midlife crisis

OK, what do I do? I'm on the "M" flash and am getting about 20 MPG with a mix of highway and work driving; hitting a max of 24 on a long trip keeping it under 75. I did have one tank at 16 mpg (all commute and cold weather).
Do I ask for a new flash or leave well enough alone?

PaulieWalnuts

Under 16 is not normal at all. Most people seem to average 18-20mpg mixed. I just did a 360 mile trip and averaged 22mpg with the M flash. I average 20mpg mixed and 18mpg with spirited city only driving. I'm anxious to get the R which most people seem to agree makes a big improvement in power and MPG.

eclps0

im hoping it will get better because i just got teh new tranny and clutch put in today. drives Great neer drove liek this before.

mmats69

Man, I average 22-23 off 87 octane on the highway and I take her to the red at least 3 times a day (only for the time being tho. right now i drive 50 miles to work). Have heard lots of good things about the R Flash but don't really know if I want to get it or not cause I am satisfied. I have the magnaflow exhaust with a normal K&N filter in the OEM airbox. Doubting seriously that it makes any difference. Rarely do I go below 20 mpg, even in the city.

jaguargod

I got 24.2 mpg on my last road trip with cruise set at 72.

KYLiquid

ive seen some dyno's show that a cat-back exhaust will lean out your A/F mix a little.

Hyperborea

I was getting no better than 16mpg during break-in (keeping RPM below ~4K and generally being gentle). Now that I'm out of break-in (about 1800 miles) and I'm revving it a little more I'm getting close to 13mpg. My drive to work is 10 miles each way that is maybe 50% highway, 25% expressway (semi-closed road with a small number of lights), and 25% city streets. The cost isn't a big issue but with such low gas mileage I'm wondering if there might be something wrong.

Raevik

Just more anecdotal here.

I drive 100% city. That means work is 7 miles away and it takes me 20-30 minutes. There's tons of lights, stopped traffic, etc.

I drive from full until the light comes on and routinely put in 13.5-14.0 gallons. I get 220-240 miles per tank.

That's 16.3-17 mpg or so. I drive it pretty hard and typically accelerate past everyone.

On the roadtrips, I get 21-22mpg with cruise at 75 or so.

I consider all this normal for the RX8. If you're getting 13, something is wrong. If you're getting >22 I think you need to sell your car and buy a station wagon

D2RX8

Just my experience...

Drove from NC to FL, about 580 miles, 360 or so on flat straight I95 with cruise set at 78 mph, got 22.1 mpg both on the way there and back. AC was on the whole way, temperature between 92 and 98F.

I have been getting around 17...18 mpg with mixed driving, shifting between 4 and 7K rpm depending on the mood

However... drove ONE TIME about 7 miles with the pedal to the metal shifting only when above 8k rpm... the rest of the tank mixed driving like above... 13 mpg!
In other words, my experience, ANY crazy driving on a tank kills mpg.

I'm happy with my 8

alcimedes

I sit between 18mpg and 20mpg, regardless of what kind of driving I do. Had it on the highway for up to two tanks at a time with no luck breaking 20mpg.

Hyperborea

I'm definitely not running it up to redline or anywhere close on every shift. I get one shift up close to redline each way most days - coming out of the on ramp to the highway. After that I shift in around the 4k-6k range and even lower if traffic is slow and/or tight.

I just filled up this morning near work because the light came on and I have to go out for lunch (no time to fill up then). I had 184.7 miles on the trip odometer and the car took 13.666 gallons. That's ~13.5 mpg. Oh yeah, I've only used Chevron 91 (the highest octane here) since it was new.

icyur2

Wow..what a difference from user to user. I'm getting 19-20 mpg with 95% in city driving. Work is about 10 min. away and I shift @3500-3750RPM! Yes, a little low, but it is still in the "break-in" period. I do not travel much on the highway with this, so do not know what I"ll get, but am happy with 20 mpg. I'm using Shell 91 Octane, but am curious on what I'll get with 87. The only minor mod was replacing my air filter with a K&N. Otherwise, everything is stock. Will update as soon as I get 2 fill-ups worth of 87 Octane. Next on the list is to compare Shell's with Chevron, then 76. ^_^

BTW, when you are city driving, are you timing your speed with the lights? Makes a big difference because it would lower the times you would have to stop...I would time it, then gun it as I zoom pass the others that sped past me to and had to wait for the light ^_^

Hyperborea

Yeah, I try and coast it to the lights if it's red. First with the clutch out until the rpm's drop below ~2500 and then with the clutch in.

Also, as I said above if the traffic is tight / slow then I shift lower than 4K - on busy city streets that's more about 3-3.5K.

I was getting mileage around 16mpg when I was in break-in and was never letting the RPMs go above 4K and was shifting almost always around 3-3.5K. This has got me thinking that there might be something wrong.

