Jacob Metz
Member
idk if this is the right forum. But I wanted to see what everyone’s getting for mileage on their nbs. I’m currently on 35s and getting 8mpg idk what to do to have it go up
Gas mileage
- Thread starter Jacob Metz
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Scottydoggs
Full Access Member
welcome to the world of "you run large wheels" they are cool, but kill mpg.
i had a 03 2500 hd pick up, came with 4.10 gears, i then added 33's, i went from like 450 ish a tank to 300 ish. i had a huge tank too, 34 gal, so i was in the 8-10 range.
for work i had to do fuel and mileage reports with your mpg avg done via your miles and gallons used. was always right around 10 mpg. and i did a lot of hwy. about 200 miles a day.
i had a 03 2500 hd pick up, came with 4.10 gears, i then added 33's, i went from like 450 ish a tank to 300 ish. i had a huge tank too, 34 gal, so i was in the 8-10 range.
for work i had to do fuel and mileage reports with your mpg avg done via your miles and gallons used. was always right around 10 mpg. and i did a lot of hwy. about 200 miles a day.
inmypassatlife
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lower it back on stock wheels, you should see your MPG go up
SnowDrifter
Full Access Member
A re gear might help, but you're still fighting physics here. These hoes are large vehicles as is. Both weight and volumetric size. Putting 35s on the thing makes it that much worse. You're basically forcing a barn with 4 wheels through the air.
'Tis the nature of the beast.
'Tis the nature of the beast.
08HoeCD
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LOL
I love these threads.
I love these threads.
Martinjmpr
Full Access Member
I'm resisting the impulse to say "sell it and buy a Prius" but I actually do get it - when you have to pay for gas, it makes sense to get the best MPG you can.
To answer your question realistically, we need more information. Year? 2wd or 4wd? Miles? Gear Ratio? What other mods do you have?
What kind of driving are you doing? Stop-and-go city or suburb driving? Long highway miles? With a vehicle as heavy as these, stop-and-go will kill your MPG no matter what else you do.
Also how are you calculating your mileage? If you're going by the DIC readout consider that unless you have re-calibrated your speedo and odo that is going to give you an inaccurate rating. Also, the DIC is not really a good way to determine actual MPG anyway, to do that you need to hand calculate.
If you want to accurately measure MPG the first thing you have to do is figure a way to calculate your actual miles driven.
Here's how I did it on my Suburban after I put bigger tires (33's) on: Get a GPS mounted. Then go to the trip meter on the GPS. Set the GPS trip meter to 0, and set the truck trip meter to 0 also.
Drive at least 100 miles with the GPS on (more is better.) Make sure the GPS is always recording mileage driven. After at least 100 miles compare the two. If you have oversized tires, likely the GPS will show more miles than the truck odometer (because your bigger wheels have a greater circumference the odometer only knows how many revolutions your driveshaft is turning, not how many miles you are actually going.)
Compare the two numbers. Let's say the truck odometer shows 350 miles and the GPS shows 360.3. 360.3 / 350 = 1.03. That means that from now on, you have to multiply the truck's odometer reading by 1.03 in order to get an accurate distance.
Set the truck odometer to 0 when you fill the tank. Drive as normal. When it's time to refuel, fill the truck up and write down the number of gallons it took to fill the truck. Multiply the miles x 1.03 (or whatever your multiplier is) to get actual miles driven and divide by gallons used. That is your ACTUAL mileage (as opposed to what's on the DIC.)
To answer your question realistically, we need more information. Year? 2wd or 4wd? Miles? Gear Ratio? What other mods do you have?
What kind of driving are you doing? Stop-and-go city or suburb driving? Long highway miles? With a vehicle as heavy as these, stop-and-go will kill your MPG no matter what else you do.
Also how are you calculating your mileage? If you're going by the DIC readout consider that unless you have re-calibrated your speedo and odo that is going to give you an inaccurate rating. Also, the DIC is not really a good way to determine actual MPG anyway, to do that you need to hand calculate.
If you want to accurately measure MPG the first thing you have to do is figure a way to calculate your actual miles driven.
Here's how I did it on my Suburban after I put bigger tires (33's) on: Get a GPS mounted. Then go to the trip meter on the GPS. Set the GPS trip meter to 0, and set the truck trip meter to 0 also.
Drive at least 100 miles with the GPS on (more is better.) Make sure the GPS is always recording mileage driven. After at least 100 miles compare the two. If you have oversized tires, likely the GPS will show more miles than the truck odometer (because your bigger wheels have a greater circumference the odometer only knows how many revolutions your driveshaft is turning, not how many miles you are actually going.)
Compare the two numbers. Let's say the truck odometer shows 350 miles and the GPS shows 360.3. 360.3 / 350 = 1.03. That means that from now on, you have to multiply the truck's odometer reading by 1.03 in order to get an accurate distance.
