PDA

View Full Version : Just got 3.73 Gears Installed



4N6KM
05-23-2013, 02:01 PM
Finally upgraded from 3.15 to 3.73 gears and I could not be happier!!! EB3 did an OUTSTANDING job with the install. Wish I hadn't waited so long, love the way the car drives.

Great White
05-23-2013, 02:23 PM
Mine came with 3.73's from the factory, and remember test driving a 3.31 car first then the 3.73 car, you can see what I ended up with. Enjoy and glad to hear EB3 did such a good job!

Bocefus
05-23-2013, 02:23 PM
congrats. what tune did you go with?

Red
05-23-2013, 02:34 PM
Sweet! I've considered doing this for a while. Congrats Jay!

Bocefus
05-23-2013, 03:02 PM
this is such a rookie question, what does it feel like having 3.15 vs 3.73? I understand its a better just curuius as to how it feels different?

To the OP did you go with FRPP or another vendor?

Great White
05-23-2013, 03:12 PM
this is such a rookie question, what does it feel like having 3.15 vs 3.73? I understand its a better just curuius as to how it feels different?

To the OP did you go with FRPP or another vendor?
come to the meeting on saturday and you can drive my car, as you drive yours. you can answer the question afterwards. ;)

4N6KM
05-23-2013, 07:04 PM
this is such a rookie question, what does it feel like having 3.15 vs 3.73? I understand its a better just curuius as to how it feels different?

To the OP did you go with FRPP or another vendor?

I went with Ford Racing gears; however, I have heard that Motive now makes the gears for Ford and Richmond. No proof, just hearsay. As for tune, I already had an email tune from Steeda, so all that was required was an adjustment of the speedometer with the sct tuner. I notice a really big change when launching, but I haven't had them too long ;)

Bocefus
05-23-2013, 07:12 PM
That's awesome. Congrats again. Got take me gf to dinner Saturday. Maybe next time?

99GT
05-24-2013, 05:34 AM
Congrats!

Dan

BMFGT
05-24-2013, 01:32 PM
nice! enjoy them over the holiday weekend:)

Jerrbear
06-09-2013, 12:16 PM
Op, I am also considering switching to 3.73 from stock. Would you be willing to let us know how much they charged for the swap? Also is the bang for your buck there? I have heard a lot about how those gears get you into the power band quicker, feel better etc but does the "seat of the pants dyno" translate into 0-60 and quarter mile improvements. Sorry to ask so many questions I am very new to the site, area, and mustang. Actually made it out to the Expo center last night to attend my first meeting.

4N6KM
06-09-2013, 01:52 PM
Op, I am also considering switching to 3.73 from stock. Would you be willing to let us know how much they charged for the swap? Also is the bang for your buck there? I have heard a lot about how those gears get you into the power band quicker, feel better etc but does the "seat of the pants dyno" translate into 0-60 and quarter mile improvements. Sorry to ask so many questions I am very new to the site, area, and mustang. Actually made it out to the Expo center last night to attend my first meeting.

First, welcome to the club! Unfortunately I couldn't make last nights meeting - on call for work. As for your questions about the gears, don't feel bad for asking to many. It is always better to research any mod before moving forward, in my opinion. The cost is a little complicated, because it varies depending on if you are supplying the gears, install kit etc... In my case I supplied the gears and had EB3 get the install items. I must appologize though because I don't want to discuss the actual cost, but I did feel that it was very fair! As stated in my post, I went from a stock 3.15 gear, and the major issue I had with that was what felt like a lag when pulling into traffic or from a stoplight. The was an initial jump, then lag, then it would go. The new gears eliminated that!!!! I don't know how much (hopefully) of a 1/4 mile time improvement there is - when is the next NVMC track day, October??? I did a lot of research and went back and forth on this for a while, but in the end, I am really happy with the new gear ratio.

Moco
06-09-2013, 06:58 PM
Here's my understanding of the issue...

Alot of us are used to 5spd transmissions from Fox or SN95 cars. For those applications, 3.73s or even 4.10s were almost necessary to get some better ooomph from a roll and a bit more torque down low (especially for 4.6 SOHC cars). However, for this generation with the 6spd MT82, and the gearing inside the transmission itself, 3.73s are the equivalent of 4.10s or greater on earlier cars.

The one thing I think alot of people overlook regarding 3.73s on a Coyote is that it necessitates a 4th shift in the quarter mile. So instead of passing through the traps at the top of 4th gear, you will be passing through right after a shift to 5th.

Also, people keep saying that with a blower, the preferred gear is the 3.31s as 3.73's make 1st gear pretty much futile.

So the bottom line in my opinion is that, you can certainly get 3.73s and be fine with them for a day to day basis - however, you will give up a little bit of driveability (slightly lower fuel efficiency and slightly higher revs at cruising speed). You will certainly get an increase off the line, but you will likely need to shift to 5th before crossing the 1//4 mile traps.

Another option to consider might be 3.55s.

