His '98 Z-28 has 3* of KR and he can't figure it out, how much ET will this cost him? the car's only mods are: Lid,!FRA,Macs w/OR pipe & a cutout. I have rode in the car and there is no audible detonation whatsoever. is 3* going to hurt his times?

 

Pulling timing will always hurt to some degree. Put a fuel pressure gauge on it Jay and see what it's at. My stock pump is weak (45psi @ WOT) and is causing KR at the top of 2nd and through 3rd. I'm putting a Walbro 340 in this weekend.

 

</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Chris99WS6PWTMET:
<strong>Pulling timing will always hurt to some degree. Put a fuel pressure gauge on it Jay and see what it's at. My stock pump is weak (45psi @ WOT) and is causing KR at the top of 2nd and through 3rd. I'm putting a Walbro 340 in this weekend.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thanks Chris! I'll tell him.
I ended up installing a 160* to go along with the HPP3 that I got from you, it worked and I had 0 KR this summer!

Take care, Jay

<small>[ November 20, 2002, 08:53 PM: Message edited by: LS1JAY ]</small>

 

If you go to the other LS1 site <img border="0" title="" alt="[Sad]" src="gr_sad.gif" /> you'll see that there is a private club formed for all owners of '98 LS1's with 3* of KR. My 98 gets full timing at WOT but it still shows 3* of KR, nobody has figured it out yet....

 

Wow, glad to know I'm not alone on this one. My 98 also shows 3-4 deg. of KR in upper RPMs

 

I'm finding that my pinging problems are most likely due to oil getting into the throttle body from the PCV system. I have audible pinging at the top of second gear. I have not ATAP'd it yet so I don't know how much KR I have, but I know I am pinging. We pulled the induction tract off and felt behind the blade of the throttle body and it's covered with oil. Oil in the engine can leave carbon deposits on your pistons and also lower the octane of your gasoline...both causing detonation. The PVC crap is a know problem with LS1's but GM wont fix the problem under warranty. This is the mod that I'm going to try to fix the problem: http://www.fbody.com/members/stevenm...ML/pcv_mod.htm
It seems that some people have had great luck with it...both eliminating their pinging and oil consumption problems. I have found that using the LS1 truck PCV valve is less likely to work. I've done some research on the issue and I can honestly say that any LS1 that I buy in the future will have this PCV problem address whether it's malfuctioning at the time or not. This problem can easily arise at any time and if the detonation is slight enough that the KR will take care of it you would never know what was going on. Other causes of your KR could include bad fuel pump, clogged fuel filter, increased engine temp, or bad plugs. Good luck...