Full throttle Electric Supercharger Build Thread

[fenton]

Originally Posted by Bu-Tang

I pretty much have no DR on mine, it doesn't kick in till like 6k which if I'm at 6k in WOT. I have yet to experience the DR line fenton has

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Today is a little busy maybe tomorrow.

[mid_life_crisis]

Originally Posted by fenton

A Dyno run will show it if you move the WOT activation switch out of the way.

Trust me @mid_life_crisis i have heard you loud and clear just haven't been back to the dyno with a DR capable controller yet.

My understanding of the DR is that it is always enabled, even when the switch is off. Just because you don't want wide open throttle boost available, that doesn't mean you want less than stock performance, correct?

I'm not expecting big gains by any means. There is just something about the way you described it once that makes me expect significant "smoothing" of the torque dip.

[MikeW]

Originally Posted by Gary in NJ

A dyno run wont show the effects of drag reduction. Dyno's are run at WOT.

Here's how much I like the power delivery as is. Yesterday Rob offered to provide me with a more aggressive DR profile. "Just send me your controller and I'll update it". No way. I will not part with the ESC for a week. As much as I want the benefits of DR, I wont drive my car without an ESC. It's like asking a superhero to give up his power Heck, I drove without any DR for a full week before I was instructed to hook it up.

I'll send in my controller when I park the BRZ for winter. Any and all updates can wait. This car is too much fun to drive.

Now you're just messing with our heads...

[MikeW]

Originally Posted by fenton

Here is a headerback FRS(stage 1 exutek) against a ESC frs(untuned)

First race is 3500rpm 2nd gear.

Second is 3000rpm 3rd gear.

This was a long time ago though and with a tune this thing is way stronger down low and up high.

Wow, you can really see the benefit of starting at the lower rpm. Much more acceleration for a longer period before the shift.

It would be good to see this done where both cars lift off the gas when they hit redline in the respective gear.

[fenton]

Originally Posted by mid_life_crisis

My understanding of the DR is that it is always enabled, even when the switch is off. Just because you don't want wide open throttle boost available, that doesn't mean you want less than stock performance, correct?

I'm not expecting big gains by any means. There is just something about the way you described it once that makes me expect significant "smoothing" of the torque dip.

It is always enabled thats why i said the dyno WILL show the difference.

What im getting at is you have to move the WOT switch for FULL activation out of the way so you dont get 5psi of boost.

The system works based on negetive pressure detected between the charger, it works to equalize that pressure once detected..... IE if you drive around at 10% throttle or on cruise control DR will never activate.

Once you request the car to accelerate beyond the limits that can flow threw the charger a negative pressure is created, the controller then pulses the charger to try and match the known atmospheric pressure.

hth

[Gary in NJ]

Originally Posted by fenton

Once you request the car to accelerate beyond the limits that can flow threw the charger a negative pressure is created, the controller then pulses the charger to try and match the known atmospheric pressure.

Right and just for clarity, it is just that - a single pulse for a fraction of a second (I'm not aware of the software routine so I don't know the potential duration). Drag Reduction doesn't run the motor PWM'd. From my experience (it's engaged twice that I'm aware of, but it might be more often) it's just a quick shot of power to minimize any restriction that the non-spinning turbine may momentarily create. The reason I haven't used it much is because I'm generally passing through the throttle zone where it would be most helpful. What can I say, I like boost.

[mid_life_crisis]

Originally Posted by fenton

It is always enabled thats why i said the dyno WILL show the difference.

What im getting at is you have to move the WOT switch for FULL activation out of the way so you dont get 5psi of boost.

The system works based on negetive pressure detected between the charger, it works to equalize that pressure once detected..... IE if you drive around at 10% throttle or on cruise control DR will never activate.

Once you request the car to accelerate beyond the limits that can flow threw the charger a negative pressure is created, the controller then pulses the charger to try and match the known atmospheric pressure.

hth

The point I was trying to make (sorry I wasn't more clear) is that my understanding is that if you turn the master switch on the dashboard (or wherever you decide to mount it) to "Off", the DR is still enabled, even though full throttle boost is not, so there is no reason to move the engagement switch out from under the gas pedal.
If DR is disabled when the switch is set to "Off", that needs to be changed.

[Gary in NJ]

Originally Posted by mid_life_crisis

The point I was trying to make (sorry I wasn't more clear) is that my understanding is that if you turn the master switch on the dashboard (or wherever you decide to mount it) to "Off", the DR is still enabled, even though full throttle boost is not, so there is no reason to move the engagement switch out from under the gas pedal.
If DR is disabled when the switch is set to "Off", that needs to be changed.

The arm switch acts as a master switch. In the off position the turbine doesn't engage nor do the batteries receive a charge. Other then valet situations, I can't imagine why it wouldn't be Armed/On. I thought it would be good for when my son drives the car...but it only took one engagement for him to understand how the system works. I may fabricate a electromagnetic switch (solinoid) so it can be keyed with the ignition system. There are simple continuous duty 28VDC solenoids that I have used in experimental aircraft that are low cost and can safely handle the amperage.

[mid_life_crisis]

Originally Posted by Gary in NJ

Right and just for clarity, it is just that - a single pulse for a fraction of a second (I'm not aware of the software routine so I don't know the potential duration). Drag Reduction doesn't run the motor PWM'd. From my experience (it's engaged twice that I'm aware of, but it might be more often) it's just a quick shot of power to minimize any restriction that the non-spinning turbine may momentarily create. The reason I haven't used it much is because I'm generally passing through the throttle zone where it would be most helpful. What can I say, I like boost.

