Getting Mileage in a Motorhome

[Beaver]

I removed the A/C unit from the roof of the MH. I noticed an improvement in handling; it is less tippy in corners. It also seems like there was an improvement in fuel economy, although there are other possible factors, such as my getting used to driving the thing, and figuring out optimal speeds (44-45 mph in 4th gear, converter locked). On a round trip from the central Willamette Valley in Oregon to Vancouver BC on Interstate 5 we were able to get close to 17mpg on a regular basis, and on one fillup managed around 18.6 with favorable winds. The MPGuino has proved to be a very valuable tool which I would recommend to anyone with a pre-OBD-II compliant EFI rig. I still have plans for aerodynamic imporvements like an under-bumper air dam, rear wheel skirts, and cleanup items like flush mount clearance lights etc. I'd like to thank everyone for their ideas and interest.
Cheers,
Beaver

[pete c]

I have a '90 toyota odyssey which i haven't put enough miles on yet to know mileage. Used to have an '86 sunrader with the 22RE auto.

Folks in the toyhouse world seem to think these things with autos actually do better in 3rd gear. The toyota OD tranny has a very high 4th gear. Driving them in 3rd is recommended by many. Others actually recommend going to a lower (higher numerically) RE as it allows the tranny to spend more time in OD.

If you want the best mileage, look for an older 22R equipped rig. Most of the 22REs are slushbox equipped. Many of the older carbed 22Rs have 4 speed sticks. These have been known to come close to 20 mpg. I suspect hypermiling should get them a mile or two better than that. I would be willing to bet that driving east across wyoming, you could do well better with that ever present 40 mph tail wind.

Another option is the winnebago lesharos. they came with the horrendous renault diesels. Many have been repowered with mopar 3.3 transaxle drivetrains out of minivans. these will do a fair bit over 20 mpg. i would love to have one of these with a tdi powertain. i think 30 mpg could be doable.

[Beaver]

With my 92 Itasca I regularly get 16-17, and occasionally into the high 18's. This is using 4th gear at or near the lowest speed that 4th will engage (45 -50 mph). Wind is my best friend and worst enemy. I've looked at the LeSharos and the Rialtas, but they don't have dual rear wheels, so I worry about tire loading. My Toyota is lighter at 6000 lbs, than the Rialtas, and the tire loading is considerably less, at @1000 lbs compared to over 1500 for the Rialta. I suspect the LeSharo is similar to the Rialta. They are definitely more aerodynamic than mine though. On Toyota MH websites I hear lots of unsubstantiated talk about 20+ mpg from these MH's, but I'm skeptical. I use the heck out of my MPGuino, and it really helps me adjust my driving habits on the fly. It also makes driving it more challenging and fun. Drafting big trucks on the freeway (at a semi-respectful distance (pardon the pun)) helps a lot, if they would just slow down for me.
As for getting better mileage in 3rd gear, I haven't found it to be helpful. First of all I would have to slow to around 35 mph to take advantage of the reduced wind resistance, but it doesn't seem to do any better that 45 in 4th. Most of the time traffic would not allow me to drive that slowly with any amount of comfort. If I ran it at 45 or more in 3rd my mileage would definitly suffer, and the engine noise would be really annoying. Let us know how you do with your Odyssey, BTW, is that a 4 cyl or a 6?

[pete c]

beaver,

that is pretty good mileage for a 6. don't know what i am getting yet, but, i fear it will be bad. i have the 3.slow V-6 as do all 90+ toyhouses. i have 120K on it and just did a valve clearance check/adjustment. all my exhaust clearances were tight, some very tight, and i fear i may have already incurred some exhaust valve burning. we will see after i get a few hundred miles on it to get an idea of mileage.

do you post at toyotamotorhome.org or the yahoo group? there is a lot of debate on the yahoo group about the use of OD. your input there with MPGuino data would be interesting.

many seem to think that they should never be run in OD due to tranny overheating issues. my take is that OD can be used, but you need to be smart about it. running the 4 cylinder autos in OD with your foot into it, is a bad idea. better to leave it in 3rd and let that 22R spin. it can take it.

[Beaver]

I've gathered a lot more data since my last post; we took a trip from Corvallis Oregon to the Florida Keys and back, mostly on I-5, I-10 and I-95. I kept close track of mileage and dumped the data into an Excel spreadsheet for analysis. We averaged slightly above 17 mpg, with a low of 14.1 (in heavy city traffic mostly) and a high of 23.8 (across the plains with a raging tailwind). Since returning I have continued with minor mods including building a front air dam from a plastic front bumper of the right size that I found lying beside the road. I also installed a solar panel and disconnected the coach batteries from the engine alternator. This seems to have helped mpg considerably, though I don't have enough data yet to have high confidence. The best investment I've made to increase mileage, though, is the MPGuino. I will be building air dams for the top-mounted stuff (vents, solar panel etc). More later...

[5bikes]

If the little Toyota RV gets 17 and I get 9 on my 33' Class A (about 16k lbs) with a Ford V10, I think I'm doing great. Ya 17 is better but then 9. But I got power, many amenities, lots of room inside, 2 A/Cs, 3 beds (1 a queen), a refrig for 2 weeks of camping, a real bathroom, more storage than we got stuff, and can pull either a car, several motorcycles or a boat. Had a old class C that got 7-8, a class B that got 15-16, with no room, shower, poor bed, etc.
I've made many mods to get 9, but the Scan Gauge is biggest help. I'll keep my Monster, was hoping to find some help getting it to 10 mpg.

[pete c]

Just got back from our first trip in the Odyssey. Got 16 mpg, mostly highway. Generally keeping to the 55-60 mph range.

Beaver, would love to see some picks of your toy airdam.

[pete c]

Originally Posted by 5bikes

If the little Toyota RV gets 17 and I get 9 on my 33' Class A (about 16k lbs) with a Ford V10, I think I'm doing great. Ya 17 is better but then 9. But I got power, many amenities, lots of room inside, 2 A/Cs, 3 beds (1 a queen), a refrig for 2 weeks of camping, a real bathroom, more storage than we got stuff, and can pull either a car, several motorcycles or a boat. Had a old class C that got 7-8, a class B that got 15-16, with no room, shower, poor bed, etc.
I've made many mods to get 9, but the Scan Gauge is biggest help. I'll keep my Monster, was hoping to find some help getting it to 10 mpg.

If you plan on putting many miles on that rig, you might consider re-powering with a 7.3 powerstroke. Don't even think about any of the newer Ford diesels. They are utter shyte.

I would think that a vehicle that can get 9 with the V-10, should get 14 or 15 with the powerstroke.

[5bikes]

I've come up with several reasons not to have a diesel. 43 matter of fact. Number one is they're expensive, and changing out an engine would never have a payback. Diesel fuel is more expensive, you have to get 5-15% better mileage just to off set the cost of fuel.
I'm now up to 9.5 mpg. Thanks to this and other forums I've added a front V shaped air dam that's reduced under belly turbulence. Both axles are low causing lots of drag.

[pete c]

Yeah, the only way a diesel re-power might make sense is if you had a good powerstroke sitting around and a fair bit of mechanical skill and the time to do it. There are a handful of older PS C Classes out there, but, they generally do bring a few thousand dollar premium. Could be worth it if you were going to put enough miles on it, I suppose.