Gears in an auto worth it? 2011+

[FiveLeeter]

I have a 2011 GT Auto, mods in sig. When I bought my car, 3.15s were the only option in an auto.

I have been stuck at 12.57 with my mods, and am dying to hit 11s. That was on street tires, finally got some good DRs, but haven't gotten any runs with them yet.

Would upgrading the gears help the auto at all? When UPR did my tune, I was discussing a 3.73/4.10 option, and Jeremy said not to do it.

Anyone here have any experience? I know that Beefcake did 4.10s and had good luck until he was blown, but he also had a lot more done than me.

Would I even notice a difference with 3.55s? Can get them pretty cheap from a buddy with a Mach that upgraded to 4.10s.

Opinions greatly appreciated.

 

[spike648]

Curious to know too!

 

[FiveLeeter]

Looking at the gear calculator at http://www.csgnetwork.com/multirpmcalc.html, I think I could get away with 3.73s and still be in 4th at the traps. Trying to get as much as I can without causing the car to shift into 5th at the end.

I think I need to get on a dyno and see where my peak power is...

 

[LAStang1234]

3.73s and never look back!!

 

[BadHabit2Break]

Looking at the gear calculator at http://www.csgnetwork.com/multirpmcalc.html, I think I could get away with 3.73s and still be in 4th at the traps. Trying to get as much as I can without causing the car to shift into 5th at the end.

I think I need to get on a dyno and see where my peak power is...

No

3.73s and never look back!!

and No. OP has a 2011, gearing is different.

I went down this same road going back and forth about 3.73's or 3.31's. In the end, I went 3.31's and love it. The car does not have that lag between gears anymore. It shifts and goes.

I found a thread by WBT who did alot of testing and numbers on his auto. He is hitting 11's with 3.31's. If you put 3.73's in, 1st and 2nd gears will become useless.

PM WBT, cool guy, who will be glad to explain things. Just make sure you have a goal set....he will ask you...lol

 

[LAStang1234]

and No. OP has a 2011, gearing is different.

I went down this same road going back and forth about 3.73's or 3.31's. In the end, I went 3.31's and love it. The car does not have that lag between gears anymore. It shifts and goes.

I found a thread by WBT who did alot of testing and numbers on his auto. He is hitting 11's with 3.31's. If you put 3.73's in, 1st and 2nd gears will become useless.

PM WBT, cool guy, who will be glad to explain things. Just make sure you have a goal set....he will ask you...lol

Touche' and this is why I have an 07'

 

[BAKnBLK2010]

Tech?

 

[Rob72]

The 1st gear on the auto is 4.17. The 1st on the MT82 is 3.66. 1st on the TR3650 is 3.38. The auto doesn't require as much gear as other transmissions.

 

[FiveLeeter]

The 1st gear on the auto is 4.17. The 1st on the MT82 is 3.66. 1st on the TR3650 is 3.38. The auto doesn't require as much gear as other transmissions.

Yep that's why I was asking.

Would 3.55s be too steep? I have a lot of local Mach guys that have upgraded to 4.10s and will sell me their gears cheap.

who moved me? I asked in 2011 because it specifically applied to the 6r80 transmission? I feel this is tech related, since it involves the mechanics of my car...

 

[Rob72]

Yep that's why I was asking.

Would 3.55s be too steep? I have a lot of local Mach guys that have upgraded to 4.10s and will sell me their gears cheap.

The serious racing automatic guys on this forum recommend 3.31 tops. They say any higher will force you to shift into the next gear in the 1/4 and not max that gear out.

BTW this forum's TECH rules are different than other forums. Things get moved often.

http://www.s197forum.com/forum/showthread.php?t=27605

 

[FiveLeeter]

gotcha.

 

[FiveLeeter]

is that WBT thread on this forum? Remember which section?

 

[BadHabit2Break]

is that WBT thread on this forum? Remember which section?

http://www.s197forum.com/forum/showthread.php?t=96171

WBT is a member here.

 

[FiveLeeter]

yea I found him in the members section, guess I was looking for a thread dedicated to gear selection. Glazed right over that one, thanks!

 

[GeorgeInNePa]

3.31s if you're staying with a 28" tall tire. The math works for 3.55s, if you use a 30" tall radial slick. If you are primarily a street car, go with whichever one makes you happy..

 

[FiveLeeter]

I am primarily a street car.

I did forget to add in the original, my DR is a 275/40/17 NT555R. I know the diameter puts me at a disadvantage, but it's all I've got at the moment.

 

[Wicked97]

We have had some pretty good luch with 4.10s

I will say with those short tires you have the 4.10s will be a little much though. 3.73 would better suit you. however you will need to have a pretty good tune to make it work right.

 

[46Tbird]

Those 275/40-17s will make your 3.15 rear gear "act" like a 3.31.

235/50-18 = 27.25" tall
275/40-17 = 25.66" tall

tire ratio change = (27.25/25.66) = 1.0619

effective gear ratio = 1.0619 * 3.15 = 3.35

Try them out and see how you like them, might be just the ticket for your combo.

 

[ssstang67]

I would think this is tech but as I've learned been on here short time there isn't much they consider tech unless ur taking something apart. I have asked the same ques from a top tuner and he said you can do more with tuning and playing with tran then gears. They said they think its a waste of time and money. Better putting it into a convertor. They said if u want gears to go no more then 3:31.

 

[Wicked97]

I would think this is tech but as I've learned been on here short time there isn't much they consider tech unless ur taking something apart. I have asked the same ques from a top tuner and he said you can do more with tuning and playing with tran then gears. They said they think its a waste of time and money. Better putting it into a convertor. They said if u want gears to go no more then 3:31.

i would say thats inaccurate advise. If your tuner can get the car to shift in to 4th properly the car will be faster with a gear. Its basic math.

I agree that a converter will pick the car up more then a gear but to each and their own.