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Discussion Starter · #1 ·
Hello everyone! This is my first post here and I'm glad I found this site as a future Mustang owner.

I'm about to place my order on a 2011 Mustang GT Premium (6-speed manual) and I'm trying to decide if I should go with the 3.55 or 3.73 axle ratio. I know that the higher ratio gives you more power off the line, but how does it effect the RPM during cruising on the highway?

Any positive and/or negative comments or experiences?

Thanks for any help you may be able to share.



Andy
 

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Welcome aboard man! this is a great community of fellow mustangers! you will get a lot of your question answered here, so ask away! now for your question

3.55 vs 3.73s there won't be much difference on highway cruising. you might lose 1/2 mpg, ONLY! so go for 3.73s man, that is the gear they used on motor trend when it ran a 12.7 quarter mile! so get the 3.73s man, hope this answers your question
 

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Discussion Starter · #3 ·
Thanks for the welcome! I appreciate your answer and your thoughts. I'm pretty sure you won't find me going to the track with my new Stang, but it will be a daily driver. It will sure have some long distance road trips (Florida-Michigan, Florida-North Carolina) coming its way.

Originally I thought that the 3.73 was a bit too extreme, but on the other hand, it is factory in the GT500 (SVT Package).
 

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Welcome aboard man! this is a great community of fellow mustangers! you will get a lot of your question answered here, so ask away! now for your question

3.55 vs 3.73s there won't be much difference on highway cruising. you might lose 1/2 mpg, ONLY! so go for 3.73s man, that is the gear they used on motor trend when it ran a 12.7 quarter mile! so get the 3.73s man, hope this answers your question
Actually 3.55/3.73 = .95, so you will get ~ 5% less mpg, or if you believe the 26 mpg then you will drop 1 mpg. Also, on cruising, you will require 5% higher rpm for same mph. I have only had my 2011 (with 3.73) for a few days, but I did take a 300 mile road trip, and only got 22 mpg. Of course car is new, mpg will improve, but I doubt I will ever see 26 mpg.

I floored my car in first gear for the first time yesterday. Holy $hit. It does rev up incredibly fast. You must shift almost immediately (~40mph). Since I do not intend to take it to the drag strip (possibly a road coarse track) I probably would have liked the 3.55 as well.

Good luck with your new car. You will love it, regardless of which rear end you order.
 

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Welcome!!!

Hello 2011 GT, First off Welcome to the Mustang Forum and Congratulations with making an excellent choice of cars! You will NOT be disappointed!

I agree with everyone that has replied so far in that you won't feel a major difference between the two final gear ratios and since your fuel mileage won't be significantly reduced with the 3.73 gears then I would definetely go with the 3.73 gear ratio. My GT has the 3.73 gears as well and it matches the power band well since it gets your RPMs up quicker to get into and take advantage of the quad cams peak HP & torque range which I believe is around 4,500 RPMs. The car revs quick no matter which gear you choose you can't go wrong. Hope this helps and good luck to you and let us know if you have any additional info or have additional questions. Take care! Jack :bigthumbsup
 

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Hello everyone! This is my first post here and I'm glad I found this site as a future Mustang owner.

I'm about to place my order on a 2011 Mustang GT Premium (6-speed manual) and I'm trying to decide if I should go with the 3.55 or 3.73 axle ratio. I know that the higher ratio gives you more power off the line, but how does it effect the RPM during cruising on the highway?

Any positive and/or negative comments or experiences?

Thanks for any help you may be able to share.



Andy
I ordered ten days ago and went 3.55 without even considering the 3.73.

The new six speed has an almost identical top gear ratio to the old five speed. That means you have all the other gears much closer to one another with the new transmission. I would bet the 2010 with a 3.55 rear end and the new six speed would accelerate about the same as the 2010 with the 5 speed and a 3.73.

Add to that 100 more horses and 65 foot pounds of torque and I don't think you need the 3.73. The 2010 with the 3.73 turn about 1,900 rpm at 60mph which is pushing things if I want to cruise at 70 plus.

I say go 3.55.

