Help for better MPG

[Scott Coburn]

1 hour ago, Jacoby said:

I think when it was all said and done it was $2250 to do a gear swap. 

 

If I slow down and run the speed limit I can average 18 on the hwy.  With the gearing though it’s hard to run less than 80 and that puts me around 15mpgs

 

in the city right now I’m averaging right at 13

Thank you for the info. Definitely food for thought 

[Jacoby]

35 minutes ago, Scott Coburn said:

Thank you for the info. Definitely food for thought 

Some more food for thought. 

 

I wouldnt do gearing unless you tow regularly or plan on keeping the truck for a while. I towed a toy hauler pretty regularly and absolutely needed the gearing. Probably the 3rd tow after the regear I had a blowout on my toy hauler that caused so much damage the insurance company totaled my trailer. Now I’m driving around in a stump puller and no heavy trailer to pull. I have no interest in getting another toy hauler so now i got a $2200 mod I don’t really need and I’ve lost a big need for my truck altogether. 

 

If I didn’t have a heavy trailer to pull I would have never even considered gearing and just dealt with the shitty performance and gas mileage. I’m considering getting rid of the perfectly good m/t tires I got and getting some a/t tires to cut down the weight and rolling resistance. Believe it or not but a simple tire swap can make a pretty significant difference. 

[Praedator]

That's a lot of lift and tires.  It's a look and you're paying for it.  Heck, when I just went from the stock hwy tires to a LT 10 Ply AT tire, I dropped 1.5 MPG or so.  That was stock size P rated hwy tire to a LT 10 ply tire in the same size.  Weight was the difference.

[Scott Coburn]

1 hour ago, Jacoby said:

Some more food for thought. 

 

I wouldnt do gearing unless you tow regularly or plan on keeping the truck for a while. I towed a toy hauler pretty regularly and absolutely needed the gearing. Probably the 3rd tow after the regear I had a blowout on my toy hauler that caused so much damage the insurance company totaled my trailer. Now I’m driving around in a stump puller and no heavy trailer to pull. I have no interest in getting another toy hauler so now i got a $2200 mod I don’t really need and I’ve lost a big need for my truck altogether. 

 

If I didn’t have a heavy trailer to pull I would have never even considered gearing and just dealt with the shitty performance and gas mileage. I’m considering getting rid of the perfectly good m/t tires I got and getting some a/t tires to cut down the weight and rolling resistance. Believe it or not but a simple tire swap can make a pretty significant difference. 

Good point. I don’t plan on hauling anything really so the gears would probably be a waste. I’m sure the M/T tires are hurting things. So when time comes to get new tires I’ll get A/T tires for sure. What about a tune. I’m wondering if I should get the odometer/speedometer tuned. I have read threads that it helps with shift point and also gives you true MPG. The dealership I bought the truck from told me they did not recalibrate the speedo/odometer after the lift and tires were added. He mentioned his trucks speedo was roughly 5 MPH off... would tuning the speedo/odometer help? Would it adjust shift points in the tranny or is that something different?

[CamGTP]

Gears are never a waste. The idea is to match the gearing and tire size correctly.

 

Not doing gears even with you not towing is still leaving a lot on the table for performance and miles per gallon. If you kept the truck for a long time and put on a decent amount of miles it would be worthwhile to do the swap.

 

A tune is a must too. Not only for your speedo but for everything else. The transmission calibration would greatly appreciate knowing what size tires are on it.

[swathdiver]

2 hours ago, CamGTP said:

A tune is a must too. Not only for your speedo but for everything else. The transmission calibration would greatly appreciate knowing what size tires are on it.

As would the ABS system!  

[rbrjr1]

Whenever I think about lifting the truck, I read threads like these and decide... nah.

[flyingfool]

smaller wheels from the work truck and get a used axle from a wrecker with the 3.08 gears, lower truck 2-3inches , run 91 octane 0-20w oil and thinner gear oil for diff, tire pressure crank it up to 45 psi.  get a tonnu cover or a flush fit camper shell for less bed turbulence. keep the stock coolant thermostat as it makes the motor run lean on the fuel maps, toss the spare tire in the garage, and remove the extra cab seats 

 

I would like to try a 4.10 axle , my theory is it will help the engine maintain 4 cylinder mode on the hwy or on grades, thus improving gas milage with the stock wheels on 17-18" rim and 33" tire

 

 

[Scott Coburn]

On 8/23/2019 at 4:34 PM, Scott Coburn said:

I just purchased a used 2018 Chevy Silverado 4x4. It’s a 5.3L V8. It has a 7 inch rough country lift and 35 inch tires on 20 inch wheels. I’m getting TERRIBLE gas mileage (11.2 mpg) mixed highway and city driving (no towing). It has a 3.42 gear ratio (not sure if you need to know that or not). 

This is my 1st lifted truck and I’m reading others getting 16-20 MPG with the same set up I have so I feel like there’s something a miss with my truck. Maybe I’m wrong but seems I should get better than 11.2mpg.

Any help you can provide would be greatly appreciated!
 

Update: I just did a tuning with a rough country tuner and WOW the difference is crazy! I’m floating at around 15.5 MPG, the transmission is much smoother and making better shifts and the truck spends more time in V4 mode. So this helped considerably. 

 

Im also thinking of doing the gear swap. I don’t pull anything with the truck so I’m thinking a 4.10 would be better than the 4.56. Is my thinking correct?

[flyingfool]

yeah i think a lot of mpg is being lost is the oem trans programming, they slip a lot for comfort..  4.56 gears sounds like a lot, it will take off quick and increase the engine toque a lot more and maintain v4 mode . but just because your in v4 mode doesnt mean your saving fuel...