3.73 gears don't put you into 5th gear at the strip
Cobra R Member
Joined: December 13, 2004
Posts: 1,708
Likes: 3
From: United States
My Boss will go over 120 in 4th before hitting limiter, Im only trapping 114.45 in the 1/4 so I still have room..(28 inch MT/Drag Radial)
The info that was provided in the earlier post is spot on from what Ive found.
I had 26 inch tall (MT/Drag radials) and still was able to reach 117 in 4th gear before limiter.
The info that was provided in the earlier post is spot on from what Ive found.
I had 26 inch tall (MT/Drag radials) and still was able to reach 117 in 4th gear before limiter.
Last edited by UnrealFord; Jul 7, 2012 at 08:13 AM.
Bullitt Member
Joined: May 9, 2011
Posts: 261
Likes: 6
From: Michigan
When you start adding more power to your car, you will need to hit 5th with 3.73 gears unless you stretch your engine rev limit beyond 7000rpm with a Tune, or run taller tires.
The 5th gear ratio in the MT82 6-speed manual (2011-2013) is a 1:1 ratio, which is the same as 4th gear in all of the older 5-speeds. The biggest change is not just the power in the 5.0 Coyote engine, but the rpm capabilities. With the rpm now being 7000rpm instead of 6100rpm or lower, like in the 1997-2010 4.6L Modular engines, or 1983-1995 5.0L engines, everyone is having to unlearn those gearing changes of old.
The max speed in 4th gear will be limited on how tall of a tire your running with your 3.73's. On the 2011+ Brembo GT and Base GT, the tires are 27.2" tall, the Premium and GT/CS all-seasons tires are 27.7", while the slicks many people run on the Mustang's are 28" tall.
Below is a quick chart showing the differences in RPM and Tire Diameter:
max speed in 4th gear with 3.73's and 27.2" tires:
27.2" = 100.3mph @ 6100rpm
27.2" = 115.1mph @ 7000rpm
27.2" = 121.7mph @ 7400rpm
max speed in 4th gear with 3.73's and 27.7" tires:
27.7" = 102.1mph @ 6100rpm
27.7" = 117.2mph @ 7000rpm
27.7" = 123.9mph @ 7400rpm
max speed in 4th gear with 3.73's and 28.0" tires:
28.0" = 103.2mph @ 6100rpm
28.0" = 118.5mph @ 7000rpm
28.0" = 125.2mph @ 7400rpm
The 5th gear ratio in the MT82 6-speed manual (2011-2013) is a 1:1 ratio, which is the same as 4th gear in all of the older 5-speeds. The biggest change is not just the power in the 5.0 Coyote engine, but the rpm capabilities. With the rpm now being 7000rpm instead of 6100rpm or lower, like in the 1997-2010 4.6L Modular engines, or 1983-1995 5.0L engines, everyone is having to unlearn those gearing changes of old.
The max speed in 4th gear will be limited on how tall of a tire your running with your 3.73's. On the 2011+ Brembo GT and Base GT, the tires are 27.2" tall, the Premium and GT/CS all-seasons tires are 27.7", while the slicks many people run on the Mustang's are 28" tall.
Below is a quick chart showing the differences in RPM and Tire Diameter:
max speed in 4th gear with 3.73's and 27.2" tires:
27.2" = 100.3mph @ 6100rpm
27.2" = 115.1mph @ 7000rpm
27.2" = 121.7mph @ 7400rpm
max speed in 4th gear with 3.73's and 27.7" tires:
27.7" = 102.1mph @ 6100rpm
27.7" = 117.2mph @ 7000rpm
27.7" = 123.9mph @ 7400rpm
max speed in 4th gear with 3.73's and 28.0" tires:
28.0" = 103.2mph @ 6100rpm
28.0" = 118.5mph @ 7000rpm
28.0" = 125.2mph @ 7400rpm
And I agree about relearning the gearing. The easiest way for me was to equate it back to my LS1 T56 but add a set of 4.88 gears.
I agree, I miss my 2 over drives but even with the steep gearing of these cars I still get better avg mpg then my old LS1 T56.
Mach 1 Member
Joined: February 10, 2010
Posts: 536
Likes: 2
I think the usefulness of the 5th gear as a 1:1 has a lot to do with the type of driving you do frequently. I do 4-lane highway driving every day where I travel about 20 miles one way to work on a road with a 65mph limit. Which actually means everybody drives 65-80 safely. Being one of the "faster" drivers in this "acceptable" range means I'm frequently passing people over 65 and 5th gear is perfect for decent torque and smooth passing. If 4th was 1:1, I'd completely find 5th unusable. I'd be passing in 4th and shifting back into 6th for overdrive.
GT Member
Joined: September 5, 2010
Posts: 160
Likes: 0
Well on my 2011 GT (brembo) with 3:73 gears and the stock tune and the 27.2 tall tire no way in hell is the motor going to hit 7000 rpm . With the stock tune if i didnt pull the gear at 6500 it would be on the limter at 6700 and car would turn off the gas, put the brakes on ,put the car in reverse, and throw out the boat anchor .It has to be the most assnine thing i ever see a car do .I now have the Ford TSB tune in the car. That fix alot of stuff that was wrong with the first tune . I now can shift the car 6800 but one rpm over it on the revlimter again . With the TSB tune the car dose not think the world is coming to a end if you hit the revlimter but still stuck *** compair to my EVO 8 when i hit the revlimter in it. there no way its making it to the end of a 1/4 miles with 27.2 tall tires with out having to shift into 5 gear or changing the revlimter . I change the car over to a 27.7 tall tire now and I hope to make it through the 1/4 in 4 gear this next time out .
Shelby GT500 Member
Joined: March 3, 2004
Posts: 2,634
Likes: 0
From: Richmond VA
Well on my 2011 GT (brembo) with 3:73 gears and the stock tune and the 27.2 tall tire no way in hell is the motor going to hit 7000 rpm . With the stock tune if i didnt pull the gear at 6500 it would be on the limter at 6700 and car would turn off the gas, put the brakes on ,put the car in reverse, and throw out the boat anchor .It has to be the most assnine thing i ever see a car do .I now have the Ford TSB tune in the car. That fix alot of stuff that was wrong with the first tune . I now can shift the car 6800 but one rpm over it on the revlimter again . With the TSB tune the car dose not think the world is coming to a end if you hit the revlimter but still stuck *** compair to my EVO 8 when i hit the revlimter in it. there no way its making it to the end of a 1/4 miles with 27.2 tall tires with out having to shift into 5 gear or changing the revlimter . I change the car over to a 27.7 tall tire now and I hope to make it through the 1/4 in 4 gear this next time out .
Mach 1 Member
Joined: April 20, 2010
Posts: 733
Likes: 1
From: Norfolk, VA
You might notice that the very top of 2nd gear in a stock GT 3.55 is 62mph!
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