Quote:
Originally Posted by 57taskforce
With 4:11s and a 4l85 in the suburban I could just squeak out 15mpg on longer highway trips. I don’t think that was bad at all considering it was a heavy ass Loaded 3/4 suburban. Mine was an 01 with the adjustable fuel pressure regulator. I always wanted to crank it up some to see how it would run but never did.
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That's good to know as I've been gathering details on others, and know of another 8.1 swapped squarebody burb on 1-ton axles and 3.73 gears getting 15-17 on highway runs. Larry's running 4.56's on both and typically averages 12-13 on the highway, but that's usually at 80mph + when he can!
Larry's tweaked fuel pressure at the regulator on both of his and mine is running the early return style rail with the same regulator. He's got his cranked up to 65psi I think. 8.1's like the bump in pressure. I'm going to play around with it too.