Selecting the Right Gear Ratio - Need Help 5.0 A6

[Sigma6]

Hi All -

Probably should have joined awhile ago. Been pretty content reading rather than posting til now when I’m on the fence. Looking for some input from user who have a similar setup and/or Auto.

I got a 2013 GT Convertible that I mainly putz around in. Currently has the 6R80 and 3.15 gears. Running 275/35/20 tires (27.6 diameter). Got it lowered 1.5”, has relocation brackets and lower control arms, panhard bar.. etc.

I am debating a gear swap to 3.55. Why? Just because I’m looking for a few more grins and fun around the street when i am out. It’s a weekend car, I do take some road trips so I’m highway driving it too. But no track or road racing.

Anyone gone up to 3.55s or has any input? Love to hear. I know I am probably loosing in the 1/4 time but that doesn’t matter. How’s off the line performance, am I going to roast 1st gear with 3.55??

 

[Juice]

I cant comment on the choice of 3.55s w/auto.
But you will need a tune. Changing the gear ratio will corrrect the speedometer, but the N/V value also needs adjusted in the tune, or the trans wont shift correctly.
N/V is vehicle speed devided by engine RPMs in a 1:1 gear ratio. (3rd or 4th usually)

 

[Sigma6]

I got the tuning. Parts, etc already. More so looking for input of gears. Thanks

 

[Sky Render]

The first gear on the autos is already pretty steep...

 

[RED09GT]

I've heard of a couple guys go 3.73's or 4.10's. One member that has been gone for a while, Five Oh Brian went to 4.10 gears and was happy with the results. He has a thread in the Drag Racing sub form that is a good read.

It should positively change the way the car responds but you may find yourself itching for more after adjusting to the 3.55's as the thrill may be gone in just a few days with the small change.

 

[Sigma6]

I've heard of a couple guys go 3.73's or 4.10's. One member that has been gone for a while, Five Oh Brian went to 4.10 gears and was happy with the results. He has a thread in the Drag Racing sub form that is a good read.

It should positively change the way the car responds but you may find yourself itching for more after adjusting to the 3.55's as the thrill may be gone in just a few days with the small change.

this is sorta input I’m seeking (thanks) is there a better place I should be going or sub forum seeking?

 

[RED09GT]

The Mustang Chit Chat forum is the more appropriate place for a discussion like this and will likely get more hits.
Easier said than done but if you can find someone with an SN-95, or a 5 lug converted fox that has a 26" tall tire, you could pop them on and feel the difference that you'd see with the gear swap.

 

[JEWC_Motorsports]

3.55's are a waste, do 4.10's and have fun.

 

[Sigma6]

The Mustang Chit Chat forum is the more appropriate place for a discussion like this and will likely get more hits.

Can someone move this thread or do something, otherwise can I just start a new one there?

3.55's are a waste, do 4.10's and have fun.

is this 1st hand experience? Have you driven and /own both!

 

[JEWC_Motorsports]

Ive had 3.15's, 3.73's, 3.31's, 4.30's and back to 3.31's. If you really do not plan on drag racing do 4.10's, the 3.73's and 4.30's were fun on the street but my car is mostly a n/a drag car so i put the 3.31's back in it. I also have a 6F Circle D stall in my car.

 

[Sigma6]

Ive had 3.15's, 3.73's, 3.31's, 4.30's and back to 3.31's. If you really do not plan on drag racing do 4.10's, the 3.73's and 4.30's were fun on the street but my car is mostly a n/a drag car so i put the 3.31's back in it. I also have a 6F Circle D stall in my car.

What I’ve read throughout the archives of this site, it seems the majority doesn’t think higher than 3.55 in the 6R80 transmission. What tire size were/are you running? I could be swayed to 3.31 but with 3.15 I don’t think the cost vs benefit is equal. So I have it to stock or 3.55. Hoe was 1st gear with 3.55... traction good?

 

[JEWC_Motorsports]

I run a 28" drag radial. On the street there is no traction.

 

[Sigma6]

I run a 28" drag radial. On the street there is no traction.

So what you’re saying is I’m not gonna have any traction on the street on 355s?

 

[JEWC_Motorsports]

No, ive never had traction on the street lol.

 

[Sigma6]

I get traction on the street with 3.15 as long as I don’t mash the peddle from a stop), I’m hesitate for 3.55... anyone have input?

 

[JEWC_Motorsports]

Its the same for any gearing. Ease into the throttle and its fine. Hit the go pedal and spin.

 

[Sigma6]

Its the same for any gearing. Ease into the throttle and its fine. Hit the go pedal and spin.

what made you get rid of the 3.55?

 

[JEWC_Motorsports]

Never had them but i swap gears because i change what i do with my car. Drag, corner carving, roll racing.......and because i get bored.

 

[06 T-RED S/C GT]

Hi All -

Probably should have joined awhile ago. Been pretty content reading rather than posting til now when I’m on the fence. Looking for some input from user who have a similar setup and/or Auto.

I got a 2013 GT Convertible that I mainly putz around in. Currently has the 6R80 and 3.15 gears. Running 275/35/20 tires (27.6 diameter). Got it lowered 1.5”, has relocation brackets and lower control arms, panhard bar.. etc.

I am debating a gear swap to 3.55. Why? Just because I’m looking for a few more grins and fun around the street when i am out. It’s a weekend car, I do take some road trips so I’m highway driving it too. But no track or road racing.

Anyone gone up to 3.55s or has any input? Love to hear. I know I am probably loosing in the 1/4 time but that doesn’t matter. How’s off the line performance, am I going to roast 1st gear with 3.55??

IMHO! Unless your running a F/I application such as turbo, s/c or nitrous? your not really going to notice much of a difference by upgrading to 3:55 gears when running larger diameter 20" wheels/tires and especially when running an auto trans. For your particular application, upgrading to 4:10 gears will provide the much better off the line performance over 3:55's.. But if your more concerned with highway mileage during road trips? then you may want to consider 3:73's instead, providing of course on how often you take road trips lol. If having more fun around the street is a higher priority over highway mileage? then go 4:10's.. As for loosing 1/4 time? you would actually gain your 1/4 time with 4:10's over 3:55's.. However, being as you don't track or road race, it's pretty much a non factor which doesn't really matter, to begin with anyhow. As mentioned, it all comes down on what you consider is most important. If it's off the line performance? go 4:10's. If your preference on the other hand is seeking a balance between performance/off the line and highway driving? then I'd strongly consider upgrading to 3:73's over 4:10's which IMO would provide the best of both worlds. Anyhow, just my opinion

 

[Pentalab]

1st gear is extremely low on the 6r80...( 4 something). Your 275-35-20 tires only have a 3.79" sidewall. 5th gear on a 6r80 is .98:1 so not quite 1:1 ratio. Your 6th gear is OD.

I'd say your wasting your time. You already have 1 extra gear compared to the 05-10 cars equipped with the 5r55 automatic...(5 speed auto, 4th gear is 1:1 ratio).