Community Forums

TheCatsRV · 11-11-2021, 08:22 PM

If you need to soup it up, a Chevy BB may be the cheapest option. Intake manifold (Edelbrock Performer?) and exhaust headers at least. Cam maybe. Look at the ignition if yours is tired. Fuel injection too. I saw a 1989 Triple E that s had a Rochester QuadraJet.

2nd the vacuum gauge idea. It'll tell you if something may be amiss in ignition too. Idle and very economical cruise the engine should be drawing 20 lbs. Deceleration 25 maybe more. WOT will drop it down to 0 and very poor economy. Higher the vacuum, the better the mileage.

RM Art · 11-11-2021, 10:36 PM

Quote:

Originally Posted by Bill Inman

I have had a carburetor 454, and now own a TBI 454. They both benefitted greatly by using AC Rapid-fire spark plugs,, gaining about 2mpg on average. Nothing else needed.

Bill - Interesting. AC Rapid-fire spark plugs you use have palatium or iridium material firing pin?

78 Stretch · 11-11-2021, 11:06 PM

Well if you have a carb change to a vw carb to start the engine then add a HHO system to run on hydrogen this is what I did on my 2009 Georgetown 34' there I installed a 200 amp alternator and 4 HHO dry cells running 25amps each and getting 40mpg I'm happy with that since I have a V10 with volo computer running the injectors and SSL exhaust keeps the engine clean also,I also put one on my sons tractor trailer and hes getting 20mpg hauling 50,000# of cargo

RM Art · 11-11-2021, 11:25 PM

Quote:

Originally Posted by 78 Stretch

Well if you have a carb change to a vw carb to start the engine then add a HHO system to run on hydrogen this is what I did on my 2009 Georgetown 34' there I installed a 200 amp alternator and 4 HHO dry cells running 25amps each and getting 40mpg I'm happy with that since I have a V10 with volo computer running the injectors and SSL exhaust keeps the engine clean also,I also put one on my sons tractor trailer and hes getting 20mpg hauling 50,000# of cargo

2009 34' RV - getting 40 mpg / Tractor doing 20 mpg - hauling 50K lbs. cargo

Very interesting. Please elaborate a bit more...

Roadwarrior7 · 11-12-2021, 06:10 AM

Quote:

Originally Posted by Soppy

Banks headers and cold air intake will make a difference as well.

Retired mechanic and race engine builder here.
Please explain in technical detail how a cold air induction INCREASES fuel mileage. They most certainly can increase HP due to a denser air charge but I doubt they increase fuel mileage when they slow fuel atomization.

Steve VDL · 11-12-2021, 07:36 AM

You can reduce fuel consumption on any vehicle by reducing aerodynamic drag. I removed all roof top A/C, ladders, vents, and obstructions to airflow on my 35' Triple E Empress. MPG increased by about 0.75 to 1 mpg. Other most economical routes are to use a free flowing exhaust and an OD. Your goal is to fill the combustion chambers with a fuel air mixture at the lowest possible RPM to maintain your speed.

2upServant · 11-12-2021, 08:06 AM

Would look at how many miles you are driving, where you will be driving, and what was suggested as to which motor you have. If it is carburated, I will bet you have 4>11 gears. Some simple mods may get you a couple of MPG upgrades.

lonfu · 11-12-2021, 08:25 AM

I've owned half a dozen 454's. last one was in a Itasca moho, drove it for 20 years and 140k miles. yours is not fuel injected I believe, but the carbs on these are notorious for the jets getting clogged up.
first I would try in injector cleaner like seafoam, then go for a rebuit unit from a top quality rebuilder. There are several in texas where you send yours in and they rebuild it with a full lifetime warranty.
2nd slow your butt down, drive 50 mph and see if you hit 10mpg, these were designed with the fuel shortages in the 80's in mind.
3rd, make sure the fan clutch is operating correctly, another weak point on 454's.
4th check the plug wires they will need fiberglass high temp boots on them to keep them working correctly.
5th, check the exhaust man gaskets, get stainless steel ones not the cheap felpro's.

garyb1st · 11-12-2021, 09:02 AM

Weight and speed. Our big V8 pulling 26,000 up and down the highway get's us an honest 6 mpg. Don't like it and would prefer a diesel but and it's a big but. BUT I don't think I'd like the cost of service. I'm pretty sure that would more than offset any improved mileage.

