Possible new class 5 rig. Am I nut's to choose gas motor ?

[klahanie]

So, can you guys stand another gas vs diesel tread !!! 🙃

Okay, maybe, just maybe, we might proceed with a long deferred new camper rig. It's grown to be a new, long wb F4/550 with a >12 x 7x 7' habitat. On 37" duallys - to start. Expect atleast 15K loaded. Nothing novel. But ... what motor ?

First , a little background ... we have an F350 with the infamous 6.4 diesel, previous truck was a gas. Both hauling a small pop up slide in, but heavy(ish). Shorter trips done to the ones planned but also sometimes was DD. For us it's been good and worked well. I'm up for a change tho.

Second, application ... new dedicated RV; long distance, cross country, 65mph cruiser; off highway for overnights; and just enough gravel and exploring to make the roadtrips worthwhile.

Now, I've read a lot of gas vs diesel over the years and think I'm familiar with most of the angles. I'll say this for one big factor, I know for us what the fuel cost difference has been over the years (1cent per litre difference, today's fill up) and know that fuel prices will be variable/no one knows the future.

For years I've thought if we got a new rig we'd go gas, the 7.3L - even with a big(ish) truck - because, great gas motor and because - well, you know - the big, bad wolf: diesel emissions and potential cost to repair etc. And we HATED the regen routine on our current truck. Haven't experienced DEF requirement but I already don't like the idea and the lost real estate needed for the tank and extra jug.

So gas looks good ... but ...

1) I've run the numbers on fuel costs but am still nervous about possible fuel consumption for the 7.3. Road fuel is expensive in Canada. Have read 10ish mpg on a recent thread. But our rig could be worse.

Truth, I've never been clear on the differnce between towing and heavy hauling (or wind load from a camper) with respect to fuel consumption "gas vs diesel" so hard to mine data from the web where a lot is empty or towing big.

Question... For the rig and the application described would 15% more fuel consumption be a fair estimation using the Ford gas vs diesel motor?

2) Carrying extra fuel is important to us. Important enought that, for this new truck, if gas, that would prob mean installing Ford parts for an aux mid ship tank and relocating the EVAP cannister outside the truck frame rails. I don't like J-cans. Still lose storage real estate. Vs if diesel, it would mean simply checking off the ~$550 dual tank option. And done.

3) Drivability. I think the 7.3 would be fine loaded up. But, there are a number of mtn ranges in BC to cross on our trips so the truck will work plus I really have no idea for long distance, cross country stretches if gas has any downsides (tiring, noisy, something else. IDK).
ON EDIT: either motor would have 4.88 gears and the 10 speed. Again, trying for 37 duals not the 41" military SS.

4) It seems most of these similar 5/500 set ups choose diesel. So not sure if I'm missing something. btw am only planning Can/US travel.


If you made it this far, thank you !

I'm not 100% sure on which way to go. Comments welcome.

 

[rruff]

If you are looking for permission to go with gas... granted!

I haven't driven either, but the diesel specs... are impressive. More power and double the torque... and with the turbos you shouldn't lose much at altitude. But, I don't think I'd want the diesel unless a full delete was also planned.

High altitude steep highway passes are where the 7.3 will struggle a bit I think, but you won't back up traffic if you keep the revs up. Also, on variable terrain the diesel will do a lot less shifting.

 

[Sparse Gray Hackle]

Either motor (7.3 or 6.7) will do the job. If you’re concerned about range, IMO the 6.7 is the better choice. The difference in torque will also favor the 6.7. Flip A coin…

 

[Mickey Bitsko]

So, can you guys stand another gas vs diesel tread !!! 🙃

Okay, maybe, just maybe, we might proceed with a long deferred new camper rig. It's grown to be a new, long wb F4/550 with a >12 x 7x 7' habitat. On 37" duallys - to start. Expect atleast 15K loaded. Nothing novel. But ... what motor ?

