Last night between 10:40 and 11:00 pm I did two log on the same stretch of road. The first log had a KS of 7 at 6000 rpm and went down to 4 by 7500 rpm. Timing was pulled about 3 degrees as a result.

The second run had NO KS in this rpm range at all. It looked great. It had about 3-2 KS in the lower rpm. It was almost insignificant.

My question is: Which log is the "correct" log? I do not know if I have to modify the tune or not.

The logs are attached. Both are 3rd to 4th gear. Please focus on the 3rd gear part of the pull. That is where the issue is.

 

AFR for both runs?

l8r)

 

AFR is the same at 11.3:1 in the lower rpm, 11.2:1 in the mid range and 11.1:1 in the high rpm with taper to 10.9:1 deep into redline. I am using 93.3 octane gas. I mix it at the pump, hence the 93.3

 

Are you still running the XEDE, or are you just on a flash now?

Seems to me like there is a big jump in timing between 5500 and 6000 RPM. I'd probably look at smoothing that out a little bit (i.e. lower the timing in the 6000 RPM range by 1 or two degrees).

Could have also been just a momentary lean spot during the first run that caused the knock sums.

l8r)

 

I am still running the Xede. Here are the two logs in excel charts. The first one has the KS and the Knock buffer (voltage multiplied by 10 to show it on the graph so the 19.1 spike is actually 1.91 volt spike).

Notice that in both charts the knock event does not reappear in 4th gear when the car hits the same rpm as in 3rd gear.

Also, the "real tim" is the actual tim since I am running an Xede. The Xede traces the OBD2 tim pretty well, albeit, at lower timing. The Xede timing usually peaks at 18 by redline.

 

They are both the real log. Hehehe.

Was the car up to temperature? Even if the coolant/oil temp gauges are at temp
the car sometimes wont run consistently until its been brought up to temp using WOT hehe. I guess the turbo needs to get nice and hot or something.

One way to address this problem is to do runs till you get some sort of
consistency. So do a third, then a fourth, etc and see if the logs settle down.

This isn't always feasible. And even if it works its still not optimal for street driving.

The actual reason why the car doesn't run the same from pull to pull is not well understood as far as I know, other than the temperature issue. I see the same sort of thing on my car so if you solve this problem let me know.

In my case using 100 octane gas on my 91 tune for the most part eliminates this sort of consistency issue. This suggests that those knock counts are real and that detuning the car for 91 will achieve a more consistent tune. This is what I did and it works to some extent.

 

what are you trying to determine? further tuning? safety?

 

I did four logs tonight. The first log had a knock event similar to the first chart/log I originally posted. The next three had isolated KS of 1-2 that were no where near the first log.

It is safe to say, that at least on my car, the first log is not to be used to tune the car. I think the car was not really warmed up as someone on here indicated.

In one log I did a 3rd/4th gear pull all the way to redline in both gears. There was just 1-2 KS here and there. I will post the chart once I make it.

Edit: Here is the chart of the 3rd and 4th gear to redline. Very clean with no timing pull. AFR 11.3:1 tapering to 11:1 by redline in 3rd gear. 93 octane gas.

 

Actually, if you are consistently seeing that spike on your first WOT pull, then I would do one of two things:

1.) detune your car slightly in that range, because during regular street driving this will be one of the more common scenarios (i.e. putzing along, engine not 100% up to temp and then ... WOT!)

2.) refrain from going WOT unless you know for sure the car is 100% warmed up.

Personally, I'd have to go for (1) ... better safe than sorry, and I don't think it will take much of an adjustment to iron out your 5500 to 6000 RPM range.

l8r)

 

I am going to let the car really warm up before I do runs tonight. I will let it idle until the fan kicks in and drive it around before the runs. Then I will see what the results are.

In daily driving my car does not even go into boost. I drive to and from work with the turbo in vaccuum. I shift at 3k rpm and drive 65 mph and around 2800 rpm on the freeway.

 

SISSY!!!!

j/k

l8r)

 

Are you serious? What's the point of having an Evo as a DD if you're going to drive it like an old lady. Buy a beater or motorcycle.

 

I think it is ultra cool to drive a badass car like the Evo calmly and slowly. It makes a statement that I have a badass car and I do not have to prove it by speeding around on the streets and freeways when there are other cars around.

Besides that, the Evo is my first turbo AWD car and the fun part is learning how to tune and modify a turbo car. I have learned so much about turbos in one year of ownership. In the past few months I have learned so much about tuning thanks to the guys on this forum and Vishnu forum.

I also have my dedicated race car and when I want to speed I simply go racing.

But I still manage to do those WOT runs that are simply intoxicating. On my last gas tank I did 23 WOT runs and still managed 20.4 mpg thanks to my slow driving style. If I quit the WOT pulls, then my mileage would hit 26-27 mpg.

 

I have trouble driving my evo smoothly if I don't drive fairly agressively. To some extent this is the cams but let's face it the car really likes being between 3 and 5k rpms, if not higher.