How much knock?

[tiggerfan]

I have a tiny bit of KR between 2100 and 2200 rpm. Its about 1% of the cells at those rpms. I'm debating if its worth adding a hair to the 2000 rpm PE table, or if this isn't worth dealing with. The Fuel Trims look good and I don't have knock anywhere else in my table.

[WS6_GreeN]

Any knock is bad knock IMO. If you can fairly easily eliminate it and you dont think its false, I'd go for it.

[TT_Vert]

rather then add PE why not reduce timing in the given RPM vs. g/cyl?

Dave

[WCP]

I would say pull 1-2* of timing right befoe it starts to show knock

[tuneman]

to night we dyno tuned my bosses ls1, there is no mods' done to this car and is 100% stock (at the moment).
During the dyno tuning we had 0 on the KR value. We had advance up to 29 degrees at WOT using 98 octane fuel.
During the tuning we orginally where trying to get a nice flat AFR reading about 12:1 (might lean it out a little later)
Anyway back to MR knock, we did not have any knocks, how ever I did notice that the motor sounded tinny at higher revs, we did think of pinging but after turning of the dynos cooling fan we both said it just sounds like a tinny motor, both of us are mechanics'.

What I found after getting a noticable increase on the dyno and doing a road run, that the KR value increased under full load just before gear change !! and then retarded the timing during the change 5000 rpm was the point.
The retard happened as the WOT was made and a downshift happened (BTW this a AUTO) there was an increase in engine noise then it went away this happened for all gear changes until the traffic got in front of us.

I have noticed on some gen 3s' is australia that lots are noisey and lots are replaced due to this.

I also reprogram the early gm powered machines and have found that cam/valve train noise increases at higher RPM, and have to raise the noise threshold to mask out the engine noise, I dont recommend this but it is very strange that the gear change would do it.
???

[Chris@HPTuners]

29 degrees is a lot, most stockies will only take 24'ish on 98. Knock sensors are not reliable especially at high RPM. I see many engines that are pinging like crazy but the knock sensor is flatlining (and also the opposite is common).

when an LS1 pings at higher RPM its not a very nice sound. a distinctive "crack".

personally, i would pull the timing back.

As for the timing reduced during the shift, thats the effect of the upshift torque reduction.

[tuneman]

thanks for the reply
I will knock it back some
the noise is a funny noise this motor is making, when we did the road test I could not hear any noise that sounded like pinging, it was a realy strange thing as there is no levels on the KR during any dyno tuning maybe due to only tuning in 2nd gear (this is the way that we do all tuning) this reduces the top end speed and is a lot safer than doing 200km/h plus.
the noise is only happening on road, got me stumped.

Today I was playing around with my VS Vsik applied the standard tuning done to most ls1 poweried cars.
trimed up the wot pe values from 11:1 to 12.6:1
then got stuck in to spark timing, well I found on these motors (3.8 ecotec) thetiming values that gm have in there is almost spot on for 91 octane, yes I was trying out for power on 91, yes I will be normally using 98 it was just I was in a area that did not have 98, these ecus dont have a low and high octane tables, pitty.

I have knock under extream high reving loads, I have knocked it back 2 degrees at the starting points, I will wait until tomorrow to hear the difference. ;D

We also got right in to Lean Cruise I can not wait to do another long cruise if you play with this do it with extream caution, we were supprised to see tourque figures increase to a point by leaning it out, funny thing ???

[tech]

24* is stockish?

21 24 29 32 34 38 41 41 43 43 42 42 42 41 41 41 41 40 40 40 40 40 40 40 40
21 24 29 32 34 38 41 41 43 43 42 42 42 41 41 41 41 40 40 40 40 40 40 40 40
21 24 29 32 34 38 41 41 43 43 42 42 42 41 41 41 41 40 40 40 40 40 40 40 40
21 24 29 32 34 38 38 38 40 40 40 40 40 41 41 41 41 40 40 40 40 40 40 40 40
19 24 30 33 34 36 37 38 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40 40
22 25 27 30 33 33 35 36 36 36 35 37 38 38 35 35 35 35 35 36 36 36 36 36 36
26 27 26 29 30 33 33 34 35 34 33 34 35 37 33 33 33 33 35 35 35 35 35 35 35
24 26 24 28 29 29 30 30 31 31 34 34 34 36 32 32 32 32 33 33 33 33 33 33 33
22 24 23 26 28 28 27 28 29 30 34 34 34 36 32 32 32 32 31 31 31 31 31 31 31
20 22 19 24 25 26 26 27 28 25 29 29 33 35 31 31 31 31 31 31 31 31 31 31 31
16 18 13 17 21 22 21 24 25 22 28 29 33 35 30 28 28 29 31 31 31 31 31 31 31
15 17 11 15 18 18 18 21 23 20 26 27 32 34 27 27 27 28 31 31 31 31 31 31 31
13 15 8 12 15 15 15 19 22 19 25 26 32 33 26 27 27 28 31 31 31 31 31 31 31
12 15 7 10 14 14 14 17 21 18 24 25 31 32 25 28 28 29 31 30 30 30 30 30 30
11 14 6 9 13 13 14 15 17 18 24 24 30 31 25 28 28 29 30 30 30 30 30 30 30
11 13 6 9 13 13 13 15 17 18 24 24 29 30 25 27 27 28 28 28 28 28 28 28 28
10 13 6 9 13 13 13 15 17 18 24 24 29 30 23 24 25 28 28 28 28 28 28 28 28
10 13 6 9 13 13 13 15 17 18 24 24 29 30 23 24 25 28 28 28 28 28 28 28 28
9 13 6 9 13 13 13 15 17 18 24 24 29 30 23 24 24 27 28 28 28 28 28 28 28
9 12 6 9 13 13 13 15 17 18 24 24 29 30 23 24 24 27 28 28 28 28 28 28 28
9 12 6 9 13 13 13 15 17 18 24 24 29 30 23 24 24 27 28 28 28 28 28 28 28
9 12 6 9 13 13 13 15 17 18 24 24 29 30 23 24 24 27 28 28 28 28 28 28 28
9 11 6 9 13 13 13 15 17 18 24 24 29 30 23 24 24 27 28 28 28 28 28 28 28
9 11 6 9 13 13 13 15 17 18 24 24 29 30 23 24 24 27 28 28 28 28 28 28 28
-4 2 6 9 13 13 13 15 17 18 24 24 29 30 23 24 24 27 28 28 28 28 28 28 28
-4 2 6 9 13 13 13 15 17 18 24 24 29 30 23 24 24 27 28 28 28 28 28 28 28
-4 2 6 9 13 13 13 15 17 18 24 24 29 30 23 24 24 27 28 28 28 28 28 28 28
-4 2 6 9 13 13 13 15 17 18 24 24 29 30 23 24 24 27 28 28 28 28 28 28 28
-4 2 6 9 13 13 13 15 17 18 24 24 29 30 23 24 24 27 28 28 28 28 28 28 28


That's my stock table from a 00 Camaro.