10 mpg help

[stewwalker]

I have a 1995 Suburban K1500 with 33"s, 3" lift, and a little extra weight. (front bumper, rear bumper, drawer system in the back, roof rack, ect.) I currently get 10 mpg in the city and 11 or 12 on the highway. My question is, is there any way to increase my gas mileage? I know the TBI 5.7 isn't known for getting good mileage but 10-12 is getting expensive.

 

[herm]

what gears are you running? what rpm are you cruising at?

 

[stewwalker]

3.42, I cruse the highway at 65-70 turning 1600-2000 rpm depending what gear I'm in.

 

[WoldD90]

Buy a second set of wheels and street tires... That is probably the only way you will get any better mileage.

Or, take the truck back to stock and get a few more mpg. All that extra steel weights a lot, combine that with the lift and cool tires and you are destine for crappy gas mileage.

Worst case, by a beater for 2k, that will get you through the high gas prices.

 

[herm]

the rack will hurt a lot too. i am getting somewhere around 1mpg difference in town with my rack on my pickup. I will be removing that and just using it with the camper to increase my mpg, esp at highway speeds.

 

[stewwalker]

1 mpg? What does your rack look like...... I have a Surco that doesn't look like it would cause to much drag.

http://www.surcoinc.com/R-BR_SR5.html

 

[herm]

mine is pretty small and all components are round.

 

[Eaglefreek]

My roof rack knocked off almost 3 MPG. It's big and heavy. I'm not familiar with the MPG's in a Suburban but I have owned many full size vans and no matter what brand or engine, I always got 12-13.

 

[shovelbill]

10 in the city? .....i'm having a hard time believing you get 10 in the city with that gear/tire combo and the weight.....have you re calibrated the speedo for the 33's? 10 is actually great.

1,800-2,000 rpms is good for a diesel, not a sbc. you must really have to smash the pedal to pass or take hills, huh? no need for overdrive.

let's face it, these trucks are as aerodynamic as a refrigerator, add to that more drag from the lift.....increased rolling resistance from the larger tires and the worst offender.....the roof rack. 12 on the highway really isn't too bad for what you have. 4.10's would be better.

borrow stock wheels and tires to see what the mpg difference is under the conditions you drive in....that'll tell you if a gear swap will help, all else being equal.

 

[ericvs]

Hey, Here is a post from another board I posted. Some of it may apply to your case. It is a bit wordy though. Good advice above, for sure.

"Don't know much about gas trucks, BUT a couple of things you could possibly do to increase your fuel mileage (every little bit helps). Check out this link, granted he spent a bunch of dough, but there were some small things that made a bit of a difference: (yes he is annoying and it is a bit goofy, but the ideas might help)

http://www.spike.com/full-episodes/288b ... n-3-ep-523

You are not going to be running a 30+ mpg truck w/o a diesel (IMO), but if you were at 19 or 20 that might be a bit more respectable. I will try and rate them in order of easiness:

drive slower (This one might actually be the hardest to do!)
keep the a/c off
keep the excess vehicle weight down - maybe take that cinder block out of the back
see if there are any tuners (or chips) for your truck to increase fuel economy
new exhaust and/or intake
electric fans instead of a engine driven fan
freewheeling front hubs - reduce engine drag
Go back to stock tires - or, as mentioned above, re-gear maybe
Lower wind resistance - no rack etc..."

Good luck. 10 mpg is tough.

 

[stewwalker]

10 in the city? .....i'm having a hard time believing you get 10 in the city with that gear/tire combo and the weight.....have you re calibrated the speedo for the 33's? 10 is actually great.

1,800-2,000 rpms is good for a diesel, not a sbc. you must really have to smash the pedal to pass or take hills, huh? no need for overdrive.

let's face it, these trucks are as aerodynamic as a refrigerator, add to that more drag from the lift.....increased rolling resistance from the larger tires and the worst offender.....the roof rack. 12 on the highway really isn't too bad for what you have. 4.10's would be better.

borrow stock wheels and tires to see what the mpg difference is under the conditions you drive in....that'll tell you if a gear swap will help, all else being equal.

I have to stomp on the pedal pretty hard to pass on the highway. Fortunately in south Texas it's relatively flat so I don't have to worry about hills, but I have learned how to draft 18 wheelers pretty good.

I have not re calibrated for the 33"s. I have heard mixed results. Some say it makes a difference, some say it's a waist of money.

 

[shovelbill]

how have you clocked the mileage then, with a GPS?

when your speedo says 65 you're actually going around 69 mph without recalibrating.

 

[bob91yj]

I've got an '88 2wd 'burb on 33's with a 454 under the hood...I wish I got 10mpg! I feel your pain, unfortunately the only way I've found to improve my MPG is to leave it in the driveway and drive something else!

 

[TurboChris]

Isn't that the truth...with my 2500 I get 8 in the city and 10 cruising at 65mph and that's driving like a grandma...

 

[stewwalker]

I changed out the catalytic converter a few weeks ago. I just did the math on a 225 mile trip, I used 15 gallons. 225 divided by 15 = 15 mpg!!!! Maybe that did the trick.