Great White
06-09-2013, 08:05 PM
I am still in 4th gear when I go through the trap in the 1/4 mile with 3.73 gears, bone stock 12.85 @ 110.4 mph. Not sure where you got that information

Moco
06-09-2013, 08:47 PM
I am still in 4th gear when I go through the trap in the 1/4 mile with 3.73 gears, bone stock 12.85 @ 110.4 mph. Not sure where you got that information

Well, I stand corrected then. I had read that bit from similar threads on other Mustang forums. Seems like its bum scoop.

Great White
06-09-2013, 09:49 PM
Well, I stand corrected then. I had read that bit from similar threads on other Mustang forums. Seems like its bum scoop.
Unfortunately there is a lot of misinformation on many sites. Rumor becomes gospel and therefor fact.

Not picking on you just want to clear some things.

I typically use 2nd gear in bumper to bumper traffic to start off because 1st gear is short with 3.73 gears and if I were to start off with 1st, skip shift would likely kick in and put me into 4th gear instead of 2nd when shifting (hate skip shift!)

My average mileage for mixed city and highway is 19 mpg which includes aforementioned bumper-to-bumper traffic, all highway mpg is 27 mpg.

Cruising on the highway at 70 mph in 6th gear my car is at 2200 rpm. Not sure about your 3.31 gears but can't imagine that there is much difference.

This has all been documented during my 54,000 miles and has been found as true average for my car.

A perfect overall gear would most likely be 3.55 for blown applications based on issues with traction with 3.73 & 4.10 gearing, and 3.31 gears not having enough uumph off the line.

Moco
06-09-2013, 09:54 PM
Unfortunately there is a lot of misinformation on many sites. Rumor becomes gospel and therefor fact.

Not picking on you just want to clear some things.

I typically use 2nd gear in bumper to bumper traffic to start off because 1st gear is short with 3.73 gears and if I were to start off with 1st, skip shift would likely kick in and put me into 4th gear instead of 2nd when shifting (hate skip shift!)

My average mileage for mixed city and highway is 19 mpg which includes aforementioned bumper-to-bumper traffic, all highway mpg is 27 mpg.

Cruising on the highway at 70 mph in 6th gear my car is at 2200 rpm. Not sure about your 3.31 gears but can't imagine that there is much difference.

This has all been documented during my 54,000 miles and has been found as true average for my car.

A perfect overall gear would most likely be 3.55 for blown applications based on issues with traction with 3.73 & 4.10 gearing, and 3.31 gears not having enough uumph off the line.

Good info. Thanks for the input.

Red
06-10-2013, 10:14 AM
I could argue that 3.31s have enough, "umph" off the line. I put down a 12.43 @ 115 mph in the quarter with 3.31s, however there were some other, minor, mods included on that run (Exhaust, CAI and Tune and suspension). I think, with the 6 speed, 3.31s aren't that bad, however a 3.55 might be better, and a 3.73 could be a bit much. I kept trying to decide what to do, but now that we're selling the car, I don't have to worry about it LOL.

Bocefus
06-10-2013, 10:28 AM
dumb question, I have no clue what my gears are. how do i find out if i have 3.31, 3.15 etc. ?

Moco
06-10-2013, 10:57 AM
dumb question, I have no clue what my gears are. how do i find out if i have 3.31, 3.15 etc. ?

Rob,

Usually with our cars, there is a sticker on the driver's side inner door panel that will list the rear end ratio. I remember looking at yours at the track and it wasnt there. Alternately there should be another sticker on the differential itself that will list the ratio. My apologies, we didnt look at that when we were under your car on Saturday.

There is a third, mechanical way to figure out your rear end gear ratio and it entails putting the rear on stands with the tranny in N, and rotating the wheels and counting revolutions of the driveshaft (or vice versa).

With that said, Im pretty sure you dont have 3.15's.

Great White
06-10-2013, 11:01 AM
3.15's typically are in the automatics from the factory

Bocefus
06-10-2013, 11:04 AM
Eric,

Thanks for the info. I do remember that now you metnioned it. Sometime this week I will use that nifty jack you gave to me and raise up the rear to get a look at the tranny.

lol that last sentence is kinda funny.

Bocefus
06-10-2013, 11:05 AM
3.15's typically are in the automatics from the factory thanks. do you what the default typically is for 6MT?

Moco
06-10-2013, 11:19 AM
thanks. do you what the default typically is for 6MT?

I think base cars and non special edition cars come with 3.31s. Track pack and others may have factory 3.73's. Im not sure about CS cars.

Great White
06-10-2013, 12:23 PM
I believe the base MT comes with 3.31 for the Gt and 2.73 with base v6 with MT. Mine is a non track pack with 3.73 factory gears.

Great White
06-10-2013, 12:45 PM
found this http://media.ford.com/images/10031/2011_Mustang_GT_Specs.pdf

and this http://mustangsdaily.com/blog/wp-content/uploads/2011/04/2011-mustang-breakdown.pdf

Bocefus
06-11-2013, 08:01 AM
interesting, thanks