LLY Exhaust Temps Too High???????????

[crazy]

I have a 2005 K2500 LLY. At 65 mph, the exhaust temp runs about 810 degrees. Does anyone know if this why my fuel mileage is so horrible. (that is 810 degrees empty and on flat ground. I get about 14 to 15 miles per gallon. Pretty horrible if you ask me. (empty) I have a friend with a 2004 cummins that is a dually 4X4 and he gets 15. I would appreciate any imputs.:mad:

[Kennedy]

That is perfectly normal for exhaust temps. 17-18 mpg should be pretty easy, but you did not state what speed you were traveling or any other specifics on your vehilce.

[Mark Rinker]

Higher than my stcok '02LB7. Probably mostly due to cat and ECM programming differences. I routinely get that pulling an empty 30' trailer. My '05 is getting similar mileage to yours, but again, pulling an empty trailer. Don't fully understand why the huge difference, but only apparent thing is the cat.

Well within safe range, but I wouldn't argue that you are burning more fuel for the same ground speed, and it shows in your mileage.

Oversize tires? Any other drag-inducing modifications? Hung up parking brake shoes?

[crazy]

The speed is 65 mph. With no wind. I have never gotten over 15mpg. The only modifications is the edge attitude with monitor and a k&n filter. The tires are completely stock. It has plenty of power though. But when fuel is 3.10 a gallon there isn't really a savings I don't believe. I have the allison auto in my truck. Does anyone know the best settings for the edge for the best fuel economy.

[Mark Rinker]

Probably 'OFF'. :)

More power takes more fuel, in most cases. Some LB7 owners claim a mileage increase with tuners on the first 'Tow' setting, but its hard to keep you foot out of it when you got the Juice on tap...

Consider John Kennedy's economy tune (www.kennedydiesel.com) for your LLY. Maybe considering 'losing the cat' if you don't have emissions testing where you live. I think ambient temps might also play a factor, my mileage really suffers in the heat.

Also - welcome aboard. Nice to see new faces around here!!

[SoTxPollock]

Mark, I'm curious. Why do you think your mileage suffers in the heat? I would think since the air is hot its less dense and therefore the engine would be compensating, needing less fuel. I've always gotten better mileage in the heat. Is your cooling system fan coming on often? That could explain it if it is.

[madmatt]

Your right that colder air is more dense, thats also why it helps build a bigger "fire" so to say. Everyone knows that fires need oxygen to burn. Colder air packs w/ it more oxygen then warm air in the same given space wether it be sq. in on sq. ft. More oxygen in the same charge(say 24 psi) =bigger fire which in turn makes more power allowing u to make the same HP using less fuel to build the fire that makes it. Do ya follow me???????? C where I'm going w/ this???? I will note though that I get less MPG w/ my gas truck because I idle it so much more warming it up and keeping it warm.

[Kennedy]

I might suggest a merge with teh thread in the Performance shop. I've added my $.02 in there...