1973 dodge motorhome areo

[seuadr]

kinda interesting as i look for fuelly reported mpgs between the 5.9 (360), 5.2 (318) magnus and the 3.9 v6 magnum the mileage isn't that much better. about a 2mpg spread on average. (though some diplacements suffer from a very low sample size)

[freebeard]

duckduckgo.com/?q=antireversionary+headers&ia=web

Using Vena Contracta to broaden the power band, on the lower end.

[aerohead]

Leaving the original 1961, 235 CID slant-six, I ripped out the 3-spd, and 4:56 rear end, and replaced with a M4 overdrive and 3:50 rear axle out a 1977 model Dodge D100 pickup.
Top speed went from 50-mph to 95-mph ( with aero pkg ).
Fuel economy went from 11-mpg @ 50-mph, to 21.5-mpg @ 65-mph.
Lower speed reduced fuel economy.
With zero aero mods, It gained 5-mpg.
I had to fabricate a custom hydraulic slave cylinder mount, for the 'modern' clutch ( mocked up in plywood and subbed out to a local machine shop ).
Also a custom driveshaft due to length differences.
And I had to modify for the different foot-operated-cable rear brake emergency brakes, from the original central driveshaft dash-mounted hand-parking brake.
I paid $150 for the trans, and $ 150 for the rear end at a nearby wrecking lot. Pulled them myself and carried them to the truck in a Radio Flyer wagon.
Chrysler Corp didn't waste $ on R & D.

[seuadr]

you know one of my first thoughts was "i wonder if i'd be better off with a slant 6 in this.." but the general train of thought i'd read was that the performance between that and the 318 probably were not worth the effort - since the 318 fits easier than the slant 6 apparently?

[aerohead]

Seems like the small V-8's potential for reserve power and lower service loading
would equate to greater longevity than the six in the motorhome.
Like with a motorcycle, there might be situations where 'accelerating' out of a developing situation might be safer than a panic stop.
The six is 'wide' in its 'slanted' side, while the tunnel-ram-esque intake manifold eats into space on the opposite side.
Guys I knew with the lightest Dodge van, with 318 and auto reported 22-mpg.
The six-passenger Chrysler Newport was good for 22-mpg with the 318.
Trade rags claimed that V-engines were cheaper to manufacture than in-lines.
And being 'shorter', hoodlines could be dropped for better aero.
Prompting transverse FWD configurations.

[seuadr]

OOOF. the trans van i looked at this weekend had the frame rotted out from the rear axle back, including the shock mounts. not willing to take on THAT much project - i'm not convinced that it could be saved without some significant welding, welding that i'm not capable of given the critical nature.

i have one more i can take a look at in this area, and then that plan may pivot to a bus or box truck.

to that end, i may be going to look at a 17'ft chevy box truck with a 6.5L diesel in it. forums that discuss that motor say that it regularly is in the mid to high teens when conservatively driven - with the city performance gearing in place, so, there may be some opportunity there.

a good buddy from highschool also indicated that he has a compound turbo setup for that era motor and, from what i'm reading about those, that could be an improvement possibly if properly set up with more highway oriented gearing.

has me rubbing my chin anyhow

[Piotrsko]

What a diesel gains in mileage is modified by the increased fuel price to be a lot less economical. Not the full reason you buy one.

When gas was a buck a gallon, I was buying fuel for $0.50, then it made sense. It does still get 20mpg mixed driving, but here in Reno, gas is $3.98 diesel is $5. Crap diesel is cheaper, but I like not having fuel related issues like alky and water contamination. Haven't needed to drain my fuel filter yet in 22 years.

[seuadr]

Originally Posted by Piotrsko

What a diesel gains in mileage is modified by the increased fuel price to be a lot less economical. Not the full reason you buy one.

When gas was a buck a gallon, I was buying fuel for $0.50, then it made sense. It does still get 20mpg mixed driving, but here in Reno, gas is $3.98 diesel is $5. Crap diesel is cheaper, but I like not having fuel related issues like alky and water contamination. Haven't needed to drain my fuel filter yet in 22 years.

fair point. my train of thought was lower end torque may help with overall performance without laying into the throttle as much for things like going up hills.

of course, i was not thinking of the disparity in price, and, honestly, i've never owned a diesel so i don't know that is valid and worth the extra cost.

mostly i was thinking about how the truck is for sale cheap cause the box is beat to hell and i have a friend that knows their way around them.

most of the box trucks and vans that have longer frames and/or aren't sprinter style vehicles are big V8 and V10 engines, which i want to avoid. even the 5.4 triton mpg is pretty disappointing in my personal experience - but that experience only includes "stock" scenarios.

honestly before i started thinking about this project, i didn't put much thought to drivetrain configuration and the like, other than the general "bigger motors use more gas" and "4x4s use more gas" sort of reasoning.

[cRiPpLe_rOoStEr]

Originally Posted by seuadr

i may be going to look at a 17'ft chevy box truck with a 6.5L diesel in it. forums that discuss that motor say that it regularly is in the mid to high teens when conservatively driven - with the city performance gearing in place, so, there may be some opportunity there

Replacing the mechanical fan for an electric one (dual-fan setups from GM's own FWD models fitted with the Buick 3800 V6 have been reported to be quite easy to source at junkyards there) is a good measure for fuel savings.

a good buddy from highschool also indicated that he has a compound turbo setup for that era motor and, from what i'm reading about those, that could be an improvement possibly if properly set up with more highway oriented gearing.

I'd take overboosting this engine with a grain of salt...

[seuadr]

Originally Posted by cRiPpLe_rOoStEr

Replacing the mechanical fan for an electric one (dual-fan setups from GM's own FWD models fitted with the Buick 3800 V6 have been reported to be quite easy to source at junkyards there) is a good measure for fuel savings.




I'd take overboosting this engine with a grain of salt...

I know little about it. He mentioned that perhaps 2 smaller turbos could be set up to boost sooner than 1 big one