3.73 Gear

[bigretic]

I know it's been talked to death...I have a 13 740'ish rwhp...strictly a every other weekend car. How much does this gear take off the top end? Not that this car will ever see a buried tach in fifth gear....just curious. And would I see any benefit going to 3.73 @ 740 rwhp?

Thanks guys.

 

[railroad]

You will love them and might get to use 6th gear.

 

[1 Alibi 2]

Had 3.73's done with the rest of my upgrades with less than 700 miles on the car.
The 1st time I drove the car, I knew the 3.31's had to go..

 

[Vinnie_B]

I know it's been talked to death...I have a 13 740'ish rwhp...strictly a every other weekend car. How much does this gear take off the top end? Not that this car will ever see a buried tach in fifth gear....just curious. And would I see any benefit going to 3.73 @ 740 rwhp?

Thanks guys.

Personally owning a 2013 Shelby Super snake ( Wide Body) with 775RWHP and 3.73 gearing........trust me you wouldnt regret going with that rear end gearing.

 

[biminiLX]

The 1st time I drove the car, I knew the 3.31's had to go..

This.
If you’re running a sticky tire (drag radial or comp spec rubber) you’ll love 4.10s
DONT FEAR DA GEAR
-J

 

[Norton]

For those of you who swapped gears, have you lauched hard with your new setup? If so, do you have any gear whine? I've had a set of 3.73s on the shelf for years, but stock gears are quiet and I can't bring myself to risk losing that...

 

[Dirks9901]

For those of you who swapped gears, have you lauched hard with your new setup? If so, do you have any gear whine? I've had a set of 3.73s on the shelf for years, but stock gears are quiet and I can't bring myself to risk losing that...

This is the first car i have had that doesn’t have at least a 3.73 gear. I’m going to enjoy the 3.31’s


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[1Kona_Venom]

I know it's been talked to death...I have a 13 740'ish rwhp...strictly a every other weekend car. How much does this gear take off the top end? Not that this car will ever see a buried tach in fifth gear....just curious. And would I see any benefit going to 3.73 @ 740 rwhp?

Thanks guys.

Curious, what's your RWTQ at? Bolt on car or...?
I drove 2 stock cars with 3:31's. The one I own now has 3:73s. If your talking top end on the street, um, I can still do a buck 30 down the interstate with room to go. Clearly plenty of top end to get a free ride to jail and loose my driving privilege's.

3:31s suck

For those of you who swapped gears, have you lauched hard with your new setup? If so, do you have any gear whine? I've had a set of 3.73s on the shelf for years, but stock gears are quiet and I can't bring myself to risk losing that...

Finding the right shop to do it is key. I don't have much if any gear whine. If you ever owned an 03/04 Cobra with solid diff bushings, the NVH is about the same. As with everything to gain a wider smile, you have to make compromises

 

[biminiLX]

For those of you who swapped gears, have you lauched hard with your new setup? If so, do you have any gear whine? I've had a set of 3.73s on the shelf for years, but stock gears are quiet and I can't bring myself to risk losing that...

Unless you’re launching at the track, the 3.73/4.10 or any gear swap for that matter won’t whine if set up correctly. Even the original stock 3.31s will whine after a track launch.
if you have those 3.73s set up correctly you will be VERY happy!
Good luck
-J

 

[biminiLX]

This is the first car i have had that doesn’t have at least a 3.73 gear. I’m going to enjoy the 3.31’s


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Really?
plus I’m pretty sure this is the first mustang you’ve had with a 2.66 first gear and 0.50 sixth.
315/35/20 DR and 4.10s are 2000rpm at 80mph
Think about that! Unless you’re doing standing mile regularly, the gear swap
is tied with a rear tire change as best mod you can make!
My 3.31s whined after a first drag test so Ford paid for a gear swap for which I paid for 4.10 FRPPs then I built the rear and went 3.73s due to bad advice. After whine on that set from track launches I rebuilt the rear and went 4.10s again and loved them again.
Hell my built 9” has 4.00 gears at 1110rwhp and I love them! Don’t fear it the gear. Car is SO much better all around after a 3.73 /4.10 gear swap
-J

 

[Norton]

Finding the right shop to do it is key. I don't have much if any gear whine. If you ever owned an 03/04 Cobra with solid diff bushings, the NVH is about the same. As with everything to gain a wider smile, you have to make compromises

That's about what I thought, but appreciate the first-hand confirmation.

