orangematics

i know, i know there are numerous threads about the MPG the FE is getting...but today i got 9.4 mpg!!!! It seems like the less amount of gas in the tank, the more gas it uses... when the fuel gauge was at half way point, I got out 16 mpg... and today when i started my trip the tank was on the 1st bold mark (4th mark from e) and now the orange fuel light came on... currently i am still at breaking in the 8 at 450miles... maybe it would get better when it gets broken in??? or is my 8 a lemon??? or maybe i am calculating it wrong: i take the miles i drove and divide it by the amount of gallons it used. suggestions???

texian

I have read all of the milage reports on other threads, and it freaked me out when I did. I didn't order the car to be a VW TDI, but I drive way too much to get 12 or 13 MPG.

But I took a chance and picked up my A/T on Wednesday, and drove it in auto mode the 250 highway miles home no faster than 70. I had my 15 year old son with me and the air conditioner blasting all the way.

When I filled up, I almost did a dance when I realized that the first 250 miles on the car delivered me 28.5 MPG!

I have since driven another 250 miles, about 70/30 hiway to city. I filled up twice at the half tank level, and in both cases got over 23 MPG.

Of course, I will not always drive this beaut as conservatively as I have so far, but it's nice to know I can squeeze that kind of economy out if I need to.

I have a buddy who also has one, and his habits/results parallel mine.

Having said all that, I'll be really glad when break in is done!

TomsterRX8

With 1,650 miles on the odometer my latest tank averaged 16.3 mpg on roughly 50/50 city/highway. Semi-aggressive driving.

Not good.

jdl

For what it's worth, my break-in log is here for my gt/mt.

8_wannabe

Orange, I'm not sure how you're calculating this but it sounds like you're introducing a lot of inaccuracies. If you are assuming that each mark on the fuel indicator equals 1/4 of the tank that's grossly inaccurate. And even if it were correct, you're eyeballing it to see when the needle is "on" the mark.

There is only one way to accurately measure consumption. Top off the tank (make sure it's really topped off.) Set your trip odometer to zero. Drive around a couple hundred miles. Top off the tank again (make sure it's really topped off.) Divide the number on your odometer by the number of gallons you took to refill the tank. This gives you miles per gallon. Follow this procedure precisely; you are probably getting around 16 mpg.

Magar

My first tank (80/20 Hwy/City) got 21.4; Second Tank, not so good with 50//50 H/C) Got 17.5. This baby purrs like a kitten, but drinks like an elephant!

Can't wait till the third tank cause I should be past the magic 600 mile maker!

orangematics

how do i know when the car is 'really topped off'???

R32

My question is indirect about mpg. What I really want to know is, can I get 250-300 miles between fillups? If so, then this issue would no longer be a concern of mine.

Thanks

jdl

You can. But...
I'd say you would be doing most -- if not all -- freeway driving to get that. I posted my break-in mileage log here where I hit your target mileage twice (so far.) I anticipate increased fuel economy as break in completes. HTH.

rodmeister

I agree with "8_wannabee." Orangematics is just demonstrating the inaccuracy of the fuel gauge. Everyone should use the method described by "8_wannabee" before reporting low gas mileage.

BTW, I fill my gas tank and let the gas pump's auto shutoff stop the filling. Inconsistencies between auto shutoff's on different pumps should be very small, say less than a quart, and won't dramatically affect MPG numbers, if you fill an almost empty tank. A one quart error should be less than 2% of a filled tank or 0.3 MPG at most.

To increase accuracy of MPG readings:

1. Fill up a nearly empty tank (within your comfort zone) when taking your fuel measurement to reduce measurement error. An exaggerated example: a one quart measuring error on a one gallon fillup would introduce a 25% error, but a the same error would cause a 3% error on 15 gallons.

2. Use the same pump at the same gas station if possible.

3. Try to place the nozzle in the same angle and depth each time if you are using the pump's auto shutoff.

4. Averaging several tankfuls tends to further reduce errors in measurement.

rotarymagic

I can't (haven't tried all highway driving yet), maybe you will be able to?

