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Thread: flying toilet

  1. #1
    Join Date
    Sep 2006

    flying toilet

    what is leakdown,what does it do?

  2. #2
    Senior Member MASTER BUILDER
    Join Date
    Mar 2003
    For injection. Basically leak down is the amount of fuel that the barrel valve is sending to the port nozzles at idle.

    A setting too high and the motor will run but it will be rich and on alcohol will take for ever to build heat up. too little and the motor will build heat fast.

    For all the cars we have that have run mechanical injection (we have enderle pills) We start with a 110 pill and the leak down is 30-35% with no idle poppets (for alcohol) I have never run gas with the injector cars

    Once that is set up we run the car in the shop see how fast it builds heat and see if it will go on the brake clean and adjust from there. Once you find a set up that your program likes right it down in case you start to have problems and make some changes . Then you can always go back to your starting point

    Good luck

  3. #3
    Senior Member EXPERT BUILDER
    Join Date
    Jul 2005
    VERY WELL SAID DAK ! Jim, just remember that is for an endele barrel valve, if you have a Rons barrel valve i think you might want to start with an 85 main jet and 25 to 30 percent leak down. Just make sure you know how to operate your leak down tester properly so you dont get it backwards.

  4. #4
    Senior Member RACING JUNKIE
    Join Date
    Jan 2006
    I agree with both DAK and Don,
    There's lot's of variables with getting the right settings on the leak down.
    EX: if you buy a new hilborn stacks injection from Hilborn it will come preset at 26/28 PSI leak down and they recommend a 110 pill starting point. Everything want be right but it will be close.
    Ron's, hilborn, and Enderle all have different barrel valves. I too start at 30PSI leak down and except for the enderle hat on a tunnel ram, i've had to come down to get good response. I have run as low as 18PSI with a 2 7/16" stacks injection with a PG 150-1 pump. Most people i know do not have EGT setups so they go by the temp of the motor.
    I have 3 different setups, a bowl,stacks and blown and they all require different leakdown settings, but i think the leakdown setting has been pretty well explained.
    I can remember running blown gas 40 yrs ago when no one had ever heard of a leakdown reading the hilborn barrel valve had a slot that looked like a screwdriver slot in the end of the barrel valve, you set that parallel and adjusted it until the throttle was crisp. Days gone by but still good in theory.



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