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Fellow Suburbanites... how's your mpg doin'?

dangerousdave said:
See my sig.

Wife can drive it like a hot rod all day, many stops, and get 16.7mpg, we have hills everywhere here, too.
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... and tires and speedometer is accurate reading? You've got the same spec's I have with 3.73 rear... I'm thinking I've got some progress to make. 20 mpg sounds really, really good... you've got me salivating diesel fuel now...
 
Dave01 said:
I'm not sure why a prefilter would boost mpg or drop it. If the lift pump can't build pressure through the filter you'll starve the IP and fishbite, if fuel is feeding properly the fact it's filtered better shouldn't change mpg. Not sure I understand why you saw those results.
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My sock had lots of flakes causing it to slightly starve and dog it up hills. Now that I'm on my 2nd filter I am noticing the gauge not going down as fast I'll see my next fill up.
 
Well... okay, since the tread is getting thin... if I change up the tire size, how do I recalibrate speedo/odo? Will the tire folks do it? No fancy dancy computer talky tool to chat with on board stuff in my tool box.
 
I didn't recalibrate - it shifts fine, cruise works fine, I know to add 4% to speed and mileage calculations. Beyond just wanting things accurate, is there any reason I REALLY SHOULD make the adjustment?
 
235/85/16 would be about 31.5" tall, about same as 265/75/16s
285/75/16 would be about 32.75" tall, which would drop RPMs but increase surface friction, although I dont think our torque monsters care about a little surface tension at 2000rpm.
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But you also raise the height of the vehicle and add wind resistance as well as surface friction/resistence with taller/wider/more agressive tire.

Going up even a slight grade will require more fuel to maintain said speed,and overcome all other factors above.


373 or 410 will get you better milage below Xamount of speed[stop and go below 40 mph] because the gearing will help put it in motion with less effort.

342 will get you better milage at hgwy speeds while cruising do to the obvious [maintaning speed for longer distance].

I've come to grips with it. I drive a heavy brick and get 19 to 20 with stock chip and skinny med. compound tires[60.000 mile] and 17.9 to18.5 with the triple tune set to econ. And that's 95% hgwy.
 
The extra resistance from wind or surface from taller/wider tires may easily be overcome by the potential energy in the fuel just to get the engine to turn over at 2000rpms, since we have high torque in that area. So if you have short tires and spin 2300rpm and can get taller tires and spin 2000rpm at your cruise speed the slight change in resistance may not matter. Its not good for a 3.42 guy trying to tow, but for a 4.10 guy used as a commuter you weigh the trade offs.

A 255/85/16 tire seems perfect though, about 33" tall and not too wide. Others have gotten taller wheels, 17, 18, 19" ect... but you have to be careful and not get them too wide and need negative offset.

Operating temperature seems to play a good role in economy, so the cooling system if too good keeps you below 195F then economy may suffer.
 
A Haa said the blind man now I see;

3:73 & 4x4 may be your limiting factor Steve that and the burbs brick like aerodynamics :D ATT & a re-tweaking possibly of your Kojo chip to make the most of it, is your next upgrade
 
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