what are we gonna do?

[HotLines]

I'm sure I am not alone when I say I am building a new engine, this one will be a 360 turbocharged W2 head roller cam engine.

The dilemma I am experiencing now in my head is about the gasoline and what it will be like during the summer of 2011. I know this may seem funny to some but I don't quite understand where the octane rating will come from once the EPA ups the ethanol from the now 10% to the 15% which is now allowed. I guess what I am saying is that when they raise the ethanol to 15% will they also raise the octane of the gasoline to make up for the ethanol which basically has no octane rating or will they play some kind of game at our expense as its been throughout our lives?

Whats your take...

 

[BadAss71]

I have a suggestion as far as what fuel I would run through that turboed mill, if its available in your area. I have been seeing a lot of guys around here in phoenix running E85 with much success in turbo applications. The octane is higher than premium and it costs a bit less. The only down side to E85 is that its very corrosive.

 

[Gryzynx]

Best to educate yourself about octane ratings. If you want to read all the chemestry mumbo jumbo, check out the entry in Wikipedia. There's a good chart comparing octane ratings between various fuels.

http://en.wikipedia.org/wiki/Octane_rating

Now, ethanol actually has a very high octane. The reason you make less power with ethanol is that it contains less BTU per given volume than gasoline. Less BTU will reduce cylinder pressure and therefore, power. There also is a difference in the stoichiometric ratio for differing fuels. Ever thought about how and why the big horsepower engines at the strip run on alchohol? Simple, increase the fuel to optimize the air/fuel ratio, (it won't be 14.7 anymore), and increase the compression ratio. You can also dial up the boost because higher octane fuel will sustain higher cylinder pressures without detonation. Same principle can apply to other high octane fuels like propane.

The only reason you need high octane ratings is to sustain high cylinder pressures. Too much pressure will result in preignition which kills power and parts. High octane will support higher cylinder pressure which = higher horsepower, but you have to tune for it.

Downside of ethanol and other alchohol fuels? Top fuel racers have been dealing with it for years. Alchohol is corrosive, particularly to aluminum parts. Another problem can be lubrication, or the lack of it. Lead was added to gasoline to provide this quality. Modern fuels of course are lead free and the result is increased valve seat wear in our engines. Hardened valve seats were the answer.

Alchohol content in fuel will change things, but it does not have to be a buzz kill!