Raptor75

You don't need to pull the fuse to reset the EMC, do a search. There is a start up sequence that will clear it. Did it once about 3 years ago and it was pretty easy.

ecsw

ECU you mean? I did the search. most ppl were talking about disconnect the battery. There should be a easier sequence, isn't it?

Raptor75

Yup, messed up my acronyms.

Here is the procedure.

Reset KVRAM:
Hold the odo reset button (it's black, and inside the right round gauge area) in while turning the key to ON (Acc. position). you should see TEST on your dash. Turn your car off and repeat the process once more.


Reset KAM:
Turn your car on, hit the brake pedal 20x really fast, you should see the oil gauge sweep.

Note: All the resets are done without starting the car, just turn it to ACC.

These will clear everything in the ECU and reset it.

Good luck.

ecsw

the 2nd one KAM, is it to ACC. or all the way to on?

it sounds complicated. is it for all Mazda or just rx8?

ecsw

^ lol. I finally found the room fuse. It says "Interior Light" in the description on #14 next to the driver door.

That seems to be a lot easier.

Star Mazda Atlantic

Here is my problem. Even if I believe you are 100% correct, by your arguments and logic the benefit of lower octane is possibly more power. The benefit of higher octane is a possible avoidance of knocking and wear and tear or predetonation. I would call that very bad advice for people who are not looking for a performance enhancement but rather hope to reduce problems and expenses.

Raptor75

As long as all the dash lights come on your good, just don't start the engine up.

It is really a lot simpler then it looks. Once you do it, you will see it is really a snap.

Raptor75

That is why I said "As for Octane the higher ratings only prevent knocking and if your RX-8 is not knocking then you're just throwing money out your tail pipe." Most RX-8 don't knock with 87 but if you have one of the few that do, higher octane makes sense. Otherwise it is a waste of money. It is of course your prerogative to spend your money as you see fit. Making the oil companies richer is just not one I would choose.

Now if I were you I wouldn't believe a thing that I am saying. I would do some research. See what some of the really knowledgeable guys are saying like Mazda Maniac, Rotary God, Charles Hill, etc... who dwarf my knowledge of the rotary and then come to your own conclusions. I will bet that if you do our views will be much closer.

jmc23200

Using 87 is to help gain as much mpg as possible and lower the cost at the pump. It is not to boost overall performance or to be used on the track. The knock sensor will adjust so most engines do not knock and can use the lower octane gas efficiently. While you save at the pump and gain in the mpg area, you lose at the throttle. I have been well under 200 miles per tank for awhile now and decided I would give 89 a try for a couple tanks, and then try 87(instead of 93). With 89, the throttle is different. There isnt as much punch when lightly using the throttle, but with WOT, it feels about the same. I can't comment on MPG 100% accuratly yet, but so far it's looking good. Besides, if your engine dies, you have a 8yr/100k mile warranty. They are not going to test your gas to find out the octane levels, just like they are not going to test for synthetic oil.

04Green

iTrader: (1)

I did the same thing, went with 89, no reset, it felt like the throttle cable was stiff and hosed. Did NOT improve MPG. Maybe needed reset or more time, did not like feel though...

ken-x8

It will adjust by retarding timing, so that the lower octane gas can be used without damage. Since the timing will be off-design, I would expect efficiency to be reduced. Hopefully not enough to offset the cost savings.

Engines vary. There are posts here from people who find their cars to run better on 87, so optimum for their cars isn't what Mazda thinks it should be. There are also posts from people who were not happy with how their cars ran on less than 91.

Personally, I don't really want to find out how mine will do on lower octane.

Ken

RX-8GT6spd

I use 93 octane exxon gas and my car runs great

ferg

i get knocking on 93 but 87 is perfect, im sure the guy who had this car before put in 87 from the start

Bigbacon

iTrader: (4)

so far I put whatever I feel. I stay away from 87 but other wise it's what ever mid grade the station has so normally 89 or 91. no problems.

Krazed_Rx8

iTrader: (5)

Sooooo are people still using the new shell v-power? Thinking of giving it a try, currently use chevron w/ techron

Bigbacon

iTrader: (4)

I use whatever station is nearest to me when I need to get gas. I don't care about the brand at all. Gas is gas to me.

