Ignition timing and vac advance (280i)

[RCK974X]

I've never quite got to solve the perfect ign timing for my 280. It ran great on UK 4 star, but now I'm in NZ, It's down to Super Unleaded, which is supposed to be 95 Octane. Car runs really well with vac adv disconnected and 10.5 deg static, but with vac adv connected it kicks back, but OK on mid to high throttle. (obviously as vac adv only efective at light throttle).


No big deal, it still gives about 26mpg on a decent run, just interested in anybody else's experiences ....