- Sep 17, 2008
Something to know and remember: 100LL has four times the lead that 80 did, and 80 was pretty close to the old leaded Mogas. That extra lead causes much faster sparkplug fouling in aircraft engines designed to run on 80, and it doesn't do the oil much good, either. Converted auto engines could suffer the same way, especially if they're liquid-cooled.100ll is ok for the engine. There is no issue there. The issue is O2 sensors are of a generation after leaded car gas. Catalytic converters can’t run on 100ll. There was no need to to develop an O2 sensor to use 100ll. Using an O2 sensor can be somewhat handy but it is only going to give an average of how many cylinders are tied to that pipe up wind of the sensor. Airplanes tend to run temp sensors. At work we run one in each exhaust, each cylinder head, and one on the turbo inlet. The mixture is extrapolated from that crossed with the fuel flow. If you want the efi to run on an o2 sensor like your car, you either have to run unleaded gas or be ready for the engine to run on a limp home mode when it gets fouled.
Straight 100 (the green stuff) had eight times the lead of 80. Don't see it or 80 anymore. Once in a while I'll hear of some airport having 80, but it would be rare. What refinery is going to bother with such tiny volumes?