kimkim

guys, just wanna ask if its safe if i use 100 octane for my miata. i usually use unleaded only.

pdexta

iTrader: (17)

You should probably tell people a little bit about your miata so they at least have a chance of being able to provide you an educated response.

aug

iTrader: (7)

lol.. I would have answered this, but that last sentence put it over the top. Troll?

90R

iTrader: (4)

could be a girl who's not as mechanically inclined as some here.


Running a higher octane rating doesn"t get you anything. You'll want to run the lowest grade that doesn"t cause knock.

FRT_Fun

iTrader: (19)

If they are asking this question do you think they know what knock is?

aug

iTrader: (7)

Unfounded inferences are dangerous

Doppelgänger

iTrader: (12)

100 is soooo yesterday. I run 175.

thirdgen

iTrader: (26)

100 Octane will destroy your engine. Especially if you run Unleaded Only. I only run leaded fuel, the lower the octane, the higher the lead. The lead will lubricate the cylinders thus making your car faster. Every 5 octane numbers that you go down = the same effect as 1 psi of boost.
If you're making 0 boost on 87 octane, 72 octane with lead additive will produce 3 psi with no turbos or nos.

y8s

iTrader: (8)

MON, RON, or R+M/2 (AKI) "octane"?

stock car is a waste of money to run 100 of MON or R+M/2. 100 RON is about what "premium" AKI is in america.

Preluding

iTrader: (10)

Yes, it is safe for all applications.

If your car doesn't have any kind of forced induction(Turbo or Supercharger) you can even run regular(~87 octane) gas and easily get away with it.

thirdgen

iTrader: (26)

Imagine that, no response from OP...

thymer

iTrader: (5)

Awesome.

bellwilliam

iTrader: (1)

may be op dont get some of your humor. just confuse and scare him/her a bit.

dustinb

Run the highest octane possible. It burns cleaner and saves the owls.

Joe Perez

iTrader: (8)

Ok, folks. The OP does not live in an English-speaking country, nor in a place which uses the same rating systems and conventions to describe gasoline as we do in Canada / the US.


kimkim, yes, it is safe to run 100 octane fuel in the Miata so long as:
1: It is unleaded, and
2: It does not contain a high concentration of alcohol. (10-20% is fine.)

If the fuel is leaded, then it will cause gradual degradation of the catalytic converter and the O2 sensor.

If the fuel contains a high percentage of alcohol, then it might cause damage to certain rubber or plastic components of the fuel system, however this is not likely to occur in a short period of time.


There is no benefit to running 100 octane fuel as opposed to regular unleaded fuel (87 R+M/1 or 91-92 RON) unless your engine is specifically built for this, such as having a very high compression ratio or being turbocharged to a very high pressure.

18psi

iTrader: (76)

e85>*

That is all.

dustinb

Speaking about octane, I heard a few years back that running a higher octane (87 vs 94) on a regular car would actually reduce the power it makes. Is this just one of those rumors that has no merit?

Joe Perez

iTrader: (8)

It is theoretically possible, depending on what chemicals were used to boost the octane. If the act of raising the octane causes the energy density of the fuel to be decreased, then yes, you will make less power burning high octane fuel in a low compression engine than you would with a fuel that, by way of not having been diluted by octane-enhancing compounds, has a higher energy density.

Whether this is a practical concern today with commercially-available gasoline is something I honestly don't know.

chpmnsws6

iTrader: (12)

On a cross country journey, my buddy put 87 octane in his car instead of the normal 93 and it resulted in a 2.5mpg increase at 70mph running cruise on flat ground. I don't know if those results are typical, but it was what we experienced on the trip.

90R

iTrader: (4)

this is something we found in the early days of SSC. Lower octane made more power on a stock engine. The higher octane we were guessing took too long to burn. Leaving unused BTU's out the tail pipe.