Highway driving - PowerStrokeNation : Ford Powerstroke Diesel Forum
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post #1 of 5 (permalink) Old 12-30-2010, 06:30 PM Thread Starter
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Highway driving

Since I have moved to Tampa FL I do alot of driving on I-75 and I-275. I have noticed that if I drive about 62 to 65 at about 1900 rpms I get around 20 MPG. But yesterday I went to Ocala FL and I was in a hurry and I drove about 75 at 2300 RPMs. I burned alot more fuel than a normally do. I have noticed to according to my gps that my spedo is about 5 mph of slower than I am going. Does any else notice this. I plan on removing my muffler soon to see if this helps. I would love to get a gear vendor over drive because at 70 I am about 2300 rpms and I would love to turn about 1800 rpms at that speed and I think I would have enough torque for 1800 rpms at 60mph.

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post #2 of 5 (permalink) Old 12-30-2010, 06:54 PM
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Re: Highway driving

There's a reason the speed limit was dropped to 55 back a few decades. It wasn't for safety. Huge mpg losses are to be expected as you increase your speed. Gearing won't solve this problem, slowing down will. Then further improvements can be made by gearing.

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post #3 of 5 (permalink) Old 12-30-2010, 10:51 PM
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Re: Highway driving

Slowing down is powerful, but gearing does have an effect at a given road speed.

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post #4 of 5 (permalink) Old 01-01-2011, 06:25 PM
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post #5 of 5 (permalink) Old 03-27-2011, 09:35 PM
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Re: Highway driving

Originally Posted by ocracokeisland View Post
I have noticed to according to my gps that my spedo is about 5 mph of slower than I am going.
Mine reads 70 on the speedo, and 66-68 on the GPS. With the speedo at 75, GPS says about 70-71.
But, the error seems to be non-linear as the speedo reads about 1-2mph fast at 45 on the speedo.

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