Greg
 

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well you have to take into consideration one thing. what do all mustang owners want their car to be able to do? outrun the respective comparable model of the camaro ss, and if you want to do that id say it is a must for the 3.73. also like others have said it does depend somewhat on if your going to be taking it on courses or strips; but mainly on your powerband preference. for me i love having tons of torque with low rpms- up to around 100mph due to cops. so with that being said 3.73s are a no brainer. and just to make sure you put another kill under your belt when u pull up to that cocky brand new SS.
hope this helps man.
 

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Gentlemen

I think I am right in pointing out that the 3.73 represents 3.73 revolutions of the driveshaft for each revolution of the rear wheel. The 3.55 represents 3.55 revolutions of the driveshaft for each revolution of the rear wheel.

That is only a rough 6% difference. That difference in real life would be very hard to discern. The performance difference even more so.

I consider either gear performance gearing with little between the two. A slight difference but only that.

The quality of the driver makes much more difference. Hone your skills.

I have been drag racing, tracking and other racing for over 40 years.

I have a base GT with performance axel and 6 speed on order, no other options. I am old school, I wanted the lightest possible car with the horsepower available.

I consider the 2011 GT to be worth whatever it takes to get one

Copper Man
 

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I ordered ten days ago and went 3.55 without even considering the 3.73.

The new six speed has an almost identical top gear ratio to the old five speed. That means you have all the other gears much closer to one another with the new transmission. I would bet the 2010 with a 3.55 rear end and the new six speed would accelerate about the same as the 2010 with the 5 speed and a 3.73.

Add to that 100 more horses and 65 foot pounds of torque and I don't think you need the 3.73. The 2010 with the 3.73 turn about 1,900 rpm at 60mph which is pushing things if I want to cruise at 70 plus.

I say go 3.55.

Greg
Try 55 ft/lbs and closer to 87hp. The 10GT has dual knock sensors and pushes it to 335lbs of tourque when running 91octane and above. (i get SOOO TIRED of having to point that out on a MUSTANG forum..lol).

(Noteworth: And many of the early 10 dynos were putting the 10Gt at closer to 335 to 340hp..and many of the early dynos are also putting the 5.0 at 425 to 430hp so...no need to get into all that.)

I will say the 3.73s do about 2700rmps at 80mph while the 3.31s did around 2100 to 2200 at 80mph. That i know from personal experience on my 4.6l GT.

If you want to paste camaros..get the 3.73. If you REALLY DONT CARE about acceleration and or DO A BOAT LOAD OF HIGHWAY driving..consider the 3.55s.

Choice depends on your driving habits and preference.
 

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The 3.73's are terrific at acceleration. However I'm revving above 2000 @70 mph. Taking a trip to Tennessee this sumer and don't mind the minor loss of mileage. For me, kicking Camaro butt from light to light is well worth it!
 

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Try 55 ft/lbs and closer to 87hp. The 10GT has dual knock sensors and pushes it to 335lbs of tourque when running 91octane and above. (i get SOOO TIRED of having to point that out on a MUSTANG forum..lol).

(Noteworth: And many of the early 10 dynos were putting the 10Gt at closer to 335 to 340hp..and many of the early dynos are also putting the 5.0 at 425 to 430hp so...no need to get into all that.)

I will say the 3.73s do about 2700rmps at 80mph while the 3.31s did around 2100 to 2200 at 80mph. That i know from personal experience on my 4.6l GT.

If you want to paste camaros..get the 3.73. If you REALLY DONT CARE about acceleration and or DO A BOAT LOAD OF HIGHWAY driving..consider the 3.55s.

Choice depends on your driving habits and preference.
As you neglected to point out, the new car is not only putting out more hp than advertised but more torque as well. I think 65 foot pounds will be more accurate than 55.

Pasting camaros, or any other car, is the last thing I care about. I understand a very small bit of that need to beat a rival but drag racing is all about hp and that all comes down to money. When I hit the open road it is all about me in my own world just cruising care free. If I see a camaro and he wants to race, I'll rev the engine hit reverse, and let him take off in blaze of burned rubber while I head the opposite direction just to be back on the road doing my own thing. I don't get where a person feels any real sense of victory in drag racing a stranger. It should be about driver skill rather than hp and unless both drivers are in identical cars that won't happen.

