Cobb Datalog..too aggressive?

kneedeep · 06-09-2013, 08:58 AM

I just installed Cobb tuning on my 09. It did not feel right so I made a datalog. The log is of a 3rd gear pull from about 2500 in my 35i. From what I've read it seems like all the timing corrections at WOT are bad news. I'm totally stock running stage 1 93 oct. I plan to drop to 91 and see if that helps but I'm bummed that the 93 has issues since I'm using 93 gas. Any ideas from the experts?

Lambobimmer · 06-09-2013, 10:01 AM

Quote:

Originally Posted by kneedeep

I just installed Cobb tuning on my 09. It did not feel right so I made a datalog. The log is of a 3rd gear pull from about 2500 in my 35i. From what I've read it seems like all the timing corrections at WOT are bad news. I'm totally stock running stage 1 93 oct. I plan to drop to 91 and see if that helps but I'm bummed that the 93 has issues since I'm using 93 gas. Any ideas from the experts?

I am running stage II on 93 so I will see if what my log looks like compared to yours. I would suggest that you send this info to Cobb to get their input. They can also make some changes or suggestions of needed.

nicknaz · 07-09-2013, 01:44 AM

Hey OP, that log is a bit concerning. check out rows 11 to 28 (2504 to 3043 rpm) column H (boost... you need to subtract 14.7 to get how many PSI you are boosting) and column T (air to fuel ratio)

You are going from no boost to full boost and your air to fuel ratio is staying above 14:1, this where it looks like you are getting a lot of detonation (rule of thumb I've seen is more than 3 cylinders doing -3 degrees correction at the same time)

Later in the log, at around 3900rpm when the AFR settles in 12 and high 11 there are no timing corrections.

Would be interesting to see what the tuner has to say about such high AFR from 2500 to 4000 rpm especially given the boost at that time

07-09-2013, 01:44 AM	#3
nicknaz Lieutenant General 3187 Rep 10,509 Posts Drives: C6Z Join Date: May 2008 Location: NorCal iTrader: (0)	Hey OP, that log is a bit concerning. check out rows 11 to 28 (2504 to 3043 rpm) column H (boost... you need to subtract 14.7 to get how many PSI you are boosting) and column T (air to fuel ratio) You are going from no boost to full boost and your air to fuel ratio is staying above 14:1, this where it looks like you are getting a lot of detonation (rule of thumb I've seen is more than 3 cylinders doing -3 degrees correction at the same time) Later in the log, at around 3900rpm when the AFR settles in 12 and high 11 there are no timing corrections. Would be interesting to see what the tuner has to say about such high AFR from 2500 to 4000 rpm especially given the boost at that time
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