3.15 or 3.55 for my GT Daily Driver? 3.55 Worth the upcharge?

[roadpilot]

It’s hilarious that this is an actual debate.

ask yourself why Ford offers these options.

it’s the following: higher number = more acceleration. Lower number = more economy. Has zero to do with transmission smoothness or anything else. It’s all about maximizing performance or… not.

The 3.15 is an option because a huge chunk of buyers neither know nor care what ratio they have and putting the 3.15 in a bunch of Mustangs gives Ford better overall MPGs to meet CAFE and federal requirements (and avoid fines/fees).

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[9secondko]

The 3.15 is an option because a huge chunk of buyers neither know nor care what ratio they have and putting the 3.15 in a bunch of Mustangs gives Ford better overall MPGs to meet CAFE and federal requirements (and avoid fines/fees).

I mentioned that already in post #47 of the thread. But the post you quoted was referring to the debate of what the gears were intended for. And the fact that Ford offers better gearing for those who want it.

 

[BoostRabbitGT]

Has anyone who owns a non-Performance Pack GT with the default gearing experience the vehicle creep forward suddenly and/or unexpectedly during gear changes at low speeds? I test drove one recently and while not as abrupt or harsh as my '19 Ecoboost (which that happens every once in a while, but that also comes with turbo lag as well every so often), it is still noticeable enough for me to bring it up here in the first place.

I didn't notice this in GTs with the 3.55 gear ratios (both PP and non-PP) and I'm thinking this might influence which gearing I go with once I decide which non-PP GT I go with (which admittedly won't be for a while).

 

[horned-toad]

experience the vehicle creep forward suddenly and/or unexpectedly during gear changes at low speeds?

huh? You mean like a surge or a modest lunge at parking lot speeds with little or no throttle? In the A10? Welcome to the shit-ass trans programming and cheap-sh*t valve body.

Otherwise it could be the anti-stall/minimum desired RPM intervening when the new gear selection drops below it.

You really need to get out of your own head. Quit buying Mustangs with automatic transmissions in them. THEY BLOW CHUNKS. If you persist then get Wengerd et. al. to fix it.

Put 2000 RPM on the clock and keep it there (or higher) unless you're rolling to a stop.

 

[BoostRabbitGT]

huh? You mean like a surge or a modest lunge at parking lot speeds with little or no throttle? In the A10? Welcome to the shit-ass trans programming and cheap-sh*t valve body.

Otherwise it could be the anti-stall/minimum desired RPM intervening when the new gear selection drops below it.

You really need to get out of your own head. Quit buying Mustangs with automatic transmissions in them. THEY BLOW CHUNKS. If you persist then get Wengerd et. al. to fix it.

Put 2000 RPM on the clock and keep it there (or higher) unless you're rolling to a stop.

A modest lunge of varying distances. It's annoying whenever it happens but ultimately not enough of a dealbreaker to consider a manual. Guess I'll be getting whoever it is you referenced to fix mine, whenever that happens. Hope your day goes better.

 

[IFFV68]

The 15 MPG was probably for the manual. I know mine with the 3.73 gears is rated for 14 MPG in the city.

As far as acceleration, I'd recommend you test drive both and see which one you prefer more. And yes, the higher the gear, the higher the RPM when cruising. However, with the 10A, I wouldn't be too concerned about high RPMs at 75 MPH.

Great advice.
You need to test drive both 3:15 & the 3:55 & drive the same route, same speed. Then you can decide which one you want or need?
I have the 315s in my GT with no regrets. I do a lot of city driving and they still fly down the highway.
As far as gas mileage goes it really doesn’t matter.
This is a Mustang, not a Honda.
Good luck with your choice.

 

[Hoofprint]

Have 2 2024 GTs in my house.
Convertible A10 PP (355)
Coupe A10 non-PP (315)

the coupe has 500 miles on it so haven’t really gotten on it (much) yet.

Honestly there is not much of a difference. The best way for me to describe it, the coupe feels a little heavier…if that makes any sense

 

[BoostRabbitGT]

@horned-toad, thanks for the 2K RPM advice. Shifts from idle have been noticeably smoother. How do you keep the car at 2K with the auto on Normal though?

 

[horned-toad]

How do you keep the car at 2K with the auto on Normal though?

grip+hold one of the paddles (right?) and the trans will now shift only on command. The 'S' (or is it M?) mode on the shift-stalk will do likewise I believe. I don't have an Eco+A10. I refuse to own any car that isn't manual transmission. Even when I had the F150 with its A10 it had a feature to lock out higher gears. But of course Ford software team didn't bother to carry over that feature to Mustang... Brilliant, eh?

 

[roadpilot]

Even when I had the F150 with its A10 it had a feature to lock out higher gears. But of course Ford software team didn't bother to carry over that feature to Mustang... Brilliant, eh?

I know this clown was banned, but the F Series trucks have this feature so you can keep it out of higher OD gears when towing. Last time I checked, most folks don't tow with a S650.

