2013 Sonic 1.4T Knock Drama

Hey everyone!

I have a 2013 Sonic I've been tuning around with for a while now, and I just can't get this car to stop knocking 1-2*. I have tried every fuel in town (that isn't E85) from 91-93 octane. Running E10 93 definitely helps some when I average it, but doesn't eliminate it and I'm getting a little frustrated with the car. I'm so used to my old LNF Cobalt's with the direct injection behaving so nicely. So, I'm reaching out for some help here.

I knocked the car back down to ~15-16psi today and still knocking. That's whats interesting to me the most, is that the KR is basically the same at any boost level above stock.

Attached a recent log doing a couple 3rd gear pulls, and the tune. As you can see ... I'm not running hardly any timing now in the tune. Fuel in the car on this log is 91 E0.

Is something mechanically wrong with my car or am I doing this all wrong? Am I allowing ECT and/or IAT timing modifiers to be too aggressive in adding timing? I have been considering going ahead and installing 42's + flex fuel sensor so I can run E85 and see what happens. I just hate to throw money at it though. I realize these are small bore motors, but geez...

Edit; Also going to try a new set of NGK BKR7E-4644 and maybe re-torque the knock sensor this weekend.

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I think you're just running too much advance. I've been running this tune on my Cruze for the last 60,000 miles on 93 octane E10 @ ~18-20 psi. See my spark table below:

Attachment 75335

You're running about 3-5* more advance than I am in boost cells, which is roughly consistent with the 1-2* of knock you're seeing. I backed off mine until I saw no knock, then went 1.5-2* further retarded since it's my beater and I want it to last.

Wow... okay, thank you for that. Pretty eye opening. I'm going to do two things and test again tomorrow:

1.) I'm toning down the IAT and AFR modifiers. They are adding so much timing back in that I think I'm chasing my tail and its putting me back in that 1-2* KR range.

2.) Based on those results, I'll shape more timing out of the map like you have.

I really miss my LNF's sometimes :)

Quote:

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Originally Posted by Gimpster

Wow... okay, thank you for that. Pretty eye opening. I'm going to do two things and test again tomorrow:

1.) I'm toning down the IAT and AFR modifiers. They are adding so much timing back in that I think I'm chasing my tail and its putting me back in that 1-2* KR range.

2.) Based on those results, I'll shape more timing out of the map like you have.

I really miss my LNF's sometimes :)

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Yeah it's really bizzare how little timing they can take

Is it actual knock? What RPM? about 5,000 rpm?

With a full ZZP exhaust system, I can easily hear actual knock in my Cruze 1.4T. It sounds like someone is perpetually snapping a bundle of toothpicks in your engine bay. At my own risk, I played with the knock sensor calibrations to get rid of what I believe was false knock, it was totally killing my top end pulling timing. It now more happily revs to 6k under load with no knock retard and no audible actual knock.

Quote:

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Originally Posted by steelmesh

Is it actual knock? What RPM? about 5,000 rpm?

With a full ZZP exhaust system, I can easily hear actual knock in my Cruze 1.4T. It sounds like someone is perpetually snapping a bundle of toothpicks in your engine bay. At my own risk, I played with the knock sensor calibrations to get rid of what I believe was false knock, it was totally killing my top end pulling timing. It now more happily revs to 6k under load with no knock retard and no audible actual knock.

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I havent actually played with any of the knock sensor settings as it's something I usually avoid for reliability purposes. I've been running this tune for over 60k mi without issue. Personally, I think I'll keep my peace of mind, but my Cruze is just a fallback/beater car, so

Great suggestion/insight!

The knock on my car is typically like 4000-5500 RPM. I've not played with any knock sensor settings either, kinda wary ... this is also my beater but I would hate to slay it :)

I HAVE heard audible knock on this car before though. I got a tank of 91 a while back from Caseys in a pinch, and there is no way it was 91. I stepped on it and sounded real bad. Was a long wait to get rid of that tank of gas.

Small update- after knocking down all the AFR and IAT timing adders, and reducing the high octane map even more... things are looking much better. Some more timing to knock out at near redline, but looking better.

Lazy 1-2 pull, but they all looked like this.

Attachment 75356

Yup, your logs are starting to look a lot like mine. Crazy how much torque these little motors make.

Yah it's like a little diesel on the torque!

My only tuning annoyance now is getting the thing to hold boost until redline, but that might require some mechanical mods to fix that.

i am pretty sure what you see there is exhaust gas backpressure causing knock, lower boost just slightly and you problem will be gone.
i saw this on all 1.4T I did and this are a lot...
amazing how low your timing is...here in germany i can run 14-16 degree at top end easily

Okay, I'm intrigued.

Do the EU cars have different cylinder heads? Are they direct or port injection? I know I've seen Opel exhaust manifolds for sale for K04, but the flange was totally different than what we have in the US. I know from having visited Germany a couple times your premium fuel options are better ...

I have thought about putting an exhaust on my car, but like I said earlier, this is my daily driver. I feel like I would get pretty tired of hearing a free flowing exhust on my daily commute. I usually reserve that sort of stuff for the weekend toy car.

Quote:

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Originally Posted by dertobi

i am pretty sure what you see there is exhaust gas backpressure causing knock, lower boost just slightly and you problem will be gone.
i saw this on all 1.4T I did and this are a lot...
amazing how low your timing is...here in germany i can run 14-16 degree at top end easily

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In happier news, I finally squashed my max engine torque bug(s), and I am seeing 18.5-19psi all the way to redline now. Also seem to have all of the knock issues sorted out on 91, and I'm pretty happy with the car for what it is.

Quote:

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Originally Posted by Gimpster

Okay, I'm intrigued.

Do the EU cars have different cylinder heads? Are they direct or port injection? I know I've seen Opel exhaust manifolds for sale for K04, but the flange was totally different than what we have in the US. I know from having visited Germany a couple times your premium fuel options are better ...

I have thought about putting an exhaust on my car, but like I said earlier, this is my daily driver. I feel like I would get pretty tired of hearing a free flowing exhust on my daily commute. I usually reserve that sort of stuff for the weekend toy car.



In happier news, I finally squashed my max engine torque bug(s), and I am seeing 18.5-19psi all the way to redline now. Also seem to have all of the knock issues sorted out on 91, and I'm pretty happy with the car for what it is.

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The only mod I ever did to mine was an ebay short-ram intake. Pretty much only drive it in sub-freezing temps, so I'm not worried about IATs

Would you be kind enough share you HP Logger CH config file good sir?