When I take it in for the thermal blanket/reflash recall (this is a group 1 car - late 2004 build) I'll ask the service dept. to look at this too.

icyur2

Hyperborea, just out of curiosity, do you fill it up totally when you stop by the gas station? Reason I'm asking is that I've been doing this "study" of my gas performance by filling it with 10 gallon, then run it till I'm near empty (at the E line) before swinging by for another refill to another 10 gallon. I figure, when the light comes on, I have about 3 gallons left...so...based on that watch how it goes. So, if you want, try to fill it with only 10 gallons vs. a full fill-up. Curious on whether that makes a difference. Also, my drive to work is pretty straight..hardly any hills..does your drive have any? That also might make a difference between our mileage.

Well, if this doesn't pan out, hope the new flash will solve your problem..I'm concern it might make mine worse because I'm getting pretty good mileage..I'm in group 2 :p

JonsToy

Sorry, but I can't see how this method of computing mpg can give an accurate reading.

icyur2

Well, before I fill it at 10 gallon, I use up as much gas as I can (basically, I run it until it is slightly at or below the E line), then stop and fill up another 10. Granted, this isn't exactly accurate, but close enough. I mean, when the light comes on, you are above the E line and should have about 3 gallon from what I'm reading on other threads. So, you figure whatever mileage you are getting will be based on that 10 gallon you just added. Of course, you will also have to take it to the E line again (or close to what you can eyeball), and estimate from there. Are there any other ways to estimate the mileage? I figure this will at least give me a rough estimate on my car's performance.

The key to this whole thing is to empty out as much of your gas BEFORE filling up with 10 gallons. [QUOTE]

alcimedes

Or you just fill the tank entirely, write down how many gallons it took, then divide the trip odo by the number of gallons you just put in.

DaGnome

Heh yea.. people have some odd methods of calculating mpg..

I use my Palm to keep track, using a simple database I wrote via SmartListToGo.

I keep track of the actual miles at fillup, calculate the miles driven by the gas it took to fill it up (I always bring it down to E before filling)..

One thing I did notice that every milage calculator seems to have gotten wrong.. many will calculate your cost per mile.. but they use TODAYS fillup price rather than the price of the gas you actually just emptied.. kinda odd.

Either way.. So long as you keep track of exactly how much gas you use vs how much driving you did, your MPG will be accurate.

The only reason you really need to empty your tank as much as possible is if you are concerned with results being skewed due to different gasolines mixing. By emptying the tank as much as possible, you can be pretty sure that your driving on 93 octane or 87 octane depening on what you filled it up with.. if you are mixing octanes and even filling station brands, you won't get a true reading (Though it'll probably be close enough for most purposes).

icyur2

The reason why I don't want to fill it up all the way is the ease of computing the mileage my car is getting. Easier to divide by 10 vs. 13.9, etc.. Wouldn't it be easier to just take your mileage and divide by 10? You'll know EXACTLY how your car is performing by just looking at your odometer when driving. And like DaGnome said, I empty out my tank as much as possible to get the most accurate reading as possibe: Same gas (91 Octane) and same vendor (Shell).

Again, as mentioned on my 1st reply, I'll be doing a test on other vendors to see if they make a difference (76 & Chevron). Next would be a different octane (87). From what I'm reading 87 works pretty good..and..with the gas prices, that would save me $2/fill of 10 gallon. Anyone did this test yet?

JonsToy

OK. I'll give you 'ease of division' argument, though most $1.00 solar calculators do a pretty decent job of division these days. But you can't just eyeball E on the guage with any sort of with any sort of consistency and expect that there's the same amount of fuel left in the tank as the last time you eyeballed E. Now, if you ran it completely dry, then put in 10 gallons...

By the way, my low fuel light turns on with about 2.6 gallons left in the tank.

icyur2

Hah! Very funny..if I was filthy rich and willing to run it completely dry..sure..I'm game

Anyways, it isn't completely accurate, but close enough When my lights comes on, with my avg. of 20 miles, I add that to what I read on my speedometer and then drive into a station when it nears it..so..that would make it 60 miles left on my car if I had 140 miles in the speedometer, which would mean a stop at or near 200 miles..close enough?

alcimedes

I've noticed the light comes on at different times. I've had it on, parked, then come out and it doesn't come back on for another 10 miles or so. How would you know how much gas you've actually used up?

I suppose it would give you a rough estimate though. I'd rather just write the numbers down, and do the math on a calculator.

Hyperborea

I fill up totally for the reasons given in the posts by others - accuracy. Besides I can do the rough calculations in my head and I've got a calculator for the more exact answer.

Pretty flat. I'm in the Silicon Valley and I work and live in the valley so no climbing up the mountains around us here.

I'm going to bring this up with the dealership when I bring the car in for the thermal blanket/reflash recall.

Almero

Im getting the same no matter how I drive, can u PLEASE tell me what this m-flash

zoom44

the pumpm shifted some gas from one saddle bag to the other so the level changed and the ligth went off.