before i purchased my mustang i always debated if i should go with 3.55 or 3.73 , a lot of people seemed to say that with 3.73s you will have to shift into 5th gear at the end. i don't know if i was doing something wrong or what, but i was at about 6700 rpms in 4th at the finish line and i was glad i didn't have to shift.

how many of you with 3.73s go into 5th, I'm assuming if you spin tires more from the start then you will have to go into 5th?

 

5th at the strip is a NO NO :-)

 

You'd have to be running awful fast to need 5th in the 1/4 with 3.73's.

 

Theres a reason why old school muscle came with 4 on the floor, shifting to fifth is one of the deadly sins! Glad to hear youre likin the gears man

 

i guess i was wrong, i through some people were going into 5th

 

You won't hit 5th stock, but will if you get a tune and bolt ons.

 

Or go with a Powerglide and shift once

 

Or rock crusher too! But nothing beats an 8 speed cvt

 

I trap from 115-117 mph, and with 26" tall drag radials I had to shift into 5th with my 3.73's. I promptly bought a pair of 28" tall drag radials and no more need to shift into 5th.

 

For me 5th still has torque to pass but not as zippy as being in 4th

 

Well the Boss 5th gear is 1:1 unlike the GT's MT82 which is 4th gear. The only problem is figuring shift points and how fast you can shift. If you can get into 5th in the boss it might help but you're gonna have to shift out early of a few other gears. Not sure if it will help. I have to shift out of 2nd and 3rd to get all of 4th in the 1/4. Good thing is that I am at full hp and tq from 3000-6000 so it doesn't matter when I shift out.

To the OP: I would try a few passes shifting out at different rpm's and see if 5th gear helps any. But I doubt if it will. Worth a shot though.

 

[QUOTE=AlsCobra;6392478]Well the Boss 5th gear is 1:1 unlike the GT's MT82 which is 4th gear.
[QUOTE]

They both use the exact same MT82 Transmission.

 

My boss is on the box as I go threw the traps at 117 mph in 11.8 seconds........... I'm expecting to start shifting to 5th. Soon......... I'm not buying
More tires just to not shift....... I can handle shifting

 

Only bolt ons CAI
and UPR uppers lowers and drag radials

 

Sorry. Had it crossed up with the Shelby trans.

 

IIRC, the rumor is that the 3.37s were picked to maximize the stock 1/4 mile..and you should be just a hair under redline in 4th on a perfect run...and it sounds like BOSS302R was darn close (nice job)...

As others have mentioned, with any power adders, the 3.73s will theoretically require a shift into 5th and therefore slow you down...
...but they're still a bit more fun on the street, so there's that.

I went with 3.55s but it was a toss up. There are advantages and disadvantages to each but the difference is pretty slight.

 

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

 

GREAT INFO......

 

Wrong. The Boss 302 and the normal GT 5.0's use the exact same transmission and gearing; 5th gear is a 1:1 ratio. The major difference between the Boss and GT is the engine rev limit by the factory, 7500 vs 7000, and the power produced at the rev limit.

 

Already corrected myself but thanks anyways.
It's pretty crippling that it's not in 4th though. 1:1 5th is just about worthless.