whats the best freeway speed for maximum gas mileage?
 

at what speed should i be going on the freeway in order to maximize gas mileage?

i do pretty good at 70 with the cruise on.

ive been told or ive read that in 6th gear it is 68 mph. i think you just need to keep the RPM's below 3.5k in any gear.

Isn't it 65 mph? or is it 68...

time to use the search yet again...

been up to 124 mph, have had the 8 for a couple months now, and i havent even been in 6th, ever :(

either way its not much fun

This is what I have got with the cruse used as much as possible.
55-60mph.....29.5mpg
65-70mph.....27.5mpg
75-80mph.....24mpg

i cruised at 80 for 200 miles all highway and i got less mpg than when i have fun.

on my way back from san diego I averaged between 60-110 through the mountains and I acheived 24mpg's.

My best test so far was 23 mpg @ 75 mph, cruise control, fairly flat terrain.

It's a zen thing - you minimize the vibration, you find a place where the rotar runs steady and you don't feel any resistance like you would when you are in too low a gear, and the car just runs like glass. Hwy 5 has some sweet spots and Hwy 101 between San Miquel and Salinus can be fine, and 85 is legal. Head winds and side winds will steal gas so your best run will be From San Francisco to LA, Less side wind on Hwy 101. Hwy 46 running from 5 to 101 very bad Karma - There was a reason James Dean died there - Passing big trucks very bad medicine.

james dean is dead?

Quote: James Dean is Dead?
Very
head on in a nice little sports car
They show pictures and have a memorial to him at the Jack's Creek Ranch Cafe on 46, that's where they took the body after they pryed him out - put him right there on the pool table.
The guys at Black Well's Corner (largest parkinglot in the world) says he bought an apple and coke on the way -

I shift at 3k to 3750 if its cold. But when it warms up, I think that it is better to put less stress on the engine by not shifting so early. So a typical shift would be around 4k to 5.5k. Unless I am over 70 mph, will I be in 6th gear. Have gotten 20 mpg 60% city 40% highway with ac.

i think theres a memorial at the Griffith Park Observatory also.

0

it depends on the drag coeficient of the car, the norm is that the best possible gas mileage hovers around 55 miles an hour, going slower means that you're using a lower gear and therefore revving higher and going faster means more aerodynamic drag which needs more power to overcome it.

So unless you're a granny you'll never get best possible gas mileage.

i've gotten 26.XX going a steady 75-80 mph..

then again i get 21 mpg @ 110 so i usually go faster...

I average about 23.2 mpg at 68-69. I spend 25% of my commute in traffic so that's my average mileage, not just highway. I average 22.4 with the AC on.

HooHAH
 

[QUOTE=
So unless you're a granny you'll never get best possible gas mileage.[/QUOTE]

Granny's Rule!

:jump:




- Also if you fold in your passenger side mirror, pull in your antenna, and keep you car polished, you get better tank time

Call a porsche a porsche :)

http://www.margie-bookshop.se/ovrigt/se-034.jpg

https://www.bbc.co.uk/worldservice/s...1_dean_300.jpg

I logged the gas mileage on the way to Oaklahoma City last year. I stepped up in incriments of 5 to 10 mph. 75/85/95 mph. Gas mileage 20/22/23. I could not believe it. The only reason I can think of is inertia. The rotor has autorotation to counter the fuel burn at or around 4k rpm in 5th and 6th gear. Piston engines have the oposite piston working against any autorotation. Piston engine cars will not see this benifit.

so you got better mileage going faster?... hmm

We will reverence fine machinery :worship:

Does any historian know the make of the other vehicle?

I bet the memorial at Griffith Park doesn't serve good meatloaf

Also extra passengers, AC, music, headlights, luggage, all contribute to cost-

News said that Share holder meeting at Mobil/Exxon had members demanding tha retired CEO return half his over inflated retirement, and some said this is just like ENRON - Boxer up in arms and FTA snooping around - might get those gas prices down yet.

55mph is still probably the most fuel efficient driving speed, but these days with the highway speed limits at 65, if you go 55mph you're going to end up being rear ended one day, so forget about that nonsense. Anywhere between 60 - 65mph is fine.

That's only when you're not stuck in the orgasmic 5 - 15 mph bumper to bumper traffic jams.

Winfree, he was hit by a Ford Tudor.

In general, the most efficient speed is the lowest speed you can go in the highest gear. Given that most interstate highways have a minimum speed limit of 45-50, that would be your most efficient speed in 6th.

I'm with you. If I was worried about gas milage I would have bought something else. Besides the wife drives the RX-8 and puts here own gas in it.

