# Eco Boost 3.73 Vs 3.55



## classicmazdaman

I'm considering a new tow vehicle and sold on the EcoBoost. It should have plenty of power with either rear-end for my 298RE as I'm currently towing with a 2000 Sierra 5.3L/ 3.43 rear-end/ Z71 4x with ease.

I would appriciate some feed back from current owners about their NON-Towing fuel milage with the 3.73 or 3.55 Ecoboost.

Thanks!
Chad


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## cdnbayside

The 298RE is a big heavy trailer. To get enough payload capacity to tow that trailer, you need the max tow package which only comes with a 3.73 rear end. I suggest the max tow package and heavy duty payload package. Real world fuel economy from mine is 15 mpg city, 20 highway that's with 3.73 rear end.


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## CamperKev

I have the 3.73's in my truck which is part of the max tow pkg. Not towing I average 14.8mpg around town and anywhere between 17.6-21mpg on the highway depending on how gentle i am with my right foot.	The truck tows GREAT!! My trailer is 7500lbs and maintaining 65mph on the steepest hills she never goes over 2600rpm's! The only thing I would recomend is getting the HD pkg or atleast get the max tow pkg. I believe they come with the 3.73 gears with the 4.10 as a option and if your going to tow then thats the best way to go!!!! Good luck, Kevin


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## Stance

I have the EB with 3.55's towing a 210RS. Even with a trailer shorter than your's, I still wish I had the 3.73's. While towing, the 3.55's tend to go out of overdrive on some small hills like the steeper overpasses. I think the 3.73's would stay in OD more often.

Not towing: I get 16-19 mpg around the suburbs depending on how gentle I am with the gas pedal and types of roads. I get 20-22 on the highway depending on wind and hills. Towing I get 8 to almost 11 on the highway depending on roads and wind.


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## Brooklinite

cdnbayside said:


> ... Real world fuel economy from mine is 15 mpg city, 20 highway that's with 3.73 rear end.


Same here.


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## gzaleski

I would go with the 3.73


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## DFG

2012 S/Cab Ecobbost 3.73 with HD Payload and Max Tow: non trailer Highway @ 65mph 21-22mpg, @70mph 19-20mpg, city 14-15mpg. Towing 301BQ avg 9 mpg. To date it has been a good tow and commuter vehicle.


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## classicmazdaman

All,

Many thanks for the input; you convinced me!!

Bought a '12 FX4 EB Crew Max Tow with 3.73 gears yesterday.... love it! Can't wait to hook-it-up. Can't believe the torque.

Again Thanks!
Chad


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## Collinsfam_WY

Be sure to break the motor in before towing. Congrats on the new truck!!!

-CC


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## CamperKev

Congrats!! You will not be disappointed! Remember you need to put a minimum of 1000 miles on the truck before towing for proper break in.


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## Todd&Regan

Glad to see a forum on Ford's Ecoboost. I have a 2012 F-150 XLT and tow my Outback 270BH with it. The camper's wet weight is about 6700lbs. This truck tows my camper with ease and plenty of power to spare! The 3.73 axle ratio is a must if you're going to tow a camper. My truck is equiped with the regular tow package and the off-road package. The off-road package comes with the 3.73 axle ratio. Have to get either the max tow package, the off-road package, or FX4 to get the 3.73 axle ratio.
Hope you're enjoying your new F-150 Chad! Also, if you haven't read it in your owner's manual yet, Ford recommends the use of premium fuel (93 octane) for the Ecoboost when towing.


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## venatic

Great choice! I've got the 2011 F150 Screw with max tow package. Pulls the camper like a dream. I always drop out 6th gear when towing.


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## Angel On Guitar

OK, I guess I'm the odd man out here. We have a new 298RE and tow it everywhere with a 2012 EB F-150 that has the 3.55 gears and it never is an issue. When you look at the numbers it has the payload and towing capacity to do the job and we have found that to be the case. Would the 3.73 do better? Probably on bad hills or mountains but so far ours has stepped up everytime we've needed it. It does drop from 6th to 5th occasionally but it isn't excessive and as long as it is in tow mode I suspect it won't be a problem. If it ever did become an issue we can always swap the gears and reprogram the chip but right now I don't see the need. BTW, we recent weighed our rig and it was only 7850 lbs fully loaded, a full 1000 lbs under the rated 9800 lb tow rating. The payload and GCWR were also well within bounds. Mileage = 11-12 mpg towing over various terrains (no mountains) and on the open road with no trailer it is 17-19+. We love it and it works for us.


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## Todd&Regan

Angel On Guitar said:


> OK, I guess I'm the odd man out here. We have a new 298RE and tow it everywhere with a 2012 EB F-150 that has the 3.55 gears and it never is an issue. When you look at the numbers it has the payload and towing capacity to do the job and we have found that to be the case. Would the 3.73 do better? Probably on bad hills or mountains but so far ours has stepped up everytime we've needed it. It does drop from 6th to 5th occasionally but it isn't excessive and as long as it is in tow mode I suspect it won't be a problem. If it ever did become an issue we can always swap the gears and reprogram the chip but right now I don't see the need. BTW, we recent weighed our rig and it was only 7850 lbs fully loaded, a full 1000 lbs under the rated 9800 lb tow rating. The payload and GCWR were also well within bounds. Mileage = 11-12 mpg towing over various terrains (no mountains) and on the open road with no trailer it is 17-19+. We love it and it works for us.


There's not going to be large noticable difference between the 3.55 and 3.73 gear ratio with the muscle the Ecoboost has. The 3.73 gear ratio won't down shift quite as much as the 3.55 when towing uphill or against a strong winds, that's about it. If the 3.55 gear ratio works well for you, I wouldn't even consider changing the gear ratio which would cost around $2000.


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## 26rester

I know that the ecoboost has plenty of low end torque. What I do not understand I tow with 5.3 1500 Burban. I ordered this truck with 4.10 gears and smoth ride package. Towing our 26rs in the little hills of Ohio and the big hills in Kentucky. I am honestly getting 12.5MpG. Now that is not all with the OB. Our old camper was a bobcat 201 sb weight empty was 4580 loaded about 5400. I did an exhaust upgrade to 3" and a KN air filter and box. Installed a bully dog programmer and flashed the computer. This truck is making good power and torque and very pleased at 225,000 miles and still going.


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## Todd&Regan

26rester said:


> I know that the ecoboost has plenty of low end torque. What I do not understand I tow with 5.3 1500 Burban. I ordered this truck with 4.10 gears and smoth ride package. Towing our 26rs in the little hills of Ohio and the big hills in Kentucky. I am honestly getting 12.5MpG. Now that is not all with the OB. Our old camper was a bobcat 201 sb weight empty was 4580 loaded about 5400. I did an exhaust upgrade to 3" and a KN air filter and box. Installed a bully dog programmer and flashed the computer. This truck is making good power and torque and very pleased at 225,000 miles and still going.


No doubt the 5.3L is a great engine, that's proven with the mileage yours has. With the mods you made and a 4.1 gear ratio, I'm sure it tows very well. But the 5.3L will soon be extinct. GM is introducing 3 all new V8's for their trucks starting in the 2014 model year. I haven't been able to find any information on them except that they'll be direct injection, which GM says will produce greater low-end torque and better gas mileage.


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