Cummins New 5.0 V-8 Diesel?

[bagman]

I've been reading up on this new diesel engine from Cummins and have come to the conclusion, it would be a perfect motor for Class C & B+ motor homes based on either the Ford of Chevy/GMC Cutaway Chassis. There are different versions of this light weight engine, two to three hundred pounds lighter than your std. 6.6 or 6.7 diesel and the one that will power the next Nissan Titan PU truck will be 300 HP & 555 ft, lbs. of torque. I bet this Cummins weighs less than the Ford V-10 Gas! Just imagine the improved fuel economy. In a test Nissan Titan it registered 1,600 RPM's at 65 MPH. What say you? Bags.

[ECones]

RobbieH wrote:

ECones wrote:
If the additional cost of the unit had been $15K for diesel, for us and I suspect many Class C buyers, that would have been a deal breaker. We'd still be pulling a trailer.

The cost to go from an E450 C to an F550 C was a lot more than $15k for us (more like $40k+), but it was the logical choice. We did not need the extra room, but needed the ability to tow 7000+ lbs. We've taken ours through the Rocky Mountains a few times, and with trailer in tow, have never slowed down a bit, and haven't had to put the foot to the floor to do it. I'm a die-hard Dodge/Cummins fan, sold my 2006 Ram to help buy the RV (2006 probably the best year for Cummins), and I have to say I'm really impressed with the new Ford 6.7 diesel. Oh, and for comparison sake, our Thor 33SW with 7k lbs behind it gets around 9.5-10 MPG. This will go up once it is broken in, which on a diesel can take 20,000+ miles. We are just over 7,000 on ours so far.

I understand. But your requirements are far more strenuous than ours 😉

[RobbieH]

ECones wrote:
If the additional cost of the unit had been $15K for diesel, for us and I suspect many Class C buyers, that would have been a deal breaker. We'd still be pulling a trailer.

The cost to go from an E450 C to an F550 C was a lot more than $15k for us (more like $40k+), but it was the logical choice. We did not need the extra room, but needed the ability to tow 7000+ lbs. We've taken ours through the Rocky Mountains a few times, and with trailer in tow, have never slowed down a bit, and haven't had to put the foot to the floor to do it. I'm a die-hard Dodge/Cummins fan, sold my 2006 Ram to help buy the RV (2006 probably the best year for Cummins), and I have to say I'm really impressed with the new Ford 6.7 diesel. Oh, and for comparison sake, our Thor 33SW with 7k lbs behind it gets around 9.5-10 MPG. This will go up once it is broken in, which on a diesel can take 20,000+ miles. We are just over 7,000 on ours so far.

[SRockwood]

carringb wrote:
Ford has to down-rate the EcoBoost in the Transit to only 13,000 pounds GCWR, in order to mass the Medium-Duty test cycle. And... it could even pass with a full profile body attached to the cutaway, which is why there will be no EcoBoost Class C motorhomes. Only the 3.7L base gasser or the diesel. It simply isn't capable of shedding enough heat under severe conditions, or last long enough for Medium-Duty customers.

PS - All new Forest River coaches are rated for 7500# towing, and Thor puts an 8,000# receiver on all their new coaches.

I've towed many miles with my V10, and also towed some with an EcoBoost F150. Even with the much lighter trailer, it wasn't very hard to get the EcoBoost into "power train protect mode" because the cylinders get hot fast on steep long grades.

Huh. Something new every day.

I wonder if the Transit may have issues with heavier weights at the slower speeds it generally sees, not to mention the smallish air inlets on the front.

Sounds to me like Ford needs to sacrifice a little spool-up for reliability. Too small a turbine housing for the rated power results in poor delta-P (more pressure in the exhaust manifold than the intake manifold), which means massive heat-soak and white-hot exhaust manifolds.

I've been racing turbocharged cars for over a decade now. If I can get a small OEM turbo (T25) making 230whp/wtq out of a 2L 4-banger known for poor cooling on CA's 91 octane to last seasons of racing (40 minutes at WOT except for split-seconds of braking), surely they can get a modern 3.5L 6 making less than 300whp to last. 😄

Either way, I take it back: V10 is still fine with me (I have 2).

[ECones]

klutchdust wrote:
Add the cost of the diesel engine option verses the fuel savings first. The diesel engine in my pick up added 15K to the cost of the truck.

For my wife and me, that's the answer. We were discussing this weekend why you don't see more diesels in Class Cs, and my impression was cost.

Yes, the diesel will get better fuel mileage, but Big Redneck posted above that he has 61,000 miles on a diesel Class C that gets 14 mpg. My wife and I are getting around 8.5, so in 61,000 miles I'd expect to save under 3000 gallons of fuel.

If the additional cost of the unit had been $15K for diesel, for us and I suspect many Class C buyers, that would have been a deal breaker. We'd still be pulling a trailer.

[carringb]

RobertRyan wrote:

That is the problem with turbo engines under load

I'm pretty sure it has more to do with the power/displacement than the method of induction. Many turbos handle full output just fine. Not many engines put out over 1HP/Liter continuously.

[RobertRyan]

carringb wrote:
Ford has to down-rate the EcoBoost in the Transit to only 13,000 pounds GCWR, in order to mass the Medium-Duty test cycle. And... it could even pass with a full profile body attached to the cutaway, which is why there will be no EcoBoost Class C motorhomes. Only the 3.7L base gasser or the diesel. It simply isn't capable of shedding enough heat under severe conditions, or last long enough for Medium-Duty customers.

PS - All new Forest River coaches are rated for 7500# towing, and Thor puts an 8,000# receiver on all their new coaches.

