402 LS2 Knock Retard - or lack thereof
 

Forgot one other question in my other thread, but figure it would be better to keep the topic separate anyways...

Knock retard - I have seen ZERO on my new motor. I have also heard zero, not that I want to. My maybe flawed searching doesn't pull up much of anything recent (bigger discussions are around 2 years old). After reading about various issues here regarding an LS2 in an LS1 vehicle, will the sensors work, will they not pick up knock, etc., what do I need to do?

Something I can do to make sure the sensors are working without risking damage? Although I haven't pushed it at all yet, for some reason I can't imagine that there just has never been any knock...

Thanks for any input.

Yes, the sensors are basically microphones which pickup acoustical transients. Therefore you can knock close to them with a hammer and they will detect it. Same is true with a banging header - pulls false timing.

I saw a few degrees of knock when my car stalled a few times during the initial tune with the 416. Since then I haven't seen any knock at all, even when increasing the timing 8 degrees at WOT and running a little over 13:1 AFR. I can't hear any knock, but the car is loud even through cats and a full exhaust :) I reduced the timing after that run, since it didn't give a noticeable gain.

My guess is the sensor map is completely wrong for having them in the side of the block, and they probably aren't picking up anything.

Yea - there is something screwy with mine... I need to get under it when I get back from Hong Kong and figure it out. My guess is there is something up with the harness considering I can nail the headers with a hammer and it still doesn't pick anything up...

Not 100% on the LS1 stuff but I can tell you on the trucks (4.8, 5.3, and 6.0) that they no longer recognize a thump or bang as did the early knock sensors. Today OE's have fine tuned these sensors and the sound frequency that they identify, detonation or spark knock will typically generate a frequency (sound wave) somewhere in the neighborhood of 5000-7000Hz. Most knock sensors (pezioleletric crystal) will only respond to that frequency of noise.

In the early stuff, they resond to any metallic knocking noise, ie rod knocks, exhaust manifold leaks, loose brackets, etc. They operate differently on many later model vehicles.