As far as effciency? don't know how these rotor things work.
But my 914 with an aggressive cam and carbs and header I get better milage @ 80 that 70. Something to do with air speed through the induction system speeds up and fuel is atomized better through the carbs just before the main gas jets come in. Then milage goes to hell and car speed is really fighting aerodynamics. Like pushing a brick.

BTW what is the Cd numbers for the 8?

drag is .31 according to mazda..

i read this on another thread but it said that peak gas mileage is around yor peak torque which in the mt is at 5500rpm, is dat correct, please correct me if im wrong.

5500 RPM ? That would mean that the injectors are @ full duty cycle. Do you know how much gas an injector can flow wide open? ALOT
just for reference previous car MCS averaged 35 MPG but keeping my foot in it and maintaining peak torque not only resulted in really haulin butt but the computer indicated 9 MPG

which is about right as I average 6 MPG on the track with the Porsche.

i cruised at 95mph. i went 190 miles and had a 1/4 tank of fuel left.

Easiest question I've seen all day.

The Answer is: 87 mph. Everyone knows once you hit 88, the flux capacitor comes on. :SHOCKED:

i can make it all the way from here NE Fort Worth, to Magnolia TX, about some 270 miles away on one tank... even though I have cruise control i didnt use it on the last trip because I was having some "fun" in the car. (saw my speedometer hit 140 for just a bit) wheeee!

But I just drive it and have fun, milage is always in the back of my mind, in the city its always going to suck, 200 for a tank is an avg of mine for 100% city driving.

i've learned to just 'let it go'

I get an average of 190 before the e light comes on. I have given up on getting good mileage, I just have fun now this car is too much fun to shift at 3,750 rpms. :rock:

100mph!

G*D D*MN! I've never seen so much misinformation in one thread!
Full injector flow at the torque peak? 55 MPH median speeds? Lowest speed in the highest gear ?!?
http://www.mazdamaniac.com/portal/smiles/domotwak.gif
There is a somewhat "magic" point at which the target A/Fs change on the RX-8. It has a lot to do with the calculated load, which is based on throttle position, vehicle speed, airflow, temperature and time at or above a certain RPM.

On my car, this cross-over point is about 4200 RPM.
If you have access to a WBO2S, you can find this point yourself. Just drive at different constant RPMs above 3700 RPM and watch for the A/F to drop from 14.5:1 to 13:1 at some point.

Keep the car below this point and you will maximize your fuel.

That said, I have done several LONG trips in the past few weeks. 500 to 1000 miles at a time. On these trips, I have kept different average speeds for each tank of gas.
I did legs at average speeds of 65, 75, 82, 95 and 105 MPH.
The 75 MPH yielded the highest MPG at 22. The 82 and up yielded identical MPG numbers at 16. 75 was 20.
I also had an additional leg where the "average speed" was about 95, but that was because half of it was a 60 (lots 'o cops) and the other half was at 135+ (fun with Corvettes). I don't think that one really counts, though my mileage was about 16, which is my normal city mileage.

Leave it up to dominion to deliver the best Sig pics. kudos, man.

actually, 0mph will yeild the worst possible fuel economy. why? because you are going no where, yet you are still using fuel, meaing you are getting 0mpg. i don't know about you, but i consider 0mpg pretty damn poor :mdrmed:

welp drove to Miami and back last night. it's a full tank round trip. did 100 mph 2/3 of the way there, got into traffic in lauderdale and did 80 the rest of the way. got 152 miles right at half a tank. did pretty much the exact opposite coming back, actaully went a bit faster in places and idled a bit @ some construction. pulled into gas station with gas light on. 305 miles on 13.546g with gas spilling out. that's 22.6 mpg.

I have the 4AT, so I've got the .69 4th gear vice the .84 6th gear.

The last 3 trips, same route, same distance, I used Shell V-power (always gives me the best long trip mileage): High and low #'s depend on which leg of the trip I'm on (half is coastal plains, the other half is 2-3000ft elevation and hilly).

80mph (3300rpm): 24-26mpg
75mph (3000-3100rpm): 25-26.x mpg
70mph (2800-2900rpm): 25-26.x mpg

So I just go 80mph :) .

Using any other brand of gas, you could subtract about 2mpg from those numbers.

Best Mileage Speed
 

The speed at which I get the best gas mileage is directly dependent on the speed of the 18-wheeler that I am drafting behind. Even with a slick car like the 8, wind resistance is a real drag on MPG.

When no 18 wheelers are to be found going at an acceptable speed, I get the best MPG at approx 63 mph.

I find it's cheaper to be all alone than to fill in all the holes and dings from the rocks flying behind the truck/car I could tailgate...