Got gas this weekend, $20.07 for only half a tank at $3.09/gallon. I was surprised to find a sort line, I drove past two lines that were at least half a mile long each. Another was hard to tell because it snaked through a couple of side streets first, though I counted over sixty cars (had to kill time waiting at the light).

I jumped in line at the shell station on I-10 and Fairfield (exit four i think). There were only 30 cars ahead of me and was done in about 15 minutes. They only had premium which was scaring a few folks a way, so the line moved quick. They also didn't have the credit machines running so people left cause they didn't have cash.

Spent those 15 minutes reading car and driver so it wasn't really wasted :P

 

I put regular in my car last week after 2 years of nothing but premium. On the 2nd tank I got a CEL. I put octane booster in it and topped it off with 94 and it went off in 2 days. I'm going to try the same thing this week with plus 89. I should be fine with that. I don't think she like going from 93 to 87 that quick. Any opinions?

 

To me the incentive to run non-premium would seem to be LESS now rather than more.

When regular was $1.799 and premium was $1.999 then the premium for premium was a little over 11%. So folks might want to try mid-grade (5.56% higher) or regular. With regular going for $3.299 and premimum $3.499 over this past weekend the premium to use premium is now just 6% and 3% for mid-grade. So while the cost of a gallon of ANY gas has gone way up, the percentage you have to pay extra for premium is the same (in dollars and cents) and less percentage-wise.

Dennis

 

https://www.rx8club.com/showpost.php...2&postcount=34

 

You are not factoring in the ACTUAL gas price difference. Although the regular to premium gas price ratio may be less now than it was 2 years ago the actual dollar amount you pay for a full tank is much greater. For most people it is the bottom line that counts. With everything else getting expensive a few dollars you save on something that does not seem to make any difference on the car (FOR MOST PEOPLE!) you can use it for something else.

I have used premium grade on my car for no reason other than I can afford the couple of dollar difference. With gas prices escalating as it is I am switching to a lower grade (89octane).

 

It costs the same amount extra to run mid-grade and premium as it did before, just the base-line is a lot higher. As I said, the premium on premium is a lot less that it used to be.

My last two tanks in the 8 (pre-Hurricane) were mid-grade with no ill effects. No increase in mileage and no ping, knock, or loss of performance I could detect. With $3.299 gas and cooler weather the 8 is parked and I am enjoying top-down (and 23-25mph city) in the S2000. The next time I fill the 8 I will be using mid-grade again, unless I decide to try a tank of regular just to see.

Dennis

 

It's not so much that it's just a few dollars more to put super in the tank, it's how fast your burning the fuel, and how many times I need to refill that I'm more concerned with.

 

If (AND THAT'S A BIG IF, just to satisfy the higher-octane-is-better crowd) your car can run on a lower octane gas then your rate of burn (hence mileage) should be about the same (and sometimes better). This means you fill up your tank about the same time as before. The only thing you should notice is extra cash in your pocket.

For those people who disagree with what was said read the bottom.


Disclaimer: This post does not in any way claim that lower octane fuel SHOULD be used if said fuel causes adverse effect on the car's performance. You have a god-given ability to make your own choice and decision. I suggest you use it.

 

with what I paid for this car, I can't afford to put in premium right now with gas soaring well over 3 bucks a gallon here...it's going to have to make due with regular (87) until prices come down and my savings goes up again...

 

Ideal for everyone!! How about using half premium and half 87 (or 89)?? Save a few bucks

 

yeah, 88 octane!

 

(93+89)/2 == 91 Octane Rating ----> TRUE

 

Does anyone remember the C&D article on octane? Like 3 years ago, using a 3-series BMW and a racetrack. Compared performance, and lap time on 3 grades. Their conclusion was that for the difference in $, 20 cents a gallon or 40 cents whatever, performance was enhanced on higher octane. So more expensive gas provides better performance (shorter lap times, horsepower, torque, etc. Drivers and gas were not consecutively tested so that they started on 87, for example, then 4 attempts later they were not on 93 so that shorter lap times were from practive).
The point was, that, unless you were at the race track, and it didn't matter to shave off seconds around the neighborhood, performance difference wasn't enough to warrant "better" (or more expensive) gas. Residue difference may be a different matter, however.

