Stealth Ag

iTrader: (7)

Well Im currently running a e-flash, and the tuner told me to "slowly up the boost until i see no more than 5 counts of knock and then back it off some"


The two logs i have here are

20psi in a 3rd through 4th run

23psi in a 2nd through 4th run


My question is, i get very high counts of knock (7) at only one part of the log.

Is this telling me i need to fatten that part of the map and ill be able to keep the boost there (because 90% shows little to no knock)?

Or is this telling me to back off and be happy with the 20psi?

Or would this be suspect for "phantom"

Thanks for anyone who takes the time to form an opinion.

l2r99gst

iTrader: (2)

I looked at your 23psi run and the first area of knock that you had looked like it was at the shift. This could be phantom or could be knock due to lift-off. You can search for posts from jcsbanks on this, but you may need to lower the timing in the lower load cells at these RPMs.

For the second area of knock (around 5 counts), that looks real. It appears to happen about 6500-6600 RPM or so. So, you either need to lower the timing by a degree or two, increase the AFR, or lower the boost in that area to get rid of that knock. I would suggest to lower the timing a tad if you want to run that boost. Otherwise, I would suggest to simply lower the boost by a psi or so.


Eric

Mellon Racing

iTrader: (38)

hard to say without wideband but you probably could fatten it up a touch and quell that knock and keep your timing/boost where it is. It's not so much knock that you couldn't handle it.

jcsbanks

I don't think it is lift off (yours is too late and does decrement the octane number, lift off det is earlier and doesn't decrement the octane number) or phantom knock.

From your logs I believe that you probably have an area of block timing, or if not quite a block there isn't enough taper of ignition timing with load. This way of tuning ignition maps results in low boost having conservative timing and high boost having excessive timing.

23 PSI should have less timing than 20 PSI but your ECU is I believe from the logs trying to run the same timing for both.

I've already bored or irritated many of you so I won't go on too much, but IMHO the knock sums you see should be randomly scattered across the RPM range, ideally below 4, and similar on a properly mapped car whether you run 20 or 23 PSI.

Stealth Ag

iTrader: (7)

well i guess this is where i get into the question that is covered 1000 times on here yet i dont understand fully...


What load cells to look at in order to pull some timing and stop the knock?


I guess then it gets into the whole 2bite load and fun stuff like that.


any suggestions welcomed.

jcsbanks

Depending on induction and how much boost taper, 260 mid, 230 top.

Can you post up the timing at say 5000 or 5500 RPM at 200+ load please? Are they all the same or does it taper as load increases?

l2r99gst

iTrader: (2)

You don't have to get into any of the 2-byte load stuff. You can easily see what load cells you're hitting by looking at your RPM and timing. In my experience, knock will pull about 1 degree of timing for every 3 knock counts. So, if you have a knock count of 6 at 6500 RPM and your logged timing is 10, go look for the cell at 6500 RPM that says 12 in your high octane timing map. That is the cell that you are in.


Eric

C6C6CH3vo

iTrader: (9)

That one log has two occurances of knock.

The first was between a shift and very likely noise because the throttle indicated mostly open, RPM was transitioning from 6400 to 5800, and moreover the load calc transitioned from 16 to 129%.

The second occurance up closer to redline is very difficult to tell if true ping or not because it started under full throttle, but shows the same count pattern as the prior which makes me think otherwise as well.

Do some more logs