Spinmonster

I first tuned the car's LTFT's and got hem to be non-positive near zero. I then brought the car back to 12.5: using a wideband w/collector mounted bung. Some problems while tuning timing...

When I finished with the tuning I kept getting KR on hard launches and shifts. The knock retard is at 1800-2400rpms and not floored. Even with a sudden hard rev at idle and standing still it was there....small but there. I thought to myself is it the compression at 11.4:1 too high? I run the same cam and CR in my C5.

I added race gas - 100 octane...pulled silly amounts of timing at those rpm's and still it was there. It isnt showing as a misfire and I cant see how it is actually an ignition issue. I had the stock timing table and there are three things I can think of. Anyone with any input that is willing to post please do so.

1-The knock sensors are hearing clutch chatter.
2-A quirk with the sensitivity of the HPtuners/LS2 knock sensors
3-I missed something in TQ management

When I floor the car in 3rd or 4th I go from 2000 or so to redline with no KR. Got me stumped.The tune is preliminary just to get the car livable with my list of mods growing. I just got the fuel trends and A/F in line. I will wait for further tuning when HPtuners finally gets the software to us single license users and my mods are done. I still have some head work and small things here and there to do.

MODS:
224/230 114lsa dot to dot.
Ported heads 65cc
.04 cometics
UD pulley
FAST manifold
Air cleaner
Kooks headers

Car pulls awesome and is faster than my C5 now with nearley identicle mods and CR. If I didnt see the data-log I would say it was an awesoem tune. Keep in mind that this isn't at some high rpm under heavy load where cylinder pressures are crazy, just sudden revs or idle to get into gear or play at a light.


Any ideas?

RedHardSupra

iTrader: (1)

i had a very similar situation, but it wasn't much clutch, i think it's the stiff suspension making noises setting off knock sensors. i spent 2 months and countless gallons of 100octane chasing it down, and i gave up. i desensitized the sensors a bit, and it did help, but it's still there at some silly moments (aka hitting bumps and potholes in the road). as long as you don't knock at wot, you should be good. don't panic, and don't start pulling timing just because it knocks, it won't help, if anything it might make it drive like *** (stumbling/bucking) and these low rpms (which is like 80% of driving).

Spinmonster

I don't think its suspension since I get it most of the time at idle with the car not moving when I suddenly mash the throttle hard under no load. It actually does it only 10% as often in gear and hitting the throttle in the same fashion; ie... it does it one in ten times while moving.

ringram

Check out your burst knock values.
Basically a protection for the engine, pulls timing in anticipation of knock based on ariflow delta's.
You might want to do some testing in that area.