I'm just wondering if this is a possibility or not, considering how loud the sound of 900-1000psi air suddenly escaping to atmosphere is.

Is it possible that the knock sensor could "hear" it and register false knock?

I am getting knock with a 125-shot from my NX kit. I get no knock with N/A runs. I am using 57/33 pills.

Sometimes it takes a second after engaging to register, sometimes it's right as the spray hits.

My O2 sensor values look OK too, so I'm not running lean. They are a littler richer than my N/A runs: high 800s, low 900s.

Any ideas? I am not pulling any timing, and am thinking I shouldn't have to, because I am almost certain even NX says it's not necessary with their kit up to a 150-shot. Isn't that true?

Plugs are Autolite 104s gapped at .040". Accel 300+ ignition with Accel coil and Extreme 9000 wires.

Thoughts?

 

I have never seen a nitrous leak cause false knock,it would have to rattle the solenoid around violently near the knock sensor to even be considered.What do the plugs look like right after the run,if it's ONLY when the nitrous is on,im doubting it's false.

Irregardless what NX says,i ALWAYS pull some timing. I spray a 150 hit,pull 2° through my MSD,and my exhuast hits the floor so i have the knock sensor limited to 2°.

 

My car does the same exact thing. I asked around last summer for help and no one seemed to know what it might be. If you find something PLEASE e-mail me . Mine runs fine (NO KR) N/A but pulls every bit of timing the table will allow. I even retarded the tables 5* and it still pulled all it could.
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Did this happen right when you started to spray or after that? Does it happen all the time now even while not spraying?

 

My ntrous is set to come on at 3000rpm. The knock starts about 3500-4000. It has no knock or KR off the spray.
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Its difficult to desensitize the knock sensor. Even with laptop tuning. Alot of LS1 guys that run nitrous are putting resistors inline with the knock sensor. It will keep the computer from immediately pulling your timing out, and still offers the insurance that if you do get a real knock situation, the computer will pull timing. It just isnt quite as sensitive, so false knock will not effect the timing curve. Do some searches for knock sensor resistor install. There should be a few instructional webpages.

 

Have either of you tried running some higher octane(100+) fuel to see if the knock improves or goes away.

How do your O2 readings look at wot.....should be upper 800s to lower 900s.

 

I only run 100 octane. Heads and Cam car with TNT nitrous. Its required. My Lt's are up in the air. Have to get to the dyno to test the new fuel pump, and injectors.

 

Yes to the 100 octane and the O2 readings are in the upper 900's
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