Posted: Tue May 15, 2012 12:49 pm
Hi Chris
As a follow up, I am sure Al will correct me if I am wrong, with mechanical fuel injection on methanol, as I said you run an AFR about 4.5:1 for best torque, for best power about 5.3:1 so from peak torque to peak power you blead off fuel to lean out the enging, Al's referances to the top end being "fat" you control this with a poppet valve and a calibrated blead back (pill) to the fuel tank, the spring and shims in he poppet valve control the opening revs (load on the poppet valve seat) and the spring rate controles how quickly it opens, the pill controls the ultimate leaning out.
Another issue that comes up is when having staged and you have the trans brake on, you are holding the engine at the stall revs of the converter and have a spark cut rev limiter stopping you bursting the converter. You are pumping so much un-burnt fuel through the engine that it starts to cool everything down too much, often they fit another lean out set up to take about 5-7% of the fuel away to stop the engine becoming too cold, even though these engines have no coolent.
Best regards
Mike
As a follow up, I am sure Al will correct me if I am wrong, with mechanical fuel injection on methanol, as I said you run an AFR about 4.5:1 for best torque, for best power about 5.3:1 so from peak torque to peak power you blead off fuel to lean out the enging, Al's referances to the top end being "fat" you control this with a poppet valve and a calibrated blead back (pill) to the fuel tank, the spring and shims in he poppet valve control the opening revs (load on the poppet valve seat) and the spring rate controles how quickly it opens, the pill controls the ultimate leaning out.
Another issue that comes up is when having staged and you have the trans brake on, you are holding the engine at the stall revs of the converter and have a spark cut rev limiter stopping you bursting the converter. You are pumping so much un-burnt fuel through the engine that it starts to cool everything down too much, often they fit another lean out set up to take about 5-7% of the fuel away to stop the engine becoming too cold, even though these engines have no coolent.
Best regards
Mike