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Author Topic:   setup on alcohol?
Dirt Roller

Total posts: 13
posted March 08, 2002 06:06 AM
Can anybody give me advice how to setup a engine for alcohol. I know they need lots of compression and need a very good fuel pump. but what are the basic numbers I should watch about running alcohol, so I don't burnup my engine.

Dirt Freak

Total posts: 333
posted March 08, 2002 11:09 AM UIN: 23443678
I dont know about the high compression,i have run 11.1 with allky. Then you just need the fuel pump and regulater for allky. I have seen a few cars useing the 9 pnd pump and no return with no problems.

Dirt Freak

Total posts: 240
posted March 08, 2002 01:33 PM
If you can afford it, get a carb from a shop that sets them up for you. The runners and such are larger and flow more fuel. you will need a lot of fuel with alky and jets are usually in the 94 to 100 range. My BG carb that I bought had 99 jets in it and when I raised the compression from 10.5 to 1 to 13.5 to 1 I called BG and they said the carb didn't need to be touched. Bigger jets won't be much use without a well built carb thou so spend the money on a good carb. BG isn't the only one out there, so look around. anyone have any other suggestions for carbs? the more compression the better and as far as the engine parts go really, anything will work, its up to you how much you want to spend.

[This message has been edited by uforacing51 (edited March 08, 2002).]

Dirt Forum Racer

Total posts: 82
posted March 08, 2002 02:00 PM
I would highly recomment purchasing a KSE belt driven pump. It will take care of your fuel pump needs as well as your power steering pump. They are pricey new, but look around and find a used one. I have seen them for around $350-$450 on some auction sites. There are hardly any internal parts to go wrong and can easily be rebuilt (just seals and O-rings). You will not wear one of these pumps out. The benefit is that you will always have the volume necessary for alcohol and the pressure is controlled by the speed of the motor, so you don't have to regulate and your idle is alot cleaner. It is internally regulated. I have seen a lot of people run into trouble when they first get into alcohol when they didn't use this type of system. It's bullet proof. Make sure you run at least -10 supply from your fuel cell to the pump (I use -12) and use -8 from the pump to the carb.

Dirt Freak

Total posts: 390
posted March 08, 2002 05:38 PM
kbethke, The one thing I would like to bring up is this........because it takes almost twice as much alky as compared to gas to produce the same amount of BTU's it ONLY takes half as much of a lean condition to burn a piston.

while you are learning what a motor likes you want to be on the rich side, NOT THE LEAN SIDE........

I run a big 3/8 on a average night I will burn 9-10 gallons in a 15 lap feature. If I were to run gas it would take about 5-6 if you lean a gas motor by a little in a alky motor it will be almost twice as much of a jet change......

You can have the carb jetted tooo rich and not lose too much power......because it takes twice as much fuel to create a rich condition to cause the same problems you would see in a gas motor........AGAIN, ONLY 1/2 AS MUCH OF A LEAN CONDITION........that's why you here people telling about burning pistons.

I agree with buying a KSE or simular belt driven fuel pump. VOLUME is a big part of alky..........I get a lap for .6 gallons, 16-17 second 9 gallons a minute SOUNDS fine, But it's not.........if you brake a lap down 1 second sections for a alky motor on a big track at times you will need a LOT more volume for a split second here and there every lap......those are the lean spots that will hurt the motor.

Also, the mechanical pumps are fine for small dry-slick tracks......but if you ever go race some where else, you will need to purchase a belt driven pump.....The rubber diaphram in a mechanical pump will drop in pressure and volume when it gets heat in it......that's why the sell a insulator help keep the heat out of the fuel pump so the diaphram doesn't give up too much......NOT TO KEEP THE FUEL COOL AS MOST PEOPLE THINK.

Rubber streches and gets weak, that again causes a lean condition........If you lost one motor because you were going to save a few hundred dollars up front.......HOW MUCH DID YOU SAVE????? You lost more than ever, because to keep the new motor from dieing the same way you will still need to purchase the belt drive fuel pump.......

Keep the 1/2 as lean before melting a piston in mind when buying a pump, or making a jet change.........


Dirt Roller

Total posts: 13
posted March 08, 2002 06:35 PM
Thanks for all your input. I"ll keep this all in mind. I think I already have a good alky carb to use. I"ll have to get a belt-driven fuel pump for sure.

Dirt Newbie

Total posts: 1
posted March 09, 2002 07:24 PM
Another thing to think about is the heat range of your spark plugs. For some reason you need to run colder plugs with alcohol or you'll burn a piston. I had an unfortunate experience with that one time and have heard of others with the same problem.

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