Thanks to the feedback and suggestions on the board I put 5 gallons of Unocal
100 unleaded in a tank of the 91 octane crap that we have in CA. The result was
0 knock retard. I guess it was real knock and goes to show that the LT4 knock
module was doing it's job. I very happy to have discovered this prior to buying
a set of composite LT4 covers. I like my stock steel covers anyway.

 

Glad I could help out. I've been battling KR for a LONG time...

 

I don't think the composite covers would have helped anyway. The covers muffle the audible noise a bit, but the knock sensor "feels" for the frequency of the noise.

 

It was a great suggestion. I had put 3 gallons of 100 in with the previous tank
but did one fill at the 3/8 level so it probably diluted way down. I was hoping that
the octane might still be around 92, but I'm sure it was not. The 5/15 ratio did the
trick. I definately need to put some good stuff in the tank when I go to the dyno.
Thanks again for the suggestion.

 

Rob,

I agree and also had some doubts as to the sound reduction the LT4 covers would
provide. The LT4 covers reduce what we hear from above but would not do much
for internal sound. As you said, what the sensor "feels". They must do something
because others have posted on this same topic with positive results.

 

That is nice to hear about a successful resolution to a frustrating problem. Also, that is another reason I am glad I live in an area where 93 octane is readily available.