5.4L vs 6.8L in small Class C

[mr61impala]

We have been looking at Class C vehicles in the 24' range typically denoted as 22H, 23C, etc., we will not be towing a "toad".

I see mostly units with the 6.8L V10 but occasionally one pops up with a 5.4L V8.

For many years my parents had a 22' Mini Winnie with 360 Chrysler power and it had plenty of get up and go.

1). Does a modern 5.4L engine have as much grunt as that old 1977 Dodge had?

2). Is there any significant mpg advantage when selecting the 5.4L as opposed to the 6.8L? (Most 6.8L owners claim 7-8 mpg range, I have not seen any reports from owners feeding 2 fewer cylinders).

Over the years I have towed 3 smaller TT with 2 different 1/2 ton pickups and find traveling around 60 mph to be optimal, I don't anticipate traveling any faster in this rig.

[ericsmith32]

mr61impala wrote:
I think we have ruled out the 5.4L V8 as unsuitable in any class C.

Yesterday I saw a Coachman Freelander 27 QBC with a walk-around rear queen bed for a low price. It was powered by a 6.0L GMC engine.

The 6.0L engine is nearly halfway between the 5.4L and the 6.8L in displacement and GMC seems more like Chrysler in the regard that their V8's put out more power per cubic inch than these 2 Fords do.

Would a 6.0L be suitable power for a class C motorhome?

If so, what size coach would be a reasonable load for this engine?

When I first started looking almost all I found were Fords, now I am seeing lots of GMC powered coaches as well.

Trying to keep my options open.

Thanks!

Even though I'm a Ford guy the 6.0l is sufficient but the 6.8l does the job better. Comparing mine to my grandparents. The power band of the 6.8 seems perfect for motor home. The 6.0 wants to rev to make power. In your size range you'll be fine with the 5.4.. Finding one another story!

[2dogtravellin]

We had a 21ft MH on an E350. It was WAY underpowered for going up any hills. We averaged about 8mpg. We now have a 24ft MH on an E450 6.8l V10. We can go up any hills we want, especially when we engage the tow/haul. Amazingly, we now average about 10mpg.

For driving comparison: We live in the California hill country and tend to go up into mountainous areas. We also both like to hang out at 60-70 mph.

[mr61impala]

Harvey51 wrote:
We have the 5.4 L V8 in our E350 with 20 foot house. Weight is 4030 kg. I only found one fuel consumption check in my log - 4.25 km/L which I think is 10 miles/US gallon. Probably travelling close to 60 mph. I am happy with the power, even in mountains where I slow down a bit.

I thank you for your input!

[Harvey51]

We have the 5.4 L V8 in our E350 with 20 foot house. Weight is 4030 kg. I only found one fuel consumption check in my log - 4.25 km/L which I think is 10 miles/US gallon. Probably travelling close to 60 mph. I am happy with the power, even in mountains where I slow down a bit.

[mr61impala]

rvit wrote:
We have the 5.4V8 in a 2014 22' Pleasureway and it is certainly adequate. The 5 speed transmission helps. But I'm sure the V-10 is the better choice when in hilly terrain. The gas mileage difference is minimal (1 mpg) and the noise the 5.4 makes when it's working hard is annoying.

In my case it was a matter of $$. I saved $8,000 versus the V-10 model.

Am I correct in thinking that your coach is more like a Class B, with its smaller frontal area than the typical Class C with the full width overhead bunk?

Any are you saying you gain or lose 1 MPG as opposed to the V-10?

Thanks!

[rvit]

We have the 5.4V8 in a 2014 22' Pleasureway and it is certainly adequate. The 5 speed transmission helps. But I'm sure the V-10 is the better choice when in hilly terrain. The gas mileage difference is minimal (1 mpg) and the noise the 5.4 makes when it's working hard is annoying.

In my case it was a matter of $$. I saved $8,000 versus the V-10 model.

[mr61impala]

I think we have ruled out the 5.4L V8 as unsuitable in any class C.

Yesterday I saw a Coachman Freelander 27 QBC with a walk-around rear queen bed for a low price. It was powered by a 6.0L GMC engine.

