Engine/Transmission (1998.5 - 2002) Fuel Mileage Improvement - Towing

[John Berger]

I can't believe I forgot to post this. I got the first tow with the Montana 5ver when I went to Bristol last weekend. First trip up, running I-26 then 19/23 with grades and hot weather: 11. 8 mpg. Speeds varied from 61 to 67, usually in the middle, not using cruise control. Coming back home, we saw a ton of rain in South Carolina, which slowed me down to the mid-40's a couple of times, I got 12. 2 mpg. The best I ever did with the lighter travel trailer was 11. 1 mpg and that was with the SBC installed. The best mileage I ever got with the stock clutch was 10. 2 mpg. I think there are two primary reasons for the difference: The Montana is a bit more aerodynamic than the Nomad was, although it is still a big box. The other reason I think is the better South Bend Clutch. My stock clutch must have really been dragging the mileage down.



Another theory: Is my engine finally breaking in at 80K miles? I've done some extensive heavy towing in very hilly country since April. Coincidence? What do you guys think?

 

[NVR FNSH]

Aerodynamics. Power required is proportional to speed squared if I remember correctly. I really can't imagine the clutch had anything to do with it.



Brian

 

[Turbo Horseman]

My guess is your enigine got a little too hot and set a code which cuts the power 40%. Unfortunately it doesn't cut the fuel consumption. Probably increases it because you're on the accelerator more. This happened to my truck without getting near overheating. Thought my lift pump was going for the third time. Had the code reset and the radiator pulled and the fins cleaned.



Truck runs like new again.



Stupid, stupid D/C.



Have your codes checked.

 

[NVR FNSH]

Can you offer any more details regarding the 'overheating' setting a code? What temp/where on the gauge where you running when the code set? I got near the top of the normal operating range on the gauge while towing a couple of weeks back..... Now, I'm curious.



Brian

 

[Forrest]

I'm with Brian ... the aerodynamics work.



I had a 78 Ford Bronco towing a 20' Aristocrat. I put a 2' wing on the Bronco & gained 1. 5mpg. I had no idea that $40 on sale piece of plastic would make that much difference.

 

[jboehm]

Been towing a 30 foot Jayco 5ver the past 3 years with a 98. 5 2500, automatic. . Not full time, mind you, but best I got was really, really close to 16 mpg TOWING! And average 14-18 on 30 mile commutes and around town, in summer,. . but, and I think this is a BUT... you have to keep your foot out of the throttle towing. In other words, I can cruise at 65, with pedal to use, but. . don't. The worst I got was about 13mpg, towing. . but that was in with a headwind to boot. Stock everything then too!!

 

[John Berger]

The reason I was thinking clutch was not just the fuel mileage, but the engine sounds and truck vibrations as well. My wife noticed it too, when I pulled the trailer the first time after the clutch was installed. Acceleration was much smoother, especially on grades. The engine didn't sound like it was working as hard and there was less vibration in the drivetrain. If a clutch is going bad, why wouldn't it have an effect on the drivetrain, and consequently, fuel mileage? As for aerodynamics, the Montana 5ver's have the rounded cap on the front and back of the trailer, plus you don't get much sway with a 5ver, which would probably ease the work load on the truck. I lost my TT in a wreck, which also happened to be the first extended trip I took after the South Bend clutch was installed. Prior to that the best fuel mileage I ever recorded was 10. 1 or 10. 2 (can't remember off the top of my head). I got 11. 1 (best) and 10. 6 (worst).



Regardless, I'm tickled with the increase in fuel mileage. Oo. Oo. Oo. Oo.

 

[Steve Campbell]

Part of that gain...

in fuel mileage, is the front of the 5er is closer to the back of the cab than the TT.



Read John Holmes review of his use of "air tabs" in issue 37.

 

[keimmmo]

I have towed several trailers over the same roads with the same truck... major differences in how different trailers pull and the economy I get!!! A topper really helps with a pull type!



Steve

 

[NVR FNSH]

If the clutch was slipping enough to decrease fuel mileage you should have smelled it long before you got thru a tank of fuel



Going down the road the clutch is 100% lock-up or at least it should be.



Brian

 

[pwr2tow]

Wind direction and speed play a big part in MPG.

The speed you fillup the tank and if at the same station and even the same side of the pump plays another part. Alot of variables come into play.



Ron

 

[MLee]

another thing might be, is if you fuel in the morning, when it is cool versus the evening when the day has been hot. the fuel, when pumped in the am is denser, i believe it was in Jim Anderson's article in issue 37 on trailer towing. (don't gout me on that. ) just my penny's worth.

Marv.