Easy Driver

I'm not an expert, but isn't this a sign that something is wrong with your ignition timing? Couldn't it be just that with 87 the timing is so off that the ECU starts retarding it? I just can't figure out how you'd get more detonation with higher octane gas unless the ignition timing was off.

HiFlite999

iTrader: (2)

A few thoughts.

1) There may still be some occasional cases of bad gas from a discount station, but, especially compared to the past, it's rare. The major reason for this is the EPA which has a lid clamped tight on the entire gas distribution system. Formulations vary little because they're spec'ed by EPA. Underground tanks are double walled and very closely monitored, usually by an independent company, and any leakage where water and gas are exchanged will result in huge fines.

2) A rotary is super sensitive to detonation. Here's the deal. What one wants on the power stroke is for the air/fuel burning to start at the plug and proceed as ball of flame from the plug to all corners of the combustion chamber. The 'classic' way of thinking about detonation is supposing the charge self-ignites from compression heating like a diesel. Unless you're changing compression ratios (by adding a turbo or high-compression pistons, for example), it's not likely to happen this way in a car already built which is using the recommended octane fuel. What happens in real-life detonation is that after normal ignition, the flame ball radiates enough infrared light energy that a region of the combustion charge some distance from the original burn also ignites in an uncontrolled way. (If you want a mind's eye picture of this, think about a house fire with a smoldering couch. It releases combustables which rise and gather at the ceiling. Eventually, something starts a burn somewhere in the cloud, and "boom" the whole thing goes off at once, shortly after.)

You can see the effect of this in overall car design where basically the larger the cylinder bore, the closer to detonation you run, thus requiring a lower compression ratio for safety. (The farther the initial flame front has to travel, the more time there is for IR radiation to "remotely" set off the rest of the charge.) One way around this was to run 2 spark plugs per cylinder which has been done many times in the past. Here's a modern example of "dual-plugging" to allow higher compression in a rather big bore cylinder.

http://www.gunsmoke.com/motorcycling...lug/index.html

Notice the the stock R100 has a 2-valve head which forced the single plug to be located off-center which makes an already large bore cylinder "burn" like an even larger one. People think that 4-valve heads give better "breathing" which they do of course, but arguebly the biggest improvement in 3 and 4-valve heads comes from being able to locate the spark plug in the center, thus minimizing the distance the flame front has to travel, which then allows for a running a higher compression ratio than is possible for a cylinder of the same bore with and off-center spark plug. (Whew!)

Modern engine controls rather muddle these various engineering effects, but that's what they are fighting against. The Renesis has two plugs per rotor because it (desperately) needs them, having as it does, essentially a huge "bore". Lose one of the two plugs (particularly, I think, the leading) under load and chances are you're gonna blow the apex seals; unless the ECU has an instant fuel cutoff upon the detection of detonation, retarding the timing alone won't save the engine.

3) Will running 91-93 octane save an engine that would otherwise die with 87 after an ignition system malfunction? Dunno, but it might.

Easy Driver

HiFlite999, a very interesting and informative read. You should wikipedia that. I find myself scratching my head a lot reading these forums at all the folks who want to second guess the advice of the engineers who designed their engine.

Krazed_Rx8

iTrader: (5)

Guess im gonna give the new shell v-power a try tomorrow...

Pilgrim

I've used Chevron, but around here (Yakima, WA) there is a string of Conoco stations that carries no-alcohol gas, 100% premium for Zoomie and my Harley. So that's what I use.

Pilgrim

Pilgrim

After a certain point, the octane becomes immaterial and it's the additive package that matters. The cutoff I observe is 89. Although I use 91 whenever I can I'll use 89 if that's all that's available when I really need a fillup. I think the Techron additive in Chevron is the best around for engine cleaning effect, but all the top tier gases seem to be good that way.

Pilgrim

Spirograph

I was recently told that the importance of running higher octane on a rotary is that it keeps your combustion chamber cooler than lower octane, and thus prevents breakdown of viscosity, leaking side-seals due to different expansion rates of steel and aluminum, etc.

invasion08

iTrader: (7)

The best gas for the 8 is 91-93 octane. The best gas ever was last summer when it cost 4-5 dollars a gallon. Yes some people run 87 octane without any issues, and the price difference between 87 and 93 octane is only a few bucks per fill up. The 8's ecu is programmed for the use of 91-93 octane so thats what i put in. I like to fill up my car at Hess

mmats69

87 from day 1 until I sold the car. no problems at all.