my 2500hd is a heavy pig, i know.
but is there any possible way to get better fuel milage?
i have heard local tuners say that they can get the same MPG as a 5.3 with a 6.0.
but it appears the trucks they are speaking of that are getting good mpg with the 6.0 are usally 1/2 rcsb trucks.
my truck of coarse has 4.10 gears out back and i was thinking of doing gear swap to like some 3.73 maybe.
im not trying to out run anything!!!
except my pocket book,but at the same time, i do not want to lose any of the stock performance that i do have now, which is none really.
i just dont wanna lose power, i wanna gain or stay the same. i just want get better fuel economy like a 5.3. it just doesnt seem to be possible to me, that a 6.0 could get the same MPG as a 5.3?
thanks Ed

 

I've heard of a couple of guys from work who get pretty close to 20mpg hwy with the 2500 and a 6.0. I was talking to them at lunch while they were discussing which was better diesel or gas, and how much you have to drive to make the diesel pay you back.

None the less the simple bolt on's can work wonders for gas mileage. I have a GMC RCSB with the 4.8, and I can get up to 22 hwy. I did the intake, exhaust, and tonneau cover. I looking forward to when I get some more money for headers and then a tune to get the last bit of effieciency.

 

The low down on ANY LSx engine is that it's great on gas cruising on the highway but utterly horrible stop and go.

The 6.0 gets better gas mileage than the 4.8 on the highway by virtue of the fact that it never has to downshift to 3rd. I get over 23mpg on the highway. In the city is a different story though. I average around 13mpg. And that's in a ecsb 1500. A 2500 will be worse. Maybe get a "gas mileage" tune from Charlie Wheatley would be my suggestion.

 

I owned an 03 HD with the 6.0, with the 4l80e trans, and 3.73 gears and I averaged 11.5 in town and maybe 14-15 highway. This is after adding a CAI, better exhaust, 05 e-fans, and a custom tune. You will never get the same mileage as the 1/2 tons, sorry that's just the way it is. And if you swap the 4.10's for 3.73's, by the time you've spent the money to do so, that's a lot more gas you could've put in the tank.

 

LOL, i hear that!!
i may just end up getting rid of the truck, as bad as i hate too.
there just is no justification in a 2500hd with 30k miles any longer.
also as far as a 6.0 getting better fuel mileage on the highway than a 4.8 is
cough, cough,is a horse crap!!

 

Just get a Cobalt SS to complament the truck.

 

No, actually it's not. I was surprised myself, but it's true. The 6.0 never has to downshift like the 4.8. This is in a 1500 BTW.

 

my dad's truck is an 03 2500 automatic with 4.10s and gets about 5-8 but that is pulling a 16000 pound trailer

 

my 05 2500 hd gets about 10.8-11.5 around town if i drive normal. it gets 13.5-13.8 at just over 70mph and will do 14.5 or better at 60-65ish. all it has done at the moment is a k&n panel filter and 285/75/16's. it gets between 8-10 when loaded with 7000lbs of trailer and motocross stuff.

i'm planning on an exhaust, CAI and a tune in the near future to see what it can do.

 

get an intake($200) and throttle body spacer($100) helped my 6L alot! also free flowing exhaust could help. not to mention this will get u some more hp and tq helping the truck not to have to downshift or rev up hi to get up and go as much