The 6.0L engine is nearly halfway between the 5.4L and the 6.8L in displacement and GMC seems more like Chrysler in the regard that their V8's put out more power per cubic inch than these 2 Fords do.

Would a 6.0L be suitable power for a class C motorhome?

If so, what size coach would be a reasonable load for this engine?

When I first started looking almost all I found were Fords, now I am seeing lots of GMC powered coaches as well.

Trying to keep my options open.

Thanks!

[S_NotFree]

I had a 29 Ft class A, no slides ..it weighed about the same as yours. It had the Ford 460 V-8 in it that is a pretty strong engine and probably more torque than the V-8 you are talking about.. but I still felt the need for more power, so added a Banks system to it that made a huge difference. Besides all of the negatives already about the smaller engine, you also have to consider resale. It would be very hard to resell and a dealer knows that and would not give you much for it. Most of us would not buy the smaller engine option in anything heavy or that we use for towing.

If you are seriously considering buying the V-8, I would call the Banks Power people and discuss. Maybe they can add some of their systems that will give the V-8 better power than the V-10 and if you buy it and find out it is underpowered, you at least would have options to beef it up without selling or trading. I am on my 3rd Banks system now and have been extremely pleased with the power they add.

[S_NotFree]

mr61impala wrote:
Thanks to all for your thoughtful input!

I am still hoping that an owner or renter of a V8 powered Class C would weigh in with some real life feedback and data.

I understand that the larger engine (305 hp, not 362 hp) will be more powerful, I am just wondering if the V10 that does such a good job in a #14,500 31 footer with multiple heavy slides is really essential in a #11,500 coach with less storage, smaller tanks and no slide.

I can see where a smaller/lighter coach with the V10 would be lots of fun shooting past the 31 footers in the mountains.

It just seems like a coach that weighs 30% less could somehow get by on 20% less HP, even accounting for the final drive gearing.

[mr61impala]

5Mainecampers wrote:
Another factor regarding any RV besides weight is the wind resistance; it takes more power for a box to cut thru the wind. Furthermore, due to the wind resistance most MH are hard pressed to get more than 10MPG, regardless of the motor.

Totally agree, the Class C with bunk over cabs will all have this huge constant that will vary little from one coach to another.

The variables would be total the mass and the available power.

Sounds like the 6.8L is the powerplant of choice.

My original post was intended to determine the viability of a small Class C equipped with a 5.4L, for example if a super nice coach popped up for a great price is it worth a look see.

I still wonder if 2 identical coaches differing only in engines would get the same MPG over a given route.

Would the 5.4L get better mpg because it is smaller of would it get worse MPG because it is running harder.

It might depend upon the terrain as well, ie smaller might be better on level ground but worse on grades.

[RobertRyan]

j-d wrote:
V10 doesn't have the bottom-end, off-the-line "grunt" the old Big Blocks like 460 Ford, 454 Chevy, 440 MoPar had. But it's definitely got more than any small block V8 like 351 Ford, 350 Chevy, 360 MoPar. And once it gets moving, it'll outrun any of them. Only one it can't top is the 8.1 Chevy but that engine's discontinued now, and rare in used Class C's.

Yes you really need to spin them to get the torque

[DaCrema]

I have made just over 11 mpg going 60 mph enough times it is not an accident. But more often I get high 9s or low 10s. I have a LD 26.5 MB on an E450.

[pnichols]

Monaco Montclair wrote:
we have a 29ft Montclair by Monaco.6.8l.before we towed we got 12.6, checked it many times. now the clock is 25k miles.still 12.6

Wow ..... that fuel mileage from a V10 powered 29ft RV is beyond world class .... it may be a world record!

I wonder what's different in your setup that's making this possible?

[Cobra21]

Healeyman wrote:

mr61impala wrote:
Thanks to all for your thoughtful input!

I am still hoping that an owner or renter of a V8 powered Class C would weigh in with some real life feedback and data.

I gave you 75,000 miles worth of real life experience with a small V8 powered Class C in my post above.

We are doing the same with our 21' and chev. 350! Nice rig, but they are older.

Brian

Tim