3.55 or 3.73 with ecoboost
11-09-2011, 08:03 AM
#21
You are going to be great either way. I have a 2011 6.5 screw with 3.55 and pull a 5200# boat. It pulls great and I have never had any regrets going with the 3.55. I you do primary driving and some random towing my vote is for the 3.55. If you plan to add larger tires at any time then I say get the 3.73. Just my thoughts.
11-09-2011, 08:17 AM
#22
Senior Member
It might only be a extra hundred rpms but you constantly running that over the coarse of your vehicles life. The 3.55 will see around 19-20 mpg and 3.73 will get 17 mpg. 2 mpg extra gives you 50 more miles per tank. For me that's over 1000 extra miles per year. Anyway good luck with your choice!
My sides are killing me from the laughter. Where is your proof on this?? I can lower my RPM's by a couple of hundred and reduce my aero drag by 15-20% by simply slowing from 72 to 65 and only pick up .5mpg. That is a way bigger change than a 3.73 to 3.55 gear change. A 5% gear change up or down will never equate to 2-3 mpg in these trucks. NO WAY...EVER! You sound like one of those diesel drivers who say they get 25 mpg.
My truck routinely gets 20 mpg all day long on the freeway with the 3.73's. The only time it has even been close to 17 was running into a 30mph headwind when it was around 18. Same wind coming back it was almost 24. I've driven both trucks and the mileage was within a few tenths.
11-09-2011, 08:20 AM
#23
Senior Member
11-12-2011, 07:46 PM
#27
It might only be a extra hundred rpms but you constantly running that over the coarse of your vehicles life. The 3.55 will see around 19-20 mpg and 3.73 will get 17 mpg. 2 mpg extra gives you 50 more miles per tank. For me that's over 1000 extra miles per year. Anyway good luck with your choice!
11-12-2011, 07:48 PM
#28
My sides are killing me from the laughter. Where is your proof on this?? I can lower my RPM's by a couple of hundred and reduce my aero drag by 15-20% by simply slowing from 72 to 65 and only pick up .5mpg. That is a way bigger change than a 3.73 to 3.55 gear change. A 5% gear change up or down will never equate to 2-3 mpg in these trucks. NO WAY...EVER! You sound like one of those diesel drivers who say they get 25 mpg.
My truck routinely gets 20 mpg all day long on the freeway with the 3.73's. The only time it has even been close to 17 was running into a 30mph headwind when it was around 18. Same wind coming back it was almost 24. I've driven both trucks and the mileage was within a few tenths.
My truck routinely gets 20 mpg all day long on the freeway with the 3.73's. The only time it has even been close to 17 was running into a 30mph headwind when it was around 18. Same wind coming back it was almost 24. I've driven both trucks and the mileage was within a few tenths.
Last edited by Mike Up; 11-12-2011 at 07:51 PM.
11-12-2011, 08:03 PM
#29
Nathan
Originally Posted by Mike Up
Doing research on this forum and others will tell the story. There is a significant gain in mpg with the 3.55. No need to be a jerk about it. Just research. If there were no difference, Ford simply wouldn't offer it. It's for mileage.
11-12-2011, 08:08 PM
#30
Senior Member
There are plenty of Ecoboost... not 5.4 owners with 3.73's that get the same mileage as the Ecoboost with the 3.55's. I'm not comparing anything with a 5.4 in it....total different motor. What does significant mean to you. I employ 33 techs driving an array of different vehicles putting 40-60K on them every year. 4 are Ecoboost trucks. All are 4 wheel drives SCREWS. Mine is the only longbed. Three are 3.73's and one is a 3.55. His mileage is no better. I actually get better mileage than most people here report regardless of gears. Texas is flat. I routinely see 20 mpg average tanks. They are usually 420 straight highway and around 100 of mixed rural/city. The 3.55 to 3.73 difference is not big enough to warrant a big increase. There is absolutely no way it is 2-3 mpg.