first thing i did tonight was cut one wire on my IAT sensor and run from the 5v thru a POT back to that wire. then i got into edit and programed that IAT table so it will pull up to 8deg and add up to 4deg of timing depending on where the IAT is at. the stock pcm no longer controls my fueling so i can mess with that sensor input all i want. it worked great, i can just twist the pot and adjust my timing all over the place without haveing to reprogram each time.

next thing i did was put a timing curve in that a buddy of mine sugested. here are the numbers

up to 2800rpm 16deg
3200 15deg
3600 14deg
4000 13.5deg
4400 13.0deg
4800 12.5deg
5200 13deg
5600 13.5deg
6000+14deg

now with the twist of the POT i can pull those numbers down 8deg or up 4deg.

now for the results, probably nothing to suprizing here. look at the "notes" to see how much timing was pulled or added. when i note KR there was not any audiable knock and the loged KR was aound 1deg is all. i usualy saw about 2-3deg more timing than i expected so there is another table messing with me somewhere.



it really likes the timing. on the green run i was seeing about 18deg in the mid rpms and ~21deg up top. this is on 92 octane. one thing to note is when i put the megasquirt on it seems to have messed up my gtech rpm calibration and i just noticed this tonight. i think all these numbers will go up about 100hp when i get the rpms recalibrated.

all runs were at 11.8-1 a/f ratio. i might mess with that but need to not mess with too many things at once. i tried pulling the timing back to +0deg and adding some more boost and it showed KR still. i dont know if it is real or not. it seems like better fuel helps with the KR but i still show it sometimes.

i had the truck shifting very early and locking early too so i could get a nice long pull in 2nd. i also let off before the 1/4, i just wanted the hp numbers in one gear.

tomorrow i think i will put the timing at +4 and make a run, then add some fuel and see if it slows down and if that KR goes away. if i can get it to go away then i will try adding a little more boost.

 

Nice data.
Need to buy one of those.

 

Is your truck an 02? I know the 02Fbodies have a timing issue where it floats a little from what the Edit program says. On my buddies 02 we were stumped then seen a post where others had the same issue. Anyway, cool work on the resistor pot. I might need to get with you on that part, cheap timing tuner! Want to make some $? Pm me.
Charlie

 

Keep in mind that changing the IAT messes up the MAF flow rate. The two sensors work in unison.

Ryan

 

I would say if you put in better gas, and there is still KR then you know its false. Just tune it out alittle. Scale the Knock aggression back some and go run it again.

Rick

 

looks to me it liked the boost more than the timing

 

yes, i definately made more power on the more boost and less timing but looking at the logs it showed quite a bit more KR. here are the screen shots of the last 2 runs. i am having a hard time knowing how much to sweat the KR but the run with the higer boost looks like enough to worry about to me.


here is the green run from above. +4 timing and 9.5psi




and here is the blue run from above. +0 timing and 11.5psi

 

yep, i dont think you can do what i am doing if you are still using you maf for anything.

 

Interesting. I'm curious if it will slow down when you add fuel. For me, going from 11.8-1 to 11.2-1 on the same timing gets rid of KR. Just don't know if it's slowing me down or not.

 

just did some reading on the gtech website. i thought it measured tq and then calculated hp but it is the other way around. it measures hp(sort of) and then calculates tq. with that in mind i dont think my hp numbers will change when i recalibrate the tach.

 

Parish, on the G-tech hp graph I assume the spike 3.5 seconds in is the 1-2 shift, the spike 6 seconds in is the 2-3, whats the one at 8 seconds? Converter lock-up?

 

i had it shifiing way low. and locking low also. that curve from 3.5sec to the end is all locked in 2nd gear. not sure why it gets jumpy. i dont feel anything when running it.

i did just download the latest gtech software and hard ware and it seems to smooth the graph a lot.

 

Interesting data.

I would not go leaner than 11.8:1 and I would not fiddle with that, too many changes at once.

 

"and i would not fiddle with that"

what do you mean? you wouldn't even try and make it richer? i am atempting to only do one change at a time to see how it all compares.

 

I'd go 11.5:1 AF since like 80% of the folks I know would shoot for that AF. The difference in power between KILL and SAFE might be 20-30rwhp but the guys I know who tune for SAFE seem to change shortblocks when they feel like it not cuz they ate one.

 

here is a screen shot with the same data but updated software.

 

ok, got some more testing and data. i am learing some things here.

i made 6 runs

first run was -0deg and 9.5psi, this was the most i could run last night with 0 KR and was the same tonight. this run is in the screen shot below in blue.

2nd run i ran the same -0 timing and 10.7psi, it picked up hp but also showed a slight amount of KR, this is the 2nd run in the screen shot. in red.

3rd run i ran the same -0 timing and 11.6psi, it picked up more power and felt strong but showed even more knock. 3rd run in green.

4th run, -0deg timing and 11.6psi. i droped my fuel from 11.8-1 down to 11.4-1. the power was exactly the same and the knock was exactly the same as the 3rd run. i didn't post this one up.

5th run, put the timing at -4deg and kept the boost at 11.6. i also left the fuel at 11.4 since it didn't seem to hurt anything. this run kicked ***. pulled strong and had 0 KR. the hp didn't fall off at all. this it the blue run.

6th run i tried the same thing but more boost, about 12.8psi. fuel at 11.4, timing at -4deg. hp stayed the same and i got some KR. didn't post this one.

finialy i made a full 1/4 mile run with my shift points back to normal and pulled a 10.95 at 125 with nearly 0 KR(just a touch at the shifts). not sure what to try next but running gtech 10's on pump with no KR makes me prety happy. i am totaly blowing off all 4 tires on the launch too so with some traction it would be better, also have 150lbs i can pull.

 

grrr, ok, i am out of bandwidth so no pic till the 1st. 300gig just dont cut it i guess.

i will just tell you the hp peaks

1st run was 485hp
2nd run was 500hp
3rd run was 524hp
5th run was 528hp

 

Ok, let's see if I've got this right. You see your best power on 12-13 degrees of timing, and going from 11.8 to 11.4 didn't hurt power but didn't supress knock.

 

adding fuel didn't help get rid of the KR but it didn't hurt power either.

i made prety much the same power on the 3rd, 4th, 5th, and 6th runs but with the timing pulled back to a max of about 13deg(i know it doesn't add up but that is where it is at) i got 0 KR.

so 13deg(14-4+?) timing shown on efilive and 11.6psi and 11.4-1 a/f ratio seems to be my current best no knock tune. i think i could put that fuel back up to 11.8 but might just leave it at 11.4 since it didn't appear to hurt.