Hi all,
I recently got my third 7 a 89 GTUs. My other cars a 86 and 90 GTU have been great!! I have always been told and observed a rule of using no less than 91 octane. Recently I was informed that Mazda's only requirement is 87 octane minimum. I have also read that too high of an octane (91-93) will rob a rotary of some of its performance. What do you think!!!


Thanks

 

This is indeed true. With N/A platform FC's the best performance you will see is from 87 octane. In a TII application, the higher octane helps to prevent pinging. Higher octane in TII's will help even more, especially with higher ambient temps.

 

WHY?

 

You always want the *lowest* octane that the car will properly run on.
The lower the octane, the faster it burns, but the more prone it is to
preigniting. Higher octane simply means a slower rate of burn, which
is necessary in most high compression/forced induction applications.

 

The following website will answer all your question about octane levels in gas

http://www.autopia-carcare.com/mytabpremgas.html

 

Not exactly right. Octane only refers to a fuels ability to resist preignition. Pump fuels will generally follow the slower burn rate theory, but race fuels won't necceasarily. Some of the fastest burning fuels are the extremely high octane fuels used in NHRA Pro Stock and F1. Run alot of RPM you need a fast burn rate.

Chris

 

The reason a non-turbo rotary engine runs BEST on low-octane fuel is due to the shape of the combustion area of a rotor face. Since the combustion area is so long, a quick burning fuel is better hence the use of low-octane fuel which will burn faster than say 93 octane.

Plus 87 is much cheaper than 93...all the more reason to use it!