StewC625

You'd rather people insist on putting out crap info instead?

nycgps

iTrader: (1)

87 is OK for this car, but it also depends on where you live. especially if you're near sea level, lets not get into that for now.

but I cannot use 87, why ? Because I Premix, 8oz, which is *alot*. Premix will lower the AKI, I have some sort of hesitate problem if I do 87oct + 8oz premix. but As soon as I go back to 93, my problem disappeared

Im going to try some 89 next time. (today or tomorrow)

So, if u use 87/89 and your car shows no problem, use it. Its not about rather you can afford it or not, I mean if you can afford 87, Im pretty sure a buck or 2 extra for Premium will not kill you. but hey, it adds up, and its great that you can save a few bucks for another bottle for beer !


Im sick of noobs too ! Stop spreading BS info !

Rick

Stu, I've had two engines in my 8 and they both make a lot of noise using 87 octane, but sound normal using 92 octane. The original engine ran just fine but was replaced because the Tech could not keep it from Knocking (or whatever you want to call it) using 87octane which BTW he insisted I use. However, after he installed the second engine Mazda changed his way of thinking and said to run 91+octane only.

After I broke in the second engine I wanted to see if it would run good on 87 octane. Well, I filled up the tank and went for a spirited drive and as soon as the RPM got up to around 4K the Knocking, pinging, or whatever starts.
BTW, I'm no expert ,but I've been around rotors a long time too and was very surprised to hear a NA rotary ping ( or whatever).

StewC625

Don't know what to tell ya there. Someone put starbucks coffee in the gas pumps?

4me2

Quality regular gas works just fine. If there isn't any knocking, you are just wasting money.

Rick

That is true, but people should know that "knocking" can happen ,and that it will shorten the life of the engine. Maybe it is time for a " what octane were you using when your engine died at 40k miles" thread.

4me2

Warm weather seems to like regular gas, and winter likes high octane gas.

StewC625

Well, although my experience with regular gas seems to bear out your first comment, you're off on the second one - warm weather promotes knocking, cold does not. Regular gas, being more volatile (i.e. explosive, with a higher vapor pressure and lower vapor temperture) promotes easier starting in colder weather, but those same properties can cause knock in hotter weather.

Too general a comment, I'm afraid, 4me2.

4me2

I just notice knocking under heavy loads when the engine is still cold. So in the winter it takes longer to warm up. Of course this is on my 8.

swoope

iTrader: (5)

why are you putting heavy loads on a cold engine.. that is your first mistake..

please read the owners manual..

beers

nycgps

iTrader: (1)

Have you ever see any true athletic will start running the track for 400m without any warm-ups ?

I think thats your problem.

and like stew said, you should use higher octane when hot, lower when cold.


Im gonna have my fill-up tomorrow morning, gonna try some 89 this time. still the same old 8 oz premix.

swoope

iTrader: (5)

ya know i just thought about it for a second.. it is likely a winter vs summer gas thing..

in fla usa i dont think we get the switch.. and i do run 87 most of the time. unless i am going to do something ugly...

i almost never have a problem.. every now and then i fill up at a place that is out of the norm.. will get a tank of gas that does not want to play... so i wait for the next tank..

btw, i premix ~ 4oz. rp..

beers

StewC625

1) Of course it will take the engine longer to warm in the winter than summer! It's cold out!

2) Never go WOT until your engine is warm. Very hard on any engine - piston or rotary!

donack456

I'm surprise no one told her to check the oil level, I'm sure she was not the only one that has tested drove that car. This needs to be done every 3k miles or 4th fill up.

Thats another easy driver tip the gas cap, add gas treatment and check the oil level. All those are simple user fixes that can save you time and money probably.

If this not the problem definitely take it back to the dealership, its still their car. have them fix it or keep it.

4me2

Hey all, my RX8 is my work car also, at 4:30 am. I don't want to wake up my family just to baby this car. If the engine dies, well that is life.
But I don't have any knocking, at all, after the engine is warm, so everything is OK.

carcrazy95

Just to throw my humble 2 cents into the discussion, I also have only used regular 87 octane in my 04 RX-8 (14,000 miles). NEVER any problems of any kind (I'm also a long-time rotary fan, had a '73 RX-4 and the Suzuki RE-5 wankel motorcycle back in the 1970's and 1980's). I did several "scientific" comparisons, with multiple sequential full tanks of 87, 91, and 93 octane. The only difference I found was consistently better gas mileage (about 1.5 mpg) with 87 octane.

Most of us are used to reciprocating piston engines, where compression and octane needs are directly correlated. But, octane does not give an engine "more power", and higher octane gas does not have "more power" in it. Actually, regular gas has somewhat more "energy" (=BTU's) in it than high-octane, which is why rotaries sometimes get better gas mileage on regular (as I consistently have).

The wankel is not a reciprocating engine. The combustion chamber is also a very different shape than in a piston engine - it is long and narrow vs. disk/tubular shaped in a piston engine. This actually makes the wankel less thermodynamically efficient than a piston engine, but is also one of the reasons it can tolerate lower octane fuel. This is one of the reasons the rotary is sometimes used in some third-world countries, because it can happily live on a low-octane diet (VAZ used to make rotary engine cars in Russia, where it was hard to get anything other than "regular" gas).

A high compression piston engine needs higher octane to prevent detonation. The extra power comes not from the "high test" gas, but from being able to run a higher compression ratio (= more power), which is made possible by the higher octane gas preventing the engine from grenading itself. Unless the rotary has forced induction, or is run hot and hard, it's not the same situation.

So, like others have said, if regular works without problems, there's no harm in using it (Exxon-Mobil makes enough money, why contribute even further to their corporare executives retirement fund by unnecessarily burning money in the gas tank).

StewC625

^^^ IMPRESSIVE ANSWER! ^^^

A low post-count, brand new user who posted an absolutely killer answer!

Good job dude! Elara or someone: Can we credit this guy's post count with 1000 extra??