SFS550

How does everyone feel about 100 octane?

I've pumped 100 octane before but didn't notice much of a difference performance wise. The car did run smoother though.

Benefits?

Down side?

healthservices

Engine management system has no provisions to take advantage of the extra octane. So no advantage

sevenup_guy

Without remapping your car for 100 octane, there will be no benefit. Maybe the 535i, with the correct remap and increase in boost can see gains with the 100 octane.

mookish

yeah, what they said

JayArras

Can only imagine what THAT costs per gallon!

HiOffcr

I asked thia question about 10 years ago in a Ford Lightning Forum I belonged to. I was told by an engine builder that:

"Even some unmodified engines may benefit from higher octane gasoline. As under-hood temperatures increase, the engine needs a higher octane gasoline. In a dry climate like much of the Southwest, the lower humidty also contriubtes to increased demand for octane. On a low-humidity, 100-degree day with the air conditioner on, an engine's octane appetite can increase by three to four numbers. The benefit to using a 100-octane gasoline in high-performance street engines goes beyond the octane number. The distillation curve of the gasoline defines the temperature at which various amounts of gasoline are evaporated. Gasoline must be in a vapor form to burn, so the more readily it vaporizes (within limits), the better it will work in your engine. 76 Unleaded Racing Gasoline has a low 90-percent point compared with street gasoline. This can be a performance benefit in some engines because of the ability of the gasoline to evaporate more readily, contributing to more complete burning, which in turn leads to greater efficiency and power."



As always....your mileage may vary.

SFS550

I think the 100 octane was about $8 or $9 a gallon at the time, probably $10 now. In case you're in L.A - this was 76 Unleaded racing gas from a gas station in Pasadena on Arroyo Pkwy off the 110N's final exit.

I wouldn't say there's no benefit...after I pumped the 100 octane I noticed the car running much much smoother. I couldn't notice an increase in power at the time since I had the wife in the car and she's easily scared of the slightest pedal push. I'll get some more and give everyone my "official" findings.

vkhong

May have some benefit on a hot summer day when launching car at a drag strip, but no real benefit otherwise.