I'm looking at a couple of Vmax Crewcabs. Both 2wd and 4wd right now. Most have 3.73's and one has 4.10s. Just wondering what kind of fuel mileage difference one sees with 4.10s vs the 3.73's. My daily commute is 55 miles one way (so 110 total).


I'm hoping with the AFM and a bit of tuning that I can get the mileage up to a better. I'm just wondering how much the 4wd eats up compared to 2wd, and how much the 4.10 eat up vs the 3.73's.

I'd like to at least be close to where my ECSB 2006 4.8L is for daily mileage.

 

You really wont see any difference. LSX motors love cruising at around 2500rpms.

 

The BEST I've ever gotten with my 07 Vmax CC/SB 4WD with 3.73's is 16.3 highway driving like a grandma. Do NOT believe that 19mpg on the window sticker. Realistically you're looking at 15mpg on the highway. Less if you have a heavy right foot.

 

I have heard that 4.10's can actually net better freeway mileage than 3.73's on the AFM engines due to the higher RPMs allowing the 4-mode to stay enabled more at cruising speed. I have the 3.73's in my Vmax and the 4-mode is NEVER enabled at any speed above 65-70mph and even at 60 mph it only will activate on completely flat highway on cruise or when decelerating. If I were to do it again, I would have gotten the 4.10's.

16 mpg freeway is a good number too. The best I have netted on a single 150 mile trip was 18, but that was about 30% freeway at 70 mph and 70% country highway at 55-60mph driving like I am checking mileage...LOL The only stop-n-go driving was a few small towns I had to go through.

 

16.3 on the highway? Before I put the cam in (with AFM) the VMax would easily get 22mpg on a tank of pure Highway driving. I had tuned it to hold the 4cyl mode at higher speeds and MAP.

With the new cam my guess would be around 18-19 and mine is a 4wd truck.

 

I have 3.73's in the sub if I didn't take it out of stock and was doing it again it'd definetely be 4.10's

 

go with the 4.10s there want be much diff

 

Looking at a chart on ratios, about 150 rpms at 60 MPH.

 

LSx motors may love 2500 RPM, but at that engine speed they are gulping the gas. LSx engines get their best mileage at 1600-1800 RPM.

Whatever combination of transmission gearing, rear-end gears, and tire height gives you ~1800 RPM is what you want.

In my Avalanche, I replaced the stock 3.73's with 4.10's and experienced a loss of 2 mpg across the board.

 

before i lifted mine i was averaging 13.5 with 4.10's