jimt_yz400

LIFETIME SPONSOR
Dec 25, 2000
314
0
Is it possible to do something to this pig of a motor to get better gas mileage?
I've installed a KN air fliter and this seemed to have a small affect. I now get 8mpg pretty much steady whereas before I'd get down to 6mpg.
Would running a synthetic oil like Mobil 1 help?
Would I have to run synthetic in the differential also and the tranny ?
 

jeb

Member
Jul 21, 1999
633
0
I understand your pain. I've owned 2 454 GM trucks and 1 460 ford in our RV. They are all pigs and there's just not squat you can do about it to make any significant difference. My last 454 was in a 99 GMC suburban and it was a lot better than my early 80's 454. I got about 13mpg on the hiway with the 99, 9-10 all around and 6-7 towing a trailer down the hiway. The older one got about 9-10 no matter what. While 3mpg isn't much, it's big in percentage gain. I now have a diesel truck and that's the only way I've found to get good mileage out a full size truck. 17mpg consistently all around town driving with 300 HP and 520 ft lbs of torque in crew cab 4wd full size truck. I can live with that.
 

jimt_yz400

LIFETIME SPONSOR
Dec 25, 2000
314
0
I've actually knocked around the idea of doing a Diesel convertion but I think that would WAY too much money!! I was told about $6,000 for the motor and then we don't know if the tranny would hold up.
It's really too bad since we'd use the thing more if we could go more than 200 mile on a tank!! Heck, I'd be happy as a clam if I got 10 -12mpg!!
 

Highbeam

~SPONSOR~
Jun 13, 2001
665
0
Give Gale Banks a call. I think it's www.Bankspower.com. His kit will maximize the efficiency of your 460. That engine is a particular project of his that he likes to make examples of. The thing is it is a pricey kit and you have to weigh the costs vs. the benefits and how long it will take you to break even. The site gives mileage improvement % over stock so you can do the math.

I do have to say I am amazed that a K&N gave you a 30% increase in mpg. My K&N didn't do squat.
 

jimt_yz400

LIFETIME SPONSOR
Dec 25, 2000
314
0
I wouldn't say 30% increase. It's just that I used to get 6mpg climbing hills and bucking a head wind but now it's a little more and maninly more consistent than it used to be, but maybe my calculations are off!! I know that
using my friends GPS last weekend the speedo is fast by 4mph.
 

Highbeam

~SPONSOR~
Jun 13, 2001
665
0
If your speedometer is fast that means the mpg is worse than you think. As far as synthetics, there are some good stories out there about people getting much better mileage when they switch to synthetic. I replaced the rear differential's oil in my pickup with synthetic and can't say I've noticed any difference.

You are pulling around a heavy vehicle, motorhome right?, so I wouldn't expect very good mileage. Is everything running well? A crappy tune or poor alignment can hurt your mileage pretty bad.
 

Katoom

Member
Feb 19, 2002
35
0
I've never talked to anybody who got better than 9mpg with a 460, with fuel injection. I wouldn't spend too much money trying to get better gas mileage. If you have an automatic transmission that could be part of the problem too as they tend to be rather ineffecient. Some aftermarket ignitions such as MSD and Jacobs claim mild mpg improvements but I haven't ever tryed one. Or you might be able to get an extra mile or two by "side gapping" your spark plugs, but then you have to change them more often.
 

Dirty Dave

Sponsoring Member
Jul 31, 1999
216
0
95336
What year and model vehicle is the motor in? I have an '83 E350 4X4 long van with the 460,auto trans, & 3.50:1 gears. I have added the following:
Edelbrock performer 650cfm carb/manifold, torque plus intake gaskets, Doug Thorley Tri-Y headers, 3"exhaust w/Dyno-Max RV turbo muffler. The carb isn't smog legal for the van but all the smog stuff hooks up and it works excellent. I get 7-8mpg towing 22' weekend warrior trailer and 13-14mpg without. I am thinking about performer cam if I rebuild the motor. The intake gaskets are the ones with the screen over the intake ports and they work as advertised (until the motor spits back through the carb) I could feel an improvement right away.
 

jimt_yz400

LIFETIME SPONSOR
Dec 25, 2000
314
0
Dirty Dave,
It's a '90 Flair Motorhome with a 460 fuel injected motor. It'a REAL pain to work on it also!! I'm not even sure if I could change the darn belts on it since you can't get in over the top of the radiator and it's difficult to do it from the bottom. So, I'm not sure that I can do to many things to the motor given the
design of the motorhome (Class A). Thx for the advice though.
 

Dirty Dave

Sponsoring Member
Jul 31, 1999
216
0
95336
jimt, since it has f.i. disregard all add-ons I have except the exhaust system. one of the other guys in this thread mentioned the 'banks' performance stuff,,,they use the same header style I have and combined with a nice low restriction muffler and 'large' diameter pipe it is about all you can do. good luck. hope to see you on the trail sometime!
 

dave186

Sponsoring Member
Nov 19, 2001
904
0
With FI you should be getting a bit better mileage than that. I would take it to a good shop and have them give it a tune up, maybe change the plugs and wires. I have a 1975 F250 with a 390 and when im pulling a 14' camper and 3 bikes in the back, it gets about 7-10 depending on how many hills you climb. Empty it gets 10 city, 13 highway. Thats with a 750cfm edelbrock carb, dynomax headers and dual 3" exhaust with an H pipe. Im guessing you have something wrong, or has it always got that bad of mileage? if so, exhaust is probably going to give you the biggest single improvement.
 

jimt_yz400

LIFETIME SPONSOR
Dec 25, 2000
314
0
Dirty Dave,
We need to hook up sometime, you're just down the street, well sort-of, maybe 30 mile down.

