Argosy 20' MH 350 Versus 454 MPG?

[ViewRVs]

I am looking for an Argosy 20' and I am trying to decide between a 350 or 454 engine. Gas mileage is very important. Does anyone know how many more miles per gallon the 350 gets over the 454?

I know my old 345 averaged 7 MPG. I ran it hard and I guess I cold have gotten 8-9 if I slowed down.

I would guess an Argosy 20' unit with the same 454 could get 10-11 MPG. Am I unreasonable to think a 350 would be 12-13 MPG (20-30% increase)?

[crazeevw]

Honestly, thinking horsepower/torque ratings, along with your total weight of Argosy will determine your mpg. EasyStreamer has told me he can get 10mpg in his 345 as long as he sticks to 55mph. Raveson tows a Jeep Wrangler and goes a bit faster and gets 6mpg or so.
Are you trying to find Argosy w 350 vs 454, or going to try and replace 454 with a newer 350?
Good luck with your new Airstream adventure. Keep us posted.
Thanks, Derek

[ViewRVs]

I have not purchased anything YET. My wife loves the Argosy 20' motorhome. I'd prefer the 350 hoping the gas mileage would be slightly better. I am not looking to tow anything large, maybe just a small car or light truck.

I do know of two for sale (one with a 454 and one with the 350). One needs a TON of work and the other is across the country (2,500 miles away). I was just hoping to get some data on MPG before making the leap (unless my wife says she wants BOTH ).

[vswingfield]

I seriously doubt there will be much better mileage with the 350. You're still moving the same load. The smaller engine would deliver better economy when moving minimal loads, like an unloaded pickup, but moving a motorhome, even a small one like an Argy is work.

Given that, a case can be made that the small block Chevy is the best engine ever put into overall production. Huge production numbers and a great record. In spite of that, the big blocks are great engines. I would take the 454 every time.

[Smartstream]

Just for curiosity's sake, does anyone know what a Argosy 20' moho weighs?

Thanks, Dan

[idroba]

I to doubt that you will see any great increase in MPG from the 350 to the 454. The frontal area of the rig does not change, nor does the efficiency of delivery (tranny, drive line, rear end etc) from one engine to the other.

When GMC motorhomes were made the final 2 years went from an Olds 455 to a 402. On the GMC forum everyone says the economy of both are the same, 8 to 10 mpg.

On my own 310, when I had it, the 454 ran 8 to 10 mpg. A friend had an 81 280 with the diesel, and he averaged about 14 mpg. But that was the diesel talking, not another gas engine.

Slowing down is the very best way to increase mpg, along with always driving with the wind .. on the level or downhill.... grin.

[SteSpot]

on our 24' 1982 Airstream with a 454 7.4 liter Chevy engine on a P 30 chassis......it weighs about 9700 pounds empty....and it has plenty of pep....now stopping on a dime is another story.....even with new brakes. she has a lot of pep though.....paula

[SteSpot]

I forgot to add that we had to put all of the emission controls stuff back on the 454......that probably decreases the mileage as well. paula

[ViewRVs]

I could only find the weight for the 1979 Airstream 24' and 28'
1979 24' Curb Weight 9,700#, GVW of 12,500#
1979 28' Curb Weight 11,320#, GVW of 12,900#

[Smartstream]

Thanks Paula and Fred. I would guess the 20' might might come in at 7500 to 8000 #. It would be interesting to put in a single wheel rear-end from a pick-up, something with a better ratio and maybe a 4-5 liter turbo diesel.
It might make a sweet little rig with pretty impressive mileage.

Just thinking, Dan

[8rmesse]

If you intend to pull a toad behind a motorhome, even a 20 footer go with the 454. That poor 350 would be so overworked I bet it would get worse mileage.

[ViewRVs]

I did purchase an Argosy 20' with the 454. I just made it home last night from Georgia! The unit ran great and went up the Virginia/West Virginia mountains like they were not even there!

I only encountered minor issues with the tail lights. I purchased some bulbs at Wal-Mart and that did the trick. With hundreds of bulbs in these things, one is bound to go out on a trip.

The 20' fits behind my house just PERFECT.

Let the fun begin!

[dadstoy]

Originally Posted by 1985air345

I did purchase an Argosy 20' with the 454. I just made it home last night from Georgia! The unit ran great and went up the Virginia/West Virginia mountains like they were not even there!

I only encountered minor issues with the tail lights. I purchased some bulbs at Wal-Mart and that did the trick. With hundreds of bulbs in these things, one is bound to go out on a trip.

The 20' fits behind my house just PERFECT.

Let the fun begin!

Congrats!