my best ever is 21.3 mpg... on average i get 16-19 mpg mostly I am on the highway (90%). I want to be at 20 mpg after upgrades... which upgrades/mods will help the most?

what do you guys have?

 

My best ever was 20.0 between San Antonio and the OK border, after that I got 19.3 and 19.1 on the same road there and back. Mostly I was getting 17.5 on the hwy and about 15.5 back and forth to work on the hwy in winter but adding a roof rack has cut about 1-1.5 mpg off of that but I did get the 20mpg with the roof rack and a tailwind

Best mod for better fuel economy is probably going to be an e-fan, then 32" hwy tires instead of an AT or MT.

 

best I did was 23mpg having the 5speed on 32's and cruising at 65. Definitely a highway tire will help like rsc said

 

what is an e-fan???

 

PCMforless Efan conversion.


On a cool upper 50s low humidity calm day I was able to get almost 23 (22.8 is what I came up with) cruising at 70 MPH. Once you bust 70, seems like 75-77 I usually end up with 19.

Mods: Air Doc Intake w/ AFE filter, Port Polished TB, PCM for less tune and Efan, MagnaFlow CAT back exhaust. To appreciate what the mods have done, you need to understand my truck weighs in just under 6000# with me in it with MTZ 305 tires. Pics speak a 100 words?

 

I'd like someone smarter than me to explain how to factor in the cost of mods in the miles per dollar calculation.
Say we spend $1000 on mods when gas is 4 bucks,thats 250 gallons or 5000 miles at 20 mpg, and the mods got us 2 mpg.
If i drive 200000 miles ,how to figure the break point?

 

I have no clue, I did not do mods to save gas money, I highly doubt anyone does.

I did mine so when some clown in a V8 pick up/SUV/Grand Cherokee pipes up that hummers are slow, I can put him in my rear view mirror and laugh at him at the next light pointing out my 5 banger is SLOW, but then what is his?

You should have seen the look on this kid's face with his old & loud V8 GC with a giant "FLOWMASTER" sticker across his entire back window after he was telling me for 3 lights that Hummers are crap, and then had the pleasure of viewing my back door until he gave up. Priceless.

 

Nice.... I like the mental picture you just gave me... I don't call my 3 a racer by any means...i bought it cuz it will take me places alot wouldn't. And it cost me less than a ford escape or any other small suv... I wasn't worried about mileage... And i have the joy of saying my Verry first car was a HUMMER!! i will eventually do some mods to my rig. I did tires and brake upgrades. I got the hunner rack sleeve... And i plan on an air doc and k&n as well as some new shocks and pcmtune tune as well as exhaust.
But for now i gotta keep on putting the parts i need first... Bearings weren't cheap and gotta few other cheap fixes before mods... Then i will start with the big money items...

 

Umm, the thread was about mileage, mods got added so I asked the question about mileage and mods,thinking it went together.
So why the mileage mods if you're not in it for mileage.
Maybe someone else will contribute.
think,think,think..
Later: my first thought through is, at 10 % saving, it would be appx 50000 miles,after that you make money.??

 

I'm sure some people want to save on gas mileage. I'm kind of more for performance myself. I want to get the most power out of ours that I can safely. The mileage I guess is just a plus. Doing all of these mods can be costly, but in the long run is going to gain you some extra mileage which is good, but also the added performance of your H3 is an excellent outcome.