1997 K2500 Burb MPG? You?

Discussion in 'Towing' started by awcforever, Apr 30, 2018.

  1. awcforever

    awcforever Newbie

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    So I tow my travel trailer A LOT with my Suburban. Its 6000lbs roughly and I also towed a 3/4t van home the other day and I've never gotten above 5mpg towing. I took a trip to Ocean City over the weekend and it cost me over $200 in gas and I averaged 3.9mpg. Anyone else got better numbers?

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    I'm running 4.10 gears, I have 285/75/R16's 3" suspension lift, a 3" dynomax exhaust system and a short intake, upgraded the old spider injection system with the newer multi point. It tows like a dream, all the power in the world, but it digs deep in the pockets. I had a notion earlier in the year to drop a 6.0l LS in the truck but after my dad and I took a trip to Norther Virginia and back I don't see any point. He couldn't out pull me. The truck runs amazing at 330k miles, his truck has the LS in it and its an 03' and going up and down the hills in Warrenton he couldn't pull away from me. I know an LS is a better engine, but I want something that's going to be a game changer. When we pulled up Afton mountain near Waynesboro which is something like a 5% grade about 3 miles he only creeped on my by about a truck length by the top.

    Anyways, off the rant, but is that normal? No i'm not leaking fuel or anything. I do have my EGR unplugged which I'm sure doesn't help, but what do you guys think?
     
  2. JSpotMD

    JSpotMD Newbie

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    I have a similar setup. 1995 K2500 suburban on 315/75R16 (34.6"). Bone stock 7.4L TBI motor (with an open element air cleaner and cowl induction hood), 4.10 gears, 3inch body lift with an iron plate for a front bumper. Towing in 3rd at 2500-2800RPM a 7000lb travel trailer.

    Worst MPG was 8 best was 12.
     
  3. 98chevy2500SS

    98chevy2500SS 8 Lugger 350SS

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    Last I checked I’ve been getting around 8 mpg. Stock height with 265s, 4:10s, Vortec 350. MPG is just daily driving usage. I didn’t think I’d be getting this bad, lol. To be expected with a big ol 3/4 ton.
     
  4. BowtieBrody

    BowtieBrody Jesus Murphy!

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    My old 97 K1500 Suburban; Vortec 350/4L60E/3.73's got 15-16 religiously. Didn't matter how I drove, it was always 15 or 16 miles to the gallon. It was on 265/75R16 Cooper ATPs, my brother's driving it now and he mobs like he stole it. He gets like, 8 MPG on 265/75R16 Mud terrains.

    My 96 K2500 on the other hand, 454/4L80E/3.73s can get anywhere from 13 if I baby it, or 8 if I drive it like my normal habits. 285/75R16 BFG KO2s; I thought the larger tire size would hurt but it really didn't make a difference.

    Do you have an ECM tune to compensate for the EGR being deleted?
     
  5. JSpotMD

    JSpotMD Newbie

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    I found similar where it seems like nothing changes the mileage. Towing, empty, hauling, etc.

    I did get better mileage re-gearing to 4.10 from 3.73 with the larger tires on. Economy is better towing in 3rd for me as well as opposed to lugging it in OD.

    We all know these trucks are pigs, for me the issue is range towing. Glad to have that huge tank :head3:
     
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  6. Tavi

    Tavi Vehicle enthusiasts

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    Pulling a load will kill mileage fast. I think the smaller the engine, the faster it looses mileage. Pulling a hill at speed will really burn through a tank. Approaching a gallons per mile scenario.

    My TBI 454 w/4.56 gets about 9-10 in all conditions. It dropped to 5-7 with my 7x16 enclosed fully loaded with a strong headwind, even dropping to 55 mph. Mind you it still managed the 9-10 with no head wind while towing the same load.

    My 5.3 suburban got 7 in third, couldn’t hold forth, towing the same trailer empty, trying to keep up with traffic. It got closer to 10-13 if I kept it below 55 mph.

    Your travel trailer will act as a giant air damn. Trying to keep up with traffic will kill mileage.
     
  7. L31MaxExpress

    L31MaxExpress I'm Awesome

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    I get HALF my normal MPG towing my travel trailer. I see about 8-10 in the flat lands at 65-70 mph towing my 23' Jayco 6,000 lbs travel tailer that is a full 8' wide with my cammed/headers/exhaust/tuned L31/4L85E/10.5 ff 14 bolt 4.56 geared G1500 Express on LT265/70R16s. Around Dallas/Fort Worth I get about 6-8 in traffic having to constantly start and stop. Despite making the thing heavier and taller, going from a 9.5" 14-bolt with 3.73s and P255/70R16s to the 10.5" 14-bolt with 4.56s and LT265/70R16s actually netted me a fuel economy gain by allowing me to pull in and hold OD on the flat lands and accelerate with less throttle from a stop.

    This was before the 1-ton rear end, suspension and brake setup. It is ALOT of trailer when it comes to frontal area and drag.

    20150826_095953.jpg

    This was during the 10.5" full float and rear suspension install. Its a full 1-ton now. I added a Hellwig rear sway bar and summi springs in the rear for overload capacity. Like towing with a different vehicle.

    20171023_001349.jpg

    I am actually in the process of swapping a 6" rod small block 396 into it at the moment. Next spring I have plans to visit a couple of states in the rocky mountains and I just did not feel the old 350 would enjoy that much although I had no problem climbing Rutan pass last summer at the posted speed limit although I still had 3.73s and 29.5" tall tires and I was in 2nd gear at ~4,500 rpm. 20180410_185317.jpg

    The game changer for towing would be an 8.1, but I do not feel like cutting my firewall and floor to install the larger engine doghouse to make room for the tall deck big block. If I felt like going that route, I would have to find a 6spd allison, find 2" delrin blocks and longer body mount bolts and body lift the thing for trans clearance. Then it would be full bumper replacement front and rear. Which would also mean solid axle 4x4 conversion. So hence forth the reason I am not going big block, lol.
     
    Last edited: May 2, 2018
  8. 98chevy2500SS

    98chevy2500SS 8 Lugger 350SS

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    Man, how are you guys getting better?! LOL, weird how a 454 is getting better than a 350. o_O How much time do you guys commute every day? If I don't run errands, drive is about 40 minutes (20 heading up and 20 heading back). I will have to check again the next time I'm filling up, 7.5mpg seams kinda low, or maybe I am expecting unrealistic expectations. ¯\_(ツ)_/¯
     
  9. L31MaxExpress

    L31MaxExpress I'm Awesome

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    I am not shocked. The 8.1s tend to do better than the 6.0Ls pulling the same weight. Same comparison as the older 454s and 350s.

    Cosindering I have an hour commute each way everyday. I don't commute the Express van much. For that job I have a ~500hp V8 luxury sport sedan that gets 26 mpg highway at 70-80 mph and averages 21 mpg in daily traffic around Dallas area. I will say however that number can drastically drop if I put it into Sport mode instead of Eco mode. Unfortunately around here it is hard to use that power!
     
    Last edited: May 3, 2018
  10. 98chevy2500SS

    98chevy2500SS 8 Lugger 350SS

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    It sure is! It will probably attract the po-po, lol.

    I wouldn't doubt that the 8.1 would do better pulling, that thing is a beast!! :D I just thought it's a little low for an unloaded truck, daily driving. I wasn't expecting much, but just seemed a little low.
     

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