timwinters
Ejection Handle Pulled
I've burned about a 50/50 mix of MoGas/100LL in both of the airplanes I've owned. (as an aside, I refuse to burn straight MoGas in an airplane for reasons I won't go into here).
My '57 172 had a continental O300 in it. My '58 182 has a continental O470 in it. Both engines like the mix. They run smoother. They don't foul plugs. And, in general, they're happier.
With the recent increase in fuel prices I've been experimenting with the ratio of the mixture. I've been slowly increasing the mix to nearly 75% MoGas and 25% 100LL. Actually, this pretty closely replicates the 80 octane aviation fuel that these engines were designed to run on...both in octane rating and lead content.
To my surprise I've found that my O470 continues to run smoother and smoother the more MoGas I run.
As an example, I made a 300NM round trip X/C last week. Here were the parameters:
Cruising at 8500' MSL
63dF OAT
20" MP
2300 RPM
50dF Carb Temp.
Big pull 'till rough.
Enrichen 'till smooth.
And here's what I see:
This is typical, I've been seeing between 15 and 25dF spreads lately. And we're talking a carbureted engine here! Heck, I think the Gami boys would be happy with 15dF!
Before, even when burning 50% MoGas, I was lucky to get the spread below 60 to 75dF.
Another nice benefit...I've picked up 3kts at cruise since all pistons are performing more equally.
My '57 172 had a continental O300 in it. My '58 182 has a continental O470 in it. Both engines like the mix. They run smoother. They don't foul plugs. And, in general, they're happier.
With the recent increase in fuel prices I've been experimenting with the ratio of the mixture. I've been slowly increasing the mix to nearly 75% MoGas and 25% 100LL. Actually, this pretty closely replicates the 80 octane aviation fuel that these engines were designed to run on...both in octane rating and lead content.
To my surprise I've found that my O470 continues to run smoother and smoother the more MoGas I run.
As an example, I made a 300NM round trip X/C last week. Here were the parameters:
Cruising at 8500' MSL
63dF OAT
20" MP
2300 RPM
50dF Carb Temp.
Big pull 'till rough.
Enrichen 'till smooth.
And here's what I see:
This is typical, I've been seeing between 15 and 25dF spreads lately. And we're talking a carbureted engine here! Heck, I think the Gami boys would be happy with 15dF!
Before, even when burning 50% MoGas, I was lucky to get the spread below 60 to 75dF.
Another nice benefit...I've picked up 3kts at cruise since all pistons are performing more equally.
Last edited: