[budget muscle]

Was going to get 3.31 put in my 2011 V6 auto car this week but found out the 3.31 gears alone are $400 to buy or I can go with 3.55 for $180. So looks like I will go with 3.55 so I can keep the whole job of parts and labor under $500. My question is can I drive the car for a short period with the 3.55 and the factory 2.73 tune in it until I get my bama tunes? And If I have to take it in for warranty work I would also like to remove my custom tune and drive the 50 miles to reset the computer. I guess I would like to know just how bad it would drive?

 

[05mystang]

Wow that's a pretty big difference in price, I would go with the 3.55 too. They will also give more kick than the 3.31:bigthumbsup As far as the tune goes, you can drive with it no problem, your speedo will just be way off. You can easily set it back to stock and still be able to compensate for the gears. I would definitely do that if going in for warranty work

 

[happydad]

Was going to get 3.31 put in my 2011 V6 auto car this week but found out the 3.31 gears alone are $400 to buy or I can go with 3.55 for $180. So looks like I will go with 3.55 so I can keep the whole job of parts and labor under $500. My question is can I drive the car for a short period with the 3.55 and the factory 2.73 tune in it until I get my bama tunes? And If I have to take it in for warranty work I would also like to remove my custom tune and drive the 50 miles to reset the computer. I guess I would like to know just how bad it would drive?

Why don't you get the tuner first?

 

[matthewr87]

If it is an auto, won't the gearing discrepancy in the computer also affect the shift points of the tranny? That might get a little weird.

 

[need4mospd]

...but found out the 3.31 gears alone are $400 to buy...

Please do not get it installed at the place that told you that. Summit Racing has them for $190.

Your speedo will be off and you'll be racking miles up on the odometer quicker than you're really driving. For every 100 miles you drive, you'll see 121 miles on the odometer.

 

[happydad]

If you return to the factory tune AFTER installing the new gears - for warranty work - how would that work? Wouldn't you have to return the gears to stock as well?

 

[Nightmare37]

If you don't get the tuner with the 3.55's, don't even think about taking it to redline since your shift points will be way off. you could possibly overspeed the engine. lets say for instance in 1st gear WOT your car normally shifts to 2nd at ~48mph on 2.73's at 6800rpms. Well on 3.55's your car tuned should shift at 37mph 6800rpm's, but without a tune it would need 8,800rpm's to shift to second at 48mph. I don't know if the rev limiter kicks in to stop you since I haven't tuned this car yet.

If you return to the factory tune AFTER installing the new gears - for warranty work - how would that work? Wouldn't you have to return the gears to stock as well?

You can still have a stock tune and leave the changes for the 3.55 gearing if you are that paranoid. In fact dealerships will install different ratio's and adjust the PCM calibration for the new rear end gearing for you without affecting the warranty.

I don't think your PCM data-logs, so I don't know why people are so worried about jumping back to the stock gearing when you take it in to the dealership. There are really only a few ways you can tell it is an aftermarket tune (higher shift points/rev limiters, WOT timing, transmission line pressures on automatics,ect) that the dealership won't be able to see unless they are driving the car and datalogging it themselves. It's not like you pull up the screen and a giant "BAMA TUNE" pops up before you can read the engine parameters.

 

[happydad]

There are really only a few ways you can tell it is an aftermarket tune .... It's not like you pull up the screen and a giant "BAMA TUNE" pops up before you can read the engine parameters.

Just make sure you remove that SCT emblem or American Muscle decal before you bring it in to the dealer....I think they'd figure it out with those signs. :gringreen

 

[budget muscle]

Ok I took my 2011 mustang in to the ford dealer today and they hooked up a laptop to the computer port to see what paramiters they can change for me when I have my gears changed. As of 2011 models the computer on the car is compleatly locked out of anything but the settings that serial numbered car came with. The only way to change gear ratio program is with a after market tuner. The older cars you can change but not the new stuff.

 

[jsnyng]

Ok I took my 2011 mustang in to the ford dealer today and they hooked up a laptop to the computer port to see what paramiters they can change for me when I have my gears changed. As of 2011 models the computer on the car is compleatly locked out of anything but the settings that serial numbered car came with. The only way to change gear ratio program is with a after market tuner. The older cars you can change but not the new stuff.

That's exactly the same story my dealership told me about the automatics. I still put 3.73's in my GT anyhow and just put a tune on there.

 

[bifftws]

The warranty issue is specific to the problem area. The modification to the car has to have direct link the problem for it not to be covered under warranty. If your wipers go out because of a bad motor Ford can't claim an aftermarket tune casued the problem and are obligated to fix it under warranty. They can claim for most engine and transmission issues though even if the modification wasn't the issue but due to a factory defect. Always reset back to stock prior to taking it in.