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Discussion Starter · #1 ·
Hello everyone,

Is anyone using 4.09 Ford racing gears in a manual ecoboost. I have the 3.55 Torsen that came with the PP. Thoughts, input or constructive criticism.
 

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What are your plans for the car in terms of how it will be driven? Daily, occasional spirited driving, strip, auto-x, road racing, a combination of them? Knowing this will help us give better advice.
 

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What Winter said.
 

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Discussion Starter · #5 ·
Thanks for responding,
Today’s cars have plenty of overdrive to run
4.09 gears, I don’t fear the gear I’m not going to auto cross our drag race. To give you an example when I did my my Lincoln
Mark viii build 4.10 gears really put the car in its power band better than 3.37’s and with the 4-speed auto you still had plenty of over
drive. So what I’m getting at is what gear ratio puts a 6-speed manual in its power band the best because the ecoboost Mustang really doesn’t do much until 3,000 rpm and I really don’t care about gas mileage.
 

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I’m not going to auto cross our drag race.
My non-PP with even taller gearing (3.31) has difficulty with traction through first and second gear, but returns a great 2000 rpm at 70 mph. Moving to your 4.09's should bring somewhere just shy of 2500 rpm at that speed.
'Curious, if you're not drag racing, why the change? If it's only to allow you better acceleration while on the highway, it's as simple as dropping a gear (or two). A sixth-to-fourth change really lights it up on the freeway. I'm just thinking of your long-term satisfaction with the deeper gears.
 

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Discussion Starter · #8 ·
With the shorter gears you also gain an advantage driving on secondary roads, back roads or country roads how ever you want phrase it. Especially if those roads have hills
and we all know what it’s like going up a steep hill with 4cyl. As far as just stirring up the stick shift on the highway for more acceleration, I’m thinking with the shorter gears a little more pressure on the gas peddle in sixth gear would be all that is needed. Traction can be alleviated by tire selection and driving skill.
 

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Hell yeah, another Mark VIII guy! I had 4.30s in mine, and you're right, it made a huge difference in how the car performed. Much of that was due to the weight of the car, the late narrow torque curve of the 4.6 DOHC and the wide ratio 4R70W. Lower gears in a Mark VIII were pretty much a necessity, especially on the base models which were only available with 3.08s. The Mark was a complete dog until the IMRCs opened up. The MEB doesn't suffer from any of that and has a much more usable torque curve, so i personally don't see a benefit of going with gears that steep for everyday driving. While it may be fun to play around in, any gains from going with a lower final gear will not be as pronounced as they would be in the Mark VIII. Just my $.02...
 

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Discussion Starter · #10 ·
It’s too bad Ford/Lincoln doesn’t make a luxury sport coupe anymore. I also had a turbo T-bird, anyway my thought process is
with shorter gears you would keep the rpms higher to stay in the MEB’s power band. I agree the 4.6 was a dud for the most part especially the early NPI engines. Even with the DOHC engines they still were not as good as the GM new LS engines.
 

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It’s too bad Ford/Lincoln doesn’t make a luxury sport coupe anymore. I also had a turbo T-bird, anyway my thought process is
with shorter gears you would keep the rpms higher to stay in the MEB’s power band. I agree the 4.6 was a dud for the most part especially the early NPI engines. Even with the DOHC engines they still were not as good as the GM new LS engines.

Agreed, I'm still sad they retired the MN12/FN10 platform. I never had a turbo-coupe, but did have a 5 speed super-coupe back in the day that was a lot of fun.

My thoughts are the current gear offerings are already well suited to the MEB powerband, By going with a significantly lower rear gear, you're effectively moving north of the powerband onset and not taking advantage of the power under the curve. In stock form, the MEB hits peak torque by 2500rpm and holds it steady until 4500rpm. With the small twin scroll turbo, the MEB doesn't need high rpms to make it's power like a traditional N/A smallblock does. I would certainly consider it if I was to go with a bigger turbo though.

That said, it really comes down to personal preference and driving styles. That's why we're all here, if we all did **** the same way, it wouldn't be any fun.

35501
 

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Discussion Starter · #12 ·
Thanks for the info, looking at the graph I’ll leave it with the 3.55. I’m going to do some suspension upgrades steeda cradle bushings, vertical link and a few others so when I was doing those I thought it would also be a good time to do gears but I’ll stay with the 3.55. Thanks again for your help.

Who knows maybe some day Ford will bring back the T-bird/cougar.
 

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No worries. Glad you found it helpful. I plan on doing some Steeda suspension upgrades this spring myself.

Fingers crossed on ford bringing back the tbird/cougar/mark viii in a full size rear wheel drive config someday. I’ll be first in line.
 

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Considering Ford has dropped all cars but the Mustang and are now putting the Mustang name on an electric SUV the chances of something like the T-bird coupe coming along is between slim and none.

Dave
 

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4.10's behind an automatic transmission and 4.10's behind a 6 speed manual are two totally different animals. 1st gear would become almost useless with 4.10 gears and manual trans on the street. It is the automatic transmission cars that can really take advantage of the steeper gears for getting off the line. If driven absolutely perfectly the M/T car would be faster when accelerating from a stop but it would be by a very small fraction of a second. The cost would not yeild much of a gain at all and would not be noticable in the "seat of the pants" experience. All you would really be doing is spending money to shift a whole lot more. My opinion only but it comes from experience.

EDIT: I say all of this referring only to cars that are driven on the street. If this is a trak only car..... stuff the gears in there and carry on!!
 

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Is the gearing in the MT82 the same for the GT and eco?
The MT82's in the V6 and ecoboost Mustangs have different gears than the v8's.

In 2018 the GT got a different set of steeper gears in the MT82 while the ecoboost remained unchanged.

Some reference info in the pics below.



Sent from my SM-G960W using Tapatalk
 

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Well I am most likely will be the the moron ... I just ordered 4.11 gears for my 17 mustang ecoboost... I have the NX2 turbo that fully kicks in around 3500 rpms... I use mine as a daily driver so I definitely will be the Guinea pig on this one. I will update later.
 

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Well I am most likely will be the the moron ... I just ordered 4.11 gears for my 17 mustang ecoboost... I have the NX2 turbo that fully kicks in around 3500 rpms... I use mine as a daily driver so I definitely will be the Guinea pig on this one. I will update later.
Are you an automatic or stick?
 
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