renesis porting update
06-23-2005, 12:38 PM
#103
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oh yea....he'll go for that 
i've decided i want 2 blowers for the fd. one shooting through an intercooler, then the other one to mix the fuel up. i bet that'd be the **** with a cosmo 13b and the 9.7:1 n/a rotors!
i've decided i want 2 blowers for the fd. one shooting through an intercooler, then the other one to mix the fuel up. i bet that'd be the **** with a cosmo 13b and the 9.7:1 n/a rotors!
06-23-2005, 05:10 PM
#105
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nope.
i want the homoginised fuel mixture, but i want really low intake temps, so shoot the high pressure one through the intercooler, then shoot gas into the next one --be it smaller, or whatever, just to homoginise the mixture.
the second blower wouldn't create much boost, so not much heat.
maybe we can get the intake down to below ambient?
i want the homoginised fuel mixture, but i want really low intake temps, so shoot the high pressure one through the intercooler, then shoot gas into the next one --be it smaller, or whatever, just to homoginise the mixture.
the second blower wouldn't create much boost, so not much heat.
maybe we can get the intake down to below ambient?
06-23-2005, 06:46 PM
#107
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my bad...it's hot and i lose brainpower inversely proportional to the square of the ambient temperature above 70*
wtf did i just say?
but the second s/c would be more for efficiency--rather than power. i'm gonna try high compression rotors in the next engine and i'm not quite sure where i'm gonna run out of room on pump gas. maybe in the 350-400 whp range?
i'm just curious to see exactly how much gas milage i can milk out of an engine. 30 is a little optimistic, but i might be able to get consistant 25's...i'd be more than happy with that.
and if i want more power, i'll dump in a tank of race gas and go for it.
the main problem i've had all my life is my budget can't keep up with my ambition :p
wtf did i just say?
but the second s/c would be more for efficiency--rather than power. i'm gonna try high compression rotors in the next engine and i'm not quite sure where i'm gonna run out of room on pump gas. maybe in the 350-400 whp range?
i'm just curious to see exactly how much gas milage i can milk out of an engine. 30 is a little optimistic, but i might be able to get consistant 25's...i'd be more than happy with that.
and if i want more power, i'll dump in a tank of race gas and go for it.
the main problem i've had all my life is my budget can't keep up with my ambition :p
06-23-2005, 06:48 PM
#108
It's already series supercharging, one stage to the next to the next. What your talking about is done on some gas turbines with multiple shafts. Not with the fuel but with the "True Intercooling" Everything else is really "aftercooling", if you want to get technical. But we don't. Because then all the Volvos would have to change the script on the back of their cars.
06-23-2005, 11:23 PM
#110
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Couple things:
1. Port actuators: Are these driven by stepper motors? If so, controlling them requires a PWM signal. You just change the duty cycle to determine how they move/their position. Finding this signal is easy. You just need an o-scope hooked to the right wire and you can read it with the car on a dyno. Then rev the car up and watch the PWM signal change as they open and as they close.
2. Throttle signal: This one is a bit trickier but you can do the same kind of analysis. Find out what kind of signal it is. I'm willing to bet it's some kind of sampled A-D conversion going on that you could easily control/duplicate with a simple lookup table.
1. Port actuators: Are these driven by stepper motors? If so, controlling them requires a PWM signal. You just change the duty cycle to determine how they move/their position. Finding this signal is easy. You just need an o-scope hooked to the right wire and you can read it with the car on a dyno. Then rev the car up and watch the PWM signal change as they open and as they close.
2. Throttle signal: This one is a bit trickier but you can do the same kind of analysis. Find out what kind of signal it is. I'm willing to bet it's some kind of sampled A-D conversion going on that you could easily control/duplicate with a simple lookup table.
06-24-2005, 01:26 AM
#111
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i so don't want to get that complicated with the throttle...pedal position=throttle plate position. if we can get it from the computer, fine, if not, the cable. i can't stand these "mystery safe modes" and other bullshit. mazda seriously doesn't want you ******' around with the computers. i accept this, so out with the touchy bitch :p
i've never hooked up stepper control to anything, but if you're hip with that, hit me up on aim and explain how it works. i'm a quick learner.
i've never hooked up stepper control to anything, but if you're hip with that, hit me up on aim and explain how it works. i'm a quick learner.
