Thanks for looking. Real quickly, car is a 2003 turbo 6 speed pretty much stock except for 3" x pipe w/ no cats, K&N filter and lightly ported exhaust manifolds. I just purchased a COBB and installed and drove for maybe half a day of mixed driving. Was able to do to crappy 3rd gear pulls but they seemed good enough to get some data.

Tune loaded was a 93 octane tune for a basically stock car with aftermarket exhaust with cats. (again my car is catless).

Anyway, if you read the graph It appears like I am seeing knock up around the top of 3rd gear. Car has new plugs, coils, fuel filter. Works and runs excellent. What gives? Should I even be looking at that. Consider also this is in FL with 100 degree hear on OEM intercoolers, but still.

Thanks in advance.

 

Hi there,
You need to log ign angle

and you need some tweakage as it might be a little lean where it's pulling out timing. Your tuner should be able to help.

 

is IGN value not there expressed at throtttle angle as 100%? Or am I missing something.

This is an off the shelf tune from Cobb website, car has never been on a dyno. Particularly I don't care for flashes without having the car on a dyno, but people seem to have had good success with the COBB tunes included with the programmers.

What gets me the most is that this is tune for 93 and for a car with cats. Considering I have no cats but this tune still seems to be seeing knock bothers me. And this is exactly the same as other users have posted re: logs in the past couple of months in this forum. Seeing knock on a mild tune from COBB. Car has good gas in it. I'm a little confused. It runs well but leads me to believe that unless you're using the Pro Tuner feature than maybe these off the shelf tunes suck?

 

Also based on the values it doesn't appear to be lean. I mean it could be a touch fatter I guess, but it seems safe.

The only dip I noticed where it goes lean is when shifting gear which is normal, but it doesn't see to be quick to go back fat, maybe I am seeing the car react to what it thinks is lean and thus seeing knock before it can pull timing?

 

I added ignition angle and waste gate duty cycle to my logs. The ignition angle clearly showed timing being pulled until we fixed it (Sambo is the man) and the duty cycle shows how hard your turbos are trying and when the DME is pulling the turbos back to limit boost.

 

I emailed the tuner @ COBB to see what his thoughts are

 

Bottom line is the ECU is picking up knock...so it's pulling timing and in some areas...6 deg. I also have the Cobb AP and ATR...if I saw this in my log...I would do some adjustments. Just saying, but that's me. Maybe if you had some better fuel...the knock sums would decrease.

Ign angle is a logging parameter...just add in your log settings in the AP.

 

The car has been flashed to stock for the time being. I see it's pulling, but I am trying to ascertain why? It's either the tune is not great, which may make sense as all the other postings in the past few months with datalogs show the SAME results with the car showing knock sums upstairs in 3rd gear.

I was gonna say it may be the motor picking up phantom knock from having solid engine/trans mounts and being VERY loud, but I don't think that's the case after seeing other people's logs asking the same questions.

COBB should take a good look at these.

 

Lean has nothing to do with knock. Whos the tuner?

 

Sure lean and knock go together. Lean conditions may create detonation which is knocking. I am not using the the 2 parameters together, but mainly pointing to the fact that the car does not appear to be running lean anywhere but rather seems to be running right based on AFR models.


Tune is an off the shelf tune from the pre-loaded maps. Notably other logs here on this site show similar issues and they are from the pre-loaded maps as well.

 

Again I am not using the AFR as a tool but mainly pointing to the fact that if AFRS seem good we can rule out running lean causing detonation. EGTs look good as well

 

What i meant to say is your condition is not a lean condition its a octane issue.

 

that's weird cause gas is new 93 octane and car gets healthy Chevron techron add ins in between. Car has 50k miles and really is like new and runs mint.

I would think that it wouldn't look like that re: pulling timing and knocking upstairs. Maybe it is gas... That just seems like an easy scapegoat to me at this point, but everything else seems to be good.


Although, again, there's 2 other threads floating around here from recently re: the same concerns seeing knock on COBB pre-loaded tunes. Maybe its' the tune?? I am leaning that way a little, even though AFRs seem nice and car runs right maybe it's the tunes timing? I'm waiting to hear back from them, we'll see.

 

A question: Is the Knock Sum in log above really ignition retardation angle, or something completely different?

 

93 octane is not that great but it all depends on timing, boost and fuel. To much timing at low rpm can cause knock. To hot outside can cause knock.

Who did your tuning?