Dave186,
It's always got bad mileage, remember it's a bloddy motorhome(class A). It's like driving a huge oversize breadbox down the highway!! It's a little better with the KN air filter. It's only got 17,000 miles on it but maybe I will give it a good tune up.
Synthetics won't do a darn thing huh?
 

dave186

Sponsoring Member
Nov 19, 2001
904
0
If the K&N did good, definately check out the exhaust. I doubt that just switching to synthetics will do much, but going to lighter weight oils would. I wouldnt recommend putting lighter weights in the motorhome, cause its obviously going to be working things pretty hard. This also brings up another controversial topic, oil additives. I personaly have seen SOME improvement from using Energy Release. I put it in my engine, tranny, transfer case, and differentials and got maybe 0.5 MPG increase. The stuff is pretty expensive, but i have connections to the factory and got a gallon jug of it for free.
 

rickyd

Hot Sauce
Oct 28, 2001
3,447
0
Jim,
I have a 90 f-350 4x4 w/a big block.. I added the K&N, a flowmaster & use valvoline max life oil.. with the k&N & the flowmaster i picked up about 3mpg.. Picked up roughly a 1/2mpg w/the valvoline, not to mention stopped my oil leakage.. Also, inside the FI air tubes, i cut the cones off the plastic..Hope this info helps you out.. WHere do you ride at, im in union city??

Rick
 

jimt_yz400

LIFETIME SPONSOR
Dec 25, 2000
314
0
Well, if I could get a gallon of it for free I'd give it a go!!
I'll try to tune it up and see what happens. That's the cheapest thing to start with.
The reason I'm asking about the fuel economy is due to the fact that I'm taking my son up to Canada to visit my relatives. We're taking the motorhome, trailer and 3 bikes. We plan on riding in as many places as we can on the way up and the way back. I also have a stupid over active clutch fan that is REALLY annoying and I can't seem to find an answer to that either, other than replace it with another OEM part to see how long that lasts!!
Thx!!
 

jimt_yz400

LIFETIME SPONSOR
Dec 25, 2000
314
0
rickyd,
I ride all over the place. Carnegie, ClubMoto, (it's just down the street), Foresthill,Stoneyford.....I just got back from 3 days in the Mojave, a place called Jawbone, that was a real kick in the pants!!
What do you mean by the cones in the intake tubes?
Did you get a whole new exhaust and how much was it? I need something quiet for the long drives, I hope that's possible.
 

rickyd

Hot Sauce
Oct 28, 2001
3,447
0
Jim,
On top of your motor there should be 2 large rubber tubes leading to your fuel injection, if you notice there should be hose clamps roughly in the middle of the clamps..These tubes deliver air from your air filter.. what they did was restrict the air, i cut the cone off and it made a little difference..didnt cost anything either.. For my exhaust, i installed a flowmaster muffler, its a 3 chamber so its not as loud, which i like.. It has the chrome tips below the bumper too..
I go riding out at the Battlefield usually on saturdays.. I have a 2 tone brown f350 sitting on 35's.. Im a beginner too.. Hopefully we'll see you out there.....
Rick
 

jimt_yz400

LIFETIME SPONSOR
Dec 25, 2000
314
0
rickyd,
I'm going to Club Moto sat. morning. You're welcome to drop by. I'll be in a '93 Chevy p/u Teal, with a white 12ft enclosed trailer. There will be a German Shepard guarding the trialer, he's not mean and won't bite but he'll probably lick you to death (loves people, hates other dogs).
 

Dirty Dave

Sponsoring Member
Jul 31, 1999
216
0
95336
I know this is off the gas milage thread but if you ride club moto in the weeknites and you see a yellow MBZ on the road watching the crowd give a wave... We stop by every tues, wed and Thur nites about 4:30 on our way home
 

jimt_yz400

LIFETIME SPONSOR
Dec 25, 2000
314
0
Well, if you see a YZ250F with black number backgrounds with the number 21 on it that is probably me. I'll look for you when I'm out there the next time, possibley thursday night.
 

jeb

Member
Jul 21, 1999
633
0
Just got back from a 1440 mile trip with my 460 equipt 29' 95 Coachman Class C RV. Hauled a 19.5'x8.5' tall double axle enclosed trailer with 4 bikes and lots of gear in it. Most of the driving was on interstate where we did anywhere from 67-72mph in 65 and 70 zones. Trip fuel average was 5.07mpg. Just the price you pay unless you have a diesel, IMO. Pays off in savings of hotel and restaurant bills. Fuel cost was $330 for 3 guys to ride from Friday to the following Thursday. Pretty resonable, I think.
 
Top Bottom