Gas millage HWY trip

[H3Lady]

I went on a 200 mile hwy trip and the best I got was 18 mpg with no load and cruise set at 60-65

I am an easy old driver. no gunning and just cruising.

I have 500 miles on my h3

[H3Lady]

I went on a 200 mile hwy trip and the best I got was 18 mpg with no load and cruise set at 60-65

I am an easy old driver. no gunning and just cruising.

I have 500 miles on my h3

[HummerJim]

65 mph seems to be the best mpg area for the H3 on the highway. I've done lots of highway now, with over 6,000 miles and running on Mobil One Synthetic in the crankcase, and I get around 18 highway, pushing it up to 75-77 mph for long periods, seems to down the mpg considerably, to about 16.5 mpg. 18.7 mpg is still my best tankful and that was in Kansas with a strong tailwind from the West, and 12.5 mpg is the worst, when it was new, in Dillon, CO, off-road with hours spent in low range and speeds never over 15 mph. I think it has a lot to do with the frontal and induced air drag the body has at highway speeds. I also tried three tanks of premium and found no difference at all in the mpg or performance.

[H3Lady]

I have a supplement advertisement from GM for the H3 and on the cover is says.

quote

20 MPG hwy"

OH I used Quaker state pure synthetic extreme too, as my first oil change. Super reviews for HWY suv useage

[HummerJim]

It also says 20 mpg is with the manual transmission, 19 mpg with the automatic. And I would think from my experiences 20 mpg with the manual is possible. As your engine breaks in your mileage wil increase - mine did, but it has over 6,000 miles on it.

[HummerJim]

If you really want to confuse yourself, go to
http://www.fueleconomy.gov. Government mileage ratings are done on a treadmill/dyno type machine at a temperature of 69 degrees F, at sea level, and a pressure of 29.92 mb. Temperatures and pressures other than these will affect your ACTUAL mileage. For the highway mileage rating the average speed is 48 mph with a maximum speed of 60 mph and no wind resistance because the vehicle is on a treadmill or dyno type machine. The highway mpg is done with a warm engine and the city is done with a cold start up. Obviously most peole realize these figures are not real world and should be used as a baseline comparison only. The notation at the bottom of the government blurb says it all, "Your mileage will PROBABLY be 5 to 25% lower in actual driving conditons. Government ratings are with a professional driver under laboratory conditions."

[Marc H3]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by H3Lady:
I went on a 200 mile hwy trip and the best I got was 18 mpg with no load and cruise set at 60-65

I am an easy old driver. no gunning and just cruising.

I have 500 miles on my h3 </div></BLOCKQUOTE><span class="ev_code_BLUE">I got 18.8 on a short trip with some city driving too. I am very happy with those numbers.

I would expect 19+ if I drive on a longer highway trip.</span>

[f5fstop]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by H3Lady:
I have a supplement advertisement from GM for the H3 and on the cover is says.

quote

20 MPG hwy"

OH I used Quaker state pure synthetic extreme too, as my first oil change. Super reviews for HWY suv useage </div></BLOCKQUOTE>

Most likely there is an asterisk with a statement that clearly states, "estimate." Or, another disclaimer.
In addition, the engine will get better mileage as it breaks in. Also, the use of synthetic fuel will not show an increase in fuel mileage. The weight of the oil affects fuel mileage. Almost all oils, with the second number, under 30W are considered fuel efficient in this day-and-age. The first number is more important for cold engine start ups. Lower numbers get the oil to the top of the engine faster.
That is one reason why using 10w-30 versus 5W-30 in the summer, will not affect overall fuel mileage. The top number is effective after a set engine temp.

[Marc H3]

<span class="ev_code_BLUE">Since we are talking gas mileage, I thought I would show everyone again my newest creation.

So here is my rendition of the H3's newest bumper sticker for those that might like to "show off" their love for the H3's super gas mileage. </span>

[Mr Hank]

Take heart with the popularity of the H3 there will soon be some performance enhancements that might help you wring out another 1-2 mile to the gallon.
Synthetic Oil is always a must.
An aftermakert air intake of at least a KN air filter will help a little.
I'm sure a high flow (quite) muffler will be available soon.

Lastly (I don't know why) the H3 has an engine driven cooling fan. This is 1960's technology and causes a huge drag on the engine. Hopefully someone will build an aftermarket electric cooling fan and an underdrive pully this should free up about 15-20 hp and make a difference in acceleration and gas milage.