There is no switching over, so to speak. It uses an average of both, depending on the octane number. At 0, it is using 100% of the low map and at 255, it is using 100% of the high map. Halfway between, it will use the number halfway between the low and high map.

Eric

 

Ah ok that makes sense. except for one thing. Some mail in flashes make the high and low maps the same. And people say it still pulls timing. What does it pull the timing based on from there?

 

I just logged a pull after some jerkoff messed with my MBC, the octane number dropped to about 96, knock was as high as 36 and timing was pulled all the way down to -7 from what should have been 8 degrees advanced that's 15 degrees pulled. Somebody tell me what that low octane map does please.

 

Timing is still pulled. In the DSM ECU it was .35* (roughly 3 counts for 1* pulled) of timing pulled per 1 knock count. I haven't had the time to validate this on the Evo yet, but in most logs that I have seen, along with the respective timing maps, this seems to be the case for the Evo, too.

Eric

 

Wow, good info
I'm used to tuning with a utec where you shoot for no knock at all. However I would guess with the ecuflash you could tune for the application. Example:
Drag> some knock is ok since the race is over faster than the "octane" # would degrade enough to loose much power at the end.
Track> tune for as little knock as possible since you would be pushing the car for long periods of time therefore having a longer time frame for the "octane" # to degrade
Street> this I have to ask "how long does it take for the octane # to return to 255 if no knock is seen?

Question2? Does anyone see alot of knock on the 2 step? at the track I was getting up to 17 count knocks while on the 2 step at the light, yet 0's all the way down the track. I have it set at 6k rpm. I asume this will also degrade my octane # before even leaving the line. If so, maybe I should just launch old school.
thanks

 

Do your timing numbers match the cells they should? Timing is pulled and stays pulled for a while it has little to do with octane numbers.

 

You will get some knock using the launch control.. remember that feature was developed by mitsubishi as a protection to the drivetrain and not a driver aid..

 

You should still tune for no knock. Timing will still get pulled due to knock and you will lose power. The octane number is meant to be more of a long term correction, due to bad gas or some other conditions that may be causing prolonged knocking.

As long as you are under load with no knock, it returns very quickly. I don't know the exact algorithm, but good data has been posted around here.

If you ease into the two step rather than just smashing the throttle, you will avoid the knock counts. But, even so, your octane number should just about immediately go back to 255 once you leave the line under load. You can log it to test it out.


Eric

 

On the track whther drag or road course you should be using 100 octane. Assuming that the 100 octane gas is good quality gas and your AFR is set @ 11.2:1 and you are running a stock timing map, then you should not see any knock to speak of. IMO, the best cure for knock is higher octane gas assuming that your car is properly tuned.

 

LOL

Point taken, yet I'm sure its mostly used for racing don't you? One of the reasons I used the utec on the suby was for the LC and FF shifting. Unfortunatly without it, even using N20 to spool the boost drops real bad inbetween shiftswith a GT35r with 82 hotside. Do you know of any development in the works for a secondary rev limit for FF shifting on the ECUflash? I know guys who just bounce of the rev limit no lift shifting but......
\Thanks
Initially I was only asking to see if this is normal. My subie doesn't knock using the LC. Thanks again. I'm learning alot here and only past experience is with the utec on WRX/STI's. So I have alot to learn. Apreciate everyone's input.
peace

 

I don't know. I turned off everything except rpm, knock sum, octane, since I still don't have excel (I know, get it right) and all those # made for one cluttered log.

So I guess your saying that even if I get only a 1 count of knock, timing will be pulled?

 

I agree that increasinng octane on a basicly stock map will keep knock down. I saw this myself as I did use strait 100 at the drags. No knock running 25-27psi on the stock map with a all stock car (with MBC) except on the 2 step.
However, I have also learned that the best fuel to use is what you were tuned on due to differences in burn/combustion rates and other variables. But using strait 100 unleaded when you usually run a mix of 91/100 to make 94 for daily driving I would assume wouldn't change enough to change the burn varialbles and would prevent knock.
For example: Once I added about 30% 111octane leaded to my 100 when the suby was tuned on strait 100 unleaded. Thought it would add a little head room. the car ran like crap. I'm sure the lead had alot to do with it even diluted. On the other hand I couldn't get c-16 on one drag night and so tried the 111 leaded on the c-16 map and just turning the boost down about 2 psi, the car ran fine.
thanks for the support and input.
Peace

 

ok wait im still confused on how the maps switch over?

So even if both maps are the same timing will still be pulled?

Also with .97 the highest octane number is 100 right?

also a higher octane gas will not change your AFR will it?

Because the stoichiometric ratio is based only on mass of air to mass of fuel right?

or am i wrong?

 

bump

 

There are two types of protection offered by the ECU..

Think of the High and Low maps as repeatedly walking under something and hitting your head, over time you will duck a bit lower to clear the thing your hitting your head on.. once you no longer hit your head, you don't have to duck any more..

Think of the knock sum, and the corrections associated with this in the same way.. if you stand upright, the first time you hit your head, you quickly duck, and you will keep hitting your head and ducking until you learn to duck before you hit your head..

If you set your maps the same.. you will basically always bump your head, and rely on your reflexes to duck every time it happens..

One is a proactive response, that returns to normal if the condition is no longer there.. The other is a reactive response to an immediate danger..

Get it?