First , a little background ... we have an F350 with the infamous 6.4 diesel, previous truck was a gas. Both hauling a small pop up slide in, but heavy(ish). Shorter trips done to the ones planned but also sometimes was DD. For us it's been good and worked well. I'm up for a change tho.

Second, application ... new dedicated RV; long distance, cross country, 65mph cruiser; off highway for overnights; and just enough gravel and exploring to make the roadtrips worthwhile.

Now, I've read a lot of gas vs diesel over the years and think I'm familiar with most of the angles. I'll say this for one big factor, I know for us what the fuel cost difference has been over the years (1cent per litre difference, today's fill up) and know that fuel prices will be variable/no one knows the future.

For years I've thought if we got a new rig we'd go gas, the 7.3L - even with a big(ish) truck - because, great gas motor and because - well, you know - the big, bad wolf: diesel emissions and potential cost to repair etc. And we HATED the regen routine on our current truck. Haven't experienced DEF requirement but I already don't like the idea and the lost real estate needed for the tank and extra jug.

So gas looks good ... but ...

1) I've run the numbers on fuel costs but am still nervous about possible fuel consumption for the 7.3. Road fuel is expensive in Canada. Have read 10ish mpg on a recent thread. But our rig could be worse.

Truth, I've never been clear on the differnce between towing and heavy hauling (or wind load from a camper) with respect to fuel consumption "gas vs diesel" so hard to mine data from the web where a lot is empty or towing big.

Question... For the rig and the application described would 15% more fuel consumption be a fair estimation using the Ford gas vs diesel motor?

2) Carrying extra fuel is important to us. Important enought that, for this new truck, if gas, that would prob mean installing Ford parts for an aux mid ship tank and relocating the EVAP cannister outside the truck frame rails. I don't like J-cans. Still lose storage real estate. Vs if diesel, it would mean simply checking off the ~$550 dual tank option. And done.

3) Drivability. I think the 7.3 would be fine loaded up. But, there are a number of mtn ranges in BC to cross on our trips so the truck will work plus I really have no idea for long distance, cross country stretches if gas has any downsides (tiring, noisy, something else. IDK).
ON EDIT: either motor would have 4.88 gears and the 10 speed. Again, trying for 37 duals not the 41" military SS.

4) It seems most of these similar 5/500 set ups choose diesel. So not sure if I'm missing something. btw am only planning Can/US travel.


If you made it this far, thank you !

I'm not 100% sure on which way to go. Comments welcome.

Which one do YOU prefer?

 

[klahanie]

Which one do YOU prefer?

Lol. Was def gas, until recently (since the proposed rig has gotten larger).

 

[rruff]

Lol. Was def gas, until recently (since the proposed rig has gotten larger).

It kinda depends on how picky you are. Is the 7.3L "deficiency" (compared to the 6.7L) going to bug you on a regular basis, or is "good enough" speed and acceleration going to be just fine? And on the other hand, would the cost, weight, extra maintenance, extra complexity of the diesel annoy you?

 

[86scotty]

Hard one to answer. I do not like the power loss with my V10 in high altitude, which is where I prefer to be in it. But it's simple and reliable. All it uses is gas. I get about 11.5 average hauling 9500 lbs. around. I know, V10 is old tech. I would love to have some time with the new 7.3 gas. Diesels pass me all the time and it pisses me off, but I pass them when they break. And boy to they break. And when they break they cost Lot$ to fix.

I work around commercial diesels. I wouldn't wish maintaining one for personal use on anyone. If you could find a simple one (pre DPF/DEF) that would be your answer, but it would be loud and inefficient, and it's very likely not even a consideration in this conversation or in your build.

There are a few concerns I have with a personal/travel vehicle that I don't have with a commercial one which makes money. Those are being quiet at idle and reliable. That said, I'd go with a gas motor. It's also cheaper to purchase and easier to maintain.

 

[klahanie]

Hard one to answer. I do not like the power loss with my V10 in high altitude, which is where I prefer to be in it. But it's simple and reliable. All it uses is gas. I get about 11.5 average hauling 9500 lbs. around. I know, V10 is old tech. I would love to have some time with the new 7.3 gas. Diesels pass me all the time and it pisses me off, but I pass them when they break. And boy to they break. And when they break they cost Lot$ to fix.

