ECMlink Why am I knocking with such a low timing ?

[YanDsm]

Hi, I am tuning my car and I can't get rid of my knocks. I started with a 2g timing map and as far as I retard timing knocks seems to drop but I can't eliminate them. My car is now slow as hell with timing like that but still knocking. I'm running 9:1 piston with premium pump gas (91 octane here in Quebec) my boost is set to 15psi but creep to 20psi by redline on my 20g. Can premium gas be crap enough to cause these knocks or am I missing something in my tune??? thanks for your help.

 

[jdxnc]

I've found the quality of the gas in Quebec varies a lot, I've filled up and had zero knock, get gas at a different place and crazy knock. I also find it worse when the "winter gas" starts showing up.

You really don't have much knock in those logs, 0.7 at 3500rpm is not going to hurt anything. If you add more timing, does it get worse?

What spark plugs are you running?

 

[YanDsm]

yes if I add timing it get worse. I run BR7ES gapped at .028

Here is another log with more timing advance

 

[jdxnc]

I would probably try getting gas somewhere else. Is there a Petro Canada close that you can try some 94?

 

[YanDsm]

no, all gas station near my home only carry 91 octane even the Petro Canada.

 

[bastarddsm]

Put new plugs in it, and make a few pulls and look for peppering of the plugs.


Also try a gallon of xylene in a full tank an see if that helps

 

[YanDsm]

Can it break something to put xylene in my gas tank??

what will it do?? clean my fuel system or raise octane or both??

 

[Colt4G63 also]

Did you calibrate your wideband in open air recently? If not, I would start there, and then shoot for 10.7:1 AFR or slightly leaner. Maybe 11:1. The reason I say that is because any richer than 10.5:1 there's a good chance of getting rich knock.

 

[YanDsm]

yes my wideband was calibrate few weeks back and I'm shooting for 11:1 afr

So, if I put a gallon of xylene in my gas tank and my knocks went away then I'll know that it's because of the crappy gas. If it's the case what do you suggest?? Water/meth injection maybe?

 

[bastarddsm]

Keep running xylene/toulene
there is an artical in the tech section about it