 

I posted an article on another thread in regards to this matter, where when the swapped 91 for 87 octane on an M3 they lost about 12% of the performance. In everyday driving that is not a big deal for most people. For me I would rather pay the extra 20 cents, so I have max hp, all the time. Now I have to.

 

Regular should be fine then on my 2 year lease. :P

I think I will still use premium though. Just out of curiosity, how well does octane fluxuation do? Like one fill up you use 91 octane, then next time you fill up, 94 octane is all that's available. Is premium gas, premium gas? I can see myself having to mix different premium gas octanes every once in a while.

Thanks.

 

hrm... this is what I think... you bought a premium car... put the premium fuel.... thats what its designed for...

how are any of us smarter about the engine than the engineers who designed the renesis??

save on gas bill? have 2nd beater car/hybrid or use public transportation

 

I only use 87. Can't feel any difference whatsoever.

 

12%? Not 13% or 11%? How did you measure this? Was it repeatable? I can't feel any difference or measure any difference, using my gTech performance meter. Same 0-60 time ranges, same "road horsepower" readings, everything, in repeated tests.

 

A 12% loss of performance on a PISTON engine, not a rotary. And there seems to be some misconceptions about what the octane rating really means. Octane determines when the fuel ignites; the energy is the same. Higher octane gas retards the ignition of the fuel so that it doesn't ignite too early in a high-compression engine. The higher octanes start burning at a slower rate than a lower octane, thus the probability that not all the fuel will burn completely leaving some deposits inside the engine. This is why the high octanes have all those detergent additives put in by the gas companies; to help remove those carbon deposits.

Lower octane fuels burn with the same energy that a high octane fuel does. The reason they're not usually used in "high performance" cars is because they can ignite very quickly which can be bad in a very hot combustion chamber with a piston compressing the fuel to high pressure levels; it can "pre-ignite" before the spark plug fires. This is why gas octane is increased which means the burn point is raised (retarded basically) to make sure the fuel doesn't ignite until the plug fires. This will give the "best performance" under high performance conditions....the track obviously. For street use however, and regular daily driving, high performance isn't the main issue. When the engine is NOT being revved up to "high performance" levels then the maximum combustion conditions that burn high octane fuel efficiently don't happen. So what happens to the fuel? It doesn't burn efficiently so it leaves carbon deposits inside the engine. A lower octane fuel ignites earlier, quicker, giving it a chance to burn more efficiently and completely (thus the better mileage many notice) which gives better performance for the normal driving performance levels that are typical in everyday driving. Start running the rpm's up to redline and it won't perform as well as the higher octane fuel; HOWEVER....how many times do you do that driving around town? Buy the gas for the driving situation you anticipate.

I used to run 87 exclusively but I've now had to go up to 89 because of add-ons to my car. For everyday driving, 87 or 89 works fine. For high performance situations, by all means run 91 or higher.

 

I am so tried of people having this discussion. There is only $.10 difference on a litre regular vs premium gas! Whats the big deal?? You spend thousands of dollars on a car and then you save acouple of CENTS on gas becasue youre too cheap to put in premium? I dont get it.

If you do care about fuel economy the rotary engine is not the way to go.

I always drive on 94 Octane fuel, and Once I put in 91 Octane and I felt the car being very sluggish.

 

Actually near my neck of the woods it's like a .30 difference. That adds up after this car eats gas like it does and no one wants to get in this car and drive under 4k rpms all of the time. And I also live in NY where most people including myself are struggling just to make ends meet.

I'd like to know I didn't search first, sorry if he already responded to this, but if Rotarygod has an opinion on this, I'd like to use regular if I can.

 

I didn't measure it, it was what was stated in the article in Car & Driver. They measured it.

 

My bad. I didn't read your post carefully enough. I remember reading that as well. It makes sense in a very-amped up, ultra performance car like the M3, which also has very aggressive fuel mapping and engine computer programming. My Acura TL, which had a "premium fuel only" (which is what I traded for my RX8) label on it, was noticably down on power when filled with 87 octane.

As I said, I notice absolutely no difference in the RX8 though. I'm guessing that's a rotary thing but I might be wrong.

 

struggling to make ends meet but you got an rx8....

not that i know that much about new york... but don't most people commute and not even have cars?