Test at a mile high, so a bit slower than low altitude.
Forced induction creates basically the same cylinder pressure at various elevations, so octane still makes a significant difference. I would wager a full second reduction off their reported times with proper fuel.Octane makes significantly less difference at elevation, engines don't knock as readily with a lighter air charge in the cylinders, which is why they still sell ultra low 85 octane up there in the nose bleed statesDoubtful the Lobo was pulling timing at a mile high, but they didn't say what fuel was in it. Either way, 87 is basically 91 in those conditions, and 91, 93.
I'm not sure what you think that post illustrates? Power loss at altitude is fractional for a forced induction engine. Octane still plays a major role in performance for a FI engine because, as I said previously, cylinder pressure remains consistent under boost, regardless of altitude. Cylinder pressure creates heat, heat requires octane, octane allows full timing. It's not difficult.Nope, not exactly, bit it would be nice if they didn't lose performance. They do lose less performance than a naturally aspirated vehicle, though. There's a lot of basic primers on the subject, this was just the first one I came across, it describes it fairly simply:
Close, but not exactly. Heat doesn't require octane, heat-induced pre-igniton requires higher octane. Cylinder heat and charge air temperatures can actually be higher at altitude, because the air is thinner, so our intercoolers don't work as well, plus turbine speeds must increase to develop the same manifold pressure, etc. But, the critical part that suppresses knock at altitude in both NA and FI engines is the charge air, while the density is increased with FI, the charge air mass is decreased due to higher temperatures generated by the induction system. The mass flow equation used to calculate fuel injected pulls fuel out commensurate with the total reduction of mass of oxygen in the cylinder, this reduces BSFC and pulls the engine away from the spark advance knock limit. The minimum octane requirements for each engine and charge induction will vary, but the effects of altitude are non-trivial. Either way we don't conclusively know if TFL's engine pulled timing or not on the run.I'm not sure what you think that post illustrates? Power loss at altitude is fractional for a forced induction engine. Octane still plays a major role in performance for a FI engine because, as I said previously, cylinder pressure remains consistent under boost, regardless of altitude. Cylinder pressure creates heat, heat requires octane, octane allows full timing. It's not difficult.
BooyahTest at a mile high, so a bit slower than low altitude.
There's no replacement for displacement!Booyah![]()
![]()
![]()
BIG Block 2.5L Hybrid.