A good idea whose time isn’t quite ready. Ethanol comes from corn. It is distilled and made into a “green fuel”. When used as a fuel additive it raises the octane of the fuel…….but at the same time lowers the boiling point of the fuel (gasoline). The ignition point of 10% ethanol in fuel is at 1200 F. When it gets to 20%, the ignition point is 970 ….this is when all of the older vehicles (OURS) will be parked – most times very inconveniently parked…
Brazil is building water-cooled cars that run on 95% ethanol with 5% water. Nice, but OURS aren’t water cooled.
Check out Wikipedia.org ETHANOL.
From this point on I will explain from MY personal experience how ethanol affects our air-cooled Things.
When ethanol was first introduced here in Idaho a decade or so back, I was building Thing engines with the stock compression ratios of 7.5 to 1. All was happy!!! After they started putting the ethanol in the fuel at 5% of the total volume, we started to notice our engines were running hotter than before due to the ethanol. Over time it became worse – the engines were harder to dial in after tune ups.
When the ethanol ratio went to 10% we started getting vapor lock really badly on hills, as well as on many flat stretches of Idaho roads on warm days. The lower boiling point of the fuel was the direct cause of our vapor lock in the air-cooled application. Our gas mileage dropped 2-3 MPG as well.
I started building engines with lower compression ratios to accommodate the higher running temps. Even that wasn’t enough to stop the vapor lock. We now have to run electric fuel pumps. They pump through the stock mechanical fuel pump and stop the vapor lock. We set the electric pumps on a toggle switch under the left side of the dash panels. While driving and we feel vapor lock starting, we throw the toggle switch on and run the pump until it stops the locking up.
The ethanol is also very corrosive and is not good for older gas tanks. We have had to replace a few tanks because of scaling inside the tanks. I went to the fuel depot (Chevron) here in Boise to ask a few questions. The guy in the office said they trucked the ethanol into Boise from SLC because it was corrosive and they didn’t want it in the underground pipe lines, so they mix the ethanol blend on site from the trucks . He said it was better to have the extra maintenance on the tanker truck trailers than to have problems with the interstate underground pipelines.
Here is my way around this issue. I build to a compression of 6.8 to 1. Also I run German 009 mechanical distributors set to a max of 32 degrees . The dwell seems to be best at 48 degrees. I also use 1835cc pistons & cylinders to try and gain back some power for the loss of compression. So far so good. On our rallyes we usually do 320 miles per day at normal posted speed.
Most of our engines are running 1800-2000 oil temp at 60 mph with ambient air temps around 850-900 .
– Mike Humeston
