So this is my car now.
I was running the stock EVO IX map with a test pipe and intake setup.
I've been adjusting fuel only...in an attempt to get a perfect AF ratio before touching timing. However, I've found some areas of knock that I really have a hard time explaining.

Any insight would be appreciated.

ScreenShot #1
This shows 1 count of knock. The throttle position is 29%...the AF ratio is leaner than stoich however the load is pretty low.

Is this tunable via ecuflash? This seems like a closed loop tuning area.




ScreenShot #2
This shows AF ratios slightly higher than 11.5. Stock timing is retarded in this area ...however I'm still getting a slight bit of knock. With timing retarded, shouldn't I be knock-free?





ScreenShot #3
This shows AF ratios fairly rich with stock timing. I'm getting knock however. Isn't factory timing pretty conservative? If so, why am I getting any knock?




ScreenShot #4
I'm getting knock with rich AF ratios and very little timing. Why?



ScreenShot #5
I"m pretty damn rich here. Still getting knock with very little timing. Again, why?

 

is this all with the same tank of gas? What gas? Also, are you running the stock mivec map but higher boost?

 

1-2 counts of knock is to be expected and, most of the time, normal. it sometimes will affect timing advance, by retarding it by a degree. i have seen 5 counts of knock on a completly stock 05 MR. knock doesn't always mean its the acutal engine thats knocking. other parts such as the clutch, downpipe, lifers, etc. could be making noise, and the ecu will pick it up as knock.

 

Stubborn counts of one and two, especially on transitional loads will be difficult to get rid of. In your case there might actually be some physical engine noise that is being picked up, the downpipe hitting the crossmember, etc.. That you might want to check.

Also check the adjacent cells your working with, if there are large jumps of timing between the cells your working with, the ECU could "knock" when it happens This happens most frequently when the load rapidly jumps from lets say 160 to 200, and there's a multi-degree change in timing.. This is actually why some tuners use blocks of timing in those problem areas...

 

93 octane and stock boost with less taper. All logged during the same drive.

Yeah, I was considering that. Butt the car is pretty much stock. Oh well. Hopefully you're right.

Thanks, I'll check that. I usually like to smooth out my maps but haven't done that yet.

 

Your freaking about 1-2 counts of knock during a transistion? LOL. Quick tip, get the sand out of your vagina. If you hit a bump in the road correctly you'll get 1-2 counts of knock. Take the air/fuel to high 11's or low 12's on pump. Raise the boost to about 20-25psi or wherever you get 2-3 counts of repetable knock when going wot. Either keep it here or back it off 1-2 psi. If you get to 25psi on pump and still aren't knocking then add a degree of timing from 4000rpm' to redline at your load level. Rinse and repete until you get knock. You may start getting knock at 6000rpm's to redline so stop adding timing here or go back to stock timing at these levels and keep adding at the 4000-6000 rpm area. You may find you have to reduce timing from stock at your boost threshold level.

 

Thanks for the confirmation.
I am removing the sand from my vulva with duct tape.

I always thought people were running too rich. I tune my other car for 11.5. Everyone here thinks that's too lean.

 

Yeah, well other people are stupid. I run 12.4-12.6 AFR in my eclipse at 30psi.

 

That's the comment I make to myself all the time when I'm reading stuff on this forum.

I tune my other car to 11.5 across the board.
I dunno if I'd run 12.4 because I'd rather advance timing instead.

I just got back tuning the EVO to 11.5 across the board. Stock timing, no knock.
Feels so much better than 10.8.
Timing will come when I have some more time. Thanks fer your advice.

 

Im around 12.0:1 in my built 1G 6bolt. Thats at 27PSI running 112 oct Sunoco Supreme blue. My EGTs are always safe like that and some room to spare. Pumps a lil different tho.

 

10.0 to 12.5 af will see very little difference in power compared to other changes, that 10 or so hp is a sacrafice many people make for a good safety blanket, everyone reads stuff and take it as the word, thats why people think you have to be in the 10s rich to be safe
as for the orig question, like said, dont take little counts so seriously they will appear and dissapear no matter what you do

 

Whats the difference between pump and race gas that you engine atomizes the fuel different requiring a different under load AFR? I say pump gas is more volitile and needs changes to the timing map. Its the old strewed things "learned" from the SAFC days of DSM's that make people richen the car up on pump gas.

 

Although I do agree that people generally run a little richer than I run my car, I think there are too many people who are inexperienced and can do damage.. There are several reasons people run their cars richer..

1) It slows the combustion rate down a bit
2) It cools hot spots

Both of those things give you a margin for error that could save your engine..


Like I said, I have generally run my car leaner than most people recommend, however I have to admit there really hasn't been a huge difference in power that running a little richer and the slight added safety margin isn't worthwhile..

Until people understand the basics of tuning, they are best off to err on the side of caution..

 

The difference between pump and race gas is octane.
Resistance to preignition and detonation.

It doesn't require a different AF ratio.
If you kept all things the same you wouldn't see any difference.

It only allows you to run a leaner one and more timing because the high octane is less likely to detonate.

Personally I think there is a big difference between running a 10AF and a 12AF.
Try running the car into the 9's and see how it feels.
If you compensate with timing you might make up for it a little...but there's still a considerable difference.

 

Spoken like a true drag racer. Not all of us need the ragged edge of fuel to make that extra 4 hp so we can get through the traps at .05 seconds faster.

Especially people that road race. I would rather run a low 11 afr and not worry as much about detonation on any grade of fuel. 11 afr is fat and happy. Probably not making the absolute max power possible, but i'd rather not replace my expensive motor anytime soon. (did too much of that on my old turbo hondas!)