Originally Posted by
Cat 1
Did take some real quick muffler pressure readings yesterday and despite this being a fairly restrictive muffler (from an OS 40FP) the pressures were lower than I suspected. Also I noted that the mixture setting does change the pressure independent of rpm. As you tend toward lean at peak the pressure drops slightly which is not really what we want. The slight pressure drop seems to proceed the rpm decay just slightly..
That makes sense: at peak RPM, there is that small range where the improved efficiency of leaning out basically cancels out the reduces supply of energy, AKA RPM remaining constant, but because of the smaller mass flow of fuel, less gas is produced. So indeed, when going from overly rich to overly lean, just a fraction before reaching RPM decay, the pressure will drop
Originally Posted by
Cat 1
We could drift down the road of adding sensors to measure and relay data but in an effort to KIS I think we might have two basic options now - the E-pressure is not much simpler than the solenoid setup but it is cheaper as the pump is $3 and easy to find.
To me it seems the E-pressure set-up is bulkier?