06-24-2005, 12:08 PM
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I don't know how much benefit the computer-controlled throttle adds to the engine, but its more than 0; it does have a positive benefit.
The stock pedal unit, AFAIK, has two pots in it. The computer reads the v from these and cancels out the differences (noise reduction). This value, and the RPM of the engine provide the coordinates in the lookup table for the appropriate throttle position. There is one table for acceleration, and one for deceleration. Basically, if you are at low rpms and you mash the pedal, the throttle will not snap open. Instead it will open progressively, and the computer should be maintaining an optimal amount of opening to accelerate the engine as fast as possible.
So why not open the throttle all the way at low rpms? Well, at any given rpm we want to cram as much air as possible into the engine. The way to do this is to use the intake velocity to pressurize the rotor chamber to the max right before the intake closes. If the chamber is pressurized too quickly, the intake flow will be stalled by air spilling back out of the chamber. Therefore, the velocity of the air is crucial, since high velocity air of the appropriate volume will fill the chamber more completely than an intake with no restrictions, but little velocity.
So by keeping the throttle partially closed, we can maximize the velocity of the air going into the engine, allowing the chamber to be pressurized higher than if we do not maximize velocity. Higher pressures means a higher volume of air trapped in the chamber, means more power.
Also, with the 2 sets of ports opening, the ideal throttle positions may change as well, since the timing and surface area of the intake has changed. The computer-controlled throttle lets us optimize the velocity throughout the powerband. The only drawbacks are complexity and decreased throttle response, since the stepper motor has a finite number of positions and there is inherent delay in the control systems.
All I'm saying is that the electronic throttle system has tangible benefits in terms of power. I would love to see a dyno of a stock renesis vs. one with a conventional throttlebody of the same size. I'd wager the stock system makes more power throughout the powerband.
The stock pedal unit, AFAIK, has two pots in it. The computer reads the v from these and cancels out the differences (noise reduction). This value, and the RPM of the engine provide the coordinates in the lookup table for the appropriate throttle position. There is one table for acceleration, and one for deceleration. Basically, if you are at low rpms and you mash the pedal, the throttle will not snap open. Instead it will open progressively, and the computer should be maintaining an optimal amount of opening to accelerate the engine as fast as possible.
So why not open the throttle all the way at low rpms? Well, at any given rpm we want to cram as much air as possible into the engine. The way to do this is to use the intake velocity to pressurize the rotor chamber to the max right before the intake closes. If the chamber is pressurized too quickly, the intake flow will be stalled by air spilling back out of the chamber. Therefore, the velocity of the air is crucial, since high velocity air of the appropriate volume will fill the chamber more completely than an intake with no restrictions, but little velocity.
So by keeping the throttle partially closed, we can maximize the velocity of the air going into the engine, allowing the chamber to be pressurized higher than if we do not maximize velocity. Higher pressures means a higher volume of air trapped in the chamber, means more power.
Also, with the 2 sets of ports opening, the ideal throttle positions may change as well, since the timing and surface area of the intake has changed. The computer-controlled throttle lets us optimize the velocity throughout the powerband. The only drawbacks are complexity and decreased throttle response, since the stepper motor has a finite number of positions and there is inherent delay in the control systems.
All I'm saying is that the electronic throttle system has tangible benefits in terms of power. I would love to see a dyno of a stock renesis vs. one with a conventional throttlebody of the same size. I'd wager the stock system makes more power throughout the powerband.
06-25-2005, 01:22 AM
#114
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Originally Posted by tuj
I don't know how much benefit the computer-controlled throttle adds to the engine, but its more than 0; it does have a positive benefit.
