I have an 87 suburban 2 wheel drive with the 454 and turbo 400 trans. What should I expect for mileage. I currently get 7-8 mpg. Is this average?
That's about as good as it will get with a 454tbi and th400. Adding headers with free flowing exhaust and a custom tuned chip you might be able to hit as high as 10mpg.
Hey AGB We bought our 86 suburban c2500 with 454 (and 83k original miles) in April 2013. I was getting about 10mpg from the start, then we installed E3.40 spark plugs, air and fuel filters, new wires and dist. cap/rotor. I then flushed the radiator and replaced the water pump, thermostat, heater core and alternator. Living in Florida in the summer, I drained the oil and put in Rotella SAE 30 with an extended life Fram oil filter, lubed the chasis and frame. On our first road trip 1200 miles away we were getting up to 12 mpg. On the return trip we had a fully loaded trailer and were getting roughly 8mpg. Afterwards we were getting about 10mpg, but with using E85 regular unleaded fuel, our mpg is gradually getting worse. I am in the process of installing 2 different types of hydrogen generators to feed directly into the 4bbl carb. If that goes well and produces enough, then we'll attempt to switch to run solely on hydrogen and disable the original fuel system. I have run a different hydrogen generator on a 96 sedan and it made quite a difference! We went from fuelling up once a week to once every 3 weeks with the same amount of normal use! We ran that system for 2 years and (outside of maintaining the generator) had no issues with it. The rough engine idle (V6) calmed down within 2 weeks of the install, and the oil changes went from every 3000 miles to every 6000 miles. I saw a post online in the oil and gas industry that warned against using E85 or even E90 unleaded in lawn equipment as it corrodes the rubber and plastics and kills the engines rather quickly! (Google it) I hope this info helps. You might also find some fuel saving info on www.panaceatech.org (No, I'm not associated with them. lol)
