Diesel mileage

[Sludgy]

Matt, the old "Diesel mileage" thread won't come up in the new format. You still have a few bugs in the new programming.

At any rate, the F350's last fill up got 15.2 mpg, all city driving. This mileage is about 1 mpg better than before the EGR valve was replaced. The truck definitely upshifts sooner and the revs stay lower. So I may have had a bad EGR valve all along.

I just finished adding a plywood bed cover to the truck. This probably won't help much in city driving, but I'm going to test highway mileage on a long trip to northern Maine in early June. Maybe with the cover I'll get into the mid 20's. (Fingers crossed)

[Matt Timion]

Originally Posted by Sludgy

Matt, the old "Diesel mileage" thread won't come up in the new format. You still have a few bugs in the new programming.

Do you mean this thread?:

http://www.gassavers.org/showthread.php?t=810

You can visit the diesel forum here:

http://www.gassavers.org/forumdisplay.php?f=9

[Sludgy]

Well, I built a plywood tonneau cover for the truck, and tested it this weekend. I took a ~700 mile trip to my camp in N. Maine.

The results were disappointing, only 19.7 mpg. This is worse that a trip last fall to N.Carolina without a tonneau. I had my tires at 80 psi, and drove under 65 most of the way. It was very rainy, which probably hurt the mileage. Anybody here measure mileage in the rain vs dry?

Curiously, I could tell from the gas gage and Scangage that the mileage wasn't very good over the first part of the trip, so I gave up trying to keep it under 65. I drove 70-75 during the last leg of the trip, and the mileage seemed to get significantly better at the higher speeds=.

This sounded crazy to me at first, but my truck is turbocharged. Maybe the turbo isn't at an efficient point at low speeds? Anybody out there have similar experiences with turbos?

[krousdb]

No experiences with turbos or diesels but I swear that I read somewhere that tonneau covers actually hurt FE on a truck. I dunno, just something that stuck in my brain. I'm probably just confused.

[Compaq888]

Originally Posted by krousdb

No experiences with turbos or diesels but I swear that I read somewhere that tonneau covers actually hurt FE on a truck. I dunno, just something that stuck in my brain. I'm probably just confused.

same here. Mythbusters also did a piece where it shows that the tailgate up was better than tailgate down.

[MetroMPG]

Originally Posted by krousdb

I'm probably just confused.

Yup, I'd say confused! Tonneaus are better for FE. To test this properly, you'd have to do back-to-back runs, not just compare two separate trips under different conditions.

Diesel & turbo info - I'm sure if you headed for a VW forum you'd likely find plenty of diesel specific info.

Surely there's a forum for your specific truck somewhere, isn't there?

[Sludgy]

Originally Posted by MetroMPG

Surely there's a forum for your specific truck somewhere, isn't there?

Yes, there are a bunch of diesel truck forums out there. I've been there. Unfortunately, about 90% of their respondents eat bananas, and their knuckles touch the ground.

At Gassavers, the average IQ is at least 30 points higher.

[GasSavers_Ryland]

yes, the turbo sould work best at higher engine speeds, and with that added air bost your efficency, you said you have a scangauge, so why not try different speeds, on the same road, and find out where you hit your peak? your engine might not be tuned to run efficently at low speeds, after all, who drives 65 any more?

[krousdb]

Originally Posted by Sludgy

Yes, there are a bunch of diesel truck forums out there. I've been there. Unfortunately, about 90% of their respondents eat bananas, and their knuckles touch the ground.

At Gassavers, the average IQ is at least 30 points higher.

I'm not sure if that was meant as a compliment or ann insult.

[MetroMPG]

And bananas are one of my favourite foods...

I would have thought the turbo advantage would come from increasing power at low RPM where losses to friction are lowest. A non-turbo would have to rev higher to develop equivalent power.

A turbo CVT vehicle seems like the best mix of technologies to me.