ways to improve MPG & performance?

[chaotic]

So i love my suburban i just bought a 2000 Suburban 2500 LS with the 6.0l motor. My question is i don't mind the 12mpg (On a good day) but i'd like to see if i can get it to 14 - 16mpg. The truck currently is all stock no mods. Will adding a cold air intake help? Is there anything else i can try. Thanks in advance

[MWright936]

The best place to start would be an aftermarket intake. I put a K&N FIPK II on my truck. I only got about .5 mpg increase, but it definitely boosted performance and made it sound better. It would also help to follow that up with exhaust and either a programmer or custom tune. Those are next on my list, but I gotta have the $$ first!

[Pete95Sierra]

My intake gave me about a 1 MPG boost in fuel mileage and it made it run much better and gave a nice boost in power. the next thing i would do is put a hypertech chip in it. they make one called the max e-con that is made to improve fuel mileage and will give u a nice power boost too. exhaust is always a good upgrade as well

[tbplus10]

The 6.0 is a fuel hungry engine. A friend of mine has a 2003 Suburban with the 6.0 and has finally managed to get 16-18 highway out of it, at least its consistant tho it gets the same mileage loaded or unloaded.

Heres whats been done to his truck so far:
Borla cat back exhaust and replacement high flow cat
Dryflow air filter (drop in, cold air kit actually hurt mileage by 1 mpg)
Hand held programmer (not sure of the model)
Transmission shifter improvement kit from Transgo
Indexed the spark plugs
Gear change from 3.42 to 3.07 (the gear change had the greates effect on MPG + and performance -)

So far the 6.0 has proven to be a powerhouse with no real means to achieve economy. But you can make performance upgrades that'll degrade the MPG more than it is, so be careful. These upgrades have also caused other issues, right now the truck has a check engine light thats pointing at the High Flow cat, and the idle surges when its cold.

[phoebeisis]

My 1998 Suburban 1/2 ton 2wd 202,400 miles gets very surprisingly good highway mpg-21.3 at 70 mpg with the cruise control on. This is the MPG I got on a 3000 mile trip from New Orleans to Flagstaff to New Orleans. I was stunned at this mpg from a 5300 lb very high mile vehicle with no tricky cycl shutdown etc.
I did use 43 psi in the tires( door say 32 front, and 41 rear) and my tires are a bit worn . I also use Mobil I 5w30 oil. I suspect my efforts-tire pressure didn't have much(maybe 1 mpg?) to do with the good mpg- it is all GM and the 3.42 diff. and a really well worn in engine, though usually high mile motors get poorer mpg!

I agree with TBPLUS10- the tall gearing is the way to go. The indexed plugs are a good idea-and free!
Some sort of reprograming for mpg and a shift kit that locks up sooner sounds good also.

I'm pessimistic that intake and exhaust mods can improve part throttle fuel economy-they shouldn't and they aren't cheap. They sure can cost mpg.

PS-TBPLUS10- how tough was it to install the 3.07 gears?? I'm undwer the impression that installing new gears isn't for the amateur wrencher. Don't you have to shim and check etc-stuff that experience really helps on- not simple wrenching parts switching!

Luck,
Charlie

[tbplus10]

PS-TBPLUS10- how tough was it to install the 3.07 gears?? I'm undwer the impression that installing new gears isn't for the amateur wrencher. Don't you have to shim and check etc-stuff that experience really helps on- not simple wrenching parts switching!

Yea, experience with setting up gears is a must when regearing. Theres a lot of assembly, checking measurements and patterns, and repeating until you get the gears correctly shimmed. These are important steps, neglecting to shim new gears could lead to early gear failure, incorrect break-in can have the same results. Newer vehicles with ABS present problems regarding the speed wheels for the ABS, proper set-up and sometimes adjustment. It took me about 5-10 regears to get comfortable and not feel like I should have an experienced set of eyes looking over my shoulder while doing the job.

[phoebeisis]

tbplus10,
Thanks for the tips. This will be one job I'll leave to the experts.I sure don't want to redo it or worse have it breakdown in the TX panhandle on one of our long trips. I like your state , but not so much that I want to spend 10 days in some small town off Hy 287 or I-40 waiting for gears and repair.

Thanks,
Charlie

[zippy]

Phoebeisis is right about the importance of tire pressure. Much fuel is unnecessarily waisted due to under-inflation. I wouldn't go to 42psi without checking your sidewall info. Forty-one is the limit on many XLs while others are higher. Also, if you go too far above the recommended front pressure, steering is going to start feeling light and braking distances will increase. I run my C1500 Burb (20MPG on a good day) on the highway at 36/42psi (cold).

[phoebeisis]

Zippy, you're right of course. My 1998 2wd 1/2 ton Suburban calls for 32/41 or something very close to that. On the highway I run it about 42-43 psi (measure dead cold). This is right at the max on the sidewall on the front P tires, but under the 50 psi on the rear LT tires. It is a little bit of a risk- steering is a little lighter- but over long distances it saves a few bucks. How much risk- ?? I just don't know. It is one of those things you just "weigh" without having anything to actually base your judgement on.

If I was more flush, I would get a 2002 Suburban for the better mpg and the side airbags and better brakes.

Either way, make sure you are at least at the recommended pressures- the door plate shows them.

Charlie

[kf4wsn]

I Have a 2008 silverado Max 1500 with the 6.0L and 4:10 rear I get 19.5 mpg highway and 13-14 in the city only mod thus far is a K&N filter in the factory box. this weekend adding a 24" magnaflow and dual tailpipes with 3" tips also looking into a handheld tuner we will see what I end up with