MD1

Anyone upgraded their gears to 3.55?

How are they?

Thanks

http://www.americanmuscle.com/ford-355-2011v6.html

Ltngdrvr

Lots of people have.

What are you wanting to know about them?

You will need some way to adjust the PCM for the new ratio, like a tuner or at least a speedo recal box.

Is your car a manual or automatic?

MD1

My car is a manual.

I basically want to know if there is a significant difference between the base V6 gears and the 3.55 gears for people with 2011+ V6 mustangs.

My car is tuned as well.

eurocobra

Anyone?? I would like to know as well if anyone has installed 3.55s on the 3.7 2011 V6 stang. I would advise against the 2.73s. It appears there is not a huge difference in fuel economy. I am not pleased with the stock 2.73s overall because I probably use more fuel anyhow because 6th gear has no passing power under 80 MPH. I tend to leave the car in fifth longer or have to downshift often to pass. YES THIS BURNS MORE FUEL as I have carefully calculated.

laserred38

If you're coming from the stock 2.73s, hell yes you will feel a difference in performance. If you have the 3.31s, don't bother with 3.55s and get 3.73s!

3.73-11

I was going to do 3.55s as I thought with a slightly shorter then stock tire sidewall it would be the equivelant to almost 3.73s. I ended up doing 3.73s after the shop told me the used gears I picked up would whine no matter how they shimmed them. Anyways long story short I'd just do 3.55s the 3.73s are great for making the car responsive no matter the gear your in. But with my J&M race lcas&93r bama tune it looks like i'm losing about 2mpg overall which puts me within about a 1-1.5mpg more then my buddy with a full weight premium 5.0 w/3.73s. And I have a lighter weight car with lightweight 18" wheels. Which is exactly the point people make when comparing gearing a 3.7 to a 5.0. Geared similarly they will get close to the same mpg on the hwy anyways. Before I was averaging 26.5+mpg in my daily commute untunned running 93octane. First tank since getting the gears&tuning it looks like i'm going to be right at 24-24.2mpg,. Which is disapointing but we'll see once I've had a few tanks run through it. I'm going to switch to my 93perf tune later and see if that helps out mpgs. But yeah if your running stock size tires which are right at 27" overall dia I would stick with 3.55 gears. Just my .02c

MD1

So what would you recommend if I was upgrading the 17" stock wheels to the 19" brembo GT wheels?

3.73-11

^well if you run the factory brembo tire size which is 255/40/19 its almost the exact same dia as the stock 225/60/17.
So I would still stay with 3.55s, I honestly wish that was the gears I had chosen instead of getting the 3.73s.
Just an fyi but with stock dia tires at 70mph flat cruising your rpm will be right at 2300-2350, 75mph is 2500+, 65mph is now right at 2200. So depending on your exhaust you may experience droning I now have drone not horrible but much more noticeable then with the stock gearing where I could be at 70mph and only turning 1750-1800rpm even with 1" shorter overall dia tires.
Also if you track your car or drag race with the stock 2.73s I was only in third gear at the end of the quarter mile and right at 6000rpm trapping between 100-103mph.
With the new 3.73s and tuning with my rev limit set at 7350 I'm hoping to only have to shift into fourth to go thru the traps without riding the rev limiter. We'll see honestly I may just switch back to my 2.73s and do the airaid intake&bama 87street tune the way gas is looking to head north of $4 a gallon for regular here shortly.
Hell I haven't been able to find premium for under $4.05/$4.10 for the last 5/6 fillups!

Storm75

I haven't yet, but sure plan to...

My '12 V6 is now one week old and the one thing I really wish I could have ordered from the factory was a different gear ratio. Because I have a convertible Ford blocks you from anything but the 2.73. Doesn't make a lot of sense to me really...

This is a great thread; thanks for the good information guys. Since I plan to do the CAI/Tune thing I can adjus for the swapped out gears also. Probably going to do all of this in another month or so.

The 3.55 just seemed like a good compromise to me.

David Young

I'm happy with my 3.31 gear ratio but if 3.55 were an option, i would have gone with them . I'm only doing around 1,735 rpm at 60 mph (automatic transmission) with my 3.31 gear ratio. 3.55 would be a perfect (I.M.O.) rear gear ratio.

Swiftsteed

Actually I test drove a new v6 2012 vert automatic with 3.15 gears on a base model, so you can have a gear other than 2.73 from the factory. Same 3.15's for a 2013 v6 automatic in the newer body update...

Swiftsteed

3.73's would be to much for a good daily driver. Works great if you track or road course the car often.... 3.55's are a nice performance increase over the 3.31's without sacrificing mpgs. I've had many v8 mustangs over the last 25 yrs and decided to buy a v6 MT82 and will be doing a gear swap from the 2.73's to 3.55's... The car is an absolute slug with these gears, I mean SLUG!!!! Anything with 200-250hp will put serious competition on this car. Even a 2001 230hp v6 Honda accord darn near beat me 0-80 yesterday... Same for a mini cooper S with just a CAI and a 300 lb driver.. Shucks a manual tranny 2009 honda accord 4cyl gave me a run for my $$$ so these v6's, IMHO, don't make more then 270-280bhp, not 305... ... The typical 13-18% drivetrain loss (aspirated & boosted) iis not accurate. My 2013 dyno'd on a manufactures dyno (which are far more accurate than a dynojet, a mustang dyno or chassis dyno) to tune of 246rwhp /199 rwtq, pretty weak sauce....

David Young

This Thread is a year old . I now have 3.73 gears.

newpony

texastboneking

Big Poppa

I agree

11SHELBYGT500

I've always gone by the 15-20% loss so 246hp falls right into line with 305 minus 15-20% loss.