Looking for some tech here. I have a device where I can manually set parameters in the spark vs airtemp table via the airtemp sensor. New product being beta tested. What I find is a considerable pull in timing in this table with the factory calibration, as much as 8 degrees of timing pull, and it seems typically 3-5 degrees pulled under normal operating temperatures. There is a lot of power available here with a few "tweaks".

Anyone on the list here have any experience with this? I can adjust the table to anything I want, within reason, and use the gauge device to set the timing factor. The gauge goes from -8 to +7 in 16 steps, but I think all I will need is maybe +4 or +5 degrees maximum.

Any ideas?

-John

 

I think you are on to something. You might talk to the people at Volant. They are great advocates of cold air intakes.

 

I'm quite familar with the factory IAT timing tables...and you shouldn't be seeing much based on normal operating conditions. However, with heat soak and other issues, I guess it could be happening.

EFILive flashscan is an invaluable tool for figuring all of this out

 

According to the table, you would have a -3 to -5 degree pull of timing in what I would consider "normal" operating air temperatures, somewhere in the neighborhood of 100-122 deg F. This would equate to a warm summer day at the track. My thoughts are that this is the cause of inconsistent ET's and HP numbers on the dyno from one car to the next. 5 degrees of timing will reduce your HP and torque substantially. So, the thought here is by taking the timing back and using good octane in the fuel, there's some serious untapped power available.
I'm looking at adding 4 degrees in this range, so a total of 8 or 9 degrees of timing is on tap. With 100 octane fuel, I think it'll do the trick.

-John

 

GNSpyder -

You're probably correct. I'm relatively new to this tuning gig...and didn't realize the tables were set with temps that low. I assume this is IAT, right? I know my magnacharged V regularly sees IAT's in the 130-140 range - but this is at the manifold, not at the MAF. The tune I run has been tweaked to account for this

 

Here is the factory IAT vs SPARK table in stock form: