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Old 02-06-2011, 01:26 PM
Flybuddy2's Avatar
Flybuddy2 Flybuddy2 is offline
Join Date: Oct 2009
Location: Fort Myers
Posts: 365

Here's a quick and simple way to check for ethanol. Kit is inexpensive, just put one drop in the test sample bottle along with a couple of ounces of fuel and the color will tell you.
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Old 02-06-2011, 08:31 PM
MrNomad's Avatar
MrNomad MrNomad is offline
Join Date: Mar 2006
Location: Tucson, AZ
Posts: 800
Default No lead 87 octane in an O-360 - RV9A

We're able to get 87 octane, no lead, without ethanol. When I built my Superior O-360 engine we ordered 7.2 compression pistons and we've seen no indication of detonation. I expect we could have used 8.5 compression pistons and not seen any detonation.

In the rite wing of my 9A, I mix 30% av with no lead and use the rite wing for takeoff and landings. The left wing is filled with no lead.

Problems? When the airplane is parked in the warm Tucson sun, no lead (left wing) will cause the fuel pressure to drop to 1lb so the electric fuel pump is turned on. After 15 minutes of flight however, that problem disappears. My guess is vapor lock which is solved by the cooler temps provided by flight.

The one time I mistakenly filled up with no lead with ethanol the engine stalled right after landing and ran poorly. Never again!
Barry - Tucson
RV9A Superior O-360 (600 amazing hours)
Dynon AP Garmin Sensenich F/P
2017 dues happily paid for an incredible website
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Old 02-18-2011, 02:38 PM
Martin Hamm Martin Hamm is offline
Join Date: Feb 2009
Location: Southport, N. C.
Posts: 1
Thumbs up MoGas use

Was a big fan of MoGas when I owned a Cesna 150. Never under stood why 2 STC's were required. Afterall the airframe does not burn the fuel. Right? After buying my RV-4 in Oct. 97 I found out. Everything was fine with Mogas until the first warm day of May. The initial start and climbout was fine, but the hot start and subsequent takeoff had to be aborted. The engne was running rough and I cleared the plugs thinking this was the problem but before I broke ground the engine quit. This problem continued until a mechanic I met told me it was vapor lock caused by auto-gas. Yes the fuel lines were insulated. I changed my procedure to include Mogas left tank and Avgas in the right. All take offs and landings on Avgas, cruise on autofuel. This worked fine until I was unable to fly for several months and the entire fuel system gummed up. Had to replace the fuel pump and lines and rebuild the carb. Auto-fuel has very pore long term storage properties. Moral to Story. Gas and oil are cheapest part of flying. Don't risk your life on less.!!
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Old 02-18-2011, 04:18 PM
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frankh frankh is offline
Join Date: Jul 2006
Location: Corvallis Oregon
Posts: 3,547
Default Exactly

Mogas is fine but relying on the "hydraulically incorrect" mechanical fuel pump is pretty risky from a vapour lock perspective.

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Old 02-18-2011, 08:10 PM
detlef lili detlef lili is offline
Join Date: May 2005
Location: Albuquerque
Posts: 163
Default More than 300hours with car gas!

Hi Chris!

Since now, we have flown on car gas 91 Octane more than 300 hours. It is an IO-360 8.5 : 1 Superior with "Airflow Performance Fuel Injection" and "Dual Lightspeed Plasma III Ignition". The FI is approved for 100% Ethanol. The Diaphragm material of the mechanical Fuel Pump is a secret. I will replace the Pump with 500Hours. I added a blast tube to the pump and had never had any problems with vapor or low fuel pressure, even as we crossed the Andes in Peru at 14000ft.
I change the o-ring in the fuel drains every year.
The first 40 hours I used Avgas. Then for a couple of hours Avgas only for LDG/TO and for last 300 hours mostly (95%) car gas 91 Octane or higher if possible.
We used in Brazil car gas with 30-40% Ethanol, with less performance but no problems.
But it is very important to filter the fuel with a very fine filter. I use the "F3C SMALL FUEL/WATER FUNNEL" from AS. The bottom line is, that you can have some very fine, like gum, particles. This gum has no color and is little bit sticky and will block your filter. It is only present if you use ethanol blended car gas.
I will keep posting here every 300hours my further experiences.
In Asia is no Avgas, that means, I can only use car gas.

Detlef Heun
RV-7 N577DL 680 hours on Car Gas, sold
RV-7A N962JG 40h
Annual Fee 2016 proudly paid
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Old 02-19-2011, 06:13 AM
Chris Hill Chris Hill is offline
Join Date: Sep 2010
Location: Del Rio
Posts: 124

Great info everyone! Thanks

Detlef, do you have any information on long term storage as mentioned in post #43? Thanks for the great info!
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Old 02-19-2011, 05:12 PM
detlef lili detlef lili is offline
Join Date: May 2005
Location: Albuquerque
Posts: 163

Originally Posted by Chris Hill View Post
Great info everyone! Thanks you have any information on long term storage as mentioned in post #43? ....

Hi Chris!
Last year, we shipped a couple of barrels of car gas into the Antarctic and added a fuel stabilizer (Sta-Bile??) Since Liliana got ill, we left our plane in Argentina for 5 month. As we came back, I filtered the fuel again, but no gum in it. I started the engine normal and flew with no problems.
But we had to change our plans for the Antarctic. We will do this flight in about two years and I`m sure, that we cannot use it anymore.
Don Rivera from "Airflow Performance" suggested to flush the injection system with Avgas if we don't fly for a couple of months.
I would recommend to drain the car gas before winter time and use Avgas in the low flying time season.

Detlef Heun
RV-7 N577DL 680 hours on Car Gas, sold
RV-7A N962JG 40h
Annual Fee 2016 proudly paid
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Old 02-24-2011, 04:46 PM
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deej deej is offline
Join Date: Jan 2005
Location: Brunswick, ME
Posts: 306

Is anyone running 87 Octane mogas with a 160hp O320-E2D? I know 87 octane is fine with the 150hp O320-E2D with the 7.0:1 compression ratio. However, if upgrading an O320-E2D to 160hp 8.5:1 compression pistons, can you still safely use 87 octane, or are you now in the 91 octane realm?


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Old 02-26-2011, 07:55 PM
Jack Tyler Jack Tyler is offline
Join Date: Dec 2010
Location: Jacksonville, FL
Posts: 219
Default 'Sport Fuel'

I didn't see a reference here to the new marketing emphasis - across many different owners of recreational engines that need E0 gasoline - to develop suppliers of 'sport fuel' in all 50 states. The basic concept is to marry together a mix of recreational groups (vintage boat, car and motorcycle owners are all examples) with mogas-compatible aviation interests in order to benefit from the larger, collective demand for non-ethanol mogas. Consequently, the collective term 'Sport Fuel' was developed to help this initiative suceed.

A short introduction to the Aviation Fuel Club and 'sport fuel' can be found at:

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Old 04-14-2011, 12:43 PM
sqwkvfr sqwkvfr is offline
Join Date: Jun 2007
Location: Kansas
Posts: 20

1979 C-152 Lyc O235;
1959 C-172 Con O300;
1960 Debonair Con O470J

All three are club planes that get flown regularly, Almost exclusively on 87 Mogas. Haven't experienced any problems whatsoever.
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