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5.7L Vortec MPG (97’ K2500 Burb)

As the title says I have a 1997 K2500 Suburban with a 5.7L Vortec. I legitimately can not exceed 5MPG pulling my 30’ travel trailer. I got 4.15 - 4.77MPG. Is that common? I was thinking 8-10MPG but man I had to fill up the 45 gallon tank 3 times from Va to SC. I have intake, high flow exhaust, and I upgraded the spider injector to the new multipoint version. I’ve contacted Black Bear Performance to see what they have to say as to if a tune would help much. Aside from the MPG it pulls like a beast! It’s nothing like my Dmax but it’ll rip! I can say I have no fuel leaks or anything she just eats it. I run regular fuel and I only fill it with Rotella T6 Diesel engine oil, 5w-40. Currently at 340k miles still running like new 😁

Quote:

Originally Posted by The Chevro (Post 368438)

A lower axle ratio would likely help but wouild not be cheap on a K series 4x4 with two drive axles. I think that you will have to live with that or upgrade to a diesel motor.

As an aside, back in the 1970's after the lower compression ratios occured it was not unusual for many pickups and other 4x4s to get 10 mpg without a trailer. Sure glad those days are over with.

Yeah, I was kinda hoping to a little better in MPG. Shoot......at this point it would be just as efficient to upgrade to a motor home and probably get the same mileage 😁

I’m also in the process of building a 6.5 Detroit right now so between the Duramax, The Burb, and the Crew cab Dually 6.5 I’ll try to make a decision in the next few months

Quote:

Originally Posted by The Chevro (Post 368565)

I’m also in the process of building a 6.5 Detroit right now so between the Duramax, The Burb, and the Crew cab Dually 6.5 I’ll try to make a decision in the next few months

Probably the best way to go. As an aside, I knew a guy with the 1975 Found On Road Dead Bronco that couldn't get more then 9 MPG with a 302 in two-wheel drive, that how bad some of those old SMOG motors were. My Jeep would get 15 MPG no problem with the 258 Inline-6 cylinder motor and a granny low 4 speed transmission. You could almost pull a stump out of the ground with the gears and torque that old CJ-5 had. :)