 

[Cucurú]

This thread may work for me on what I'm prepared to do. Thinking of going to Lebanon Ford and picking up a base GT 300A , 18 inch wheels, standard exhaust 10 speed, and 3.15 axle ratio, with a Whipple. For slightly over 50K it's a steal. I'm sure the Whipple would make up the difference on the bottom end. Cars not going to be drag race or tracked. The Whipple is just for the edge. You never know who has bad intentions out there. It's for Mother in-law. Or should I just get her an 2025 Ecoboost? Believe me, the Ecoboost no longer has a 3.55, or a sleuth of other options that'll get one out of a jam.b

 

[IFFV68]

So I assume you have the 3.55? Did you ever drive a GT with the 3.15's? Just curious if one can actually notice the difference in acceleration between the two? I have seen people post that the GT with the 3.15's feels sluggish around town especially but honestly I have no clue so that's why I'm asking

The main thing you’re driving habits.

Just going over my build again as I just added Active Exhaust to it. Currently I have the standard 3.15 gears on the order sheet. I will be using this as a daily driver here in Suburbia with the occasional freeway trip sprinkled in. My question is whether it's worth it to upgrade to the 3.55 gears for my use case? I've read some posts that the GT w/ 3.15 can feel sluggish around town (which I find hard to believe buy maybe)? What are the pros and cons for going with the 3.55 gears for my use case? Will I notice much better normal acceleration around town? Will my fuel economy suffer (city and or highway)?

Honestly I'm not really versed in gear ratios to not sure if it's worth the price of admission for my use case or not? I believe the MPG indicated on the window stickers for both the 3.15 and the 3.55 are both 15 city and 24 highway but I swear I saw one with a sticker for the 3.55 that said 16 city but I may be mistaken?

Also my build is for the 10A

Any advice would be greatly appreciated

It
It depends on your driving habits.
Personally I would go with the 3.55.
It’s quicker off the Line.
The Price you may pay could be a 1-MPG..
But,
You need to Trick the Computer..
My 2024 GT Premium Mustang is supposed to get 16 City, 24 Hwy & 19 combined.
I currently I have 457 miles on my Mustang.
I went up to Central City Colorado. I-70, I average 27.4 miles per gallon & on my return trip, which is downhill all the way I got over 26 miles per gallon.
Heavy Stop & go traffic.
Right now. I’m averaging 17 to 20 miles per gallon in the city.
The point is if you know what you’re doing you should have better mileage than it’s rated.
The Torsen? Rear End would be an excellent choice.
You also want the Brembo Brakes..
I couldn’t find any Mustangs with the 3.55 around here..
I have the 3.15.
Please remember it’s your Money.
Either way you will need an Excellent Plastic SURGEN to get the SMILE OFF YOUR FACE!
Good Luck

 

[Cucurú]

The main thing you’re driving habits.It
It depends on your driving habits.
Personally I would go with the 3.55.
It’s quicker off the Line.
The Price you may pay could be a 1-MPG..
But,
You need to Trick the Computer..
My 2024 GT Premium Mustang is supposed to get 16 City, 24 Hwy & 19 combined.
I currently I have 457 miles on my Mustang.
I went up to Central City Colorado. I-70, I average 27.4 miles per gallon & on my return trip which is downhill all the way I got over 26 miles per gallon.
Heavy Stop & go traffic.
Right now. I’m averaging 17 to 20 miles per gallon in the city.
The point is if you know what you’re doing you should have better mileage than it’s rated.
The Torsen? Rear End would be an excellent choice.
You also want the Brembo Brakes..
I couldn’t find any Mustangs with the 3.55 around here..
I have the 3.15.
Please remember it’s your Money.
Either way you will need an Excellent Plastic SURGEN to get the SMILE OFF YOUR FACE!
Good Luck

Same thing we're departing. But a 25 300A , 10 speed, 3.15, 18 base wheels. No fancy stuff. It's for Mother in-law. Not racing, no track, no challenging people around town. Just in town, freeway and country driving. The Whipple will be for an edge if needed. So since the Whipple kicks in from the get go the car should be fine with 3.15s. plus it would be nice for our family Mustang Club gatherings. Maybe slap an H-pipe for a deeper sound later. But not for racing. As with all our cars for extraction out of bad situations. Add Bimbos the Nite Pony package is needed. Don't want to hurt people's tastes, but a black roof is not our cup of tea. Badges can be powder coated by me.​

 

[IFFV68]

Has anyone who owns a non-Performance Pack GT with the default gearing experience the vehicle creep forward suddenly and/or unexpectedly during gear changes at low speeds? I test drove one recently and while not as abrupt or harsh as my '19 Ecoboost (which that happens every once in a while, but that also comes with turbo lag as well every so often), it is still noticeable enough for me to bring it up here in the first place.

I didn't notice this in GTs with the 3.55 gear ratios (both PP and non-PP) and I'm thinking this might influence which gearing I go with once I decide which non-PP GT I go with (which admittedly won't be for a while).

Mine doesn’t Creep Forward or Reverse..
I have the 3.15.

 

[Bear376]

Every need is different. My 2013 has the 2.73 differential because i spent most of my driving on the highways. My 2019 was bought because I wanted to experiment with modifications and do some track time. It has the PP and 3.73. I need another travel car and so my 2025 is going to have the 3.15. If economy was priority, I would go EcoBoost, but I really want the 5.0. I love being able to experience the takeoff power of 3.73 gears, but at 80-85 mph cruising, I prefer the quiet comfort of the lower rpms with 3.15.

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