Drivetrain 2013-'14 V6 AT gearing dilemma

While I made mention of this dilemma in my recent progress thread update, I thought it best to detail this sepatately....

I have a 2014 V6 Mustang with an A/T and the optional Performance Package, which includes a 3.31 final gear ratio. To this point, the only "performance" mods which I've made are the installation of an Airaid MXP CAI, a BBK 3.7L V6 73mm Power Plus throttle body, and a Bama 91-octane tune.

About a year ago, I purchased the parts needed for a gear change to 3.73 final gear ratio, but have stalled on installing due to indecision. Coming to the conclusion that I don't need an off-the-line rocket, I'm concerned that the 3.73 might be a bit too tall. My dilemma at this point is whether to: 1) sell the 3.73 ring/pinion gear; keeping the rest of the installation componets (install kit & pinion bearing) and instead buy/go with a middle-of-the-road 3.55 gear set; 2) keep/install the 3.73s that I currently have on hand; or 3) junk the whole idea and just stick w/ the 3.31s that are already installed.

As I have no per-determined preference for any one of the three options above, I would love to hear others experiences with either the 3.31 vs 3.55 or 3.31 vs 3.73 options.

Thanks in advance!

David Young said:

I don't want you to think I'm stalking you but I've waited 11 days for someone else to chime in. No one has . The 2.73 standard gears that came on our v6's were 'only' for Ford to advertise 'over 300 horsepower and over 30 miles per gallon. First car to have ever been able to do this . I ordered my v6 with the lowest gear ratio offered from the factory with the 3.31, like you did. This still isn't enough gear and 'should have been' the 'standard' gear ratio for our v6 Mustangs. 'If' you were to go with a supercharger, 3.31 would be enough. If not, I would go with the 3.73 gears like I did. The difference between the 3.55 and the 3.73 gears is only 150 RPM at 65 MPH. With all the hills in East Tennessee the 3.73's make pulling up them so much easier. I believe they are a lot of hills where you live? Going from the 3.31's to 3.73 was very noticeable and so much better in every way .

No matter which gears you go with, even 4.10's, you 'top end speed' will still be 'drag limited' and 'not RPM limited'.

Good luck and never fear the gear

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David:

Thanks so much for your input (and no aplogies necessary re: the 'stalking' )

I bought mine about 2-yrs old so I didn't order it w/ the 3.31s, but was lucky enough to find one w/ the 'Performance Package' which included this gearing. I've not really had any issues with its performance (or necessarily felt a 'need' to 'upgrade' its gearing), but was pretty well convinced that there was likely some additional untapped power there, should I decide to go this route. As a matter of fact, in terms of overall performance, it's a bit sad to say, but my 2014 V6 (@ 300HP) will run circles around my '66 convertible '289' V8 (@ 200 HP). To aid in making up my mind, I was just hoping for someone to respond who had some 'real world' input on this and would offer their insight/opinion (which you have and did! ).

The area where I'm at (in southeasten Colorado) is considered the 'high desert' and, for the most part it's as flat as a board (not ALL of Colroado is mountainous ) so driving in "hills" is rarely an issue unless I head to the mountains; when we do, it's normally in my wife's Subaru Forrester.

Again, my thanks for your feedack.

White Wolf said:

Gearing on my 2013 Automatic V6 (White Wolf) was the first Mod I changed after the CAI. I chose 4:10 and can tell you they are awesome. On the highway I run about 2700 rpm at 70mph. This is a City Vegas car though and 99% of the time it never hits the highway and only tops out at 50mph on any city road around here. I love them and could not imagine the car again with stock gears. 305's in the rear are the perfect tire size. I now have every Mod you can put on it except a NEW TORQUE CONVERTER which I just ordered from Circle D. It will be a 3800 Stall plus a new Aluminum Driveshaft and Upper and Lower Control Arms. This V6 can easily out run stock or lightly modified V8 in town. Thats not talk, I have done it on numerous occasions.

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Thanks for the feedback! I listed my 3.73 components as a "kit" and offerd it on eBay at a 10% discount below cost. With no takers after the days, the listing ended and, I'm taking this as a sign that the gears were ment to be installed. As such, the gear change is back on my to-do list at some point in the not-too-distant future... For now, I'm up to my neck in work/expense on my '66 convertible.

Looks like we've done a few of the same exterior mods... What else ya runnin'?

White Wolf said:

I also forgot I have a Bama Race Tune Installed with the Rev-X. Of course that really wakes things up with the other mods. Hope that helps.

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Nice! I'll bet she's a runner! I've been a bit more modest w/ my mods so far... To this point consisting of Airaid MPX CAI, 73mm TB & Bama tuner along w/ a lenghtly list of asthetics. Along w/ the afore discussed rear gears, I also have new progressive-rate lowing springs on hand awaiting installation. Mine also origianally came w/ the Performance Pack so it has factory-upgraded suspension, brakes, etc.