So who wants their ECU's "Chromed"?

[Toni]

I realize this is not ideal but what about adding an additional relay or driver circuit to handle these other solenoids?

[Stealth_RT]

Greg, I should have the GM BCS soon . . . I will get the resistance, check the actual draw, and then if all is well I will give it a whirls. I also looked into the MAC/AEM/Greddy boost control solenoid. Although this is a GREAT solenoid, it draw far too much current for our setup. According to the spec sheet I found, the MAC 35A-AAA-DDBA-1BA has a 25.4 ohm coil and draws .45 Amps @ 12 volts.

Technically speaking, 25.4 ohms at 12 volts is more like 472 mA. Still a little too hot for our cars. And even more technically speaking, IF you factor in the fact that our electrical system will never be that low on voltage (Mitsubishi uses the 14.4 volt reference), you can expect a typical 13.6-13.8 volts at any given time which then calculates out to 535 mA @ 13.6 v and 567 mA at 14.4 v. That is WAY too much.

[/GEEK ON]

Don't forget about inrush current when the solenoid is energized and back-EMF when the soldenoid is de-energized. What can the 98/99 ECU handle for those?

[/GEEK OFF]

[99 vr4]

[GEEK MODE]

The ECU is designed with diodes in place for inrush current and back EMF. The ECU is already equipped to handle the normal solenoids without any external protection. Wiring a relay in place to then control the higher draw solenoid is actually a bad idea. For instance, the BCS uses a duty cycle. This duty cycle (I can't remember the frequency range) is how the ECU can control the boost. Most relays are not so good for that. Relays like to be on or off, not switched on and off 100 times a second (100Hz). That being said, it is possible to then drive another transistor with the appropriate protection circuitry external to the ECU. But costs, complexity, and the fact that you now have additional circuits which can not only fail but add to the delay in activation render this solution not ideal.

I would recommend that you go back to the 5 watt resistor idea. This would at least limit the amount of current the ECU sees, is inexpensive, and since it is a passive component should not add any delay to the circuit.

In the end the GM BCS might be the best three port solution. Lets just see what the coil resistance and current draw are when I finally get it.

[/GEEK MODE]

[james92tsi]

GM/Delco BCS, part # 1997152

coil 24.2 ohm

volts / amps
12.0 / .50
12.5 / .51
13.0 / .52
13.5 / .54

Resistance measured with Fluke multimeter
V / A are just the amp readings displayed on my CV/CC power supply (in CV mode) at the specified voltages.

Enjoy,

James

[Goallie11]

Don't know if anyone has seen this while looking at the evoscan website but they're developing evoscan for android and iOs. Seems like it requires either Bluetooth or a USB cable but that will be incredibly convenient if we can use it to log without a computer.

http://www.evoscan.com/android-evox-can-obdii

[Chris@Rvengeperformance]

Don't know if anyone has seen this while looking at the evoscan website but they're developing evoscan for android and iOs. Seems like it requires either Bluetooth or a USB cable but that will be incredibly convenient if we can use it to log without a computer.

Android EvoX CAN OBDII MUTIII

that would be handy, but the tactrix cable can do standalone logging. Since you can't run ecuflash on the phones you need a computer to make any changes anyway.

[99 vr4]

GM/Delco BCS, part # 1997152

coil 24.2 ohm

volts / amps
12.0 / .50
12.5 / .51
13.0 / .52
13.5 / .54

Resistance measured with Fluke multimeter
V / A are just the amp readings displayed on my CV/CC power supply (in CV mode) at the specified voltages.

Enjoy,

James

James thank you.... I guess I will pick up a resistor for testing..

Tenet mitsu used an absolute ceiling of 14.4 volts for their design...

[james92tsi]

James thank you.... I guess I will pick up a resistor for testing..

Tenet mitsu used an absolute ceiling of 14.4 volts for their design...

No problem Brett! A couple more data points to get you up to 14.4V:

volts / amps
14.0 / .56
14.4 / .58

James

[Goallie11]

that would be handy, but the tactrix cable can do standalone logging. Since you can't run ecuflash on the phones you need a computer to make any changes anyway.

True, but you'd be able to review logs while in the car and moving. For instance if you have a laptop with incredibly shitty battery life like mine it'd be useful.

[Vishnu]

GM/Delco BCS, part # 1997152

coil 24.2 ohm

So we're looking at 3 options so far for aftermarket bcs then.

GM 3-Port BCS at 24.2ohms (read 25ohms on evolutionm), but let's go with 24.2 for safety sake:
~12ohm 5watt resistor

Grimmspeed 3-Port BCS at 32 ohms:
~ 4-10ohm 5 watt resistor

Evolution X Stock BCS at 29 - 36 ohms:
~ 10ohm 5 watt resistor