[Damaskinos_of_Athens]

.
Looking at ecoboost vans and it seems most have the 3.3.

Why is that?

The 3.3 can cost you thousands of pounds in towing capacity.

Is it expectations of mpg? Is there any proof of better mpg and is that small gain worth the towing capacity?

I am sceptical of any possible mpg gain, since it is a 6 speed transmission and do not tend to drive really fast.
.

 

[PeterR]

If the towing capacity of the 3.5/3.31 combo is acceptable to the owner, and assuming that we are mostly interested in MPG at highway speeds over long distances, usually in 6th gear, then yes the MPG's will be better with the 3.31 rear end than with the 3.73 or 4:10 rear end. Very simple stuff IMO.

Check the 3.5/3.31 MPG thread for the outstanding results:

http://www.fordtransitusaforum.com/...mpgs/6065-mpg-3-5-ecoboost-3-31-rear-end.html

 

[ford99]

Plus the tires on these things are small compared to the same drivetrain on an F150 for example. F150 with 3.55 or 3.73 gears and say 32" tires is probably not far off a transit with 3.31 gears and 29" tires.

Also the torque of the twin turbos kicks in pretty low lessening the need for taller gearing. So you get better mileage and all the power without penalizing yourself at highway speeds . 6 speed or not .

Think about the F150's coming out with 10 speed transmissions in a few years. At least the raptor will have one when it comes out in 2016 as a 2017 model year. Which is behind an Ecoboost that will have more power than the outgoing 6.2L.

 

[carnut]

Irregardless of any potential mpg difference (I'm not convinced it's significant), there will be less engine wear with less rpm. Over 100K miles, it's like an extra 10K miles on the motor. I also feel there is an optimum ratio to match the gearing and power. I'd rather an automatic transmission not jump to the highest gear at 45 mph. The lower the final drive the sooner the trans wants to shift up. If your REALLY going to tow then it might be worth it, but towing capability is way over sold IMO. It's like racing. Lots of people say they want to, but very few ever do.

 

[JP4]

Quieter, less wear, better milage. The EB has more in common with a diesel than a small naturally aspirated engine. Bottomless torque comes on early. I think it's in 6th gear by about 45mph and it doesn't knock or lug on regular gas. It's hard to explain if you've never driven one, but the EB is unlike any engine I've had in a vehicle. I'm not interested in towing capacity, so it was a no brainer to go for the tall gears.
JP

 

[star gazer]

I am towing a very aerodynamic 'egg' camper the weighs less than 3000 lbs. The van did not need tow mode even in the hills and did not keep dropping down 'hunting' for gears. Towed way better than my 7.3 PSD which yes is hard to believe.

But if you are towing near max, or something with a lot of air drag, then the 3.73 would be better I agree.

Dean

 

[sitio]

a nice post. new members join the listening

 

[Chance]

.
Looking at ecoboost vans and it seems most have the 3.3.

Why is that?

....cut......

My long 2 cents.....

It seems to me that Ford tries to match gearing to engine capabilities in order to please the largest number of buyers. They probably do lots of market research on what most people do and or want from their vehicles, but just like we see on this forum personal opinions, tastes, and needs vary considerably.

Fuel economy is probably important but since these vans don't have official EPA ratings it probably doesn't matter to them as much. Not saying it's trivial because the word gets out anyway.

On the other hand if fuel economy was the primary issue, it's possible Ford could install even taller gearing at the expense of other performance. But they don't because they also consider gradeability and towing (it's mentioned in their EcoBoost studies so it's at least considered). People don't generally want constant shifts because the engine can't pull the load even if it saves a little fuel (hence why CVTs are becoming more popular in small vehicles).

If the 2015 F-150 is any indication, Ford uses tallest gearing on engines with highest torque (over a wide range of RPMs). The base 3.5L V6 starts with 3.55, the 2.7L EB V6 and 5.0L V8 start with 3.31, and the 3.5L EB V6 with 3.15.

My guess is that they could also run 3.15 in the EB Transit, but on larger vans with much more aero drag than F-150 the gains would be insignificant. Once the engine has boost, adding more load through gearing does not make it more efficient. This is the reason why EB has a negative reputation for inefficiency when towing. Same can happen at very high speeds when using a lot of horsepower.

Ford papers I've seen suggest they plan to decrease EB displacement to improve fuel economy (like introduction of 2.7L EB) but that's only going to help at lower HP. At higher power levels (relative to size) most modern engines can be geared to be equally as efficient.

I personally think people like EB today mostly because of their power. Fuel economy isn't all that different in my opinion. Does anyone buy EB to save fuel? I kind of doubt it. If Ford continue to downsize EB displacement to equal power, then it will be interesting to see how buyers react.

 

[6386]

My Transit 3.5L/3.31/16" tire combo turns the same rpm at 60 mph as my F-150 Supercab 145" wheelbase 3.7L/3.73/18" tires did. My Transit 150 Wagon is rated to tow 5,100 lbs w/the 3.31 and stays the same even if you order the 3.73 gears (none of the Wagon models show a tow rating increase with the 3.5L/3.73 combo) .