Bottom line for us. With ideal conditions and not running the generator or dash air, we can probably get close to 7 mpg. And our Pace is chipped with the Ultra Power package. Previous owner put it on so can't say if it's helped with mileage. But we're in the west and there are not many outings that don't involve a lot of grades.

I don't rely on the lie-o-meter, but I do find it amusing. Mileage goes from 2.4 mpg on steep grades to more than 40+ when coasting downhill. While I don't know how accurate the 2.4 mpg is, I know when we're going up a grade that's more than 2 or 3%, we're not getting 6 or 7 mpg. And it seems we're doing that a lot.

As far as reporting mileage, I'd love to see a thread where other conditions were identified. Things like location of travel. Is travel in the flat midwest or in the mountains if the West? Even the hills in the East can be challenging. How much does the RV/toad weigh? How many years since you had the plugs replaced or other engine components checked replaced.

There are so many elements of fuel economy that a simple mileage number is almost meaningless.

MinntoMich · 11-12-2021, 10:08 AM

Quote:

Originally Posted by Roadwarrior7

Retired mechanic and race engine builder here.
Please explain in technical detail how a cold air induction INCREASES fuel mileage. They most certainly can increase HP due to a denser air charge but I doubt they increase fuel mileage when they slow fuel atomization.

Not Soppy but I'll chime in with my experience. I've noticed over the years that fuel economy for me has always been best when traveling in the morning or evening when temperatures are between 50 and 65 degrees fahrenheit. The wind is less a factor as well. Doesn't matter if it's a 4 cyl. or the 454 in my MH I think cooler air does get you more miles out of a gallon of gasoline. The exceptions were a Bronco (351) and a Taurus (3.0 Vulcan). Those got the same mileage no matter what I did.

I wouldn't spend the money on a new air intake though. The benefit on your MH's mpg would be too minor to justify the expense and mickey mouse. There are other things you could do that would be free.

TheCatsRV · 11-12-2021, 10:19 AM

Quote:

Originally Posted by Steve VDL

You can reduce fuel consumption on any vehicle by reducing aerodynamic drag. I removed all roof top A/C, ladders, vents, and obstructions to airflow on my 35' Triple E Empress. MPG increased by about 0.75 to 1 mpg. Other most economical routes are to use a free flowing exhaust and an OD. Your goal is to fill the combustion chambers with a fuel air mixture at the lowest possible RPM to maintain your speed.

So true. RVs are as aerodynamic as a shed or small house (i.e., not very). The nose of some Class As mostly in the past seemed to have some sort of slanted front for better aerodynamics but not sure if that helped. Certainly newer Class As have a very square and blocky front. The square rear does not help either.

Never been too happy with all the stuff up top adding drag but you can't seem to live w/o them (nor are some simple to remove).

Aerodynamic drag also increases geometrically in proportion to speed so travelling at 66 instead of 60 will result in drag going up more than 10%. Easiest way increase fuel mileage is to slow down.

jackag · 11-12-2021, 09:57 PM

had a 1992 georgie boy 32.5 ft with a 454 tbi engine. i consistantly get 8 to 9 mpg.
i usually drove below 6o mph. Once had the oxygen sensor go bad on a trip and mpg droped to 6 mpg. Once the sensor was repaired, went back to 9 mpg. things that can reduce your mpg is anything that obstructs your exhaust such as bad muffler or catalytic converter.of course a tuneup wouldn't hurt either.

TheCatsRV · 11-12-2021, 10:45 PM

Quote:

Originally Posted by jackag

had a 1992 georgie boy 32.5 ft with a 454 tbi engine. i consistantly get 8 to 9 mpg.
i usually drove below 6o mph. Once had the oxygen sensor go bad on a trip and mpg droped to 6 mpg. Once the sensor was repaired, went back to 9 mpg. things that can reduce your mpg is anything that obstructs your exhaust such as bad muffler or catalytic converter.of course a tuneup wouldn't hurt either.

The computer uses a limp mode in such an event so the engine doesn't run too lean and burn a hole in the pistons.

Oldman5145 · 11-13-2021, 05:41 AM

I bought a motorhome for my enjoyment. If gas mileage and economy is your main concern you have boarded the wrong ��. You need a tiny smart car and a ⛺. Sorry, I own a motorhome for me and my wife's comfort. Fuel cost is only a piece of the puzzle. I can buy a lot of fuel for the thousands of dollars spent making it economical that won't help the resale value.