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Old 09-01-2012, 07:12 AM
turbo1889 turbo1889 is offline
Motorized Bicycle Member
Join Date: Jun 2012
Location: NorthWest Montana, USA
Posts: 27
Default Re: Im new to the forum & had to ask. Turbo + Meth Injection.

Ethenol isn't a bad thing by itself. Rather that the engines aren't built to handle it. In go-kart racing (something I did a long time ago when I was a teenager) they have extremely high power to weight ratio 2-cycle engines that run on pure (100% absolutely no water content) alcohol mixed with castro bean oil that go like crazy and have extremely high compression ratios. It's just that those engines and the carburetors on them are built to run on alcohol and it will mess them up bad if you try to run them on petroleum.

With fuel injection instead of a carburetor it is entirely possible to build engines that run just as well on alcohol as gasoline or just about any mix of the two but small engines that have fuel injection systems rather then carburetors are a rarity at best right now. Give it another decade or so for the technology to catch up and hopefully there will be a lot of 25-50cc size 4-cycle weed-eater type motors out there that have injectors rather then carburetors that we can use gas with up to about 30% alcohol content without problems or even more if they put the flex-fuel software onto them.

Alcohol is good stuff (and not just for fuel) it is just that if your going to use it in your engine as fuel you need to understand that it does not burn exactly the same way that gas does and if your engine is made for gas both the compression ratio and the fuel mixture will not be ideal for alcohol and vic-a-versa. In addition some types of rubber and plastics used for hoses and gaskets and stuff don't do well with alcohol and vic-a-versa some that are just fine with alcohol don't do well with petroleum products. If your going to use mixed fuel or you want to use both fuels then your engine and all its components need to be designed to work with both.

Alcohol as a fuel isn't the problem (it is infact a superior fuel if used in an engine specifically designed to use it) its that they are trying to use it in an engine that isn't designed to use it and is intended for gas only.

Once you realize that even 96/4 alcohol that has as much of the water distilled out of it as is possible using the distilling process without having to do a second step process to get the last 4% of water out of it is 108-octane which is a hotter fuel then anything you can buy at a regular gas station and is right up there with high performance aviation fuel you start to realize that the stuff isn't bad stuff at all provided your engine is set up to use it. That of course doesn't even take into account that alcohol has a higher vapor pressure, faster burn rate, and a cooler flame temperature then gasoline. The higher vapor pressure means that it atomizes quicker and more completely in a shorter period of time which means more complete combustion and a higher RPM threshold before richening of the mix is required to compensate for incomplete fuel/air mixing before ignition. The faster burn rate means a higher percentage of the fuel is burned faster in the combustion chamber which translates to more power with less ignition advance being required at higher RPMs. All this while still having a cooler flame temperature which means the engine runs cooler and won't overheat as easily.

Alcohol in its pure form is a darn good fuel it is just unfortionatly not nearly as readily available as gasoline which is why there aren't any (that I know of) bike motors built to specifically run on alcohol and alcohol only. Yes, one could probably figure out how to make a high performance alcohol and castro bean oil burning go-kart engine work on a bike but it would cost you a cool $1,000 alone for a used one of those motors and making it work with the larger diameter tires our bikes use would require multiple stage reduction since those engines run at very high RPMs and spin small diameter go-kart tires at much higher RPMs then we use on our bike wheels. Then of course you wouldn't be able to just fuel up at a gas station but would have to buy high grade alcohol and castro bean oil and mix it yourself at home in the proper ratio just like the guys who race high end performance go-karts do.

Last edited by turbo1889; 09-01-2012 at 07:36 AM.
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