Engine Mods for the V10 Ford what have you done

[Chance]

Originally Posted by carringb

Except with their current powertrain, reviews are saying it only hits 9th gear when coasting downhills and under most conditions can't even cruise in 8th.

Chrysler admits they have had software issues with the 9-speed, particularly when equipped with the 2.4L 4-cylinder engine. They claim it's not a mechanical issue but rather one requiring proper tuning.

To me it sounds like the final gear ratio is simply too high for such a large and heavy vehicle when equipped with the smaller engines.

The thing we all have to keep in mind is that if manufacturers gear vehicles for optimum fuel economy when cruising at 55 to 60 MPH on flat roads, then it's very unlikely that a NA engine will have enough torque to hold 80 MPH in the same gear. Road load would go up faster than engine torque.

For the very same reason it's not all that unusual for some modern cars to be geared so high for fuel economy that top speed is achieved in a lower transmission gear.

Personally, I can see the benefits of these 9- and 10-speed transmissions for trucks and heavy-duty applications, but for cars the benefits of a Honda-Accord-like electrically-based CVT with mild-hybrid battery capacity seems superior to me.

[haywoodphotomaccom]

5 Star Tuner update: I have only really used the 87 Tow and Econo mode with this tuner until last week. Uploaded the 91 Performance tune last Friday so see how it works and I am surprised how much better it seems to drive. I think I will be leaving it at this setting from now on....

[E350]

This is for carringb, and any others who are interested in the Gear Vendors:

http://powerstrokenation.com/forums/sho ... p?t=281570

Dave Whitmer drives a 7.3L but the GV info would seem to apply to all engines.

[Chance]

Originally Posted by E350

This is for carringb, and any others who are interested in the Gear Vendors:

http://powerstrokenation.com/forums/sho ... p?t=281570

Dave Whitmer drives a 7.3L but the GV info would seem to apply to all engines.

I'm not sure I agree that his experience quoted below that we want to operate "at the ragged edge of a lug" applies to all engines. In fact, data confirms otherwise.

Dave Whitmer -- "From what I've found out about BMEP curves you want to operate in a high load/low RPM mode. Right at the ragged edge of a lug. for me my drivetrain delivers. 1325 RPM and 600 degrees TIT at 70 MPH. 1125 RPM and 550 degrees at 60 MPH."

Below is fuel consumption data for a Ford EcoBoost engine that clearly shows the engine is most efficient at a torque well below maximum. It is nowhere close to being lugged.

I don't have data for 7.3L but expect many newer engines behave a little differently, particularly those that have direct injection and turbocharging. They have a wider range of fuel-efficient operation that makes it unnecessary to lug (or come close to lugging) the engine. In fact, coming close to lugging these newer engines is counterproductive.

[E350]

Chance: I definitely stand corrected. My narrow experience is with the 7.3L and although it is turbocharged, it is my understanding that it has a narrow max torque band in the low rpm range which Dave Whitmer describes.

[Chance]

Originally Posted by E350

Chance: I definitely stand corrected. My narrow experience is with the 7.3L and although it is turbocharged, it is my understanding that it has a narrow max torque band in the low rpm range which Dave Whitmer describes.

E350, there is probably some of that to it because older engines didn't breath as efficiently, but I'd bet that there is more to it than even that.

I haven't followed Dave Whitmer like you have, but from the link you posted it seems that he is very interested in fuel economy, to the point of modifying his truck to improve MPGs. And that means improving the truck's aerodynamics with front air dam and possibly lowering by 4 inches (not sure that's what is meant by slamming but truck looks lower than normal) and who knows what else he does in typical driving which may approach hyper-miling techniques.

