I Might Have Hit The Wall Today
 

I always thought I could get to 30 MPG with this truck, but to do so I needed more help from my gearing. I figured an overdrive could do it.

Wrong!

It mght get me to 30 MPG, but I'd need to be Bill Gates to afford it.

First, the nearby US Gear rep - a respected and reliable firm told me the no longer installed US Gear overdrives because they could not get parts. That's sad. US Gear was once reliable, but US manufacturing is in free fall so it is a plausible problem.

Gear Vendors is still in the business, but the quote was $5,000 installed. $5,000! To justify that I'd have to drive more than the distance to the moon - 278,000 miles or so.

Maybe its time to admit I've gone as far as possible and get something else.

Ah, man that stinks. And with your axle, I reckon 3.08 is as low as they go.

Hey, you never know - Bill Gates might just read this and give you a call?

Still, over 26mpg on an F-350 is huge - the EPA guesstimate for the F-150 is only 19mpg highway, I'd reckon the 350 with its heavier everything would probably rate way lower. So you're still ahead of the game.

Look at it this way: I'm struggling to get the same kind of mileage from my Subie Forester. Half the size, half the power, same mileage.

Add a bellypan and see what that gets you? Or fender skirts?

Assuming you are not hauling anything in that 1-ton, how about switching to a lighter duty transmission and rear end from say, a wrecking yard mustang? There may be taller factory 5th gears and R&P's available if you selectively mix-n-match. Your FE would surely benefit from light duty parts and the lower parasitic lossses, when compared to the huge gear contact areas and hypoid contact patch the F350 parts have.

The other way to look at this... heck, is it's your hobby! Golf green fees are getting up there, fishing requires a boat... spend that same dough on an overdrive unit to prove a point with your truck (afterall, if you were just after a cheap commute, an F350 wouldn't be anyone's first choice) I say dam the cost, look past the paper calculation and go for it if you can afford it.

Almost 27 with that monster is still great... I'd love to get that with my Jeep. If I was driving it more right now I'd just be happy with 25, since I already passed my first goal of 22...

Are you diesel? Some vendors have come out with a MPG water/meth kit. Might be something to look into.

Just drive it.... maybe the transmission will go out and you'll have an excuse to smile (just a little bit) when it breaks!
x2 on the wheel skirts

You have really set the bar high for all truck owners looking to get better fuel mileage. I would keep going! You can't hit a wall with that thing because it will go right through it!

Haha, I just got the theme of your "Nice Road Trucker" thing. Good show, but I can't stop watching "Deadliest Catch".. don't ask me how I relate those two shows together.

Anyway... I second the idea of an 8.8" transplant from a mustang. You will have to switch your rear rims to make it cost effective, but you can get at least 2.73's for an 8.8". I have an 8.8" in my mustang and it withstands 550hp launches on slicks consistently w/o breaking.. the stock 28 spline axle's are another story, but they will hold fine if you aren't beating on it... which somehow I doubt you would be, given that you're getting almost 27MPG in a 350.:thumbup:

Edit: come to think of it, I remember reading that some Excursions had 2.73's.. maybe something worth looking into also.

I would go to a 5.9 cummins before I would put that kind of money into an OD. There should be a significant amount of friction reduced with a cummins because it is a six and has less CID. I know, I know big bucks too, but that would be the hot ticket IMO.

I've tried to keep the truck true to its mission. It can tow and haul just like stock. But a lot of these heavy-duty components limit my options.

Maybe its time for a different vehicle. Two options would be either a Chevy 4x2 half-ton or a 1994-96 Caprice. Both use the same drive train.

I can get either of them converted to T-56 Corvette six-speed. The T-56 has two overdrive gears. Fifth is 0.71:1 (about what most overdrives are) and sixth is a whopping 0.5:1.

The light-duty GM axles host gears from 2.47 to 4.88.

There are a ton of slam kits for both vehicles.

The engine choice would be either a GM 6.5 or a Cummins 4BT3.9 diesel.

Both offer some scope for aero-mods.

I can get either vehicle fairly cheap - $3,000 to $6,000. The low cost allows making exotic moves.

With either, I think 35 is possible and a project done for under $12,000.

taller rear tires?
Maybe a different Sterling or a Dana axle has higher gearing available

Dave what did you do to lower your truck in the front, springs from a 5.4? Any issues with re-alignment?

I used drop I-beams and shackles to accomplish the drop. Same springs. The truck re-aligned with no issues.

The 3.08 is the best I can do without putting a GM axle under the truck.

I've tried larger and smaller diameter tires. The current tires (235-85x16E at 105 psi)are optimum.

I've got a 94 f350 cube van with a 20 foot box and 7.3L NA deisel. I get HORRIBLE mileage in this thing. Especially over 90km/h (my consumption doubles when i get to 115km/h, but that's full throttle). It has a THREE speed auto tranny that shifts by RPM, NOT engine load! What the hell can I do to my truck to get reasonable mileage? I will continue to drive 90, so that's no biggie. What would a better tranny cost me?

The Caprice might be the better choice. Cd of 0.34 is a major bonus. On the other hand, the parts for the diesel conversion of the truck pretty much already exist. Lots more fabrication involved with the Caprice.

The GM 6.5 is almost a bolt in but gives a more crowded engine compartment. The GM 6.5 and the Cummins 3.9 are about the same weight - 700 pounds.

The Cummins is taller and may require some hood mods, but I'd just do the same hood reslope that Phil (Aerohead) did on his T-100. The Cummins would require the motor mounts to be relocated.

Either engine will require body sound deadening material.

Not only does the Caprice have a better Cd, but also a slightly smaller frontal area. The pickup has a roomier driver's position and a more upright seating position.

Much to consider.

Keep setting the bar high for the rest of us "truck junkies".:thumbup:

I've gotten 25mpg on a few commutes home from work and that is just with driving changes. When I get up off me ars and get some aeromods done, I hope the numbers will bump up.

Post-Mortem
 

What killed me is the very configuration that helps me out-MPG most trucks: 4x2 and stick shift.

The adapter kits for 4x4 automatics are pounded out in quantity (probably in China) but they have to make up 4x2 kits individually. To add insult to injurt the 4x2 manual setup does not bolt the tranny but is "divorced" - the overdrive hangs off an additional ctossmember on the frame. It is nicely engineered but saltier than something from Gale Banks.

It shows the degree to which 4x4 and automatics (two MPG-killers) have become the standard in the industry.

Maybe I should quit fighting the mechanical battle and go at it from a bodywork angle. Do like Red and get a fugitve-from-the-junkyard Insight, and take it to a custom body maker and have the roof raised five inches.

I guess I'm confused with your goal Dave. Since you are "Big Dave" I'm going to assume that you are tall and that's why you buy larger vehicles. My BIL is 6'4" and loves his Scion xB. The headroom is truly amazing and the seat goes back pretty far. True, it's a little pokey, but with a 5-speed he has no trouble getting on the highway. Do you have other needs to be addressed by your daily driver?

Think 6'10". At least thats the headroom I need.

Big Dave -

I'm sorry that the Red Baron is maxed out (for now). I hope you're not going to sell it. In the right driver's hands, it's probably the most valuable F-350 in your state.

CarloSW2

How about this nice Dodge Sprinter chassis cab? You could fabricate a nice boat tail behind the cab that could still be usefull for secure storage. :thumbup: I couldn't find a pic of a bare cab without a prefab bed.

http://www.performancecars.ca/var/ez...fullscreen.jpg

Make it look like this:

http://www.diseno-art.com/images/mcq...liner-rear.jpg

YA BABY!!!