switching from gas to alky!! questions!!!

Old 12-23-2010, 12:59 PM
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Join Date: Jul 2007
Posts: 18
Default switching from gas to alky!! questions!!!

thinking of switching from race gas to alky. fuel cell is in back of car will that work? has foam in it must i remove that or will it work with alky? do i need a return line or will my regulatr run wih a alky carb? going to buy a mallory 250 electric pump and a nickerson carb anyone know anything about this?? thanks in advance for any help!
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Old 12-25-2010, 07:07 PM
Join Date: May 2008
Posts: 51

yes pull the foam out of the tank....it will disolve and plug up regulators and ruin pumps. as long as your running carb...yes tank in the rear is fine. if you ever go to injection you can make it work but the best way is mount tank if front. you have to have a fuel pressure regulator designed for alcohol. same deal with fuel pump. keep in mind running alcohol uses twice amount of fuel and if its a larger engine which requires more fuel, you may want to up the size of the main line from the tank to the regulator and possibly up to the carb too.
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Old 01-05-2011, 07:50 AM
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Location: Texas
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Default Do's and Don'ts

Be sure to know that alcohol (methanol) is slightly acidic and corrodes aluminum slowly. Some care must be taken if you plan on letting the car set for more than a week. Be sure to empty the fuel system (cell, lines, and carb). Methanol loves to absorb water vapor and that is another reason to empty the fuel system if you plan to let it set a week or longer. Also, if you have o-rings anywhere you need to make sure they are compatible with methanol. Methanol compatible o-rings will swell after a while and seal great. But if you empty the fuel system and allow the o-rings to dry out they will shrink and the next time you use the system they might drip a little for about 10 minutes then swell back out and seal again.

Be sure to add a lead substitute to lubricate the valves and rings. VP makes a great "top lube". Avoid additives that makes the the exhaust smell like grapes or candy. Each time the lines go dry from evaporation the additive residue will remain behind and this residue will not go back into solution when methanol is introduced again. I have seen many mechanical injector type systems plug and needles become coated because of this.

Also, the grade of methanol is important. You can purchase methanol from fuel providers but they have a fairly large acceptance range for water content and that will make ET's much less consistent. Try to purchase technical grade methanol by the drum (~$200 a drum) from UnivarUSA or a solvent provider in your area. You will be glad you did.

Because alcohol engines have a much higher intake charge density, if you convert a gasoline engine over with no changes expect to see a lower high RPM range than you did with gasoline, but plenty more torque. Alky engines like larger intake port volumes than the rule of thumb implies to gasoline engines. Don't go too much larger if you use a carb to keep the fuel signal strong, but if you go injected, heads and cams can go much larger without low RPM penalty.

Alky engines run much cooler because of the high intake charge density and a lot of power can be lost if you don't allow them to get to running temp, as well temp reflects the consistency in ET's as well. If the engine is ran too cool the oil will become emulsified with methanol and water from the combustion process and drop the lubricity potential of the oil. Engine temps I practice around range from 190 to 220 degF, warm enough to prevent droplet coagulation in the combustion chambers, and to promote a distilling effect of the aqueous mixture from the oil in the crank case. Definitely use a form of evacuation system (vacuum pump or header type design) to aid in keeping the oil in good shape. You won't have to change the oil nearly as often.

You will also note that the plug gaps will need to be reduced and tell tell signs like popping out the exhaust while running down the track indicates a very rich condition.

Finally, if you plan on approaching the 800 HP mark and the engine uses a carb, the engine will begin to enter a region where there is so much fuel required to entrain through the intake that flow potential becomes reduced, kind of like reaching an asymptote. This is where injection takes over and excels.

Good luck on your endeavor.
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