Ruckus
TY 4 Stroke Master
No, the leaner the mixture the more power it developes. Like everthing else in physics, there is a balance between forces and an ideal compromise is always seemingly just one adjustment away. Because high compression engines produce more heat, they will also make more horsepower. However, if this heat reaches beyond a critical level, preignition along with greater frictional loses will start leaching away any extra power that was gained in the first place. A slightly lean mixture will always make more power because total combustion is achieved. The question is however, for how long will the engine tolerate the abuse?yzman said:
Maybe on a 2st.I have not seen that on any 4st's.
I will buy this in cases where we are doing the tuning but Yamaha has to meet emissions.Is a phazer rich in some areas?Yes probably but not others.Therefore if you lean out the whole range some areas will be real lean and that will be a power loss.Almost every 4st I have tuned likes between 12:1 and 13.5:1.The govt and most manufacturers call that rich and polluting.Running those same motors at 11:1 wich is richer is usually very little power loss.Sometimes a rich condition even smooths out some low areas.Now if run at 15:1 the power loss vs 13:1 is huge.This is just another case where Dyno charts showing before and after with AFR and HP should be posted.
I will buy this in cases where we are doing the tuning but Yamaha has to meet emissions.Is a phazer rich in some areas?Yes probably but not others.Therefore if you lean out the whole range some areas will be real lean and that will be a power loss.Almost every 4st I have tuned likes between 12:1 and 13.5:1.The govt and most manufacturers call that rich and polluting.Running those same motors at 11:1 wich is richer is usually very little power loss.Sometimes a rich condition even smooths out some low areas.Now if run at 15:1 the power loss vs 13:1 is huge.This is just another case where Dyno charts showing before and after with AFR and HP should be posted.
I have two highly modified v8 with carbs. I use a innovate wideband 02 and data logger. I run 15.2 to 15.8 afr in cruise mode at 62 mph . Wide open these engines run at 12.5. I get 23mpg no problem on both cars. And i can run wide open all day long. Running lean in low load condtions will not hurt 4 strokes and helps with gas milage. Does it matter if an engine is not getting max hp at part throttle or is better fuel economy at cruise more important?
Otter
Otter
Thats a opinion thing.I like power everywhere.Gas is cheap for now at least but I see where you are coming from.Lean running also builds heat and we have enough Phazers running hot to not make it any worse.Your cars coolant system must be able to handle it.
Boo Rad
Veteran
Well said RUCKUS. Too rich, robs power. Too lean, risk failure. Also, as Cannondale said, to find ideal AFR for peak power, you will need a dyno to give you hp numbers while you tune. Then you can work on every part of the RPM range. The data aquisition equipment will give you all the air, fuel, and temperature data.
To be fair, comparing a Phazer motor to a built motor is apples to oranges. These motors are a production piece. All of us here are interested in the potential of these motors and trying to reach it, yamaha is interested in the longevity. Therfore, they are not going to push the limits.
To be fair, comparing a Phazer motor to a built motor is apples to oranges. These motors are a production piece. All of us here are interested in the potential of these motors and trying to reach it, yamaha is interested in the longevity. Therfore, they are not going to push the limits.
