graysilverado5.3

iTrader: (4)

Was seeing around avg 12.5-13.5 city and 15.5 highway. Did manage 16.0 mpgs on a trip to Austin one time. Only mods other than tune and gears is a air aid jr intake.

james8997

I think I may just swap them in with the g80 for now!

sand man

4.10s are intresting , I wonder if I'd want them with 408ci and a turbo , might not need them but the thought is always there lol

1slow01Z71

iTrader: (36)

You do realize you have a 14 bolt right?

james8997

Who me?

CDN SS

iTrader: (1)

Little late to this thread ....... but I have 4.10 in my 2010 crew 5.3 and 6 spd and stock tire height ......went from 3.42 .......... luv them, mileage does fall off if you drive 80mph but around town its better plus yes goes into V4 alot easier
Tow 7000lb enclosed car trailer in 5th @ 2500 rpm rarely kicks down goin up hills

KC_kid

iTrader: (5)

I don't see how my mileage could get worse and I have 3.08s. 300 miles on i70 with no wind going ~76, less than 15mpg.
In town is ~11mpg.
2011 5.3 6speed 3.08 crew, black bear tune

james8997

Ouch
Mine hits 19 on longer trips at 75ish

AUTOT3K

iTrader: (3)

Well it would lose a bit at high speeds like 80mph or for me 130km/h. Because the rpms have increased a bit
I've had my 4.10s in for about a month now and I haven't noticed any losses in mileage. On the highway I just speed a touch less to make up for the gears.

I'm wondering if you calculated your mileage wrong? Or do you floor it constantly to pass people? Id be checking for mechanical issues if my mileage was that bad!

KC_kid

iTrader: (5)

It doesn't matter if I floor it to pass people or baby it, I babied it this last trip. I've had stock tune, BB 91 and BB 87 tunes, added zmax, not much difference. I got 17 once, 16 once and the rest between 14&15. I have 4x4 & 275/55/20 on stock Goodyear ls 2 rubber and stock Chevy 5 spoke chrome clad 20s. I read all over people getting 19. I got 20 with my 2001 5.3 ecsb.
Truck only has 13k miles and I just got the GM 27 point inspection at my recent free oil change. I don't know what could be wrong mechanically.

Edit: I've kept track of every time I put gas in this truck, every time it goes in a book. I write down the trip mileage, DIC MPG, reset both meters then I write down the gallons added and manually calculate MPG. Calculated is usually ~ .5MPG less than the DIC. I try to use the same pump, if I'm close to home, and I fill up it every time but never top it off.