to treat it as an issue, for a stock car, I would not do much for it other than what Alvin mentioned) will need worked out in real world driving, not in a semi controlled temp. room with no ambient variables going on.

[SPG1]

It' may not be knocking. Have you looked into the burst knock? Maybe one of the pro's will step in, but I believe there is a chance it's not knocking and the PCM is being proactive based on the formulas for burst knock that are attempting to predict knock before it happens.

For what you want, it doesn't have to go to a dyno and in reality, this issue (if you want to treat it as an issue, for a stock car, I would not do much for it other than what Alvin mentioned) will need worked out in real world driving, not in a semi controlled temp. room with no ambient variables going on.

Burst knock never moved off 0.0 for the entire log, so not sure. Very possible. I may have heard a soft ping once or twice. I don’t like any knock. I had a previous car (Fiat 500 Abarth) that gradually did this worse and worse tuned and not tuned until it started actually pinging LOUD on 93 and 94 and throwing everything at it didn’t fix it, indicating an internal failure. Terrible platform.

And I agree, may need to fix this on the street, but I know there are solid 30+ whp and torque gains from a conservative tune to clean up spark and fuel, as evidenced by ECS back in 2008-2009. Cool stuff!

[InfraRedline]

I agree with the info and suggestions given in these replies as well. On my car the one time I logged it when stock on the dyno I saw 27* as well (I know we discussed this a little on my corvetteforums post) with a little bit of knock in the 3500-4k range, and just by leaning it out from how rich the factory tune was (pegging 10.0 AFR from 5500 and up) and keeping it on the safe side and leaving it at 24* peak timing I still gained nearly 30whp.

It may not be a "set it and forget it" type thing, but if you want I can send you my tune file from when my car was stock for you to compare or try things out. For the most part it was just some small tweaks to the HO timing table and some dumbing down the adder areas of the temperature modifier tables for spark, and then some MAF and PE adjustments for fueling. To be safe it would be good to have a wideband to confirm fueling, but even just changing the spark modifiers would be a good start for testing. Or if you'd rather myself or one of us in this thread can copy them over for you if you aren't comfortable messing with it.

[Alvin]

Bone stock LS9's and LSA's for that matter are pretty high in timing. Be mindful of all the adders but they are still higher than you would think.

I've had several completely stock LS9's pick up quite well dyno tuning them. Like 40 rwhp. I did 3 ZR1's very early in the production.. to the point I don't think they were available to the public.

If you search Alvin, first ZR1 to hit dyno etc.. you should find it.

https://www.corvetteblogger.com/2008...Hits-the-Dyno/

[SPG1]

I agree with the info and suggestions given in these replies as well. On my car the one time I logged it when stock on the dyno I saw 27* as well (I know we discussed this a little on my corvetteforums post) with a little bit of knock in the 3500-4k range, and just by leaning it out from how rich the factory tune was (pegging 10.0 AFR from 5500 and up) and keeping it on the safe side and leaving it at 24* peak timing I still gained nearly 30whp.

It may not be a "set it and forget it" type thing, but if you want I can send you my tune file from when my car was stock for you to compare or try things out. For the most part it was just some small tweaks to the HO timing table and some dumbing down the adder areas of the temperature modifier tables for spark, and then some MAF and PE adjustments for fueling. To be safe it would be good to have a wideband to confirm fueling, but even just changing the spark modifiers would be a good start for testing. Or if you'd rather myself or one of us in this thread can copy them over for you if you aren't comfortable messing with it.

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.

Bone stock LS9's and LSA's for that matter are pretty high in timing. Be mindful of all the adders but they are still higher than you would think.

I've had several completely stock LS9's pick up quite well dyno tuning them. Like 40 rwhp. I did 3 ZR1's very early in the production.. to the point I don't think they were available to the public.

If you search Alvin, first ZR1 to hit dyno etc.. you should find it.

https://www.corvetteblogger.com/2008...Hits-the-Dyno/

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.

[Alvin]

We do remote tuning if you need. I would require you to have a wideband for this.

I honestly prefer to do remote tuning as I can see the car virtually over the course of months/years if needed with hours of combined driving.

[SPG1]

We do remote tuning if you need. I would require you to have a wideband for this.

I honestly prefer to do remote tuning as I can see the car virtually over the course of months/years if needed with hours of combined driving.

Understandable, I can get a wideband, whats the process of adding one to these cars? You'd need two I imagine, one for each bank. Surprised you can't just replace the factory narrowbands somehow when tuning.

[Alvin]

It doesn't need to be a permanent install. All the cars I do in house I do them with a AEM gauge I setup to be portable. I have a special cable that I sell for them that makes it much easier to use this way. I run the cables though the door jam, trunk, or open window.

[SPG1]

It doesn't need to be a permanent install. All the cars I do in house I do them with a AEM gauge I setup to be portable. I have a special cable that I sell for them that makes it much easier to use this way. I run the cables though the door jam, trunk, or open window.

Ohhhhhhh thats really convienent then, definitely can do that. Where do you mount the wideband? Exhaust outlets?