Increasing MPG - 1994 P30 454

[GypsyR]

Perspective on "so costly" I guess. You can get a wideband complete datalogging kit with a single sensor these days for $350. If you wanted to shop around I'm sure you could find just a sensor and regular gauge for less. And yes, if you want optimum tuning you might also spring for an EGT guage setup too. But even I consider that overkill for a gas engine that works for a living. First thing a diesel owner/tuner should buy though, as they are different animals.

At one time when we were tuning two stroke race bikes on a water dyno (and at the track) we were buying spark plugs literally by the gross. Nothing reads quite as well as a brand spanking new plug.

[bill06447]

My 91 has averaged 9.8 mpg over the last four years 10,000 miles. Hills and flatland, 70+ mph interstate and hours on winding 30mph PA secondary roads. Freshwater tank is generally full or close to it. Radial tires with pressures on the higher side help, alcohol laced fuel doesn't. Brakes dragging? Heavy right foot? Filters fresh, O2 sensor recent? Mine has dual cats/dual mufflers which are identical setup from a 91 155" wb 1 ton pickup.

I agree you should be getting better mileage.

[traveler1967]

Originally Posted by FFG

Getting around 6 mpg in a 25 foot Itasca Passage (1995) and want to improve this as others in the Uk are getting double this. I'd be happy with 10 so what re the most obvious things tho change/upgrade. I'm looking at Tri-y from Doug Thorley to increase torque but to help with engine and cab temps and I have a manifold gasket leak so its an obvious upgrade.
Look pretty stock as it is and I've changed a fair amount of consumable but I need to look at other options.
Its a 7.4 Chevy big block, HEI. Not really had any experience so any help much appreciated. Seems to run well but ticks under load (which I suspect is the gasket) but is quiet when cruising.
FFG

remember that in the UK they use an imperial gallon not the smaller one used in the USA, so that will account for a greater MPG reading from them

[christiaanva]

The US gallon is used in the United States and is equal to exactly 231 cubic inches or 3.785411784 liters. The Imperial gallon or UK gallon is used in the United Kingdom and is equal to approximately 277.42 cubic inches. Its exact value is defined as 4.54609 liters. One imperial gallon is approximately 1.2 US gallons.

[Kountry_star]

Originally Posted by RickNC

Get the front end re-aligned to Super Steer Specs and it should handle much better. Check your anti-sway bar bushings to make sure they are still pliable not cracked or missing. Koni FSD front shocks (PN # 8805 1006) made a significant improvement in the ride and handling on mine.

Do not mean to change the subject of the thread. but where does one find Super Steer Specs for alinements?

[Gforceone]

I’m driving a 2019 Coachman Concord Class C. Just under 14,000 lbs with Ford V10 Gas. Have gotten 10 mpg but average 9. Higher octane makes a differance here. I run 91/93 depending on availability. Biggest difference I’ve made in handling is to install a Safe T Plus steering damper. About 4 times larger than the one that came on the E450 Ford chassis. Pricey but gets rid of wondering and helps with passing high speed semis. I used to run at 70, but am now pretty much 65 mph. Not a big difference as to when you get there.

[TinCanTourst]

I've had my 94 27' Winnebago Brave chevy 454 since 95. I get 10 mpg. I've towed three different cars over the years including a Jeep Wrangler and a 14' enclosed trailer with motorcycles in it. I get 9 while towing. Go easy on the gas and easy on the brakes. I like 60 mph. The faster you go the lower your mpg.

[Gforceone]

Invest in a Safe T Plus steering damper. Improves wondering and handling on Class C and Class A. Thank

[rbates1944]

I have a 8.1L gas and average about 7.7 towing a crv on the interstate @ 65-70.
I have read may places that best mileage is around 50 to 55, if I drive that speed I can average about 9.

[HJLowell]

Originally Posted by Mr_D

6 mpg sounds about right for that vintage in a MH.

Yes
It does Mr D
I had a 88 454 , 4 barrel, 28ft P 30 chassis with gear vendors overdrive and loved it.
I also had the Banks complete kit.

Great power.
Still got 6 mpg.

[Dragon56]

We have a 1989 Vanguard 280 Classic and with proper tire inflation and if I keep it just under 95 kph , I consistently get 10 MPG with the old bus.

That's if the seas are fairly calm and we aren't climbing into the mountains, but typical conditions don't always exist so fill er up and Go camping and enjoy the good things besides worrying about the fuel tab.

Happy Camping!

Dragon

[Piros1]

Originally Posted by FFG

Getting around 6 mpg in a 25 foot Itasca Passage (1995) and want to improve this as others in the Uk are getting double this. I'd be happy with 10 so what re the most obvious things tho change/upgrade. I'm looking at Tri-y from Doug Thorley to increase torque but to help with engine and cab temps and I have a manifold gasket leak so its an obvious upgrade.
Look pretty stock as it is and I've changed a fair amount of consumable but I need to look at other options.
Its a 7.4 Chevy big block, HEI. Not really had any experience so any help much appreciated. Seems to run well but ticks under load (which I suspect is the gasket) but is quiet when cruising.
FFG

I have owned one truck with a Chevy 454 but no Motorhomes so my experience with them are different. That said from from my conversations of past they weren’t know for great fuel mileage in pickups. 10 was usually when empty and towing my TT was 5-6 at best. Now mine was not fuel injected and carbs don’t get as good of fuel mileage. A good tune up may help as suggested.
You did not state how many miles were on your rig. When my truck hit around 100,000 we were on a trip and it developed a ticking sound. I pushed it through and did a fair amount of diagnostics and replaced fuel pump and checked the valves during the trip and prayed we made it back. Somebody upstairs was watching over us as we got home and decided it was time to tear the engine down and found my ticking sound was due to the piston rings were worn down to about paper thin. My point is don’t assume you have an exhaust gasket leaking I find out on the road it is something worse. Check it out or have it check by a good mechanic. I would hate for you to broke down on a trip.

[momcat]

PPG..Back ln the day, I had a crew cab dually towing a 38 foot car trailer. If you could buy it to improve mileage, I bought it. Air flo, camshafts, gear ratios, distributors, carbs, etc. I got 7.5 mpg. If I had that truck today with the price of petrol, I would shoot it with a BAZOOKA and be money ahead. Also when I got into the mtns, the mileage went down. Momcat

[udid]

1994 Fleetwood Southwind Storm here with TBI 454 w/4L80E


I average between low 8mpg (US) to low 10mpg. If in heavy traffic I've seen it go to mid-high 6mpg. I average 60mph on trips.



I'd start with....


1. New pick up coil
2. New plugs
3. New wires
4. New rotor
5. New Distributor cap
6. New ICM
7. New sensors


Be sure your wires are covered with high temp heat shield cloth/socks.