7,5L gas vs 7,3L diesel
 

I own a 21 feet class C RV ...it has a 7,5L gas engine ( 460 )


rated at 245 hp , it is quite coward on steep hills


I face two solutions :


modify the 7,5L gas engine to 400 hp & 500 ftpds torque
or switch to a 1999 7,3L power stroke diesel


the power stroke would be out of a 99 E350 like my RV ,so no problem of
wiring harness ' i would have the whole truck


My worries: would it be Worth the move ? is it that much better on fuel consumption ? I heard lots of dont go power stroke for economy it aint that good ....
second : noise Wise Inside : is it Noisy in the cab ? when you drive 7 hours a day on a roadtrip ,it`s quite diffrent then getting to the job 30 miles away


thanks for your input !


Dan

I can't speak to cab noise for an R/V, but my 96 E350 7.5l (set up as a regular conversion van) isn't a noisy cab at all. Took it 16 hours straight to Florida earlier this year and had no issues with noise fatigue. MPG was not stellar, loaded down with passengers and luggage, so I'm sure it's even uglier as an RV. I have a preference for the 460 because it's quite durable and will run forever with regular maintenance. Sorry this probably isn't a useful post.

I had a 7.3L PowerStroke in an '02 F-350 crew cab and I have a 460 in my current '97 F-250 crew cab. Fuel cost driving the trucks empty was similar, maybe a little worse for the diesel (~13 mpg vs ~11 mpg but diesel fuel costs a little more). Hauling my slide-in camper and towing my Bronco it definitely tipped in the diesel's favor, 11~12 mpg vs ~7 mpg. Plus the '02 PowerStroke was WAY more capable on hills with that kind of load.

Is it worth it? Hard to say. In a motor home it would definitely be better power and probably lower fuel cost. But whether it's worth the cost/effort is up to you.

My '02 was definitely louder in the cab than my '97, and that's even with more sound damping. My '15 E-450 motorhome with a V-10 is probably as loud as the diesel (definitely louder than the 460 powered F-250). So I'd guess a 7.3L in a van would be louder yet. Too loud? I can't say. And I'm sure you can work on sound deadening as well.

I had a similar smaller motorhome at one time. 24' Class C with the 460 (but the C-6, three speed).

I found that a GearVendor gear splitter made a huge difference in driveability. It's not cheap, but a simpler modification than an engine swap.

I also had the 7.3 PSD in an F350. Drove that 80k miles, and while I loved the power, I did get tired of the significant added cost. Remember, those things require 14-15 quarts of oil!

Warren : I have a 7,5L gas ,so I know it`s silent ! ;-)
.........................................
thanks to you Deddy , & nothing special this is so informal to me .....

I think that MAYBE with mods like I plan at 400 hp / 500pds torque I would get similar results to a power stroke .....

...........
To add to this , my third door neighbour ( Ford F350 dually addict ) had 2 x 460 & one V10 F350 duallies that he drove to Florida all the time
he listened to a salesman and switched to a diesel F350 dually
says that he will go back to V10 for smoothness , and cheap maintenance
fo him the only positive of his diesel was 25% better torque in steep hills,
to him , not worth the switch .....

..................

thanks !

Dan

what are the plans to get your 460 to make 400hp/500ft-lbs?

What kind of MPG are you getting out of the 460? We have a 93 F350 4x4 dually flatbed
at work with a 460 and whether it's empty or loaded it gets 7mpg. We also have a 2003 E350 4x4 Van Terra Turttle top with a 7.3L. It basically looks like an RV and with it's equipment, it's right near it's max GVWR. It gets around mid 10's but drops to 9's in the mountains. Unlike our newer diesel trucks, it's been pretty much trouble free. It is a bit noisier than a gas engine.

raise compression to 9,25-9,5 ....port the heads , 1000-5000 cam , headers dual 2.5 " exhaust, twin 61mm throttle body , better cold air filtering

that should do it as per Scotty`s recipe "mad porter"

Dan

I see. That would be cool to see, I don't know enough about these engines to have a meaningful opinion, is that something that has been done before with those results? Does it give a power band that is suitable for an rv? (I guess it must perform well on the low end if it makes 500ft-lbs but "only" 400hp)

go to fb

RHP/ReinCarnation .......give it a look ...interesting !

Dan

you post says the embedded facebook post is no longer available, it has been moved or privacy settings changed...

I have a 1986 24' C with a 460. I had a complete 7.3PS drivetrain to go in it but it turns out the thing was so close to its rated gross that would not be a viable option. Instead I did the following. I put in the Edelbrock Performer cam and lifters and springs. I put an Edelbrock Performer intake and left the stock 650 4180 carb. I put on a set of long tube headers and built a nice 2-1/2 mandrel bent H-Pipe exhaust. Ignition is still completely stock. This thing hauls the mail ! It weighs 10,800 lbs and pulls a 5000 lb race car trailer. It goes up hills 55-60 mph with the cruise on no sweat. It is an absolute beast. Without the trailer it gives 10 miles to imperial gallon, about 8 US. The trailer brings that down a bit. Edelbrock claims if you do exactly what I did and it will make 465 torque and after driving it stock and modded, I think its pretty close. And it sounds good too !Side note, this was performed on a super tight 35k original mile cream puff. Results may vary on old loose ones.

the efi 460 is not an easy motor to bolt stuff on, and if you do, you need to 'TwEEC' it to make it run - no mass air option sorry.

the EARLY 7.3PS motors were less of a PITA, they are down on HP, only slightly up on Torque and the powerband is changed - you would likely need to fiddle with the FDR and definitely need to get a PCM for the 7.3/E4 that is programmed for RV - the shift patterns, lockup patterns etc are COMPLETELY different from a streetable van/truck to a cutaway or box vehicle - given that when empty, they are always loaded compared to the lesser brethren. And while the E4 is a great tranny after 92, 2nd gear is still the weak sister and you will find the rv makes liberal use of lockup in second at heavy throttle to control heat buildup....which in any configuration will be your enemy. The big engines are shoe-horned into the cutaway and burn thru insulation quickly.

Id be curious where the turbo will end up on this project, at hill climbing gear, this will run over 2000 degrees EASY.

You might find the powertrain from a wrecked F53 chassis (A class) but Id still question fitment and plumbing

lastly, Id question how slow is slow...I have a winnie 428RQ which is larger and heavier and I get up on top of high point (I80 PA) just fine and can do it at speed (7-) if I wanted to push it, but its just not wise at a fuel/longevity standpoint...the fascination of wanting to do 70 up hills with trailers I just dont get...

I don't need to go 70 MPH up to the Eisenhower Tunnel but every time you hit the slightest grade and end up in second gear gets old fast. Thats how gutless mine was. My rig can now handle most of the stuff found in average rolling country without making a nuisance of itself.

I would caution you that I have a 400hp 500lb mustang, that is the dyno numbers to the rear wheels. It has a 514BB crate motor with a big hyd. roller cam and 750 demon carb (only a weiand stealth duel plane intake for street manners). Its a beast but the mileage is crap. Also it thumps loud. You'd have an easier time going with a Hellion turbo since plenty of room under the carriage. Just have to tweek the computer and run a ton of piping. My '92 460 15 pass. van is definetly a bit of a dog up long climbs with a load of kids and trailer.