350 vs 454 in gas mileage

Discussion in 'Chevy Suburban Forum (GMC Yukon XL)' started by Kraziken, Jun 17, 2008.

  1. Kraziken

    Kraziken Rockstar 100 Posts

    I know roughly what the 350/1500 suburbans get.

    What do the 454 2500's get in gas mileage?

    I admittedly do not really tow anything yet, but plan on getting a boat in the future, and maybe a track day toy.

    I try not to drive the old Burb unless I really need it, but I admittedly take it out on the weekends sometimes just for fun. Plus my kids seem to love riding in the big ol' burb versus our two four door sedans.

  2. bobknob

    bobknob New Member

    Hello first post here so bare with me. I have a 1999 GMC Suburban K2500 7.4l 115,000 miles on it.Only thing not stock is K&N Air filter. I get depending on how watered down the gas is here in Detroit 11-15mpg depending on how i drive and how many passangers i have with me. I have a bad habit of having a heavy foot on the freeway. After 65mpg the thing is a rocketship :D
  3. cdvntx

    cdvntx Rockstar

    I just sold my '99 k1500 'burb because of lack of power and crummy gas mileage and went ahead and got a k2500 'burb. Personally, I'll take power and comfort over gas mileage any day...I haven't checked the mileage yet, but will out of curiosity.

    FUNFINDER New Member

    I've got a 1983 C20 with the 454 with 116k and the 4 barrel carbs that gets 10-13mpg. Its got the 3 speed, so anything over 55 beings to tank the mileage. How much etc I am still learning. And i hope that with a few checks/tweaks, I can improve that to the 15-17 range, but we'll see. Load does not seem to impact it as much as speed.
  5. Bluewater

    Bluewater Rockstar

    454 fuel

    Unless you are towing a large load with the Suburban I'd stick with the small block if good milage is what you are after.
  6. Kraziken

    Kraziken Rockstar 100 Posts

    I'm wondering if GM will be selling the new 4.5 Duramax turbo diesel engines seperately. I've read the 2WD Silverado's with that engine are capable of getting over 25mpg.

    If I could average over 20mpg, I'd consider it. Heck, if they offered that motor in the new Burb, maybe I'd consider a new Suburban.
  7. tbplus10

    tbplus10 Epic Member Staff Member 5+ Years 5000 Posts Platinum Contributor

    My 97 2500 Suburban with a 7.4 and 4x4 gets 13mpg with me driving, my wife can get 16mpg. Its geared with 3.43's but I live in Texas where its mostly flat and usually only tow a 3500lb boat. Mileage isnt appreciably changed loaded or unloaded. I do have headers, true dual exhaust, K&N drop in airfilter, MSD 9mm wires, a comp cams performance grind cam, aluminium heads with s/s valves, and larger injectors.
    I have a similarly equipped 99 Chevy dually but with a 350 and 3.73 gearing, it gets the same mpg.
    The big difference is available hp when pulling steep grades, the Suburban can speed up on steep grades while the Dually can only hold it's own.
  8. homer911

    homer911 Rockstar 100 Posts

    my 93 burban k2500 i manage a awsome 10 mpg. needless to say thats down hill with a tail wind in nutrual with the engine off... LOL j/k... but i do only get 10mpg.. Installed iac, tps, map, 49000v coil, 8mm wires, accel u grove plugs, headers, menderl bent Y pipe. After all that i lost 1 mpg
  9. tlperry68

    tlperry68 Epic Member 5+ Years 1000 Posts

    Expect to get 10 MPG or so around town. Even though it is low, it is nice to have some extra power if you need it.
  10. homer911

    homer911 Rockstar 100 Posts

    It dont matter if it is city or highway... I drive it like i stole it anyways!!!!!!!!

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