Cold weather & fuel rates

buzzfx4 · #1 Sat, December 26th, 2009, 12:15 PM

So it's back to the cold season and with temp's struggling to get out of the upper 20's I'm starting to get that lean drone sound from my CAI and slite sluggishness. I do have custom tunes, but the 87 performance tune I use for my daily driving tune was tuned for more of at speed performance. I do have a 93 go fast tune but 93 octane doesn't do to good in cold weather while tryin to get a decent MPG. Is there any way to adjust normal fuel rates? I know you can adjust WOT fuel but that won't solve the problem, I think.

Any suggestion would be great.

Thanks

***Power Hungry*** · #2 Sat, December 26th, 2009, 12:21 PM

At this time, adjustment of main fuel tables is not possible. Much of the reason is that if we allowed that much control, the EPA would have a fit and poop kittens. As such, we've been limited to WOT fuel adjustments only.

I have considered what it would take to add main fuel control into the programmer, but at this point it's more extensive than our development time will allow. Once we get a few projects ironed out, it's something we certainly would be happy to take a look at.

One thing you might want to try is running the 93 program with an 87/89 octane blend. Once of the things we've seen in the winter time is that the burn rate on the fuel drops due to the cold weather (not to mention winterized fuels) and we've found that a little more aggressive timing curve (or lower octane fuel) often helps improve performance.

Take care.

buzzfx4 · #3 Sat, December 26th, 2009, 07:50 PM

Thanks for the suggestion, I'll give blending the fuel a try. If that doesn't help I guess I will see if I can come up with a way to pull some warmer air of the engine,

Thanks

buzzfx4 · #4 Fri, January 8th, 2010, 12:11 AM

So, I was finally just able to fill my tank up with the 87/89 blend and change the tune or to the 93 tune. Which I'm very please to say helped with my leanness and the annoying drone of the CAI in this cold weather.

Thanks Bill for the suggestion. Now all I'm wait on is that little trani update.

O yea, one little question, maybe one of the other members might be able to help answer too. Do I have to be worried about detonation when running the 93 tune on lower octane? Or does the thicker, below freezing, colder air equal out the air to fuel range? Also, any suggestion on a air temperature where using the 93 tune and lower octane fuel should be stopped?

***Jackpine*** · #5 Fri, January 8th, 2010, 08:57 AM

Quote:

Originally Posted by buzzfx4

So, I was finally just able to fill my tank up with the 87/89 blend and change the tune or to the 93 tune. Which I'm very please to say helped with my leanness and the annoying drone of the CAI in this cold weather.

Thanks Bill for the suggestion. Now all I'm wait on is that little trani update.

O yea, one little question, maybe one of the other members might be able to help answer too. Do I have to be worried about detonation when running the 93 tune on lower octane? Or does the thicker, below freezing, colder air equal out the air to fuel range? Also, any suggestion on a air temperature where using the 93 tune and lower octane fuel should be stopped?

You shouldn't have to worry much about detonation for a couple of reasons.

First, the temperature of the fuel itself and the temperature of the incoming air cause the burn rate of the fuel to be lower. This is the property higher octane fuel has - a slower burn rate than the lower octane stuff. It is not "better" fuel, it just doesn't burn as fast. Rapid burning can cause too much expansion in the cylinders too soon, which works against the motion of the pistons and causes the "pinging" sound.

Second, if "pinging" IS detected, the spark knock sensors will tell the PCM to automatically retard your spark to stop it. Unfortunately, the spark will be retarded too much, and you'll lose some power.

I honestly couldn't tell you when to stop using the "winter" setting though. Maybe sometime towards the end of February?

- Jack