Alright, alright! The "building" does have wheels, and a very thirsty 460, Holley carb, C6 and low, low gears. I run cross country, loaded and towing, and this 7-8 mpg is sure hard on my bank account, at least in this country! It is a 27ft class c motorhome on the 1 ton chassis. Seems to me like if I had another gear, it should ease the strain on the ol' 60 and my wallet. I am in the middle of some less expensive mods, like new, skinny 10ply tires pumped to 80psi, dual exhaust, playing with the timing & a carb rebuild/replacement on the list. Oh, that right foot .... thank goodness for speed controls!

I do have experiance towing, quite a lot actually, and some vehicles tow fine in OD, some actually slow down and lug the engine, so it's back to direct. Any thoughts on hanging a built to the task AOD behind this opec thirsty monster?

If it ups the fuel economy even a couple of MPG, it really wouldnt be long in paying for itself at these horrid prices! Thoughts - experiance? Have a weiner roast with the hard earned money I would spend?

 

You will be hard pressed to get 10mpg out of a 27' class "C" w/460. Adding an OD gear might get you an extra 1mpg.

 

I wish you good luck because you need it. You have a heavy vehicle with a big frontal area, and no matter what you do, they'll kill your mpg. The best tranny would either be a ZF5 or E4OD, but they are not cheap.

 

What is your final drive gear ratio and tire diameter?

Jim

 

Gear vendors makes a overdrive unit that basically replaces your tailshaft and with it
you can split each gear and probably climb hills better and cruise more efficently.
Of course it is bookoo bucks and getting the e40 or other electric OD tranny and the
baumann TCS controller so you can control the shift points and lock up would most
likely come out cheaper!! Indexing your spark plugs to get the spark facing the center
mass of the fuel/air mixture for better ignition and burn will help and a high voltage
coil and the gap opened up will also help, Since more completely burning the fuel you
are already have will make more power and lessen the amount that gets dumped out
the exhaust or down into the crankcase. Be careful with changing the tire size and
pressure that was spec'd on that thing it could cause a bad hadling condition and
lead you to lose control or have a better chance for blowouts!!

 

I think the best (and cheapest) thing you can do is to adjust the carb for highest engine efficiency -- slightly lean mixture after the engine is fully warmed up.

 

Ok, the tires measure 30" around, and are the factory size, just 10 ply instead of 8 ply. Gears are 4.10. I guess I cant (shouldnt) complain, on the last trip I was hitting 9.5 mpg a couple of times, and averaging about 8.5. Doesnt seem to make much difference if loaded or empty, but wind is sure a factor. This was empty, running about 60mph. Seems to feel a little unstable at 65 on the rough roads. Didnt notice any difference in economy if I slowed down to 55. I did get to visit with some others driving similar rigs (what better place to compare fuel useage than a gas station on the interstate!), and found they were all similar, even slightly worse with the OD trans! Go figure! I have checked out Gear Vendors, and yeah - kind of pricey to pick up (maybe) 1 mpg.

So - sounds like I need to tune this thing to run at the existing RPM at cruise. I did do some minor tweaking before this trip, which I feel upped me about 1mpg over the last trip. I suspect a dual exhaust will help free up some power, and more tuning. Yea, I think the carb is a touch on the rich side, so I suspect a float and adjustment is in order. I dont know if this uses a standard cam, or if it is a towing/RV cam. I dont want to lose my low end torque. Headers - worthy or more weiner roast money? Probably better to pay the price and help those poor opec folks buy some new turbins

 

Trade it in, buy you an older diesel pusher, mileage will be up a lot.

 

I'd go with the full Banks exhaust kit, I think it's a single, but you gain a ton of power over stock manifolds.
Or a diesel unit with a 5.9 Cummins in it. Or maybe even swap in a Cummins in your rig- should get you up to about 12-13, maybe even 14 if you went with a 3.73 rear end.