Changing Gear Ratio

[ndhonor]

I have a 4.8L 2007 Nbs Silverado with 3.23 gears. My gas mileage is ok but I wish I had a little more power. Most of my driving is city with some highway, driving back and forth home.

 

What gears should I upgrade to for an increase in power as well as an increase in gas mileage. If I remember correctly the higher the gear ratio, to an extent, the better gas mileage in the city.

 

I do not pull a trailer too often. I also have LT265/70/17 tires.

 

Any suggestions appreciated.

[BuckFeverZ]

3.73's IMO. You notice quicker acceleration and will be better for the powertrain when you do tow something.

[ndhonor]

3.73's IMO. You notice quicker acceleration and will be better for the powertrain when you do tow something.

 

How much and which way will the MPG likely go.

 

Oh I usually average around 13.5 in the city, while getting around 18 on the interstate. I think it could be better with a different gear, not putting as much strain on the motor. It shifts often when going over overpasses.

[BuckFeverZ]

Change in your MPG's will be +/- 1 depending how you drive, but you will have more passing power and won't be hunting for gears on the interstate.

[Zembonez]

I have a 4.8L 2007 Nbs Silverado with 3.23 gears. My gas mileage is ok but I wish I had a little more power. Most of my driving is city with some highway, driving back and forth home.

 

What gears should I upgrade to for an increase in power as well as an increase in gas mileage. If I remember correctly the higher the gear ratio, to an extent, the better gas mileage in the city.

 

I do not pull a trailer too often. I also have LT265/70/17 tires.

 

Any suggestions appreciated.

Going to a 3.73 gear will give you better acceleration but might cost a little in fuel economy.What you have now is about as fuel efficient as is available.

[ndhonor]

It is supposedly better fuel effeceincy on the highway, but there is hesitation, making me think that its putting a greater strain on the engine. As I had said most of my driving is city, so isnt the gears I have making the engine work harder?

[BuckFeverZ]

My thoughts as well. Takes more pedal (fuel) to get up to speed at a reasonable rate. Also requires more pedal to keep the truck at a constant speed even at the slightest incline.

[Zembonez]

It is supposedly better fuel effeceincy on the highway, but there is hesitation, making me think that its putting a greater strain on the engine. As I had said most of my driving is city, so isnt the gears I have making the engine work harder?

I suppose in certain situations that is true. No matter what though, the engine will turn more RPMs with a lower gear... that should translate into more fuel consumption on average. It takes fuel to fire the cylinders and more firings will result in more fuel burnt overall. I don't think it would be much of a downturn but I can assure you it probably wouldn't increase your mileage..

[Bowler807]

A suggestion if I may. Rather than change the gears, get a custom tune. You will gain torque and horsepower. With the power gains and the way you drive I believe you will be further ahead with the tune.

[wanta5.3]

I couldnt tell from your picture but is your truck 4wd or 2wd. Correct me if i am wrong but if you change the gear ratio of the rear end in a 4wd truck you have to change the front diffs gear ratio to the same ratio if you ever want to use your 4wd. Because the front diff would be moving slower than the rear diff and would not be good, It would work for a couple minutes either causing a front diff failure or transfercase failure. But if it is a 2wd drive i would say 3.73. Good all around gear.

[05silvycrew]

IMHO, 3.73 gears with stock 265/70/17 size tires is the sweet spot for these trucks. Highway Mileage will be just about optimal. You won't be too low in the RPM band to gasp for power or go gear searching, but you won't be too high that you're burning away good fuel.

 

City mileage will be about the same, besides a light foot you can't do much to improve it.