Rotary Car Club - View Single Post - 13B Power @ 1 bar absolute pressure, to see what you might have if you MAN UP!

Barry Bordes · 02-03-2014, 12:56 PM

Peter,
Yes probably apples and oranges.... but I have been trying to optimize low boost settings.
This can be different from high boost tuning. Let me explain.

The TFX Engine Technology system derives its readings from pressure inside the rotor chamber. It compares the volume at each degree of eccentric rotation to the pressure readings at each degree. So we have pressure (psi) times area of the rotor face times eccentric offset which giving torque.
I am not sure if frictional forces are figured into their HP formulas but they are incorporated in the IMEP so it would seem that that would cover HP also.

IMEP is my normal tool for comparing my tuning runs. With normal "forum info timing" the mean effective pressure averaged a little over 200 psi and peak pressures of around 650 psi. This has improved to over 300 psi IMEP and 1250 psi Peak Pressure by positioning peak at 45 degrees ATDC.

But as boost goes up peak pressure becomes the limiting factor. The only way we can know the material limits of the rotary becomes a very hard lesson.
Once we get to this peak pressure limit we have to retard the ignition.

So any correction to NA as you are doing will show a loss in power compared to having the peak pressure at 45 degrees ATDC at lower boost.

Barry

*Personally your figures are way too high since you are not taking into account friction or if you are underestimating it? in the software deriving the bhp? thus it would be good to actually measure the 'brake' power directly rather than software estimation? (my thoughts on it) based off my experience and engine combos listed already that are well known.

This is where testing it with a VBOX (if you don't trust 'dyno's' would help)*

So this is indicated power of a single cycle, do you have a mean bhp? (bhp = iP-fP) over at least 1 second that you can average to confirm a 'statistical average of say at least ~100 cycles' mean pressure acting and thus power level for the sake of comparison to steady state measurement principles.
Thanks.

Yes it shows HP for all cycles and the highest RPM is usually the highest HP.

p.s. Have you ever tested your car for brake power on any system other than this to validate what it is saying you have? How are you or it measuring the frictional power (fP) loss in the engine????, you have the 'indicated power' through pressure from what I can see you posted, but its not what is coming out of the engine (brake horse power), like to know some more on how you derive your power figure?

No, only a Gtech Pro.

02-03-2014, 12:56 PM	#29
Barry Bordes Rotary Fanatic Join Date: Feb 2008 Location: Slidell, LA Posts: 191 Rep Power: 18	Peter, Yes probably apples and oranges.... but I have been trying to optimize low boost settings. This can be different from high boost tuning. Let me explain. The TFX Engine Technology system derives its readings from pressure inside the rotor chamber. It compares the volume at each degree of eccentric rotation to the pressure readings at each degree. So we have pressure (psi) times area of the rotor face times eccentric offset which giving torque. I am not sure if frictional forces are figured into their HP formulas but they are incorporated in the IMEP so it would seem that that would cover HP also. IMEP is my normal tool for comparing my tuning runs. With normal "forum info timing" the mean effective pressure averaged a little over 200 psi and peak pressures of around 650 psi. This has improved to over 300 psi IMEP and 1250 psi Peak Pressure by positioning peak at 45 degrees ATDC. But as boost goes up peak pressure becomes the limiting factor. The only way we can know the material limits of the rotary becomes a very hard lesson. Once we get to this peak pressure limit we have to retard the ignition. So any correction to NA as you are doing will show a loss in power compared to having the peak pressure at 45 degrees ATDC at lower boost. Barry Personally your figures are way too high since you are not taking into account friction or if you are underestimating it? in the software deriving the bhp? thus it would be good to actually measure the 'brake' power directly rather than software estimation? (my thoughts on it) based off my experience and engine combos listed already that are well known. This is where testing it with a VBOX (if you don't trust 'dyno's' would help) So this is indicated power of a single cycle, do you have a mean bhp? (bhp = iP-fP) over at least 1 second that you can average to confirm a 'statistical average of say at least ~100 cycles' mean pressure acting and thus power level for the sake of comparison to steady state measurement principles. Thanks. Yes it shows HP for all cycles and the highest RPM is usually the highest HP. p.s. Have you ever tested your car for brake power on any system other than this to validate what it is saying you have? How are you or it measuring the frictional power (fP) loss in the engine????, you have the 'indicated power' through pressure from what I can see you posted, but its not what is coming out of the engine (brake horse power), like to know some more on how you derive your power figure? No, only a Gtech Pro.