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5 spd to 6 spd conversion?


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Adding a sixth gear does not necessarily increase your topend. The Addition of the sixth gear is typically a second overdrive to allow for better fuel mileage and less wear on the motor & drivetrain by running at a lower RPM. In the newer cars topend is limited by the computer, not the tranny or even rearend gearing.

 

On the track or the strip you will never see 5th gear let alone a 6th. The guys who run the flying miles may but I wouldn't know as I've never been around that kind of event.

 

I would be willing to bet that in any stock bodied mustang that you will run out of aerodynamics before you run out of gear. Mustangs are bricks in the wind!

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Has anyone changed out the OEM 5 spd for the 6 spd? If so what is the top end in 5th now?

 

Thanks

Rex S.

 

 

I think these are the GT's 3650 ratios

1st Gear: 3.34:1

2nd Gear: 2.00:1

3rd Gear: 1.32:1

4th Gear: 1.00:1

5th Gear: 0.675:1

 

 

...and I think these are the GT500's 6060 ratios

1st Gear: 2.97

2nd Gear: 1.78

3rd Gear: 1.30

4th Gear: 1.00

5th Gear: .80

6th Gear: .63

 

So at 100 in the GT in 5th, a swap to the TR6060 would put you at about 84 in 5th and about 107 in 6th.

 

But, look at the 1st and 2nd gears across the two ...the lower torque of the GT properly called for a higher numerical ratio to give it a bit more grunt low-down where the NA engine lacks torque, whereas the GT500 has gobs of low torque and, therefore, a lower numerical ratio, but that would definately reduce the GT's acceleration some. Of course you can have a specialty shop fix you up custom ratio's but that's pricey.

 

Another alternative might be the new Getrag 6-speed in the '11 5.0 GT. Considerably stronger than your 3650 (tho not nearly as tough as the 6060) but it has some very nice ratios and is actually a close-ratio 5 speed with OD, since 5th 1.00:1 (not 4th like the 3650 and 6060.

 

The Getrag in the '11 5.0 uses these ratios:

1st Gear: 3.66

2nd Gear: 2.43

3rd Gear: 1.69

4th Gear: 1.32

5th Gear:1.00

6th Gear 0.65

 

You'll definately get a benefit launching the 4.6 NA motor with those ratios, imo, and you still have a taller OD than the 3650 for cruising. In the '11 5.0 GT with it's 412bHP, a 4th -> 5th shift is required in the quarter mile a few mph from the stripe, but a 315HP 4.6 just might cruise thru in 4th since it will be slower. Assuming the lower revving 4.6 won't nix that benefit (the 5.0 revs to 7,000), he Getrag *might* be just about ideal for the prior 4.6 GTs with the right tire diameter.

 

Dunno what's involved in the Getrag swap or if the stick/linkage loications match up well since I'm not aware of anyone having done it yet, but it sounds like it might have some excellent potential.

 

Just some thoughts...

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Anyone aware of someone swapping the new '11 5.0's Getrag 6-spd into a 4.6 S/GT? Just curious.

 

If a 4.6 is SC'd and making lots of low-end torque the 6060 is the ticket, but the new Getrag has superb ratios for an NA 4.6 S/GT and is stronger than the old 3650.

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Adding a sixth gear does not necessarily increase your topend. The Addition of the sixth gear is typically a second overdrive to allow for better fuel mileage and less wear on the motor & drivetrain by running at a lower RPM. In the newer cars topend is limited by the computer, not the tranny or even rearend gearing.

 

On the track or the strip you will never see 5th gear let alone a 6th. The guys who run the flying miles may but I wouldn't know as I've never been around that kind of event.

 

I would be willing to bet that in any stock bodied mustang that you will run out of aerodynamics before you run out of gear. Mustangs are bricks in the wind!

 

 

EL, I understand the double OD. Trouble with the 5spd and Open Road Racing is the car tops out at around 143 in 4th and shifting to 5th drops the engine WAY out of its powerband so it can not pick up any more speed easily. On a slight downgrade between Ft. Stockton and Sanderson we have managed to get a bit over 150 but the geraing is to tall in 5th. My thinking is splitting the ratio between 4th and 5th (like in the ZFs used in our old ZR1s) the car should be able to top the 155 mark easily. Gotta give Ford credit for making the 4.6 able to take running redline for 118 miles though. We'll rest the engine a bit on straights in 5th but have to use 3rd&4th in the twistys. Just for giggles we reset the mpg readout at the starting line and got 9mpg at full throttle :doh: Just looking into the idea. SORC is next month in Arnold, NE and that will be the final road race for the year.

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Open Road Racing, now that is something I would like to try! As a kid I would drool over the Big Red One in Hot Rod Magazine. I know its a '69 Camaro, but it beat the snot out of Vetts, Porsche and Farraris of the day!

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Open Road Racing, now that is something I would like to try! As a kid I would drool over the Big Red One in Hot Rod Magazine. I know its a '69 Camaro, but it beat the snot out of Vetts, Porsche and Farraris of the day!

 

 

Well I see you are in Keller, Texas so the next one close is the new one Marfa-Persido in mid Oct.. www.mporr.net . We can't make it due to other plans.

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