Ethanol and Carburetors

[David Conwill]

Alternative power fascinates me. A lot is made about flex fuel vehicles today, but ethanol fuel use predates fuel injection systems. I have (somewhere) an article written in the late 1970s that discusses how to render a used car ethanol compatible. As I recall, the summary went something like this:

1) 40% larger jets in the carburetor (ethanol is less powerful than gasoline, so more has to be burned)
2) glass fuel filter to catch all the nasty deposits left behind by regular gasoline use (the alcohol cleans that stuff out and will plug a fuel filter PDQ, starving the engine, the glass filter allows the owner/driver to spot that trouble before it occurs and keeps the nasty stuff out of the carburetor and engine)
3) replace any natural rubber parts with an alcohol-resistant synthetic

It's not flex fuel, but if you're proficient at quickly changing your jets, you could go back and forth between E85 and Premium in a high-compression car. Or you could just stick close to E85 stations.

Now, the question is: Is 40% still a good figure for the jet-size increase? The article in question was written with pure ethanol in mind (which doesn't work well in a cold climate like Michigan). I wonder what would be better. Probably some trial and error is called for.

I'd like to try it, myself. My Camaro has 10.5:1 compression and absolutely loves the E10 ("gasahol") Premium sold at Wesco stations. I'm just not sure what pieces in the fuel system would get eaten up by the alcohol. I believe that the metals that will be eaten by methanol are actually safe around ethanol because it's less corrosive.

Anyone have experience they'd like to share? Seems like most of the information out there is geared at EFI and owners of Flex-Fuel vehicles.

-Dave

[DanO]

yes a lot of that still applies, The only thing to note is that the 40% larger jets should be approximately 34% becuase its not pure ethanol... and when i say larger, im talking flow wise, not size.

Gasoline is 14.7:1 AFR, E85 is 9.76:1

things to look out for are corrosive nature to aluminum, ability to degrade plastic gas tanks (usually takes a while however), Fuel lines, O-rings (especially for FI cars..). Its a horribly corrosive fuel.. but it just works so well!!

[Orange Terror]

So with all that potential corrosion, do you make that much more power to make it worth it?

[David Conwill]

So with all that potential corrosion, do you make that much more power to make it worth it?

Probably not, but there are other reasons to use E85 (see the Meijer thread below). Besides, an older car like mine doesn't use quite so many vulnerable parts.

-Dave

[meissen]

Interesting thread, will keep an eye on this one for more great information in here.