Going to the drag strip is different where the goal is to beat another car and driver. On the street it is a different world, at least for me.

Greg
 

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As you neglected to point out, the new car is not only putting out more hp than advertised but more torque as well. I think 65 foot pounds will be more accurate than 55.

Pasting camaros, or any other car, is the last thing I care about. I understand a very small bit of that need to beat a rival but drag racing is all about hp and that all comes down to money. When I hit the open road it is all about me in my own world just cruising care free. If I see a camaro and he wants to race, I'll rev the engine hit reverse, and let him take off in blaze of burned rubber while I head the opposite direction just to be back on the road doing my own thing. I don't get where a person feels any real sense of victory in drag racing a stranger. It should be about driver skill rather than hp and unless both drivers are in identical cars that won't happen.

Going to the drag strip is different where the goal is to beat another car and driver. On the street it is a different world, at least for me.

Greg
Oh Greg... YouTube - Debbie Downer Noise

http://www.youtube.com/watch?v=IJ_R-G_i4Xk
 

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As you neglected to point out, the new car is not only putting out more hp than advertised but more torque as well. I think 65 foot pounds will be more accurate than 55.

Pasting camaros, or any other car, is the last thing I care about. I understand a very small bit of that need to beat a rival but drag racing is all about hp and that all comes down to money. When I hit the open road it is all about me in my own world just cruising care free. If I see a camaro and he wants to race, I'll rev the engine hit reverse, and let him take off in blaze of burned rubber while I head the opposite direction just to be back on the road doing my own thing. I don't get where a person feels any real sense of victory in drag racing a stranger. It should be about driver skill rather than hp and unless both drivers are in identical cars that won't happen.

Going to the drag strip is different where the goal is to beat another car and driver. On the street it is a different world, at least for me.

Greg
Agreed. Seems like most folks on here have this fantasy of cruising nothing but lawless 4-lane highways full of arrogant Camaro owners just begging for a challenge at every light (naturally including the obligatory smoking babe riding shotgun ready to be your trophy).

The "purists" will always harp on automatics, V6s, base axle ratios... just get what makes sense and realistically suits your expectations.
 

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My 2011 5.0 has 3.73, That's the one thing I would change I'd go 3.55's, This new 5.0 has great low end grunt, and 3.73's make 1st gear almost useless, Find myself in 5th at 40 45mph just to get the revs down. I think this engine could handle 3.31's, but 6th would be a little deep.
 

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First off, I put a 3.73 in my 2006 and I ordered a 3.73 in 2011. However, there are times I wish I had the 3.31 due to the rpms and not the mileage. I think it depends on what you are after and how you drive. As for the 3.55, it's a good compromise. If high speeds are your thing (southwest US is a good place to go), stick with the 3.31 (from experience).
 

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concidering that I'm going to use this as my daily driver, and that we have a ton of stop and go traffic here, but I do an occassional highway trip of 600 miles or more, I do the 3.55 on my new '11. I want the getup but i also want a bit better milage than the 3.73. and I still think the 3.55 will out do the Camero, if nothing but because of the drivers involved.
 

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I have 4.10's in my 2007, and they are great. However, If I was going to get a SC or Turbo, I'd drop to a 3.73.

With the extra HP and torque of the 2011, and the ability to easily get the car to 400+whp with minor mods wich would easily overshadow the acceleration difference between the 3.55 and 3.73, I'd go with the 3.55's if you are doing more freeway driving.
 

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I'm trying to decide also...
Mustang tire size is around 27" regardless of rim size so...
(3.31, 3.55, 3.73 w/ 6sp manual in 6th gear)

at 65mph rpms are 1739, 1864, 1959
at 75mph rpms are 2006, 2151, 2260
 

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I'm trying to decide also...
Mustang tire size is around 27" regardless of rim size so...
(3.31, 3.55, 3.73 w/ 6sp manual in 6th gear)

at 65mph rpms are 1739, 1864, 1959
at 75mph rpms are 2006, 2151, 2260

Exactly, it's not so much about MPG as it is RPM.
 
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