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Old 01-22-2004, 12:44 PM   #1
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Default Optimal speed for the best MPG???

I have heard various answers to this question. I have also heard it depends on the engine. What do you guys think? I am gonna guess 70 mph.
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Old 01-22-2004, 12:50 PM   #2
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I always thought it was around 55Mph, when the RPMS are very low during the TCC lockup.
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Old 01-22-2004, 01:25 PM   #3
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Sol'* correct for 2nd gear with TCC lockup, but if you were in say 3rd gear with it.... I've churned 70 MPH @ 1500-1700 RPMS and boy does that give good mileage.
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Old 01-22-2004, 01:26 PM   #4
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With that, you could get close to 30mpg on the freeway.
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Old 01-22-2004, 01:28 PM   #5
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Quote:
Originally Posted by Sol
With that, you could get close to 30mpg on the freeway.
I did for 1/4 tank coming back to school, but then the next day hanging out with smellbird, and all the idling, and around town jaunts we did, i got NOTHING.
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Old 01-22-2004, 01:30 PM   #6
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Yea, around the city it'* not very efficient, especially with stop - go - stop - go - WOT - stop

Our engines are strange like that.
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Old 01-22-2004, 01:44 PM   #7
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I know I am getting like 14 mpg, but that is in the winter, with a lot of WOT driving in the city. Should probably improve in the summer. Was thinking about changing my O2 sensor, has not been changed so that might be an issue.
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Old 01-22-2004, 01:47 PM   #8
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For anyone with a DIC, you can pretty clearly see that all other things being equal, your best mileage is between 45-50 when the torque converter has locked up. Even with a SSEi, at that speed, the DIC on my car will read somewhere around 36mpg. Take it up to 70 and it drops to about the EPA rating of 27.
I did an experiment not long ago where I compared mileage at 70mph. I checked the mileage at 70 with no one around me and as stated above, I was getting about 27. Then I got behind a semi and drafted at 70 and was getting 33mpg.
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Old 01-22-2004, 01:57 PM   #9
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I do not have a DIC, I am basing this MPG on how many gallons I get at the pump, compared to how many miles I travel.
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Old 01-22-2004, 03:09 PM   #10
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well its best not to keep accelerating and deaccelerating at hiway speeds. i normally hit the cruise between 55 and 75, depending on the limit and weather. never bothered calcutating my mpg on a trip but ive seen 340 miles on a tank...
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