I've towed many miles with my V10, and also towed some with an EcoBoost F150. Even with the much lighter trailer, it wasn't very hard to get the EcoBoost into "power train protect mode" because the cylinders get hot fast on steep long grade.

That is the problem with turbo engines under load

[carringb]

Ford has to down-rate the EcoBoost in the Transit to only 13,000 pounds GCWR, in order to mass the Medium-Duty test cycle. And... it could even pass with a full profile body attached to the cutaway, which is why there will be no EcoBoost Class C motorhomes. Only the 3.7L base gasser or the diesel. It simply isn't capable of shedding enough heat under severe conditions, or last long enough for Medium-Duty customers.

PS - All new Forest River coaches are rated for 7500# towing, and Thor puts an 8,000# receiver on all their new coaches.

I've towed many miles with my V10, and also towed some with an EcoBoost F150. Even with the much lighter trailer, it wasn't very hard to get the EcoBoost into "power train protect mode" because the cylinders get hot fast on steep long grades.

[SRockwood]

EB currently makes 380hp/460lb-ft in Navigator trim, which is more than the 3V V10 we can't get in E-450 Class C guise.

Is the Eco-boost the limiter on GCWR, or is it the transmission/vehicle they're installed in that's limiting GCWR? I don't see Ford ever allowing 20k+ GCWR with the F-150 or Transit.

Given sufficient cooling, I don't think there will be a huge difference between the two. As for GCWR, since none of the V10 Class Cs I've seen were rated for more than 5k lbs of towing and 14,500lbs GVWR, there's not much of a jump from 17,100 (F-150 EB GCWR) and 19,500lbs.

[mlts22]

The EB V6 is close to the V-10's numbers... but not there yet. It has a great power curve, flat like a diesel, but can it replace the V-10? As above, it doesn't have the same duty cycle. It makes a Ford F-150 or Transit fun to drive, but it is not going to be happy trying to handle 20,000+ pounds of stuff.

I think Ford is going to wind up adding two cylinders to the EB and using that, just like the two cylinders added to the 5.4 got us the V-10. This will produce more horses and torque than the old V-10, but have the size to handle 30,000+ pounds of GCWR. I hope Ford does this, because the biggest thing people bash the V-10 for is that it is normally aspirated, so loses power at higher elevations. Having a set of turbos would not just help here, but help with MPG generally.

As RobertRyan stated, diesels are what the rest of the world is moving to, but the US is still a gasoline holdout, mainly because of the corn lobby selling ethanol, diesel engines are still expensive here ($6-8k more than gas counterparts), and there is still a negative sentiment about diesels in the US (they are viewed as slow, smelly, and require a lot of maintenance. Even though all that is not true these days, it still persists.)

[rjstractor]

SRockwood wrote:
Ecoboost V6 already makes Ford V10 power anyway. I'd take it over the V10.

Yes, the Eco makes V10 power but not at the same duty cycle. In a commercial application the max GCWR for the Eco is only about 13,000 pounds and maybe 17K in a pickup application. The V10 is used in commercial trucks of over 30,000 GCWR.

[SRockwood]

bagman wrote:
I've been reading up on this new diesel engine from Cummins and have come to the conclusion, it would be a perfect motor for Class C & B+ motor homes based on either the Ford of Chevy/GMC Cutaway Chassis. There are different versions of this light weight engine, two to three hundred pounds lighter than your std. 6.6 or 6.7 diesel and the one that will power the next Nissan Titan PU truck will be 300 HP & 555 ft, lbs. of torque. I bet this Cummins weighs less than the Ford V-10 Gas! Just imagine the improved fuel economy. In a test Nissan Titan it registered 1,600 RPM's at 65 MPH. What say you? Bags.

If it's 2-300lbs lighter than the 6.7l, that'll still put it around 8-900lbs, or 2-300-ish lbs heavier than the V10.

mlts22 wrote:
I do think diesels are the way things are going long term, and I hope Ford does use an engine like that as a V-10 replacement option. For gassers, I hope they can make an EcoBoost V8, since this would be the next best thing for the V-10 replacement.

I just wonder when diesels will get as reliable as they were pre-EGR/DPF/DEF. I read way too many horror stories about newer engines. A diesel does give better torque/HP/MPG, but there is just something simple about a gasser engine that just needs an oil change every 5-10k miles to keep it happy, perhaps spark plugs and coils every 100k miles.

Ecoboost V6 already makes Ford V10 power anyway. I'd take it over the V10.

[wolfe10]

rjstractor wrote:

wolfe10 wrote:
Sorry, when did Ford ever use a Cummins B engine?

It was used in the F650/750 as an optional engine from 1999-2015 I believe. In 2016 they went to their own Powerstroke engine in the medium duty trucks.

You are correct-- in that size truck they offered both Caterpillar and Cummins.

Just never in the E class/van used for "non-super" C's.

[rjstractor]

wolfe10 wrote:
Sorry, when did Ford ever use a Cummins B engine?

It was used in the F650/750 as an optional engine from 1999-2015 I believe. In 2016 they went to their own Powerstroke engine in the medium duty trucks.

[carringb]

Nissan is not on an exclusive contract. They are however primary on the build allotment, so Nissan gets all they build, if they can sell them. If they can't cummins has to option to sell them to other buyers.

There is one fabricator near me who is planning on a 5.0 Cummins drop-in kit for the E-series, however Cummins hasn't been able to commit to supplying him yet (since Nissan still has time to fill their allotment) and he's finishing up on a Cummins 6.7L turn-key conversion package for the E-series currently. And also doing a build for SEMA.