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C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
Current timing with a point of advance pulled in some spots due to the KR in the log above:
It looks like the KR coincides mostly with throttle events with the exception of where you have the cursor. Can you rock the engine and see if anything hits once torque is applied and taken away from the drive train? Thinking motor mounts, intake bolt, exhaust or something potentially hitting or loose somewhere.
It looks like the KR coincides mostly with throttle events with the exception of where you have the cursor. Can you rock the engine and see if anything hits once torque is applied and taken away from the drive train? Thinking motor mounts, intake bolt, exhaust or something potentially hitting or loose somewhere.
All those events register in the total total kr channel, not the kr channel. My understanding is that is just burst/predictive knock. When I get actual knock, it registers in the kr channel and the total kr channel. If you look at the channels you'll see that I'm logging both parameters and where the cursor is, it's registering kr and total kr, so I know that's knock. In the other blips, it just registers total kr, but kr is zero.
Bit of an update. Installed the TR7IX, oil catch can cleaned out, 65f outside and did some logs. Still getting knock so unfortunately the plugs did not help nor did moving the oil line from the header (well...other than not starting a fire!).
Looks like nature of the beast is to take lower timing. I know these are ricer calculations but I am hitting 1.10g/cyl peak tq ~495wtq, 1.02g/cyl ~460wtq at 6800 which puts me around 595whp. Injectors are at 92% on E10 at 7k. Maf hits 60lb/hr.
Thing that bothers me is I can do 3 identical pulls and KR is different. Most of the time there is knock at 4200 rpm (right when the poweband starts to climb hard), and 6000rpm (that weird area between tq falling off and cyl head wanting to keep going).
Knowing I am probably riding along max spark for my setup I reduced those areas more and then took an extra degree out of the whole map for good measure.
Technically speaking, +- 4deg around MBT is ~1% loss both ways.
I will leave this open for discussion but after how much KR do you consider safe before pulling back timing? 0.5? 1? 2?
I am now running with no KR...but it is not the most agressive timing map around.
Thank you all!
Well...that's disappointing. I'm wondering if maybe your heads are actually (unknowingly) milled a bit more than .030?
Originally Posted by Apocolipse
Good point on the ZR1. They also run richer which would help cool the chambers down more which may be how they get away with it?
I am running 94 e10 at 0.82 lambda as well (want to make use of that flame speed).
How much lower are you? I get the most KR activity at 4000, 5000, and 58-6000.
ZR1's also run a tighter gap on the plugs as well.
Shame on me for not CC-ing them when I swapped...I know...I regret it.
They more than likely are as they visited AHP twice. First time was a cleanup (usually 5-10 thou) then sent back for a refresh and milled 30. So 2 things could have happened- 1) mill operator subtracted the initial 10 thou and cut 20 or 2) gav'er a good full 30 cut.
Worst case I am at 40 thou (well worst case is 60 if they did 30 twice lol) which puts me in the upper 11.8-12:1 region. THAT would make sense why I have to pull "so much"
If I add timing I see more kr which to me means it is real - and vice versa.
Stock timing is 22deg -> 24 deg after 5600rpm. I'll take 2 deg off the top for the mill and dynamic compression of the K501. Puts me at 20->22. Then 4k to 7k I am making a LOT more power than stock but would that cylinder pressure result in a reduction of 4 deg...there lies the question friends!
Looking at a g/cyl timing map I am an easy 5 cells higher than stock...and timing typically has 1deg drop per 0.04g...
Originally Posted by MTPZ06
Well...that's disappointing. I'm wondering if maybe your heads are actually (unknowingly) milled a bit more than .030?
ZR1's also run a tighter gap on the plugs as well.
Looking at a g/cyl timing map I am an easy 5 cells higher than stock...and timing typically has 1deg drop per 0.04g...
I think the g/cyl is somewhat subjective to the tune AFR. Here is a torque map from my car after I got rid of an oil ingestion problem that was knocking my timing down 3-5°:
Just for comparisons here is a recent log from the track. KR started at 5200 rpm. Looks like 20° might be the limit. Mods are MF103 and ARH headers, AHP heads with just a cleanup pass.
Have you touched your PE timing adders or timing map at all?
With GM using their "93" fuel - they command 22. Real life looks more like 20.
Shave heads towards 11.8-12:1 lets pull 2 deg out for good measure - now thats 18.
Add more power and I guess pulling 2 deg out for the extra cyl pressure is not out of the question?
I do see people running around with 22+ deg timing (my friend for example) with a BTR4 cam. He however numbed his knock sensors...tempted to tell him to go back to factory cal and see what happens....may be a good experiment.
Originally Posted by psmith23
Just for comparisons here is a recent log from the track. KR started at 5200 rpm. Looks like 20° might be the limit. Mods are MF103 and ARH headers, AHP heads with just a cleanup pass.
PE timing adders are stock. I took a degree out of the timing map around the peak torque and higher rpm area so far. Using the car for HPDE events so might take another degree out just to be safe.
That makes sense to me - if it is close to MBT you will not lose much power at all.
I see the computer was commanding 0.79lambda - did you lean it much from factory? Trying to narrow down any differences so we can try to compare apples to at least some varient of an apple lol
09-26-2018, 08:05 PM
