4.09 Diff ratio in 2018+ Mustang GT...

[Dave2013M3]

Hey guys is this possible without having to tune the car?

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[Schwerin]

I suspect you'll at least need something like FORscan to change that ratio to 4.09.

 

[Mikepol2]

No tune needed, the car automatically compensates. At least mine did. Displayed mph after the 4.09 install matched what I had calculated it would be.

 

[Dave2013M3]

No tune needed, the car automatically compensates. At least mine did. Displayed mph after the 4.09 install matched what I had calculated it would be.

Great news..Mike whats your impressions with the gears?

 

[Mikepol2]

No regrets.

Post 7 has tips I learned from removing and reinstalling the diff: https://www.mustang6g.com/forums/th...erential-housing-install.103235/#post-2589358

This thread has lots of info and impressions, including some of my posts when trying to decide to do it, and afterwards on the results: https://www.mustang6g.com/forums/th...-gears-in-the-mt82.111146/page-3#post-2597667

Enjoy!

 

[Black19GT]

No regrets.

Post 7 has tips I learned from removing and reinstalling the diff: https://www.mustang6g.com/forums/th...erential-housing-install.103235/#post-2589358

This thread has lots of info and impressions, including some of my posts when trying to decide to do it, and afterwards on the results: https://www.mustang6g.com/forums/th...-gears-in-the-mt82.111146/page-3#post-2597667

Enjoy!

I've been following along Mike, a lot of good info in those posts for sure! i had been wondering about the tune as i plan to stay NA until warranty is up and that's not for another 30,000 miles lol

Have you had any negative issues since having them installed? My car is a daily and I'm on the highway at least 50% of the time. The bonus for me is that i don't pay for my fuel being a territory sales manager.......all about "smiles per gallon" here!

I know you have said that you start in 2nd gear a lot now, do you find you need to ride the clutch much to get rolling? just worried about the factory clutch going sooner that way.

what RPM's do you see in 5th and 6th gear at say 80mph?

thanks brother!

 

[Mikepol2]

Well my car is not a DD so they have only been on for about 1700 miles but I still love them and never wish for having the 3.73's again. However I don't think it's ever been on a highway since having them installed. I almost never use 6th gear. But you can calculate the rpm's in whatever gear and at whatever speed you want, there are plenty of online calculators.

I only start out in 2nd sometimes if it's on a flat or slight downhill slope and I don't need to get out in a hurry. It doesn't take much more clutch slip than it does in first - but I bet if you try it on your car you won't see much difference either. And you certainly don't have to start out in 2nd ever if you don't want to, it's probably better on your clutch with the 4.09's than the 3.73's if you're always starting in first.

The only negative so far has been having to park it in the garage from November till now, and that freaking virus is keeping it there LOL!

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