Anyway, if he drives conservatively at 60 to 70 MPH with an "aero" truck, he's normal power requirements are probably much lower (as in lower HP) than what most of us would see with a huge tall and heavy van that may have a raised roof, air conditioner hanging on top, awning on side, and so on. My point is that because he requires so much less power than many vans on this forum, the only way he can get BMEP (brake mean effective pressure) up high enough to be very efficient is to run the engine at super low RPMs. However, the same probably wouldn't apply to a heavy and tall non-aero van. Think about it, if he's almost lugging the engine at 60 to 70 MPH with an aero truck that is probably lighter too, what would happen if that same drivetrain was replicated in a van requiring twice as much power?

Obviously the answer is that it can't happen, right? The engine would require a downshift to pull the greater HP load requirements of a camper van versus aero truck.

In my opinion his solution is to make the best out of a bad situation. His engine is simply too big to optimize fuel economy when running empty at 60 to 70 MPH. If his truck had a 3.0L 4-cylinder PowerStroke like those sold in South America, or one of the new 3.2L I5 PowerStroke like will be used in the new Transit, the engine wouldn't have to be run so darn slow in order to increase BMEP. Either of these smaller engines could run twice as high RPM and still have higher BMEP.

If you are going to apply his ideas to a larger, less aero, and probably heavier van, and particularly if towing, you really need to consider that the requirements on the engine will be much different. If so, his gearing won't work for you, or at least give you same results.

[E350]

Chance: He calls it an "Amish Barn." And he pm'd agreeing that I am screwed...

"I'm afraid you're screwed.
3.08s aren't available anymore.
3.55s might help but you're gonna have to slow down on face frequent automatic transmission failures. A GV would give you the same problem. Slowing down engine speed reduces ATF flow through the cooler and that cooks the tranny. GVs don't work in 4x4 and I've never heard of anybody driving any kind of overdrive in true 4x4 conditions. I don't think modern vans can be retrofitted with manuals. Dave"

"Back in the 60s they had three-on-the-tree trannies for vans but the shift linkages were long and temperamental. Big rigs have used "semi-automatic" transmissions (like paddle shift automatics but just no torque converter) for over forty years. We are starting to see those in smaller vehicles. VW offers a six-speed "dual clutch" tranny in the Jetta. You hit the paddle and it mechanically goes through the clutch shift routine for you. Formula One cars have used those since the 80s because they shift much faster than even the best driver. I'd recommend the 3.55s. Your 7.3 has plenty of torque to push big tires and a numerically low ratio. Dave"
. . .
"3.55s should be A-OK even with that Amish barn you are driving. The 7.3 has plenty of torque at low RPM. I commonly drive in the 1000-1300 RPM range. Watch your tranny. Maybe a tranny temp gage might be a good idea. Dave"
. . .
I want to explore the tranny issue some more, later though.

[Chance]

Originally Posted by E350

....cut....

"Back in the 60s they had three-on-the-tree trannies for vans but the shift linkages were long and temperamental.

....cut.....

This reference brought back some very old memories which puts our modern-day obsession with power into perspective for me.

The very first vans I drove were first generation Econolines with the three speed on the column. The oldest of them had a 144 cubic inch engine that was advertised to make about 90 HP, but that was gross. By today's rating it would have probably been around 60 to 65 HP net. No need to say it was slow. On very windy days (like approaching tropical storm) it had to be shifted into second to fight strong headwinds.

The two newer vans had 240 cubic inch engines and flew by comparison. The back end was so light they would smoke the tires all the way through first gear -- not that we made a habit of it. With enough road they could just get up to 100 MPH, although lack of stability made me not hold that speed for very long.

Today if someone thinks of installing a 200+ HP small V8 in a large van we immediately question their sanity. I guess required power in large part boils down to personal perspective.

[mgmetalworks]

I know the discussion was a page or two back but if you're interested in info about a 6-speed manual conversion, here is a guy who has done the swap in an E-series...

http://www.expeditionportal.com/forum/t ... RB-7-3-ZF6

[E350]

mgmetalworks: I actually talked to Chris Steuber about this a couple of years ago, and did quite a bit of internet research and couldn't find where it have actually be acomplished in a van. A First! Thanks for sharing.