I got a dead stock jap s5 turbo and ive been using 98 octane since i got the car, but recently i couldnt find any 98 so i settled with 95. The car seems to be running better, so i would like to continue to use 95.
So i did some research. Ive heard alot of different things. Ive heard i can easily manage 95 octane fuel on a stock 13bt without risk of knocking but i also heard Japan use higher octane fuel so the cars timing would be set for higher octane, hence, at least 98 octane should be used.

So my question is; Does anyone know if there is any chance of knocking on a stock jap 13bt?? What will happen if i put regular unleaded?
If so, i will continue to use 98.

thanks guys

-zol-

 

**** i wish we had 95 or 98. All we have around here is 91,92 and 100. The 100 is like $6 gallon. I think youd be fine on that.

 

US is rated different.

91 in the US is the same as 96 in europe/ Aus/NZ and 92/93 is the same as 98.

Subtract 5.5 points from Euro/Aus/NZ ratings to get the same gas as the US rating.

It is designed to run on unleaded regular in Japan. Using premium is only wasting money unless there is increased boost or other tuning issues to overcome. Generally rotary engines should be run on the absolute lowest octane you can find that the engine does not knock (ping) with, for the most power. Higher the octane, lower the power in a rotary.

 

Excellent!.. thanks Icemark. That was the answer i was hoping for.

-zol-

 

so with a stock t2 you would be fine running the lowest octane? i thought you were suppose to go high with a t2 and low with an n/a

 

use 87 octane for t2 stock... that what I use. 91 was always running hotter and more slugish.. 87 had better performance.

 

From the factory, ALL FC's are supposed to use 87 octane (US octane). As stated, you only need to use premium when you start modifying they car and adding boost.

 

The higher octane won't burn throughly on a stock engine.