Desensitizing the knock sensor
03-18-2007, 04:13 PM
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Desensitizing the knock sensor How do you Desensitize the knock sensor on LT1-Edit? I was told you can make it like a LT4 knock sensor to not get false knock. Im getting false knock at WOT from my valvetrain, RRs,hardened pushrods, ect.
Thanks
Jim
Thanks
Jim
03-19-2007, 07:19 AM
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Increase the decay retard table and decrease the attack table. Do them by a percentage at a time. I think i did like 15% desensitizing to get rid of my false knock.
05-15-2007, 02:09 PM
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There are two of those tables that can help you alter the sensitivity of the sensor.
1.) Knock Fast Attack Rate (Higher number means a more aggressive KR)
2.) Knock Recovery Rate (Higher number means the faster the KR will be removed)
1.) So take the table on your very left in the picture you have hosted, try lowering a little bit at a time. Normally it shouldn't take more than 15% - 20% to remove the false knock. Use caution when doing this, and go in small steps. You do not want to tune the computer to ignore real knock so it satisfies your logging software into showing 0. This is to help with actually avoiding false knock, not cheating a logging program.
2.) For the second part, this wont actually desensitize the sensor, but help you bring in your timing if you do get false knock. This table, which is the third one from the left in your picture, will determine the percentage of timing to be put back in, per 8 cam pulses. So in turn, raising this number will put the retarded timing back into the motor more aggressively. Use caution on this one, if it is real knock, you don't want to be adding timing while it is still pinging.
Thats odd that it is causing knock under WOT, normally valve train noise doesn't cause issues under WOT, but play around with it and see.
It wouldn't hurt to check out some other things, I'm assuming you haven't already, excuse me if I am mistaken. But you may want to eliminate the possibility of real knock, by trying some race gas, and logging, playing with the fuel and timing, etc.
Hope all this helps.
1.) Knock Fast Attack Rate (Higher number means a more aggressive KR)
2.) Knock Recovery Rate (Higher number means the faster the KR will be removed)
1.) So take the table on your very left in the picture you have hosted, try lowering a little bit at a time. Normally it shouldn't take more than 15% - 20% to remove the false knock. Use caution when doing this, and go in small steps. You do not want to tune the computer to ignore real knock so it satisfies your logging software into showing 0. This is to help with actually avoiding false knock, not cheating a logging program.
2.) For the second part, this wont actually desensitize the sensor, but help you bring in your timing if you do get false knock. This table, which is the third one from the left in your picture, will determine the percentage of timing to be put back in, per 8 cam pulses. So in turn, raising this number will put the retarded timing back into the motor more aggressively. Use caution on this one, if it is real knock, you don't want to be adding timing while it is still pinging.
Thats odd that it is causing knock under WOT, normally valve train noise doesn't cause issues under WOT, but play around with it and see.
It wouldn't hurt to check out some other things, I'm assuming you haven't already, excuse me if I am mistaken. But you may want to eliminate the possibility of real knock, by trying some race gas, and logging, playing with the fuel and timing, etc.
Hope all this helps.
Last edited by Kryckter; 05-15-2007 at 02:16 PM.
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05-15-2007, 08:28 PM
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Originally Posted by Kryckter
It wouldn't hurt to check out some other things, I'm assuming you haven't already, excuse me if I am mistaken. But you may want to eliminate the possibility of real knock, by trying some race gas, and logging, playing with the fuel and timing, etc.
Hope all this helps.
Hope all this helps.
05-19-2007, 07:08 PM
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so i installed an LT4 knock module and set all my low octane yables to zero. drove the car around and no knock at WOT all the way up to 6350. the problem appears to be 90% fixed since i did see knock twice at low rpms driving at like 25 but it left pretty fast. i going to keep logging and take it to the track to see what happens.
05-20-2007, 04:05 PM
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unfortunately datalogged the car during normal driving and knock all over the place. guess the lt4 km didnt fix anything. i'll have to go under the car now and inspect everything and then do the race gas. this is starting to suck.
