3.15 vs 3.55 limited slip?

[Farmer Fran]

the difference is not only the gear ratio when you order the 3.55 option, it is a completely different limited slip system, clutches vs Torsen

That is why it is a $1000+ option for the 3.55 on the order sheet

If you have a 3.15 LSD in your mustang, the parts, meaning a 3.55 whole center section ready to drop in ( M-4001-88355B ) from @LevittownFordParts is under $1200 plus fluids.

The gears and install kit to swap out your existing gears will run you just shy of $500 and someone who can press bearings on and get the shim packs right for the proper gear meshing.

Just check the driveshaft flange as there are differences between stick and 10 speed cars

Plus you need to recalibrate the speedo for the new gear ratio, and maybe the transmission shift points


Personally I have never found myself wanting for the 3.55 the 3.15's work lust fine for me

Again, I will be corrected but I am pretty sure my 355 is no Torsen, just normal 355 LSD

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[HWill]

IIRC

315 if you want to boost because the A10 does not like 6th gear slams
355 for a good NA build

I am 100% sure I will be corrected. But do you run 87 or 91/93

Never heard off that before.

I always ran 3.55 - 3.73 FI and atleast 3.73 -4.10 NA

 

[robvas]

Never heard off that before.

I always ran 3.55 - 3.73 FI and atleast 3.73 -4.10 NA

There's no fixed rule

Steeda runs 3.31 in their 2018 supercharged car, used 3.15 when the car was NA, and then they have 4.09's in their 2024 NA car

 

[HWill]

There's no fixed rule

Steeda runs 3.31 in their 2018 supercharged car, used 3.15 when the car was NA, and then they have 4.09's in their 2024 NA car

I don't think anyone said there was a "fixed rule".

 

[RLE55]

Again, I will be corrected but I am pretty sure my 355 is no Torsen, just normal 355 LSD

Correct, the Torsen Diff. is part of the PP.

 

[kinelisch]

I’ve had both S650 one with 3.15 and my current one with 3.55. I can honestly noticed a big difference in acceleration. Highly recommend the 3.55 gears.

 

[palian414]

I did a lot of research on this and went with the 3.55. Mainly because that is what I noticed the majority of people go with on the automatics who tried both in person at a dealership.

I have seen a lot of videos of people racing 3.15 against 3.55 and the difference is completely unnoticeable. In theory, the 3.15 is faster on the top end, 3.55 is quicker in the initial acceleration.

there is not much difference in acceleration between a 315 and a 355 with stock tires because the tires are spinning but if you have bigger tires with a lot of grip you will notice a big difference !

 

[AZ_Ryan]

there is not much difference in acceleration between a 315 and a 355 with stock tires because the tires are spinning but if you have bigger tires with a lot of grip you will notice a big difference !

Just because you have 3.55s doesn't mean you're spinning the tires lol. I've driven a GT in both gears and difference is noticeable. 3.55s are much snapier off the line. There's a reason they come on PP and DH cars.

 

[palian414]

I agree, my 2024 GT 10 speed came with 3.15 gears and it could easily break the tires loose .I really wasn't happy with the performance so i purchased a loaded 3..55 differential from Ford performance and had it installed they also programmed the computer so the car knows it has a 3.55 gear. with the stock 255's i really didn't notice that much difference off the line because the tires were spinning like crazy however the engine got rpm's much quicker and the transmission shifted quicker of course and the car was much quicker through gears. still not happy with performance off the line i replaced the stock 255's with Continental 275's 340 utog very grippy tires, wow what a difference i could use a lot more of the GT's 486 horse power.

Just because you have 3.55s doesn't mean you're spinning the tires lol. I've driven a GT in both gears and difference is noticeable. 3.55s are much snapier off the line. There's a reason they come on PP and DH cars.

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