@Fanman:

Good explanation. I don't like postings like "what, you spend $35k on the car and want to save 20 cents on the gas now???". You brought facts and a link which convinced me enough that I filled up with 91 last night. @ $2.60 sigh. Last 12 months I drove 28500 miles, but I started to use a second car.

So the cost of gas doesn't hit me that hard anymore.

(The second car gets 50 mpg.)

 

What car gets 50 miles per gallon? A VW Golf?

 

A Mazda 121 - in the USA sold as 'Ford Festiva'. The best was 54 mpg with 98% highway daily driving through the Santa Cruz mountains. I think on a flat freeway like I-5 it could push 60 mpg. With a 60-40 highway-city mix I come to avg. 48 mpg.

The car paid for itself ($450) by the gas saved ($600 so far). Great Mazda quality with now 215,000 miles :D :D :D

 

The timing is adjusted AFTER the knock sensor detects knock.

 

Bryrx, that mileage is unbelievable. Literally. I have 1200 mi on my 8 - the best 1200 mi I've ever experienced BTW - and I'm averaging 15 MPG. I've been checking at every fill up b/c I'm a financial professional and **** by nature.

I'm still try to break the car in through 2000 mi (per advice from this forum), and thus am still shifting regularly at 4000 RPM, and rarely if ever go full throttle. Sometimes I may shift between 5-6K RPM, but usually it been between 3-4K.

I guess my question is how do you do it? Our central bank has been inflating the dollar since 2001 (see real estate, oil prices) and the effects will mean higher and higher gas prices for the foreseeable future. $3 premium will be here soon as the dollar continues to decline on world markets.

If I am able to get 20+ MPG somehow, I want to know how. If you're not BSing, you got 24+ on your last tank. HOW?

1. Did you always get such great mileage? What was it like when the car had <2K mi?
2. Do you shift at low RPMs and drive at minimal throttle only and never drive the car hard?
3. What is your freeway/city proportion like?

I want to make it clear b/c people will blast me that I luv the car and will deal with the 15 MPG if I have to. I just want to get better MPG if there's something I can do besides never driving the car hard. I mean, as it is, I'm being soft with her and only getting 15 MPG. What's gonna happen after 2K mi when I start shifting at 6-8K RPM with much more aggressive driving? Am I looking at 10-12 MPG???

 

I've seen 23 MPG for a tank, but only on straight highway driving with minimal shifting and maintaining 3500 - 4000 RPM primarily in 6th.

I did often see 17 - 18 MPG on mixed driving though if not engaging in "spirited" driving.

Can't wait to get the 8 out of winter storage - I'm guessing once I do the first few tanks will be back in the 13 - 15 MPG range...

:-)

 

TJ,

Thx for the info. I guess the dream of 20+ MPG is just that. I bought this ride to drive it and if it means 15 MPG, I guess I'll just have to deal. I just hope it doesn't mean 10-12 MPG.

Oil and gas prices will continue going up until the dollar stabilizes. With the Bush defense budget and an open money supply spigot by the Fed, that may not happen soon.

Later man.

 

I had to fill up the RX8 last night and had to pay ~$2.75/gal. for 91 Octane. I am going to tell my wife to start using 87 octane, since the above PDF states that you may use 87 octane in the vehicle.

 

I've read that the PCM retards timing when pinging or knocking is detected.
My question is, does it ever advance the timing back? How does it know? Does it count milesPerLastPing or something? Or, perhaps you need to manually reset by tapping the brakes 20 times very quickly (not sure what settings, if any, this resets).
My concern is that if you switch to 87 and it pings, then you go back to 91, your timing still adjusted for 87 with no way to regain your previous performance.

 

Just a suggestion but you might want to check in to a Cosco or Sams club as I just got a membership to Cosco and their premium (93 octane in NC) cost me last night $2.22 when it is $2.40 down the street at every other gas station, them membership will pay for itself in no time with just gas purchases. By the way the membership cost me $45 for a year.

 

I've hit 52 mpg in my 2001 civic hx, routinely get high 40's ( primarily highway 75-85 mph ). If it drive it hard I get 38-40.

 

I would STRONGLY recommend AGAINST Costco gas. At least do not use Costco's 87 gas. Earlier in this thread I described that Costco 87 gas was the only gas that ever gave me a 'pinging experience' in my RX-8.

Meaning that this gas was of so low quality that the engine could not retard the timing enough.

I've used 87grade gas from any brand and never got a ping from that.

I never tried Costco's 91 mix.

 

Yes, I read your post and I have run 89 in my car quite a bit, but never have and never will put 87 in it simply for the fact that there is no need to be on the threshold of hurting the engine. I figured with their 93 why not get it and pay for 93 which is no even cheaper than 89.