94 379 fuel Mileage

doing 65mph for a day isnt gonna give you real stone cold mpg, run 65 for a month or at least a week or two.
but averaging 75 mph with a flat top classic grossed out isnt going to yield good mpg, and the pete isnt gonna do any better, being able to run paper logs would be the only benefit, but you couldnt go to a company (if leased) that requires e logs with it. your best bet probably is just to try to get the fld numbers up, being that low theres nowhere else to go but up.

 

I got a 95 379 3406 e 15 speed 321 rears on tall 24's. 5.5 winter 7 summer running 65

 

Guy who parked where I kept my truck had a Columbia like mine. He had the 14L Detroit and all he did was complain about his fuel mileage. Upper 4's to low 5's was the best he could get.

He was genuinely upset when I told him my C15 averages upper 5's with 6 - 6.3 mpg on light loads. Said I must be mistaken or not calculating properly,.. LOL Mileage vs gallons at the pump. I dont see how you can screw that up.

So yeah,.. your not the only one with that 14L S60 who gets poor fuel mileage. I've read a couple dozen posts from guys with that motor and the same complaint,.. poor mpg's.

Took me a while to get mine to this point,.. but your not going to get good mileage with a CAT and 3.55 gears running over 70 - 80 mph. Never happen. I can get an honest 6 mpg fully loaded if I baby it at 63 mph. I have 3.55 on 22.5 wheels here also. I'm typically running 65 - 68 mph in mine. The sweet spot for mine is 1350 - 1450 RPM's. Anything over that and the mpg's drop off. Egg shells when rolling from a stop. I dont hammer it between gears. I ease into it a little before climbing hills. I installed a boost gauge and try to keep the boost as low as possible when cruising. So for me,.. driving habits made a big change.



Hurst

 

Talk to Erich at ss60pd dot com and see w hat he can do for you. I have gained nearly 1 mpg wityh my 12. 7 after he tweaked it.

 

Mines a Flat top Pete 2ws 3406E set at 550 + a few 13sp 3.70 on tall 22.5's.
Going off IFTA quarterly's I'm usually a little over 5 in the winter pulling half reefer, half open deck. Summer time running mostly open deck and grain hopper it's closer to 6.5 pushing 7. I'm too stubborn to fix the A.C so idle time is zero other than when it's real cold out.

 

@Ruthless may have a suggestion for you. I thinking @rebel127 or something like that.

 

Yea couldn't hurt to have someone look at your Detroit before you go changing trucks.
Pm me if you want a # @McDaniel Trucking

 

1995 w900. 18/3.70/11R24.5/Detroit; multi stop NYC and some oversize.
My other one does better, 1996 w900. 18/3.90/11R24.5/Detroit.

I don't drive for fuel mileage.
If fuel mileage matters, drive like it matters and it will do fine if it's running right.

 

I can get 5.5 mpg out of a 2007 CAT C-15 NXS tuned to 550hp pulling 94,000 lbs gross at 62 mph. I have no experience with older, mechanical CAT's, but you can't go wrong with a yellow block (unless it's an STP and you don't have 40 grand to sink into it).

If you are in it to get better fuel economy, you should look at buying a 579 or Volvo with an autoshift trans. Most conventional trucks aren't going to do significantly better than 6-6.5 pulling 80K on an open deck.