Set the truck odometer to 0 when you fill the tank. Drive as normal. When it's time to refuel, fill the truck up and write down the number of gallons it took to fill the truck. Multiply the miles x 1.03 (or whatever your multiplier is) to get actual miles driven and divide by gallons used. That is your ACTUAL mileage (as opposed to what's on the DIC.)
OP
OP
Jacob Metz
Member
2001 Tahoe 5.3 4x4 factory gears
Martinjmpr
Full Access Member
Do you know what ratio? It should be on the RPO code sticker on the dash. Also you can create an account with GM and they will send you a build sheet that shows all the options your vehicle has based on the VIN.
Reason I ask is that if you have low gears already (like 3.42) then having big tires lowers the ratio even further and that can cause your engine to be operating at either excessively low or high RPMs. Also you didn't say what kind of driving you're doing. Stop and go driving is an absolute killer in these vehicles because they weigh over 5000lbs and every time you stop, you have to get all that mass moving again, which requires a lot of engine power.
If the issue is gear ratios, you're going to have to decide whether spending $1000+ is a good investment, because that's about how much new gears will cost (you need two sets, obviously, since you have a 4x4.) You can buy a lot of gas with $1000.
HiHoeSilver
Away!
Look at the sticker in your glove box for the codes GU6 or GT4.
castine917
Member
Our 05 5.3 tahoe 4x4 would get @15 mpg. It had 35s, 4.56 gears, an air intake, exhaust used premium fuel and a 'programmer'. Driving was mainly 45 mph city areas with light traffic. Highway time would reduce mpg.
Years before that we had a 97 f150 5.4, that would get 14. 4x4, 38s, 4.56 gears, air intake, exhaust, used premium fuel and programmer. That one spent more time on 55 mph country roads. On this one highway would help mpg.
With factory gears you are probably having to floor it to accelerate since it would take forever to get moving. How is your tune/tuneup/fuel leaks? Do you have bad bearings or brakes dragging? Are you trying to do 90 on the highway? Any or all of those will kill mpg.
As martinjmpr mentioned, gears cost as do my other modded items. The difference between your 8 mpg and my 15 will take around 35,000 miles at $2 per gallon to pay for those parts.
CountryBoy19
Full Access Member
There are at least 3 factory gear ratios available. GU6=3.42, GT4=3.73, GT5=4.10
Also, you didn't answer the question about how you're calculating mileage. As stated, with an oversize tire, unless you reprogram for that tire size you are physically travelling more miles than your odometer indicates (you're also travelling faster than your speedometer indicates). Therefore, you need to adjust your mileage numbers with hand-calcs, use a gps to track miles-travelled, or have it reprogrammed for that tire size. Until it's reprogrammed the DIC information is completely useless without doing some maths. You should be able to find info on revolutions/mile on the stock tires vs your oversize tires and scale the numbers.
FWIW, stock size tires, 5.3L 4X4, 4.10 gears I get right around 16 mpg
OP
OP
Jacob Metz
Member
Alright I run the truck completely empty then fill up. Then I run empty get totals miles ran divided buy how many gallons used.
And as for gear I believe it 373
Tonyrodz
Resident Resident
Yup, 3.73's.
CountryBoy19
Full Access Member
HOW are you getting the number of miles you drove between fill-ups? From your odometer? Did you get your speedometer recalibrated when you changed tire size? If not your odometer readings are completely useless. So your calculated mileage is just as worthless. The only way to get good numbers is to use a GPS to track distance or have it recalibrated.
HiHoeSilver
Away!
To add to this, there no such thing as completely empty, even if you run it out. You should be using the amount of gas you're putting INTO the truck to calculate past mileage.
Scottydoggs
Full Access Member
fill the tank, then drive it to a 1/4 full, then re fill the tank and use the gallons you just added in the math with the miles driven.
there is dead empty, i ran out of gas, got a few rolling re starts that gave me a short burst of go! then it stalled out dead two block from the pumps, i coasted in literally. had a 34 gal tank, it took 36 to fill it lol but this is no way to figure out your mpg.......
there is dead empty, i ran out of gas, got a few rolling re starts that gave me a short burst of go! then it stalled out dead two block from the pumps, i coasted in literally. had a 34 gal tank, it took 36 to fill it lol but this is no way to figure out your mpg.......
Wolfbraid
Full Access Member
I have an account with GM, was curious where to look on the site? I couldn't find anything regarding build sheets.
HiHoeSilver
Away!
https://www.gm.com/site-help/contact-us/chat-with-us.html
During business hours select: question about a vehicle I already own. Give them your VIN and ask for the RPO build sheet.
billnparker
TYF Newbie
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You can not rely on GPS to give you exact mileage. In general they only report your position every 15 seconds. If yo make a right turn between those points it won’t show the exact turn, rather it will reflect a diagonal line. I know this as I watch GPS on 3000+ vehicles... on any given day, we see a variance of up to 200 miles versus reported odometer report... The GPS is close, but not exact
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