brillo

Not to start another MPG thread, but one my cars first road trip from Houston to San Antonio I managed to get 25.8mpg all highway, on 93oct, going 70mph on cruise control. I wasn't running my a/c, and it was about 55degrees outside. I'm going to run home with the a/c on to gauge the difference.

For the record, I get about 15-16mpg in my Houston city driving. I have about 5,600mi on my car with the M flash.

My only mods are the MS suspension and Royal purple engine oil and tranny fluid.
I have a six speed in my car.

I know the mileage is correct as I filled up completely in Houston, hit the road, and filled up again in San Antonio at about half a tank. I drove 198.7mi and filled up with 7.707gal in San Antonio.

I'll report back my return mileage with the a/c turned on.

Shamblerock

Brillo, please do keep us posted as I am interested to hear about your return trip.

r8ped8

16 mpg downhill with a tail wind.......

rx8cited

brillo,
Great mileage on the trip. Do you know what your usual mileage is, and if so, how would you describe your driving style, city/highway %?

I usually get 20 mpg in 60 hiway/40 city with 87 octane and usually shift around 4k.

rx8wannahave

Cool, that mileage is great...is your car a stick or auto?

brillo

Hey guys, I acutally came home through Austin, so from Austin to Houston at an average speed of 67 (it was night) with a abient temp of about 71, a/c running I got 22.75mpg (128.4 mi / 5.644 gal).

So interesting, almost a 3 mpg diff with the a/c on, I tried to make the tests as close a possible cruise control, slow passing if necessary. I wonder if I had gone longer if the mileage would have been higher.

I'm going to get a K&N filter and see how that does next trip, but bottom line, I seem to be hitting the EPA guidelines. Whats wierd is, I've tried my city driving with no a/c and my mileage doesn't seem to improve, so I need to do some more accurate observations of my city driving. Bottom line a/c hurts gas mileage for us.

My city driving is usually 75-80 city/20-25 HWY. Houston has some nasty stop and go were I live.

Shamblerock

Air conditioning hurts but also be aware that the same pumps run when you circulate air at your feet and on your windshield because its de-humidified air that its shooting out regardless if you have A/C on or off. The only time it doesn't use the A/c system is when it comes out of the vents and the A/C off. Next time listen to the a/c system engage on and off when shooting air to the windshield and to the feet.

shelleys_man_06

Odd. When I went to Austin, I only managed about 21 mpg back and forth. Maybe it's the fact I'm a Cougar, or it was a bit nippy outside...

brillo

One thing I will say, is our gas guage is totally useless. when I filled up in san Antonio, it was about 4mm below the 1/2 way mark, and I only filled up with 7.7xx gal, not even half.

SDB

Is the guage consistant? If so it isn't useless it is just marked conservatively (wrong). On the other hand if it is not consistant. for example, the next time you fill up and take 7.7 gal and the guage says exactly 1/2 full, then it is useless.

brillo

thats a good point, I guess I was just being harsh since it isn't accurate by what its displaying. I'm not sure how consistant it is, I'll have to try that trip again and see what I get.

VooDoo

There's many arguments about 93 octane vs. 87 vs. 89.

For your trip, which one did you use and what brand?

Also, I totally agree with your gauge statement (see my post started 11/27).

Where in Houston are you? I'm right off 290 in Cypress...

brillo

I typically use shell 93, and for the trip i was using shell and chevron.

Hornet

Not really because Mazda claims it's a 15.9 gal tank so 7.7 is close to half. Then again the guage does get funny when you get low. In mine sometimes the needle sits directly on empty but when I fill up it's somewhere close to 3 gallons left. I'll just remain confused....

Brillo, as far as the first trip goes it appears that you came near an amazing 400 miles on a single tank. Some of us have gotten over 300 but there seems to be very few who get that good a number.

brillo

Yeah, I was quite impressed, dunno if it was the weather or what. I really want to see what I get in the middle of August driving to Austin, that will be the torture test. I'm getting a K&N filter soon so we'll see if that helps at all when I head to Austin for during Christmas.

Voodoo - I'm near the Galleria, I'm usually at the Rx7/Rx8 club meets, if you haven't been I highly recommend it.

Hornet

I'm going to have plenty of time to conduct my own test real soon. I'm going to be driving from Virginia to California. Almost 3000 miles to try to figure out how to get the best mileage!

f1michel

I got close to 24 mpg on a trip to maine last july, 80 mph on HW, ac on and good weather. I have 6 sp trans and use 97 octane. My normal mileage is about 18 to 19 mpg, 80% HW 20 city

Shamblerock

The best I got on a tank was 565KM/350 Miles. Usual driving @ 60% city 40% highway I get 380KM/235Miles to the tank.

EyeBall Fixer...(o)(x)

97 Octane?
Man! Thats Jet Fuel!
I've only been able to find 91 here in middle America.

dragula53

Measuring remaining fuel is not an exact science, and has many factors to include the design of the fuel gauge and the shape of the fuel tank.

here's some great information about fuel gauges.
http://auto.howstuffworks.com/fuel-gauge.htm

rx8cited

What kinda mileage do you get in your usual driving?