And the F-150 was rated to tow over 5,800 lbs in that configuration. My dad's F-150 SuperCrew 145" Wheelbase 3.5L EB/3.15/20" tire combo was rated to tow 8,500 lbs and turned much lower rpms at 60 than my F-150 or my Transit. If he had ordered it w/3.73 gears it would have been rated to tow 11,300 lbs! Remember these F-150s were before the radical weight reduction of the new aluminum models.

I think the Transit's tow rating is limited by it's unibody construction, and smaller brakes, not by the 3.5L Ecoboost/3.31 combo.

 

[6386]

I edited my previous post to include tow ratings.

 

[6386]

Take a look here:

http://www.ford.com/resources/ford/general/pdf/towingguides/Prelim15FLRVTT_Transit_Apr22.pdf

The next chart has different numbers but still shows no difference in tow ratings between the 3.31 and 3.73 for the 150 LR MWB Wagon model:

2015 Ford Transit Commercial Full-Size Van | Towing Specs | Ford.com

The Van models show an improvement in tow ratings with the 3.73 gears but cannot touch the F-150 ratings (full frame).

 

[unclebob]

I would be willing to bet that less than 25% of the transits are used to tow a trailer.

For most of us we need a vehicle that gets good fuel economy and still has enough power to get out of it's own way.

I ordered the 3.5 / 3.31 combo because I expect to " baby " the engine and consistently get 20 + mpg. I wanted the Eco-boost for the safety factor all that power gives me. If I need it I want it immediately.

Other people choose that combo for the thrill of driving it. And I'm sure others want it for other reasons.

That combo will pretty much do anything you could reasonably ask of it.


Sent from my iPad using Tapatalk

 

[PeterR]

unclebob,

I share your goal of 20 MPG with the low roof 130" WB 3.5/3.31 Wagon I have on order.

You will find several 20 MPG results (+/-) on this thread:

http://www.fordtransitusaforum.com/...mpgs/6065-mpg-3-5-ecoboost-3-31-rear-end.html

 

[JohnMW]

Coming from an E-350 with 4.10 axle, I thought I am taking a big leap to get the 3.73. Salesman said, "Sure you dont want the 3.31?" I said, "No, with such a big van and always loaded give me the 3.73".
If I did it over, I would go with the 3.31. The van amazes me! With a nice easy acceleration on a level stretch, my 3.73 will be in 6th gear BELOW 40 mph. Even with my decent load, it will pull almost the steepest interstate grades without dropping out of 6th. That is my experience, but I dont tow anything.

 

[Chance]

I would be willing to bet that less than 25% of the transits are used to tow a trailer.

For most of us we need a vehicle that gets good fuel economy and still has enough power to get out of it's own way.

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

I agree. The issue auto companies must be struggling with is "how" the vehicle gets out of its own way. To a large degree it's very subjective.

In Europe large vans with 100 to 200 horsepower are very common. Some are available in US too. If Ford reduced the standard engine to 200 HP for the Transit would buyers want it? I doubt it.

Buyers today seem to want power but only under certain conditions. Few drivers would find transmissions downshifting on a regular basis and engines revving to 6000 RPM acceptable. And it's unfortunate because downsizing engine is an inexpensive way to improve fuel economy.

I'm thinking that a small 2.7L V6 without turbos could get out of its way as fast as the Transit diesel, or Sprinter diesels, or ProMaster diesel, yet it wouldn't feel right on the road. In today's competitive market it takes more than MPGs or speed. We want more and are willing to pay the higher costs.

 

[orton]

I have driven my 3.5 EB with the 3.31 rear end about 1000 miles. I am very satisfied with the drivetrain. It is interesting how the transmission does not need to downshift very often because of the diesel like 400 lb-ft torque is available from 2300 to 3300 rpm. I drove my 08 Sprinter V6 five speed for 58,000 miles and had to constantly manually operate the transmission due to very poor programing. The Transit transmission is an automatic and does not require manual operation. There is excessive power available for passing. I would be satisfied with less passing power but suspect that less power would require the transmission to downshift more often.
Overall I would rate the 3.5 with the 3.31 rear an excellent choice. The only reason I would purchase the 3.73 rear would be if I regularly pulled a heavy trailer that required the additional towing capacity.

 

[Chance]

The 2.7 EB seems to be a good middle ground for the F-150 for those not needing to tow as much. May work on Transits too. Although with the larger Transits it may not save much fuel over 3.5 EB unless driven slower.

 

[carnut]

I would be willing to bet that less than 25% of the transits are used to tow a trailer.

I'd put it much lower than that. I doubt even 15% of pickups tow.

 

[Damaskinos_of_Athens]

.<br />
Has anyone hooked up a reader to the OBD port and verified at what speed they hit sixth gear?<br />
<br />
I am wondering how you can tell otherwise since I do not think there is an indicator. With 2 overdrive gears, it could theoretically be at a higher speed than expected.<br />
.

 

[onetwo]

The 2.7 EB seems to be a good middle ground for the F-150 for those not needing to tow as much. May work on Transits too. Although with the larger Transits it may not save much fuel over 3.5 EB unless driven slower.

I would have been all over the 2.7EB had it been offered with the Transit.

On the F150s the 2.7 is mighty capable with a tow rating of up to 8500lbs,

I have no doubt it would have been a fine motor for the Transit.


P.S. I will be towing with my Transit!!