Adjusting for knock

[dtru1222]

I have read a couple of tips and I was wondering if anyone else had some.

I am seeing consistant knock in the 3500 and 5k rpm range and I have read that first you want to reduce timing instead of adding fuel. Is this true?

Also read that you want to log open loop AFR. What am I looking for and what are the exact PID's?

[mikel]

No, add fuel first...

[dtru1222]

I did, and it actually increased the knock. Havent tried pulling timing yet.

[iRace559]

Adding fuel wouldn't increase knock. What conditions are you logging under? and is the car fully warmed up before logging?

I'm getting consistent knock of 3 degrees in the mid rpm range and 5 degrees in the high rpm range under WOT. I'm going to try adding +5% fuel to the midrange and 10% to the high rpm range to try and combat the knock.

[Mike_Levy]

If adding fuel increased the knock than the gas is bad. Its not high enough octane or is watered down. Try a different station.

Also, this is the third or fourth time I've heard somebody repeat that they were told to pull timing and not add gas. Who is giving out that incorrect information? Gotta be some schmuck on the Ram boards, because I know Mike frequents the LX forums. They need to be smacked around.

[dtru1222]

Adding fuel wouldn't increase knock. What conditions are you logging under? and is the car fully warmed up before logging?

I'm getting consistent knock of 3 degrees in the mid rpm range and 5 degrees in the high rpm range under WOT. I'm going to try adding +5% fuel to the midrange and 10% to the high rpm range to try and combat the knock.

Thats exactly what I was seeing and did. 3 ST in the 3500 range and 5 in the 5200 range. Added 5% to both and the peak number went up by 1 in the 5K range and it was more frequent throughout each run.

Fully warmed, nearly exact conditions as the previous runs as I logged then adjusted then logged again.

I live in the DFW area and Chevron is the best gas I have found. Everything else gives much more knock.

[sharkcohen]

Which tune are you running and what octane? If you can, try running the 91 tune with 93 octane.

[dtru1222]

Which tune are you running and what octane? If you can, try running the 91 tune with 93 octane.

93 with 93.

I ran the 91 and didnt see any knock so I decided to try to run the 93 and adjust out the knock.

[nugzo]

For me the 91 tune with 93 octane ran much better, felt better. Extremely pleased with that setup.