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tbi 454 mpg

.....in other news.....
my 350 burb is getting very similar mpg and runs perfectly? I always hear people say 12-13 in town and I have heard 15-18 on the highway. Is mine broke or am I just being accurate.
 
I think some people use the same miscalibrated instrument to measure MPG as they do to measure their, um....:whistle:
 
I checked mine the other day, mostly city driving with my 5 mile freeway trip to work thrown in, it came out to 7.6. Yesterday with over half the mileage being highway miles, it came out to 9.6.

( These numbers are figured assuming the 30% error in my speedometer is causing a 30% error in my odometer. I am confident in that due to a comparison between the odometer and the distance Google maps gave me from point A to point B.)


Side note: this thread is about tbi 454 mpg's. The fuel economy of other vehicles is irrelevant. My ZRX gets low 40's, so what?
 
black dawg said:
My 91 burb (v2500 465/3.73s/stock hieght and tires) has been getting 12 highway 10 hills/city. When I first did the 350 to 454 swap I was happy with this mpg, but I have been driving this thing alot more than expected. This mpg is driving pretty slow (60-65).

any Ideas to get a little more out of it? I have a set of headers that I have been too lazy to put on, would they help much?
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Little bit.

black dawg said:
I have been putting off either getting this thing tuned or getting set up to tune myself. Anybody have any experience with lean cruise with a big block?
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Stop putting it off. The BB tunes are by far the most left on the table from GM. It's so safe it's patheitic!

With the 3;73 gears, stock tires and height! This is a perfect candidate for Lean Cruise. The motor is hardly working at all at highway speed. Then set the MAP to kick out of lean cruise when it comes to climbing big hills or when towing a load.

Have another O2 bung welded in then drop it off over here for a week, besides the normal fix the lame GM tune I'll do the Lean Cruise with my Wide Band and dial it in. I'll be conservative here in public and guarantee 15 MPG highway or no charge! My best on a simalar BB pickup was 17.5. This is a safe tune, you can tweak 20 MPG out of them... to lean though, oil temps raise to high to leave that way as all the heat is in pistons, wrist pins so oil is only thing to keep that end cool.

On a safe tune my 1990 5.7L 2wd 3:73 gear stock tire get's 17.5 to 19 MPG highway empty mostly flatland at 70 MPH with cruise control! Goes way up at 50 MPH...
 
Mark, you will have to pm me a number, and hours that I can talk to you during the week. 15+ highway would really help. also pm a rough idea what this will cost me if you could. thanks.
 
PM sent.

If you can't get the O2 bung welded in? It's not an issue, I have a shop that does them for me. Location is important.
 
black dawg said:
.broke or am I just being accurate.
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There's a lot of in accuracy in calculating MPG, just filling up at a different pump that is not level like first, speedometer/odometer etc...

When doing MPG testing I fill up same pump each time. Speedometer MPH is checked to GPS and odometer is checked as well with milage markers.

There's a thread on another forum and the guy swears changing to 4:56 gears got him 24 MPG highway..... he's right, but of course his data to calculate is wrong... :dunno:
 
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