questionable mpg

[danzick]

So, I feel like my rig isn't getting the mileage it should be. It has a built trans with an s475 over stock twin kit and ppei tuning. Truck has 72k on it with reman injectors from LDS at 68k. Change my fuel filters once a year (about 3500 miles +-500). Running 33x12.5 20s. Ever since I started modifying it the mpgs have gone down. Towing fairly light loads (1000-3500 lbs) it gets about 11-12 and empty down the highway its an honor to see 15 but that's only if I'm lucky. Usually runs 13-14 at 75-80 mph. I see all of these people getting these insane 18+ numbers and I just don't see them.

 

[Porno Joe]

for starters you are never going to get good mileage at close to 80.

guys getting the 18+ are probably running around 60-65.

When I get on the highway I run around 70 and I know the closer I get to 80 the lower the mpg go

 

[MAXX IT OUT]

For me running around between 75-80 general nets 16-17, but in town I am lucky 12-14 with some highway. In wintertime I see about a 2-3 mpg drop in town.

 

[Hot COCOAL]

The only way i see 18 is putting decent distance on the hwy running a consistant 60-65 and no more....the further away from 60mph i go the lower my MPG gets...

At 70-75 i will be licky to achieve 16.5mpg, ive re-geared but im lifted, running 35's and my wheels arent light...between the added drag and weight id say i net a slightly lower result than a stock height/tire truck on PYO's

In town its a solid 13

33's arent too big and we've got the tq to push them, no doubt. But youre not gonna see superb economy with them, especially if theyre MT's or even AT's and 12.5 wide

Just sayin

 

[countrycorey]

I usually average around 17.5 mpg (hand calc'ed) with my current setup. Best I ever saw was 24 mpg (with this same setup, cruise set between at about 58-60 on FLAT ground with a tail wind for 100 plus miles).


Corey

 

[clrussell]

for starters you are never going to get good mileage at close to 80.

guys getting the 18+ are probably running around 60-65.

When I get on the highway I run around 70 and I know the closer I get to 80 the lower the mpg go

This ^^

 

[danzick]

I see. Well i'm always in a hurry and I could never go 65 mph down the highway. 75 would probably be the slowest I would go. yes they are mud terrains. My truck only sees about 1000 miles a year of summer driving and most of that is in town, so i never really get to see what it can do than.

 

[Porno Joe]

well if you're in that big of a hurry, why not leave sooner?

if you want better mpg, gotta slow down. plain and simple.

 

[DirtyMax9812]

I have an 02 2500HD LB7 Crew Cab with the next size up tire, and straight piped, other than that it's BONE stock.

With my Ultraguage calculating, I'm getting, on average, 14.1 MPG. I have a 70 mile round trip drive everyday, and when I'm on the 55 mph road, which is 26 miles of my journey, I'm averaging between 18 and 19 MPG. The rest of my 44 mile journey is Highway, and when I'm on the highway doing between 70 and 75 MPH, I average about 13-14 MPG...

If you want to see what your true MPG's and other stats are, You should consider getting and UltraGauge (http://www.ultra-gauge.com/ultragauge/). They are AWESOME.

It shows all the different stats of your truck real-time, and simply connects to your ODBII port. The way I have mine set, I see my Speed, Instant MPG, Air Intake Temperature, how many miles left until my tank is empty, my average MPG's, and how many gallons are left, to the tenth of a gallon, in my tank. I could set it to see my boost PSI, Torque in square foot lbs, and many many more.

There are 74 different things I can monitor on my truck, with the newer models, its more! Check it out! :woott:

 

[Chevy1925]

So, I feel like my rig isn't getting the mileage it should be. It has a built trans with an s475 over stock twin kit and ppei tuning. Truck has 72k on it with reman injectors from LDS at 68k. Change my fuel filters once a year (about 3500 miles +-500). Running 33x12.5 20s. Ever since I started modifying it the mpgs have gone down. Towing fairly light loads (1000-3500 lbs) it gets about 11-12 and empty down the highway its an honor to see 15 but that's only if I'm lucky. Usually runs 13-14 at 75-80 mph. I see all of these people getting these insane 18+ numbers and I just don't see them.

