chetrickerman

iTrader: (7)

All evo's I tune, I run the low octane timing map the same as the high octane. Reason is, because the ECU uses an algorithm when reducing timing when knock occurs, in which it takes into account the difference between the high oct and low oct map at that load and rpm, then applies that value into the knock algorithm.

So say just for example, you have 4* of difference between the 2 maps, and you get 5 counts of knock. The ECU may pull 2 or 3 degrees because of the .33* it drops per knock count, as well as overcompensating because the 4* difference between the maps. Now dropping that 3 degrees may cause more knock, and I goes into a kind of downward spiral.

Now if you don't have any difference between the 2 maps, the ECU will still pull 1* for every 3 knock counts, but it won't overcompensate or round up. If you get 5 counts, the ECU may only pull 1*, then it will check to see if that eliminated the knock (which most times it does), then bring the timing back up that 1* the next cycle.

Hopefull this all makes sense.

I use this with great results.

10isace

iTrader: (12)

I learn something new everyday I just thought it pulled 1* for every 3 counts of knock. I'll have to change my low octane maps.

killerpenguin21

iTrader: (20)

i understand what your saying, but i also think its a horrible idea to be running the low octane and high octane maps as the same thing...your eliminating a factory provided safety measure.

im not worried about how much timing its pulling out, im worried about the fact that its knocking to begin with.

Ian0611

iTrader: (41)

I think what he's saying is that by running different low and hi-octane maps, it's causing more knock because the ECU is trying to interpolate the two and it's causing timing to jump all over the place, which in turn is causing more knock. Personally, I'm not 100% certain that that's how the ECU operates to control knock but it does make some sense. What a lot of tuners do (and what I do personally) is copy the tuned, Hi-octane map over to the lo-octane map and then just drop the entire map by 2 or 3 degrees. It's possible, that if you're still using the stock lo-octane map, you're ECU is going wacko trying to interpolate between the two maps when it sees knock because they are so different, thus causing more knock.

GrumpyIX

Yep, that makes sense. I have done the same with mine, same map but -3* where it matters. I works fine. The other thing you could be checking to see if it is interpolation is to log Mut 33 with the same formula as your timing advance formula, x -20. This is the uncorrected timing advance that the ECU sees BEFORE it makes any alterations to it, so basically what it picks up from your map. This will tell you clearly whether it is a map problem or an interpolation issue.

killerpenguin21

iTrader: (20)

If that's the case, then yes that I agree with haha. But, that still wouldn't explain my random knock....

chetrickerman

iTrader: (7)

That is exactly what I meant.

It is more so a problem on the 10's, but I have seen it with 8's & 9's as well.

10isace

iTrader: (12)

I experience very similar knock. I also have very similar mods, except waiting to change stock FMIC with a 4" soon.

From various threads, I learned (I think from ER), that you have to wait a few minutes between runs. I would do a run on a flat road, pull over, turn around and do another run. There would be about 20 seconds between runs. I would get high counts of knock on the 2nd and 3rd run. Since then I do a run and drive a minute, turn around, get to the same spot and do another run, so now I have at least 2 minutes between runs. I was hoping with the bigger FMIC it would solve this problem, but you have one and you're getting knock. Try it out and see if cooling down between runs helps.

chetrickerman

iTrader: (7)

A bigger more efficient FMIC should help with this. There is 10-30 seconds between runs when I tune, that way it replicates on a small scale what the car would see at a track.

10isace

iTrader: (12)

Thanks for the advice. I looked at my low octane timing maps and they were not even close to my high octane. I think I've only been changing the fuel low octane. A little OT, but do you richen the low octane fuel map?

killerpenguin21

iTrader: (20)

while i would normally do this, lately i have been trying to compress the time between runs (see below)

i have the ets 3.5, it has been good BUT i have seen better depending on the use (mainly the garret 3.8 core). that being said the past two tuning sessions the air temp was below 50 degrees, the first night it was actually about 40.

yesterday at the track i was the car was seeing above 5k in 4th for 90% of the track. the car needs to be tuned to take that heat. which also sucks because i definitely have no place i can tune 4th gear.

211Ratsbud

iTrader: (1)

My low oct map is copy minus 4

killerpenguin21

iTrader: (20)

Entire map? Or just in boost areas?

211Ratsbud

iTrader: (1)

All boost. 100 load to my max load all rpms.

chetrickerman

iTrader: (7)

yes, from 120 load on, I reduce that whole part of the map by .5 AFR