If that is accurate, I am going to be very disappointed with that dyno. This is going to require some customization on my part to get exactly what I want.

[mid_life_crisis]

Originally Posted by Gary in NJ

The arm switch acts as a master switch. In the off position the turbine doesn't engage nor do the batteries receive a charge.

More customization.

[Gary in NJ]

Originally Posted by mid_life_crisis

If that is accurate, I am going to be very disappointed with that dyno. This is going to require some customization on my part to get exactly what I want.

As Fenton accurately pointed out, he can provide dyno numbers by simply removing the throttle switch. This will allow him to test the drag reduction without activating a full boost cycle. However this is an abnormal condition. Under normal conditions:

System Armed, Switch Not Activated = Allows Drag Reduction
System Armed, Switch Activated = Full Boost
System Not Armed, No Power

The condition you want him to test doesn't really exist (System Armed, Switch Disabled). However, it will allow Rob to see if the drag reduction program is able to recover any restriction that is created by a free wheeling turbine.

It's a valid test, just not real world conditions.

I'm not sure what you *want* is easily (and inexpensively) achievable. You want to run partial boost all the time. In order to do that you will need to pulse width modulate the compressor motor. That will require a significant modification to the controller (actually, a new controller). Moreover, PWM'ing that type of current will produce a significant amount of heat, further complicating your custom controller.

The trouble is what you *want* and what this is are two different things. This is a full throttle, full boost system. You want scalability. That scalability comes at a cost. To create that circuit you will need to design an PWM circuit that uses a microcontroller and a fairly significant FET that can handle the inrush and duration of the available amperage, plus a safety margin. I use to work for a company that manufactured ECB's (Electronic Circuit Breakers) for the aircraft industry. I can tell you with certainty, it ain't easy.

I know your motivation is to be able to have boost without ECU modification. But your plan is sending you down a rabbit hole where a known tune is a heck of a lot easier, less expensive and perhaps safer.

[rusty959]

Originally Posted by Gary in NJ

As Fenton accurately pointed out, he can provide dyno numbers by simply removing the throttle switch. This will allow him to test the drag reduction without activating a full boost cycle. However this is an abnormal condition. Under normal conditions:

System Armed, Switch Not Activated = Allows Drag Reduction
System Armed, Switch Activated = Full Boost
System Not Armed, No Power

The condition you want him to test doesn't really exist (System Armed, Switch Disabled). However, it will allow Rob to see if the drag reduction program is able to recover any restriction that is created by a free wheeling turbine.

It's a valid test, just not real world conditions.

I'm not sure what you *want* is easily (and inexpensively) achievable. You want to run partial boost all the time. In order to do that you will need to pulse width modulate the compressor motor. That will require a significant modification to the controller (actually, a new controller). Moreover, PWM'ing that type of current will produce a significant amount of heat, further complicating your custom controller.

The trouble is what you *want* and what this is are two different things. This is a full throttle, full boost system. You want scalability. That scalability comes at a cost. To create that circuit you will need to design an PWM circuit that uses a microcontroller and a fairly significant FET that can handle the inrush and duration of the available amperage, plus a safety margin. I use to work for a company that manufactured ECB's (Electronic Circuit Breakers) for the aircraft industry. I can tell you with certainty, it ain't easy.

You are incorrect about the difficulty of controlling the motor at partial levels. Keep in mind this is a brushless motor, its already getting a three phase input with each phase resembling a simple pwm. Again depending on what he has in the controller, partial throttle abilities would be simple. No extra high current FET is needed.

Depending on the structure of the controller he has, its just a firmware change. He obviously has something more there besides just a WOT switch since the capability for DR is there. The pulsing experienced may just be the lack of a slightly more complicated PID controller being programmed in depending on if he has a microcontroller in there or just a simple analog circuit.

The biggest problem with a partial throttle boost is that how much you would want would depend on throttle level and rpm, which are two things the controller is not currently receiving. (besides the wot switch) If you have those, its just a bit of programming. (and ensuring you have the capabilities in the charging system of course)

[Gary in NJ]

Originally Posted by rusty959

You are incorrect about the difficulty of controlling the motor at partial levels. Keep in mind this is a brushless motor, its already getting a three phase input with each phase resembling a simple pwm. Again depending on what he has in the controller, partial throttle abilities would be simple. No extra high current FET is needed.

Yes, you are correct. My experience was to control "generic" loads, but this being a defined load it is more easily controlled.

You are also correct in that a logic based controller will require ECU data. I'm not sure if the CAN data bus rate would be sufficient, especially during high traffic events. A direct SPI or I2C (I don't know what's used in the ECU) would be required.

Like I said above, given the effort required for what mid_life wants, an ECU tune is oh so easy. Heck, if it's dealer detection he's worried about, buy a second ECU for $600 and flash that one. Reinstall your original ECU for dealer visits.

[mid_life_crisis]

Originally Posted by rusty959

The biggest problem with a partial throttle boost is that how much you would want would depend on throttle level and rpm, which are two things the controller is not currently receiving. (besides the wot switch) If you have those, its just a bit of programming. (and ensuring you have the capabilities in the charging system of course)

It seems like this should be a simple matter for an arduino or something similar.
I realize this seems like it belongs over on the open-source thread, but I don't want to reinvent the wheel when Rob has already done so much good work. I'd rather take his wheel and put fancier rims on it.