I work around commercial diesels. I wouldn't wish maintaining one for personal use on anyone. If you could find a simple one (pre DPF/DEF) that would be your answer, but it would be loud and inefficient, and it's very likely not even a consideration in this conversation or in your build.

Thx. 11.5 is pretty good, imo. I was getting same with our 6.4 diesel @ >12,000 gvw before the delete.

For the new 7.3 vs 6.7 calcs I'm using 8.5 vs 11mpg. Maybe pessimistic but I personally have never matched usual claimed economy with any vehicle I've owned.

Appreciate your work experience. I do find the reputation for current diesel breakdowns a bit perplexing. We've had the 6.4 since new and havent had much trouble (after the delete). This motor has a rep by some as the worst made in the history of the world and forever. Basically the apex of ********.

Yet, 15 years later and diesel are still so troublesome ? Not doubting, just find it surprising but maybe its the complexity. I remember when the 6.7 was first exhibited. One wag quipped, "could they have made it any more complicated !?"

 

[rruff]

Hard one to answer. I do not like the power loss with my V10 in high altitude, which is where I prefer to be in it.

I live at high altitude, and concur that the loss is very noticeable, about 3% per 1,000 ft. So at 10k you'll have 70% left. Based on spec of 383 hp that would be 268 hp for mine. The 7.3L would drop from 430 to 301. Klahanie will be moving double the weight I am, so on steep climbs that will be something... but I still think power will be adequate for 65 mph on 7% grades. Just let it rev, or slow down and relax. I think people get nervous when they are running their big V8 at 5,000 rpm, but so long as the temps are good, they should be fine with that all day.

 

[deserteagle56]

Personally, I think the perceived "problems" with the new diesels are overblown. I know several people who own the newest (last 5 years) Powerstrokes and Ram/Cummins and not one of them has had an engine-related problem. Nor do I see a lot of posts about engine problems on the forums. Yes, a few people have had problems with their diesel engines - but compared to how many are sold, its a very small percentage. In a large percentage of those cases the problems stemmed from using the diesel as a daily driver where the engine never had a chance to full warm up and that's a no-no with a DPF-equipped diesel.

I own both a gas V-10 rig and an older Dodge/Cummins dually. Even though the old Cummins can't come close to the torque the new diesels put out, driving while heavy (10,000 lbs+) there is no comparison between gas engine and diesel. Mostly mountains where I live; the gas engine is roaring at 4,000+ rpm and shifting up and down. The diesel just motors along below 2,000 rpm, no shifting needed, a much more relaxing experience. And the big plus is that on the downhill slope the exhaust brake holds all that weight back so well I rarely have to touch the brake pedal.

 

[IdaSHO]

It always seems overblown until its your own problem.

Gassers are simply easier and cheaper to maintain.
All you have to do is keep feeding them. Even then the MPG difference isnt substancial.

And rolling at 12,000lbs or so, I rarely touch my my brake on downgrades even in my old 6.2 gasser.
Unlike diesels, all you have to do is downshift for compression braking....

 

[plainjaneFJC]

I spend enough time around diesels in light commercial applications and they just plain suck. Sure the power is great but you’ll be lucky to make it 100k with out some sort of issue, I’ll never own another one

 

[rruff]

And rolling at 12,000lbs or so, I rarely touch my my brake on downgrades even in my old 6.2 gasser.
Unlike diesels, all you have to do is downshift for compression braking....

Same here... and sometimes that isn't even necessary. If you tap the brake and don't apply the throttle after, it "knows" you want to stay in a low gear... or something like that.

 

[IdaSHO]

Yeah, depending upon the situation and the trans tuning.

 

[rruff]

Still, am curious why it seems many of these newer rigs are diesel.

Because the answer to "how much?" is always MORE!!!

Can't be "King of the Road" without the biggest and baddest...