Unleaded Fuel Only?!?!?!

[anfrey]

what compression is the b18c1? this will in part determine your minimum required octanage... your owner's manual should state the minimum octanage to be use

 

[TegSox]

Upper left:

You can use a lesser octane rating than your suppose to use, but your engine will detect knock and automatcally retard timing = you'll lose power.

Type R compression is 10.6:1
GSR compression is 10.0:1
LS, RS, GS, SE is 9.2:1

All gas is unleaded, the number is just an octane rating.