3.91 rear end ratio question - Page 2 - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

qkslvr · 02-10-2019, 11:18 PM

Quote:

Originally Posted by steakmaker

I went with the GM performance 391's with the installation kit in my M6.The kit will include everything needed and a registered UPC sticker that goes on driver's side under the hood by the hinge.This states you have orginal Gm performance optional gears installed.Had mine in for 2yrs & love 'em.I lost about 2 mpg on a long cruise,still get 26mpg,but it kills you not to go wot.

26mpg I WISH LOL. If i set the cruise at 70 in 6th gear on a flat road I still only get 22 at best... but then again I got a lot more than just gears LOL

Chris49066SS · 02-11-2019, 11:00 AM

Quote:

Originally Posted by 2010reddevil

Even with the 4.08 1st gear ratio of the auto? 3.91 still isn't enough?

I'm more interested in the added rpm on the back end. I would get a few hundred more, as I am crossing the line at about 6600 right now.

camguynj · 02-11-2019, 01:43 PM

Quote:

Originally Posted by steakmaker

I went with the GM performance 391's with the installation kit in my M6.The kit will include everything needed and a registered UPC sticker that goes on driver's side under the hood by the hinge.This states you have orginal Gm performance optional gears installed.Had mine in for 2yrs & love 'em.I lost about 2 mpg on a long cruise,still get 26mpg,but it kills you not to go wot.

Dealer installed my 3:91 gears and told me they put the sticker on the diff cover. Could you post of pic of yours so I could see what it looks like then I'd know what to look for to see if I could see mine.

sixty9fordkiller · 02-11-2019, 01:55 PM

i got a complete 15K mile Z28 differential. Came with 3.91. With 26" tires, this combo works really good to get the car out of the hole. Car looks dumb with that small of a tire but the ETs wont

If you're going with 4.10, make sure you take tire OD into consideration if your plan is to stay NA.

Also, if you plan on going FI, you need to consider that a taller rear gear may be best for you since you'll have the torque to make 1st gear on an M10 trans into spin city. The FI guys sometimes even like the 3.27 gears with an M10 trans

02-11-2019, 01:55 PM	#18
sixty9fordkiller Donkey Dick Cam Camaro Drives: 2010 2SS/RS LS3 M6 Join Date: Oct 2009 Location: Los Angeles, CA Posts: 1,998	i got a complete 15K mile Z28 differential. Came with 3.91. With 26" tires, this combo works really good to get the car out of the hole. Car looks dumb with that small of a tire but the ETs wont If you're going with 4.10, make sure you take tire OD into consideration if your plan is to stay NA. Also, if you plan on going FI, you need to consider that a taller rear gear may be best for you since you'll have the torque to make 1st gear on an M10 trans into spin city. The FI guys sometimes even like the 3.27 gears with an M10 trans __________________ Bone Stock