Wairau Rd BP no longer ultimate?

[MAC_HATER]

is it correct that Direct injection engines can deal with 91 fuel despite having mental high compression ratios? as the fuel is generally shoveled in at the last second before spark?

even though that's the case, the piles of half rooted Galant GDI's littering the country with clogged intake Valves is another problem that even the highest octane fuel cant avoid or fix

[RomanV]

Octane requirement is more about dynamic compression ratio, rather than static.

VVTI and similar helps deal with knock induced by lower quality fuels, assuming it's part of the equation for knocking back timing.

Also helps take better advantage of higher quality fuels by upping the dynamic compression ratio under low load and getting better economy.

You could have an 8:1 compression ratio motor that would knock or not depending on the cam(s) and how they're dialed in.