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preacherboy24 · 12-31-2016, **(Subject: Mpg drop isx15 )**

After looking over the comments on this thread I would have to say winter blend is the cause of the fuel mileage shortfall. I dropped about a mile per gallon. One would think if your burning more fuel you would get higher egts and the engine would run hotter since you are burning more fuel but all my figures are good so it has to be less energy content......just my thoughts.

Billdozer2 · 12-31-2016, **(Subject: Mpg drop isx15 )**

I think it also has to do with the fact that colder air is more dense. That means it's harder for the truck to push through it. I notice it especially when going down hills, where in the summer time I pick up speed but in the winter I loose speed.

Hammerhead · 12-31-2016, **(Subject: Mpg drop isx15 )**

The biggest energy content factor in summer fuel is paraffin wax. Just like a candle, the wax slows the burn rate and increases the burn temperature, thus creating more heat expansion energy. The wax content needs to be scaled back, or removed completely in colder climates, to keep the fuel from gelling. If you removed the tell from gelled fuel and analyzed it, you'd find its almost pure paraffin wax.
Winter fuel burns quicker and cooler...add to that colder more dense air and AFR isn't nearly as optimal. This is why I remapped my turbo for winter trying to control the efficiency losses.
Add in that the colder air is more dense and your aerodynamic efficiency is reduced because it's harder to push the air out of the way, and the Aero Drag vacuum at the back of the trailer is increased because of this same density creating a stronger vacuum.
Colder ambient temps also means your tires do not expand as much either, therefore creating a larger surface contact area, once again increasing drag.
The colder temps also means the rolling hubs (trailer & steering) are a lot cooler so the oil doesn't flow as freely causing wheel bearing resistance...god forbid you have grease hubs and you increase that even more!

If you own your trailer, changing hub oils to synthetic oil will pay for itself over and over again!

Ain't winter fun?

Brock · 12-31-2016, **(Subject: Mpg drop isx15 )**

Every winter some guy (usually experienced enough to know better) complain's to me about mpg loss and the first thing I ask.

"Did you add air to your tires once it got cold?"

Usually it's a no, or yes on the 10 tires on the tractor but no on the 20 on the trailers cause they don't own them.

I filled my tires to 105psi in Aug and in Oct I checked, all 30 tires were at 85psi!!

That's a lot off added rolling resistance.

Hammerhead · 12-31-2016, **(Subject: Mpg drop isx15 )**

The trailer tires might not be theirs, but the fuel they're burning is...so short sighted!

Waterloo · 12-31-2016, **(Subject: Mpg drop isx15 )**

(12-31-2016 )Brock Wrote: Every winter some guy (usually experienced enough to know better) complain's to me about mpg loss and the first thing I ask.

"Did you add air to your tires once it got cold?"

Usually it's a no, or yes on the 10 tires on the tractor but no on the 20 on the trailers cause they don't own them.

I filled my tires to 105psi in Aug and in Oct I checked, all 30 tires were at 85psi!!

That's a lot off added rolling resistance.

I love it! It ain't mine! I wish I was the guy that had the patent on STUPID! I am given a trailer rent free, and I take care of it, air, grease and inspections... The company reimburses me every penny, and I keep up on it. I'm dumb on more than a few things, but common sense ain't one of them. The more money I save the company, ME, the better off I am. Take care of the equipment, it takes care of you. A no brainer in my book. ;-)

gearhead · 01-01-2017, **(Subject: Mpg drop isx15 )**

Very wise statement my friend.

Nilao · 01-05-2017, **(Subject: Mpg drop isx15 )**

I'm seeing my the same loss. Now I'm in the NW and the lows over the last3 days in the negatives my logs have showed that the lower the temps have gone the lower my mpg. At +16 my mpg fell from 6.8 to 6.02. Last night and the night before we're -6f and -16f and I did idle which made my mpg drop to 5.12.

SquareOne · 02-19-2020, **(Subject: Mpg drop isx15 )**

Def an older topic, but pertains to my question.....at what point in the year do you seasoned guys begin to see the fuel MPG return? I've combed over my truck to make sure everything's on point, but still seem to be about .4-.6 off on mpg. Throughout the summer months, I would consistently see low 9's, but as of lately, I just can't seem to break out of the mid 8's...

- Don't get me wrong, I'm happy with the current mileage of this 2350, I just know that it's capable of more. We've had a VERY wet year so far, so that makes what I haul very heavy, and we have the occasional cold flash (although not near as bad as what many of you deal with daily), but I'm still closely monitoring those mpg's waiting on their return.