Maximus

Like Roadmeister said,

- Fill up the tank until the auto shutoff
- Drive
- On your next fill up note the odometer reading BEFORE you actually start filling up -- lets say you read "X" miles
- Now fill up the tank until auto shutoff
- Note down the number of gallons --- lets you read "Y" gallons

- Your miles per gallon = X miles / Y gallons

rodmeister

Hey, my internet name is "rodmeister" but "roadmeister" isn't bad at all. Thanks for the idea.:D

LightEmUp

I just drove from Michigan to Purdue, 283 miles before I HAD to get gas. Best mileage observed on my own car so far. Was cruising at 90 with the occasional downshift to show up a couple mustangs. Car now has 2900 miles, almost time for that oil change.

White Comet

You guys are lucky, im getting about 9mpg avg.

Skyline Maniac

Dang~ talk about a hooked up RX-7. :D

btw: JDM owners have been reporting on average of 16.5-17.7mpg on the RX-8. Just thought I'd share that.

White Comet

I wish....... They're primarily reliability mods though. Im really looking forward to meeting RX-8 owners and seeing how well the cars perform in person.

mmjames

I have about 700 miles on my RX-8 and I drive in the city, and on the Highways. I get roughly about 50 miles per quarter Tank. That is not scientific study just a rough average so far. And I admit I have a lead foot. So that is about 12.65 miles per gallon since the tank holds 15.8.

khoney

You bet. I just filled up after a 'rather spirited' 200-mile drive in the Texas hill country. I got 18.5MPG, - went 246 miles since the last fill-up. This tankful supplied numerous redlines, full-throttle passing, speeds up to 100, although a good portion was at 80, and probably 50 miles of city driving. The good news for me is that I drive harder every time I fill up, and my mileage is still increasing somewhat - last tank was 18.3.

So, 250 is possible. However, I doubt you'll ever see 300 if you drive the 8 the way it wants to be driven.

Wing

The top of the tank goes faster than the bottom that's for sure! I had almost 1/2 tank gone (60 liters in canada), so I figured close to 30 liters. I could only put 17 in!

Puppy1

I'm over 300 miles on this tank already. The light came on at 280. This has to be the best mileage for me so far. I'll know in the morning when I fill it up.

mikeb

I've got 2500 on my 8 and my mpg was around 13 or 14 and is now getting better its around 17-18

Master Phu

Just to add more fuel to the fire (both 87 and 91 octane)

I remember reading in threads where everyone was talking about changing the oil during break-in at 500, 1000, 2000, etc. intervals. Could this have something to do with how much better some cars are breaking in than others?

I've put 1800+ miles on my car and it seems to be breaking in nicely. I'm getting better gas mileage with every fill up (just got 20+mpg) and I don't intend on getting an oil change till 5000 miles.

Those who are getting high mpgs, have you changed your oil yet? And those who are getting low mpgs?

LightEmUp

I just did a 1200 mile road trip and have you used gas's from 87-94. For some odd reason my best mileage came at 91 octane. Didn't notice any difference in idling and acceleration. Oh yeah, I hit 138 mph on the freeway, this thing is so silky smooth, I still had total control over the car.

JeRKy 8 Owner

Guys this is a stupid thing to do in a hot area like where I live Florida but today in the afternoon there was a breeze thanks to some tropical waves in the Atlantic so I turned off the air and drove with both windows open. When I drive the car hard for more 10 seconds the gas gauge usually drops one notch by the next 2 minutes. Today I did not have any air turned on and windows were open and I started going very very fast to make theyellow light and the road was a little empty so I kept speeding for about 8 more seconds. I cant belive it or something was wrong becuz the gas did not go down any notches by the time I got home! It was still right above the half way mark and thats where it was before this 20 minute drive. It is weird you see I only do city driving most of the week and I had to wait today at so many red lights but the car still didnt go down a notch! I think air conditioning is making the gas go downfaster in the car somehow. I wish I could drive with air off all the time but its always very hot here.