Fuel economy and additives

100% ethanol free gas will increase your mileage, but the additional cost will probably not be worth it. The addition of fuel additives may help to clean an injector but will not help with mileage.
Basically if you do everything that can be done to increase the mileage, the only thing you will accomplish is going from really terrible mileage to just terrible mileage. RV's are not designed to be fuel efficient, even if it is a diesel. I've had diesel RV's before and the mileage is still bad, altho not quite as bad as the gasser. Of course diesel costs more so it is a wash. The only thing the mileage log will do is just remind you that the enjoyment from RVing far outweighs the cost of fuel. You are better off using the credit cards, like PenFed that offer a 5% discount on every purchase of fuel. There are other CC that may be better but that 5% discount is more than you will get from any additives.

I have good success with additives like Slick 50 and its newer derivatives. They can be added to the oil, the trans and the fuel system. They easily pay for themselves.

You can try a performance air cleaner that can be cleaned. There are some good iridium spark plugs available. Wires and injectors should be fine. Quality fuel cleaners can help keep injectors clean. Consider a tuner made for MHs. Monitor your exhaust manifold temp.

You might consider going to a larger diameter exhaust system.
With these kinds of add ons I have gotten 23.8 mpg out of a Ford diesel empty and around 13.5 pulling a TT.

I fully agree with rgatijnet1 that additives mostly just clean the fuel system and a cleaner fuel system can improve gas mileage, but not so much it will be that noticeable. However, too much of some fuel additives will have the opposite effect of lowering gas mileage until the excess amount is used up.

The only additive that will improve engine performance immediately is octane booster but only if you're using a lower octane than the engine requires. If the engine calls for 92 octane and you're using 89, octane booster will help. But if the engine calls for 89 and you're using 89, octane booster won;t do anything and may do harm not good.

The easiest way to improve fuel economy is slow down. A class A motor home is a large rectangular box that isn’t very aerodynamic.

If you’re getting 7.5 then you’re doing good. There’s not really much you can do that will improve upon that. The big aerodynamically challenged, heavy as heck RV prevents any real fuel efficiency. Keep the speed down, light foot on the pedal, try NOT using cruise. Cruise is designed to keep your speed as set, regardless of fuel usage. Keep your tire pressures placard numbers. Lower pressures for a better ride may reduce mileage, but not significantly I suppose.

Some owners will invest in a Banks power pack, or a 5 Star tune. I know no facts as to how much they help.

I think the guys above are giving you very good advice. At $2.25 a gallon your doing much better than the rest of us on the West coast. The only thing I can add is if the engine is pinging, then an octane booster will help. A pinging cylinder does not put out the same power as one that doesn't. Lighten your weight as much as possible; don't carry full water. Use paper plates instead of ceramic. Put two bottles of Chevron Techron concentrate in a full tank of gas will clean the injectors. Replace your air cleaner if it hasn't been done and slow down a bit more. There's only so much you can do with these beasts.

Tom in Tulsa wrote:

Questions:
1. Do fuel additives work and which ones do and don't. Fillups are around 50 gallons on a 75 gal tank.

2. Is going to 100% gas (no ethanol) cost effective?.

3. My Class A is 2008 (11 years old) with 53,000 miles. Is it time for a tune up and what gets tuned up? Spark plugs, injectors, wires?
I am not a mechanic and am only guessing.

1) NO, in general you don't need ANY "additives" either in your fuel or gas or transmission. The exception is a good dose of injector cleaner about twice a year. Techron.

2) You will improve your gas mileage maybe 3%. If the alcohol free gas costs more than 3% more, it is NOT worth the extra cost.
Do the math.

3) About the only thing done on a "tune up" these days is changing the plugs. BUT.....if you intend to keep it very much longer, it might be past due for a coolant and brake fluid and transmission fluid change. And a general inspection of suspension and brakes......and tires.

WOW. an RV full of info. would moving up the octane to 89 help or would that just add more cost for 50 gal. I am using 87.

I have tried a number of things over the past 15 years but only found one thing that actually worked. When I first bought the MH the exhaust manifolds were leaking so I added Thorley Tri Y headers. This increased performance but did not increase MPG, added free flow muffler, CAI and advanced timing from 4 degrees BTDC base to 9 all increased performance but saw no MPG increase. Went to synthetic oil saw no performance or MPG increase. Tried acetone in the gas once and got 9.5 mpg but never followed through to see if that was an anomaly. I then found an old vacuum gauge in my garage that I installed and my MPG went from 8.5 to 8.7 fairly consistently if I kept it over 10 in of HG. I tracked every fill up over 90,000 miles of travel and noticed better MPGs in mountainous hiway roads that are fairly straight where I could give it gas when I saw a hill then slowly back of the gas by glancing at the vacuum gauge because I new when it was going to down shift. Mountainous roads with a lot of switch backs and dirt roads up like up in Alaska drop the MPG to 8.4. I see no MPG difference towing a 2400 lb car or not towing.

Tom in Tulsa wrote:
WOW. an RV full of info. would moving up the octane to 89 help or would that just add more cost for 50 gal. I am using 87.

Your engine was designed to perform best at a certain octane. Using a higher octane doesn't improve anything. Read the owner's manual and use the octane rating they state. Using a lower octane could cause engine damage.