2015 ZL1 knock? Conclusion @ 4/27/15

[Stephen12ZL1]

Originally Posted by Nor Cal ZL1

I have had cracked compression ring landings without any smoke, but a load of blow-by in the crankcase as the only symptom. One piston had cracked the upper compression landings. A basic compression test confirmed this, but the car ran fine otherwise. Oil ring landing was fine. This was not on an LSA, but a Hemi Italian motor.

Not saying cracked ring landings would cause any knock. OP asked if there was any damage possible from knocking and I suggested a leak down test to confirm there is damage or not. I do not think the OP has any engine damage, but a quick check of health is not a bad idea.

My ring landings cracked from a bad mechanical advance curve total advance, as verified on a distributor machine (remember those?). Basically I had to rebuild the rotating assy because I was not aware that the total advance stop was not quite right. Ah the old days.

Oh yeah, the distributor machine...I have used one of those antiques. They are quite amazing. Dialing in a dual point distributor was tough without one.

[JB12ZL1]

Do the 2015 have the solid isolator? If not it could be the spring loaded isolator maybe making that noise.

[angryBits]

Originally Posted by JB12ZL1

Do the 2015 have the solid isolator? If not it could be the spring loaded isolator maybe making that noise.

Fortunately the 2014 and 2015's come stock with the solid isolator.

[shinzon]

Originally Posted by angryBits

Fortunately the 2014 and 2015's come stock with the solid isolator.

actually, the mid year build or later 2014 and all 15s have the SI, early build 2014s have the spring.

[ZO6 Bryan]

Some interesting data. Don't trust what it says on the pump. Your local stations will vary.

1st pic was some ethanol free 100% gasoline 93 octane from a local Exxon(cost about 80 cents more per gallon than usual, but I wanted to try it)
Verdict - Worthless

2nd pic is 93 octane E10 from a local Mapco
Also Worthless

3rd pic is 93 octane E10 from a different Exxon. Knock retard completely gone.

All these scans are from just the last week. I know where I am going to purchase gas from now on.
Also use a lot of Shell 93 and it was good too, because that was what I was using when I developed the current tune in my car.

Discuss.

[Stephen12ZL1]

top tier fuel rules!

[DrkPhx]

ZO6 Bryan makes a good point about the difference in gas quality between local stations. It can make a difference. I run BP 93 in mine and it's very consistent.

[Six.Two SC]

Originally Posted by ZO6 Bryan

Some interesting data. Don't trust what it says on the pump. Your local stations will vary.

1st pic was some ethanol free 100% gasoline 93 octane from a local Exxon(cost about 80 cents more per gallon than usual, but I wanted to try it)
Verdict - Worthless

2nd pic is 93 octane E10 from a local Mapco
Also Worthless

3rd pic is 93 octane E10 from a different Exxon. Knock retard completely gone.

All these scans are from just the last week. I know where I am going to purchase gas from now on.
Also use a lot of Shell 93 and it was good too, because that was what I was using when I developed the current tune in my car.

Discuss.

Wow, I woulda thought the 93 ethanol free Exxon wouldn't do as good as the 93 E10 Exxon.



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[angryBits]

Originally Posted by white ZL1

Can I get you to use the attached config file and get 10-15 minutes of data?
Normal driving, and then if you can roll into it and go WOT in 2nd or 3rd gear (whatever is safer or wherever you can get usable data), I'd love to take a look at it.

What happened to the attachment? I am sitting in my car about to do the 15 minute drive but no attachment... We'll just have to try again next weekend :(

[angryBits]

Originally Posted by ZO6 Bryan

Some interesting data. Don't trust what it says on the pump. Your local stations will vary.

1st pic was some ethanol free 100% gasoline 93 octane from a local Exxon(cost about 80 cents more per gallon than usual, but I wanted to try it)
Verdict - Worthless

2nd pic is 93 octane E10 from a local Mapco
Also Worthless

3rd pic is 93 octane E10 from a different Exxon. Knock retard completely gone.

All these scans are from just the last week. I know where I am going to purchase gas from now on.
Also use a lot of Shell 93 and it was good too, because that was what I was using when I developed the current tune in my car.

Discuss.

Good to have data to backup the theory. Not all gas is the same.

These cars are sensitive -- find good gas or get a tune for the crappy gas in your area. I think we can put this thread to rest.

Thanks Bryan

[NicKey]

In our area most of the 93 has Ethanol.

Gas does vary and can have a substantial effect on the dyno results.

We have found BP to have the best results.

[Six.Two SC]

Originally Posted by NicKey

In our area most of the 93 has Ethanol.

Gas does vary and can have a substantial effect on the dyno results.

We have found BP to have the best results.

BP is the same as ARCO, IIRC. ARCO is shit gas here in CA.


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[angryBits]

Most gas is shit gas here in CA and I plan to get tuned on the shittiest gas I can find, that way it's all good after that.

[Six.Two SC]

Originally Posted by angryBits

Most gas is shit gas here in CA and I plan to get tuned on the shittiest gas I can find, that way it's all good after that.

LOLOLOL! You're right, sadly.