Okay I've read all the posts about the 3.73 rear gears and its like the perfect compromise for fuel mileage and responsiveness. One thing I have not found the answer to is... Where will the car safely top out at without damaging the car? I know you'll have to pair it with a tune to remove the speed limiter but how fast can it go without any other gofast mods?

 

You need a GT or aluminum driveshaft to go anywhere safely above 120mph.

 

I recommend that you look at a few components to upgrade before going over 120mph. A 2014 v6 is more than capable at hitting 120+mph on a track which I will assume this is the purpose. For speeds such as those you would need to upgrade your tires to those rated for higher speed since stock tires are not rated very high. Another upgrade is the driveshaft. Some say that the driveshaft will not fail on you and that videos you may have seen were freak incidents but why risk it, I know I am not risking it. Another component is brakes. Going fast is fun but you have to be able to stop and stop fast if need be at those speeds. Lastly one thing people tend to overlook is aerodynamics. A wing and a front splitter will keep you snug on the ground. Suspension is another thing that will need looking into for an upgrade. This is all for the sake of being safe while achieving great speed. Can the car do 120+mph maybe one time or so and still be safe? Probably but why risk your car and your life when you can do things properly?


To answer your question though, I don't think anyone has taken a late model v6 mustang to its limit because it takes money and there is no real place to reach that limit (legally).

 

FWIW the perf pack V6 comes with Z rated tires (or close to it at least). No need to upgrade with those.

I will be replacing the drives haft before I see any track time. As far as theoretical top speed is concerned, just do the math after figuring your tire size and current gearing. Just remember that aerodynamics will likely keep you from hitting that theoretical speed.

 

If I remember correctly, the drive shaft becomes unstable above 120MPH with standard gears.


The issue is not the vehicle speed, its the drive shaft speed. If you spin it to fast with a higher gear, even if the car is going slower, expect drive shaft failure.


Please consider a drive shaft upgrade with the gear swap. A tune will also be required.

 

Definitely do the DS, if you can swing it, when you do the gears if you are thinking about high speeds. I did them at the same time. Two of the best mods you can do.

 

Yeah dont go over 120 with the stock driveshaft