Found something interesting and was wondering if anyone else here could back it up ?

Max timing at cruise in my Formula is set at roughly high 38 to low 39 degrees advance. My max timing constant was at roughly 40.6 degrees.


Day after hallloween i took a hr long drive(expressway) with Diacom hooked up and noticed at sustained 70 mph my timing was at 40.6 degrees and my tps was @.94v and 10% throttle opening (new best for lowest tps at 70 for me).

Curious part is that my timing had gone out to 40.6 degrees when programmed in the table is hig 38 low 39 degree? Can anyone shed some lite on this for me? Im positive my highway mode is not active and yes i double checked. Or is it inherent in the code at some point during cruise it will let out the timing to the max constant if certain cinditions meant?

If i get a chance i will verify it on the GTA as well, but im almost sure I've seen it before(actually positive) but this is the first case that i caught it in and knew i wasnt seeing things

thanks
Jeremy

 

No on else has seen this?

 

I never looked that close.
But, I usually trim the max advance down since it allows for way too much timing for the way I tune. It's easier in my book to drop it down to the max I want to see at WOT. That way if in an defensive driving emergency with a cool engine no coolant temp correction drives me over my suggested max.

 

Care to clarify on that a little bit bruce?

If i trimmed it down to where i wanted max timing a WOT to be would that not can my max timing at cruise as well?

Is there possibly something i dont understand about this table?

thought it controlled the max timing allowed only?
thanks
Jeremy

 

Yep, it limits the whole spectrum.

High timing lean cruise conditions are great for mileage but lousy for what it does to an engine. Puts alot of heat into the piston domes, and into the oil.

 

Yup yup, get an oil temp gauge and watch it. This is where synthetics rock. They do a great job of removing heat. I'll have data to back this up. We did the testing last year on our dyno and although hp gains were VERY minimal, our oil temps stayed an average 50 degrees cooler than dyno juice under heavy loading of the engine.
Anybody finished with there DIYer plug ion ignition system . It's a joke but hopefully not for long.