How little engine power is just barely enough?

[Ford_6L_E350]

V10
Displacement 6.8L (415 CID)
Horsepower (SAE net) 362 @ 4750 rpm
Torque 457 lb.-ft. @ 3250 rpm

Torque is lower, but max power is at 4750rpm and the engine pulls past that.

Mike

[Chance]

Originally Posted by Ford_6L_E350

V10
Displacement 6.8L (415 CID)
Horsepower (SAE net) 362 @ 4750 rpm
Torque 457 lb.-ft. @ 3250 rpm

Torque is lower, but max power is at 4750rpm and the engine pulls past that.

Mike

I think that for the E-Series vans engine ratings are lower. The ratings you mention apply to F-series and large F53 RV chassis.

For E-Series I believe they are:

305 HP at 4250 RPM
420 lb-ft at 3250 RPM


For what it's worth, I personally find Triton engines to become loud and rough at higher RPMs. I rarely let my V10 get much above 3500 RPM. It just doesn't sound very smooth at all.

By comparison my Honda V6 sounds great at engine speeds well in excess of 4500 RPM. It doesn't sound like it's about to throw a rod like the Tritons sound to me. Sadly I'm not a big fan of these Ford engines even though I have one.

[Silver350]

It's pretty hard to find factory output charts for any of these Ford engines, but according to what I found at Banks' site the 6.8 peaks around 3200 but TQ doesn't significantly drop off till 4000 (only drops 25 -/+ # up to that point) and peak HP is around 4200. Not sure why 5200 is necessary or helpful. Maybe an aftermarket time?

[carringb]

Originally Posted by Silver350

It's pretty hard to find factory output charts for any of these Ford engines, but according to what I found at Banks' site the 6.8 peaks around 3200 but TQ doesn't significantly drop off till 4000 (only drops 25 -/+ # up to that point) and peak HP is around 4200. Not sure why 5200 is necessary or helpful. Maybe an aftermarket time?

With the better breathing through the Banks PowerPack, I could raise most shift points and the rev limiters using the Predator (and the Predator advances timing and increases spark intensity, plus I turned off torque management). The Banks really made peak torque available over a much broader range than stock, and keeps if from choking up at high RPM (stock the V10 has kind of falls on its face above about 4800 RPM). 5200 RPM makes much more HP than 3400 RPM which would be the next gear up (2nd vs 3rd/direct). Keeping it above 5k lets me move all 22,000 pounds up a 6% grade at 65+. I don't drive just to drive. I drive to get places. Engine has never been above 222F. I've only had to pull over once, and that was because the rear diff was getting too hot pulling westbound out of death valley on a hot day.

Also the better breathing makes it sounds WAY better at high RPM.

And unlike most aftermarket exhaust, the Banks helped the low end way out too. Empty, I can pull a 7% grade all the way down to 1100 RPM and hold speed. Because of that, I dropped the OD shift way down, so 99% of the time the van stays in OD. But when I hit those hills, I like being able to drop down a couple gears and blast past all those Prii. It actually pretty fun to drive, and quite a bit quicker than my V6 Camry (plus not having to battle the torque steer )

[Chance]

Originally Posted by carringb

......cut..........

5200 RPM makes much more HP than 3400 RPM which would be the next gear up (2nd vs 3rd/direct). Keeping it above 5k lets me move all 22,000 pounds up a 6% grade at 65+.

........cut.......

I'm curious: Any idea on how much horsepower you have, and also, what kind of MPG do you get when towing that much weight?

And if you have standard 35 gallong fuel tank, don't you go through it in a couple of hundred miles? That would barely get you across Death Valley without fueling.

[Chance]

In doing additional research on this subject of low engine power and how it affects performance, I found a review of the slowest RV (which also happens to be most fuel inefficient I’ve come across) that took 25.6 seconds to get from 0 to 60 MPH. Test results had it at 6.5 MPG. Wet weight was 20,020 pounds running on a 362 HP Ford V10.

By comparison another but lighter Class A with same engine went 0 to 60 MPH in 19.2 seconds. That’s still pretty slow by car standards – which is expected. Economy for the 13,780 pound RV was 7.5 MPG.

To put it in Class B perspective, a large one-ton dually 24-ft-long Sprinter with 188 HP diesel V6 went 0 to 60 in 19 seconds. Test results showed 21.3 MPG for the 8720 pound van.

Also of interest is that a couple of Sprinter-based RVs with V6 diesel weighing around 10,000 pounds managed to hold 65 MPH on a 6 percent grade. That seems more than adequate to me.


Based on these results, and what has been discussed here, I’m still wondering why almost all manufacturers use the optional Ford 6.8L V10 instead of the standard 5.4L V8 on smaller and more aerodynamic RVs based on E350s chassis. That’s what got me thinking about this in the first place. In other words, why are V10s so popular for vans?


Thanks for all replys and feedback.

[Ford_6L_E350]

The only reason I would get a V10 would be for the TorqueShift transmission which isn't available withe 5.4 in a van.

Mike

[carringb]

Originally Posted by Chance

I'm curious: Any idea on how much horsepower you have, and also, what kind of MPG do you get when towing that much weight?

And if you have standard 35 gallong fuel tank, don't you go through it in a couple of hundred miles? That would barely get you across Death Valley without fueling.

Between the Banks, AFE and Predator, its probably in the 380-400 HP range at the crank. At the same weight, I can usually pull most hills about 20 MPH faster than my brothers stock V10. And also faster than my '08 Ram 4500 6.7L could at the same combined weight (the Ram also used more fuel, especially around town). The Ram of course didn't sound like it was working hard, since fuel cut kicked in at 3200 RPM. But on steeper grades the Ram just couldn't keep speed like my V10 does.

Around 18-25,000 combined I average 7-7.5 MPG. Not too bad considering my average speed. I would usually look for cheap fuel around 200 miles, and get fuel regardless of price at 230 miles, leaving a 5 gallon reserve.

[carringb]

Originally Posted by Chance

Based on these results, and what has been discussed here, I’m still wondering why almost all manufacturers use the optional Ford 6.8L V10 instead of the standard 5.4L V8 on smaller and more aerodynamic RVs based on E350s chassis. That’s what got me thinking about this in the first place. In other words, why are V10s so popular for vans?

Most Class B and C RVs under 24' use the V8, but off the V10. In a full profile RV, fuel economy is probably a wash. Once you put 4x4 under a van and rack on the roof, I suspect similar results in a van.

In a van, the extra power of the V10 is great for towing. Not necessary though. My dad has the 5.4L. I've pulled 11,000 pounds. It did it, and even held speed OK on the hills. But the V10 does it do much better. I can walk him on hills while I'm towing and he's not.

Also, the V10 idles smoother. But mostly I think I would feel inadequate with only a V8 after having had a V10. And no way would I ever consider a V6 in a full size van unless it had a couple turbos included By the time I hit 500,000 miles durability of the Transit should be pretty well established....

[Chance]

Originally Posted by Ford_6L_E350

The only reason I would get a V10 would be for the TorqueShift transmission which isn't available withe 5.4 in a van.

Mike

It's interesting that Ford offers the 5R110 with 5.4L but only on cutaway and stripped E-Series chassis. Don't quite get why they wouldn't at least offer it as an option for the 5.4L in a regular van. Obviously it fits and they already have the engine/transmission combo in use.

The 6R140 (or lighter-duty version) would be nice too along with a 5.4L if it fit under a regular van. The extra gear gives better overall ratios in my opinion.