The stock pedal unit, AFAIK, has two pots in it. The computer reads the v from these and cancels out the differences (noise reduction). This value, and the RPM of the engine provide the coordinates in the lookup table for the appropriate throttle position. There is one table for acceleration, and one for deceleration. Basically, if you are at low rpms and you mash the pedal, the throttle will not snap open. Instead it will open progressively, and the computer should be maintaining an optimal amount of opening to accelerate the engine as fast as possible.
So why not open the throttle all the way at low rpms? Well, at any given rpm we want to cram as much air as possible into the engine. The way to do this is to use the intake velocity to pressurize the rotor chamber to the max right before the intake closes. If the chamber is pressurized too quickly, the intake flow will be stalled by air spilling back out of the chamber. Therefore, the velocity of the air is crucial, since high velocity air of the appropriate volume will fill the chamber more completely than an intake with no restrictions, but little velocity.
So by keeping the throttle partially closed, we can maximize the velocity of the air going into the engine, allowing the chamber to be pressurized higher than if we do not maximize velocity. Higher pressures means a higher volume of air trapped in the chamber, means more power.
Also, with the 2 sets of ports opening, the ideal throttle positions may change as well, since the timing and surface area of the intake has changed. The computer-controlled throttle lets us optimize the velocity throughout the powerband. The only drawbacks are complexity and decreased throttle response, since the stepper motor has a finite number of positions and there is inherent delay in the control systems.
All I'm saying is that the electronic throttle system has tangible benefits in terms of power. I would love to see a dyno of a stock renesis vs. one with a conventional throttlebody of the same size. I'd wager the stock system makes more power throughout the powerband.
The stock pedal unit, AFAIK, has two pots in it. The computer reads the v from these and cancels out the differences (noise reduction). This value, and the RPM of the engine provide the coordinates in the lookup table for the appropriate throttle position. There is one table for acceleration, and one for deceleration. Basically, if you are at low rpms and you mash the pedal, the throttle will not snap open. Instead it will open progressively, and the computer should be maintaining an optimal amount of opening to accelerate the engine as fast as possible.
So why not open the throttle all the way at low rpms? Well, at any given rpm we want to cram as much air as possible into the engine. The way to do this is to use the intake velocity to pressurize the rotor chamber to the max right before the intake closes. If the chamber is pressurized too quickly, the intake flow will be stalled by air spilling back out of the chamber. Therefore, the velocity of the air is crucial, since high velocity air of the appropriate volume will fill the chamber more completely than an intake with no restrictions, but little velocity.
So by keeping the throttle partially closed, we can maximize the velocity of the air going into the engine, allowing the chamber to be pressurized higher than if we do not maximize velocity. Higher pressures means a higher volume of air trapped in the chamber, means more power.
Also, with the 2 sets of ports opening, the ideal throttle positions may change as well, since the timing and surface area of the intake has changed. The computer-controlled throttle lets us optimize the velocity throughout the powerband. The only drawbacks are complexity and decreased throttle response, since the stepper motor has a finite number of positions and there is inherent delay in the control systems.
All I'm saying is that the electronic throttle system has tangible benefits in terms of power. I would love to see a dyno of a stock renesis vs. one with a conventional throttlebody of the same size. I'd wager the stock system makes more power throughout the powerband.
we knew all that... my point is: if you don't know how far the throttle is going to open at any given time, what good is it? does it have a safe mode, limp mode, etc? when do they come on--under what conditions? we don't know any of that stuff and mazda sure isn't gonna tell us, so i say get rid of it on modified/ported cars.
as soon as you bolt on a turbo or port the motor, you just negated the preset rpm/load/tp/ throttle plate position points. they no longer apply, so why keep them? mazda did all their research on stock ported, n/a motors. that's what the computer is meant to control...so be it.
07-05-2005, 04:38 PM
#115
Originally Posted by tuj
The port actuators are solenoids (AFAIK) which allow the doors on the port runners to be opened progressively by vaccuum.
07-05-2005, 04:57 PM
#116
Registered
The port actuators are nothing more than vacuum diaphragms. They work the same way that a turbo wastegate works. A certain amount of air pressure or vacuum opens them. The air to these actuators runs through an electric valve. All this little valve does is open or close the air supply to the actuators based on an electric signal. It is a simple setup.
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