Unless you’re launching at the track, the 3.73/4.10 or any gear swap for that matter won’t whine if set up correctly. Even the original stock 3.31s will whine after a track launch.
if you have those 3.73s set up correctly you will be VERY happy!
Good luck
-J

As with most things, I figured the key would be finding the right shop to install them. FWIW, I've launched mine at the track (i.e., Pikes Peak Airstrip Attack and Colorado Mile) about 30 times. Stock 3.31s remain as quiet as the day I took delivery.

Guess I need to find the right shop...

 

[Willie]

Form Follows Function.... or is it Function Follows Form? The age old argument. The answer is, "It depends."

Gear choice depends on your goal, or how it "feels". One dictates the other. It's just which is most important to you. I'll post just one scenario, optimizing 1/4-mile passes. First come up with a top speed for your goal. Then you have your engine redline and tire size as constants. Given these constants, trap speed at redline at the top of transmission 1:1 gear (typically fourth), calculate ratio. That's it. The way the car "feels" is what it is. Goal determines feel, or form follows function.

If you don't drag race often and the feel is more important, throw the calcs above out the window. It doesn't matter. Feel determines goal, or function follows form.

I used to drag race frequently. Putting my numbers in, my ratio is 3.31. Although my car has 3.73's, I'm somewhat content nowadays because I do not race much at all any more. And they have been super quiet since day one. So to each his own.

 

[1 Alibi 2]

For those of you who swapped gears, have you lauched hard with your new setup? If so, do you have any gear whine? I've had a set of 3.73s on the shelf for years, but stock gears are quiet and I can't bring myself to risk losing that...

.
As mentioned before, who does the install decides the level of quiet.
My tuner's shop builds / maintains race cars, they know how to install gears.
My 3.73's are as quiet or noisey as the 3.31's.
Presume you have a Ford gear set.
People who have bought other brands are usually sorry afterwards..

 

[Catmonkey]

Another consideration might be mile racing. 3.73s will limit your 5th gear speed to around 185 mph, depending on rpm and tire choice. 3.31s should get you 200+ mph. I'm running a 2013 transmission with 3.73s. I've been debating 3.90s and 4.10s back and forth to better match my cam's rpm range.

 

[biminiLX]

Willie and Cat are correct, base it on gearing calculation with is constant for speed and tire size.
But Willie where do you get 3.31s as ideal drag gearing? Crossing top of third.
I gear mine to trap at the top of fourth at or 500rpm range above redline.
Stock ‘13-14 cams peak at 6500-6700rpm and that’s why I much preferred 4.10s to 3.73s on track. The 3.73s were too far under peak power. Plus the 4.10s feel much better around town out of boost.
Tire size plays a big part too.
-J

 

[Luillo69]

What about magnum xl with 2.97 first gear? Any thoughts about 3.73 vs 4.10?

4.10s is what I have ready for install but I’m still debating to go 3.73 instead. I will 100% drag and weekend ride, no Lol g distance at all. I will twirler the car if that’s needed.


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[Vinnie_B]

What about magnum xl with 2.97 first gear? Any thoughts about 3.73 vs 4.10?

4.10s is what I have ready for install but I’m still debating to go 3.73 instead. I will 100% drag and weekend ride, no Lol g distance at all. I will twirler the car if that’s needed.


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IMO. 4.10's if just tracking your car. But if you plan to doing alittle cruising/street/drag racing for alittle fun I'd go to 3.73 gears w/posi diff. I really enjoy my 3.73 grears in my 2013 Super snake. Just my 2 cents!

 

[biminiLX]

What about magnum xl with 2.97 first gear? Any thoughts about 3.73 vs 4.10?

4.10s is what I have ready for install but I’m still debating to go 3.73 instead. I will 100% drag and weekend ride, no Lol g distance at all. I will twirler the car if that’s needed.


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What’s your goal? If drag you need to gear it for crossing the traps around peak power or 500rpm or so past peak.
The different first gear doesn’t really change that but these are heavy cars, so if you have the tire/suspension/track, the 4.10/2.97 combo will likely 60’ hardest but in reality 3.73/2.97 will be easier on street although I never try to launch first on the street.
-J

 

[SteveWK]

I've had both and prefer the 4.10s. The car feels like my old '88 GT as far as shifting is concerned but with 700 hp. The 4.10s are easier to drive in normal traffic situations.

 

[biminiLX]

I've had both and prefer the 4.10s. The car feels like my old '88 GT as far as shifting is concerned but with 700 hp. The 4.10s are easier to drive in normal traffic situations.

110%
-J