93 octane....benefits for rotaries.....na and TIIs alike or are there????? you decide
i use 93 on my n/a 88 vert and im wondering should i be using the "good" stuff at all b/c rotaries gotta be different its in their nature you know....ultimately the ultimate question for you guys is what octane you use and why?.....for your rotary that is!!!

 

use 87 octane, our elongated combustion chambers reduce the flame front enough. Only a silly person would use higher than the kowest octane available on an na engine.

Also, you easily could have searched this topic, please do in the future. Using higher octane in an na only causes excessive carbon buildup because all of the gas doesn't burn. using it in a turbo is suggestable as you increase boost pressure from stock. Mazda knew what they were doing when they wrote the manuals. Please stop increasing global carbon counts while reducing your horsepower.

 

the only benefit of using anything other than the lowest-available octane rating on an n/a is that you have less money to waste on "mods" trying to make it accelerate faster...

(owns 87 gxl...)

edit: ^^^ you're faster than I am...

 

The "optimal" octane level for an N/A rotary is actually LOWER than the cheapest gas you can buy.

I'm not sure what type of racing it was (and it might have been 12a rotaries) but there were teams that actually diluted their fuel to achieve a lower octane level and thus better performance.

 

So any one wanna discuss timing and octane?

Am I right in thinking that higher octane would prevent detonation if you advance the timing?

 

87 oct burns better, and therefore can get better mileage also. I wouldn't bother w/ 93 on a NA of any sort unless it's a built engine. Turbos now, I always run 93.

 

how would you dilute your gas cuz now I'm curious about this topic cuz if i can save more gas im all for it =)

 

THere is no "good" stuff, they are roughly the same quality. No reason to use higher octane in n/a engines. 87 is best for best performance.

 

I currently use 90 in my TII

That's all I have to contribute :P Don't have any answers ahha

 

Yeah how would you go about diluting the fuel?

 

you want the highest octane possible with the TII. I still wanna know about the higher octane gas for the NA that has advanced timing.

 

so whats the verdict on 93 in a TII?

 

Some places still sell low octane fuel commonly called "tractor fuel" (about 70 octane). This can be added to pump gasoline to decrease the octane rating.

Octane rating is pretty linear, 50% 87 and 50% 93 = 90 octane.

I run with my timing 15° advanced over stock and have no problems with preignition on 87 octane.

Octane number is simply a method of quantifying the preignition resistance of gasoline. High octane numbers burn more slowly and are harder to ignite, low octane fuels burn more quickly and ignite more easily, thus the improved performance in a rotary. (Relative flame front velocity owns rotaries at high revs.)

 

Basic Ignition Timing
Vehicle Retarded 5 degrees - Standard - Advanced 5 degrees
A 88 - 91 - 93
B 86 - 90.5 - 94.5
C 85.5 - 88 - 90
D 84 - 87.5 - 91
E 82.5 - 87 - 90

I'm not sure if this applies to rotaries as well, considerreing the elongated combustion area. If it does hold, then if you advance 5 degrees, you'd want to use 90 octane--so mid-grade with some stabilizers.

 

a stock T2 is fine on 87 octane. You do not need premium if you are 100% stock.

 

http://www.chevron.com/products/prod...i_octane.shtml

Yes, it would reduce the chance of detonation.

Not necessarily.

http://www.toptiergas.com/retailers.html

Just to clarify that statement, "optimal" means the anti-knock requirement, not power, emissions, or anything else.

Actually, it's generally the high octane fuel that is diluted. By using the lower octane fuel that is not as diluted, more power can be gained due to the higher energy content of the fuel. Please keep in mind that this is all generalizing, as the octane rating and energy content are not necessarily related to each other due to the many possible components in a given fuel mixture. You need to contact the fuel manufacturer if you want to know the energy content and other statistics.

Edit: Downing Atlanta used the low octane fuel for endurance racing.

 

To avoid pre-ignition and detonation on a TII then higher octane seems like the right way to go. Give yourself some breathing room in case you ever spike.

 

I know you don't know about that, lol. It's 87+ (R+M)/2 with no more than 10% ethanol for the TII. See the owner's manual.

 

Wait, so what type of fuel should be used on the T2?

 

In stock form and in good condition, all 1986-1992 RX-7's are rated for 87 octane using the (R+M)/2 method, with no more than 10% ethanol. If the engine is modified in such a way as to require higher octane fuel, or if the engine is in poor working condition, then increase the octane as needed to avoid knocking.

Are the used RX-7's nowadays missing the owner's manual, or are you guys just not reading it?

 

Isn't octane used to keep the gas from pre-exploding? So reg gas is all that should be used, unless you are getting pinging.

 

I run 89 in my 87 t2. Stock with a ported wastegate. I think im gonna start treating the motor to 94 octane once a month.

As you already know, Canada's gas is very pricey. The regular 87 octane is priced at 97.9/L.

Canada choices go like this, dont know if you guys have 94.

Regular - 87 octane - RegularClean

Mid-grade - 89 octane - PlusClean

Premium - 91 octane - SuperClean*

Super premium - 94 octane

SuperClean 94, available in Montréal, Vancouver and Victoria

 

just want to do some research so if I buy an RX, it doesn't explode and take another one off the street.

 

So this site just says that gas companies are putting in different additive packages to make their gas better. It says nothing about how it's only in thier premium gas + not in the basic. What the other poster was talking about when they said 'better' gas, they thought that higher octane = better gas. Not one brand is better than the other like you link says.


But thanks for posting that link. I've been trying to prove that chevron is better than arco to my dad for a while now hahah.

 

cool guys thanks for the info