talk with kory and see if your tune has anything left in it for bringing mileage up. he may want to see some logs of you driving it in traffic and on the highway driving as you normally would.

on stock injectors, i saw 19-20mpg average empty at 70mph. cruising at 1800rpm helped. there was alot of time in tuning on that though. towing i got 12mpg. with my 45% overs and built motor, ive lost mpg. i now only get 17 at best on the highway empty at 70mph and 11 at best towing. that took a years worth of tweaking and learning just to get mpg back up to that far and now im at the limit without changing some hard parts. towing consists of a 10-12k load at those mpg. at a load your pulling i get closer to 13-14mpg.

im a nut about mpg when i tow though. filling up isnt an issue, i just hate having to stop.

 

[danzick]

Well I emailed him and asked him what DSP setting I should use. It seems to be a crap shoot for me. I guess I'll have to painfully try to slow down on my next empty trip and see what it gets. Towing I pretty much have to go at least 75. With the big hills in my area at elevations from 4-6k the truck lugs too hard and hunts between 4th and 5th. That's with larger loads around 8k or up.

 

[danzick]

I talked with Kory yesterday and he recommended my 3 setting. I guess the next trip I make in the truck I will run it on 3 and do my best to drive 70 and see what happens.

 

[THEFERMANATOR]

I'm one of those guys getting over 18 out of mine. I have stock 245/75/16 tires, 3.42 gears, and other than that it's mostly stock. Bigger tires = lower MPG, your 2nd turbo is probably adding some extra exhaust backpressure which = lower MPG, and spirited high speed driving is the final nail in the coffin. If I drive mine with a spirited foot, my milage drops down close to yours, but if I drive it sanely I have seen 18 around town. I can run 70 with mine on cruise, and see an honest to goodness 21(best I've ever gotten was 23 running 60-65), if I go to 75 it drops to 20, and 80 I don't even bother to check because it plummets. If you want MPG's run stock width pizza cutter tires to reduce drag, keep your speeds down, and keep your foot out of it. If you hear the turbo, your getting on it to hard for MPG's. It's no fun, but your not going to get good milage gettin on it.

 

[OregonDMAX]

I average 20-22 highway with a 265 tire. in my state the max speed is 55 so I do damn well depending on the elevation gain or loss. I have a personal best of 24.6 all while decreasing elevation at 60mph. I average 16 city at 5k elevation.

 

[fast03]

My old LB7 tuned ran 17-18 highway at 70. Go 80 and the mpg dropped to 15-16. City was 13-14 and towing was 10.

 

[danzick]

Well i drove about 110 miles one way today. I was able to slow it down to 73 on the edge monitor and about 68 on the factory speedo. It got 17. A little better. I imagine it could see 18 in the 65-70 range.

 

[ku 808]

So, I feel like my rig isn't getting the mileage it should be. It has a built trans with an s475 over stock twin kit and ppei tuning. Truck has 72k on it with reman injectors from LDS at 68k. Change my fuel filters once a year (about 3500 miles +-500). Running 33x12.5 20s. Ever since I started modifying it the mpgs have gone down. Towing fairly light loads (1000-3500 lbs) it gets about 11-12 and empty down the highway its an honor to see 15 but that's only if I'm lucky. Usually runs 13-14 at 75-80 mph. I see all of these people getting these insane 18+ numbers and I just don't see them.

I have the same set up same tuner on my LMM except its a single cab dually aluminum flatbed my mpg is terrible I am lucky to get 12 mpg empty. Towing she eats I went from a LLY stock with a built trans and Korys tuneing $80 a week to twin LMM $200 a week same drive around 600 miles a week

 

[melms23]

I got 14.5 with a enclosed 2 place while heading to mercer a couple weeks ago. Anytime I've bothered to check I have never gotten lower that 16 driving to school and back. Although it is a 6500 lb reg cab with small tires and no lift.

 

[Ridin'GMC]

Mud tires are a killer in mpg. I saw a 1.5 mpg drop when I switched from MT ATZ to the Nitto Trail Grappler. Another factor was I went up 3" more in the tire size and I still drive the same. If you want better mpg, switch over to a street friendly AT tires. It takes a lot of tuning and patience to figure out where the best mpg is.