Confused about engines on Class C and A

Sfla2 wrote:
A & C not same eng A has 3 valve eng more hp

Both are Ford V10's and both are 6.8 liters. One in the class A has 3 valves per cylinder, and makes 362 HP, while the two valve engine used in the lighter weight Econoline 450 chassis is only rated around 275 or 300 HP.

And the class C has a lower tow rating mainly because the chassis is lighter, 16" rims, lower RV weight, so they don't want as much weight being towed by it.

The class A also has a HUGE radiator, much taller than will fit under the hood of a E-450. Then there is a larger oil cooler on the lower radiator coolant line, and those 19.5" rims rated at 3,600 pounds each has something to do with it's larger towing capacity!

I toured the Fleetwood Factory in 1996, and they take you out to see some new chassis fresh off the delivery trucks. It was great to see it up close, and see just how big everything is on the F-53 chassis.

Usually the class A will have a higher tow rating, and it sure has a higher GCVWR, but also the class A will have a higher curb weight than the class C. Still you need to compare your cargo rating, based on a specific floorplan, and length. My motorhome was built on the Ford 17,000 GVWR, while the same 30' Bounder would be built on the much lighter weight GMC 15,500 pound GVWR class A chassis in that year. So I picked the Ford because of it's 2,437 pound cargo rating!

Fred.

A & C not same eng A has 3 valve eng more hp

E-450 VS F-53 chassis, both have Triton V-10 but different "maximum towing capacity." Set aside for the moment the 20% difference in peak horsepower rating of the V-10 in F-53 and SD pickup VS E-series, because that increase in 2006 did not change the ratings on the F-53 from what it had been when the two platforms had nearly the same HP rating. Engines, and horsepower ratings, do not alone determine what can be towed. It is also not necessarily gearing. To further confuse things, look at Ford's ratings.

E-350 van with V-10 and 3.73 gears has GCWR of 15,000 pounds, tow capacity 8300-9100 pounds.
E-350 van with V-10 and 4.10 gears has GCWR of 18,500 pounds, tow capacity 10,000 pounds
E-350 cutaway or bare chassis with V-10 and 4.10 gears has GCWR of 18,500 tow cap 10,000
E-450 cutaway or bare chassis with V-10 and 4.56 gears has GCWR of 22,000 tow cap 10,000

For several years beyond 2006, F-53 with more powerful V-10 and 5.83 gears had GCWR of 26,000 pounds and tow capacity limited by only that, up to almost 12,000 pounds, but could be as little as 4000. Recently Ford has been rating the new heavier versions of the F-53 with a slightly higher GCWR on high GVWR models to ensure tow rating of at least 4000.

Something other than power, and even the GCWR, is limiting E-series tow capacity to 10,000. Where the GCWR is 18,500 and higher, there is almost 12,000 pounds difference between GCWR and the empty vehicle weight usually used to calculate tow ratings. In the case of the E-450 cutaway, that difference is almost 17,000 pounds, but of course somebody always builds something on that chassis that adds to the vehicle weight. What's limiting tow ratings on V-10 E-series could be frame strength, suspension, steering, or a "tail wagging the dog" issue. Actually, the E-450 was once popular as a commercial tow vehicle, with a lightweight utility body and heavy duty hitches, for loads up to about 15,000 pounds, until dually pickups started catching up with higher class 3 ratings.

So yor tow ratings from Jayco don't have much to do with Ford's ratings of the chassis (GCWR) nor does it go back to what engine or engine version. Build enough house on an E-450 to bring weight to 14,000 pounds, Ford's rating says it can still tow 8000. But in building a house, Jayco has done things to make them reduce the tow ratings: lengthened chassis to move the hitch further back, installed a lighter duty hitch receiver than Ford's Class IV or V, and used up most of the carrying capacity for tongue loads.

Same with the class A on F-53. If Jayco has built that one up to 18,000 pounds of house, using up most of the GVWR, there is still enough of the 26,000 to give it a 8000 tow rating, unless compromised by frame extensions, altered balance, or lightweight towing equipment.

Assuming it was the Ford V-10, another difference the version in a class A has 3 valves per cylinder vs 2 in a class C which gives it more HP & torque.

Engines/transmissions are the same, gear ratios may be different. A C class is built on a van type chassis, where as a class A is built on more of a truck type chassis. and the A`s will usually have 4.88 gears. all that adds up to a higher GVWR and higher tow rating. I looked at one of the C`s with bunks and the CCC was very low at around 1800lbs! by the time you add all your junk and people you will be way over the GVWR. after all that I would go for a class A. mainly because a class A will have more usable interior room because the captains chairs become part of the living area given both RV`s are the same length.

Over the years they have increased the HP of the V-10. If you look at used, you may notice a different HP. Carry Cap. and tow Cap. are not the same rating.

The engine is only one component. A lot depends on the gearing and design of the transmission and the gearing in the rear end. Frame design is also an important component.

I would say you answered it, chassis. We had an F250 crew cab with a v10 gas engine. Towing capacity was 12,500lbs. We have a 33' long Class C with same engine, but only a 5000 lb towing capacity. There are Class A's out there that are larger and with the same V10, but they have a 5000 lb towing capacity. I'm no mechanic or engineer, but it must have something to do with weights and the chassis as well.