MAC BCS revisited

[Vishnu]

So I know the industry standard is 35A-AAA-DDBA-1BA: 12v 5.4W for BCS applications.

I managed to get a hold of a 35A-AAA-DEEA-1BA: 12v 4.2W Any idea if these would work at first glance? My damn multimeter is refusing to work so I can't get a proper reading on these things at the moment.

[Greg E]

This is a Brett/Adam question. I have no idea what the hardware specs are for the PWM drivers on the ECU. You may need to wire in a few resistors.

[Vishnu]

Haven't heard back from them yet. I did test this @ 12v getting ~300mA, give or take 5mA. 34.5Ohm resistance.

[RealMcCoy]

Spec on the OE solenoid is 36-44 ohms. That would be very close.

The math says a 40 ohm resistance will pass 300mA at 12V. A 35 ohm resistance should pass 343mA at the same voltage.

You would need to ask one of the guys that knows the ECU circuitry better,(I wouldn't want to bump the current flow 10% without checking first) but my guess is, that's going to be in an operable range.

[Vishnu]

I got 5 since they were cheap enough and the local supplier is a smaller business. Figured I could hand a few out to the people that know significantly more than me for testing, if they're willing.

[Greg E]

3-port is definitely the way to go. I've tried everything under the hood to find a good bleeder style solenoid that will work. Truth is, nothing worked with stock waste gates.

The stock FPR solenoid is showing a lot of promise. Hardware specs are identical as the stock BCS and swapping the connector is easy for plug and play fun and everyone enjoys the free mod action. I was going to do a write up on it after more real world testing is done. So far just me and Adam are running it.

[Vishnu]

The very next lowest wattage is the 35A-AAA-DFEA-1BA 12v 2.4W. I don't know if this is too underpowered for our application.

What's the maximum boost you've been able to push on the stock FPR?

[Vishnu]

There was one other option I was considering, a 3 port 33A. It's a different body style and uses an M5 thread instead of 1/8", but it's possible to get 12v 3W and 12v 4W.

[Greg E]

22psi so far with the FPR at 75% duty cycle.

The FPR is setup as a 3 port instead of a bleeder like stock. With the ability to block off most of the airflow, its able to operate much better than stock. The only issue (and this is more of a nuisance) is its kinda noisy when its operating.

[GTOJOE]

I broke the top nipple of my stock solenoid and glue doesn't seem to hold it so was going to buy a Mac but Michael is giving me a Perrin Performance solenoid but I have removed my fpr solenoid and remembered reading about it being used to replace the boost one. Is the Mac or similar going to work fine?

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[Vishnu]

The typical MAC's available on the market will need a resistor wired in. The one I found, I'm fairly certain is the same one used by Grimmspeed for the Evo. They claim 12v 5.4w, but the mA rating and resistance is that of the 4.2w valve. I think to safely run a mac valve directly with our ecu's we need a 12v 4W (According to the calculator is 36ohm resistance), which isn't available in the 35A model. I know the 33A model has a 12v 4w model and is a solenoid based valve also, but I'm not sure if it's capable of working as a BCS just yet. Lead time on these are 4-5 weeks, so it'll be at least a month until I physically have one.

That's just about all the information I've gathered so far on MAC. If any of the above information is wrong or completely false, please correct to spread proper knowledge on the matter.

[99 vr4]

Anything in the 300 - 350 ma range should do just fine... Remember V * I = W.... So at 12vdc 320 mA is 12 * .320 = 3.84 watts...

Just remember that relays and the such are CONSTANT wattage devices... So a 4.2w device will have the following:

4.2w / 12vdc = 350mA
4.2w / 13.6vdc = 309mA
4.2w / 14.4vdc = 291mA

You should be fine with the 4.2w device since most circuits are rated MAX 500ma..

[Vishnu]

I'm still going to try and get a hold of the 33A valve just in case it works, 12v 4w makes just about everything fall into range. In the mean time, what would the worst case scenario be if this valve doesn't work? The only thing that really bothers me is the 34ohm resistance, since it's not in that 36-44 sweet spot. The mA is within range but the resistance isn't, If you don't think that'll be too huge of an issue, I'll start toying with it this weekend at my own risk. Luckily I'm still mostly stock and the old ecu is still plug and play.

[Greg E]

I'm anxious to see your results. While the stock FPR solenoid has shown great promise, I fear it may not be able to flow enough air once we start getting in the real airflow ranges (550+whp).

[Vishnu]

Trying to make sure I have all of my information in line before I plug this bad boy in. The extent of my boost control tuning knowledge extends to only the Greddy Profec b spec 2. I was going over your manual regarding boost setting, and the terms weren't foreign, but they were different than I've ever messed around with.

I know on the evo when plugging in this, the usual thing people do is reduce ass WGDC numbers by 30% and then fine tune from there. Would that be a good starting point for the vr4 too, or are there other values that you know will work for stock boost pressure (12psi) on a mac valve?

[GTOJOE]

I spoke to my tuner about using a Mac in replacement of our stock unit which is using a bleed method and he said it will require a restrictor to work correctly in this method. Which made me think where is the restrictor in the stock system? I just installed a perrin solenoid in place of the stock unit and now I'm thinking it will need a restrictor to function correctly.

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[Greg E]

Trying to make sure I have all of my information in line before I plug this bad boy in. The extent of my boost control tuning knowledge extends to only the Greddy Profec b spec 2. I was going over your manual regarding boost setting, and the terms weren't foreign, but they were different than I've ever messed around with.

I know on the evo when plugging in this, the usual thing people do is reduce ass WGDC numbers by 30% and then fine tune from there. Would that be a good starting point for the vr4 too, or are there other values that you know will work for stock boost pressure (12psi) on a mac valve?

The stock boost controller works the same as the APEXi AVCR. The higher the WGDC % the most boost you'll get. The thing that confuses people with the stock system is the addition of the airflow corrections feature where it'll automatically raise/lower the WGDC to reach your target airflow.

In chrome 2.1 I wrote in a quick disable bit for the boost corrections so you can just tune via the WGDC tables and not have the code auto correct for you. In chrome 2.0 you have to zero out the entire corrections table.

The problem with the stock boost solenoid is it can't bleed away enough air to give your more than a few psi change over your wastegate pressure. If you're running 20psi gates and want to run 22 lbs of boost, the stock solenoid might be fine.

The 3-port solenoids act like a blocker instead of a bleeder which is why they work so much better. Your limitation at that point is the amount of air the solenoid can block to maintain your desired boost/airflow. I would start with 45-50% and go from there.

GTOJoe, I've experimented with drilling out pills and running them in-line with the stock bleeder setup. It sucked. Lots of experimenting only to get a few psi worth of boost control. The 3-port setup is the way to go. I chose to experiment with the factory FPR 3-port solenoid as its the correct resistance for the ECU driver and its free. :)

It does work well up to 24psi so far btw. Beyond that we haven't done any experimenting yet....

[Jimvr4]

Anything in the 300 - 350 ma range should do just fine... Remember V * I = W.... So at 12vdc 320 mA is 12 * .320 = 3.84 watts...

Just remember that relays and the such are CONSTANT wattage devices... So a 4.2w device will have the following:

4.2w / 12vdc = 350mA
4.2w / 13.6vdc = 309mA
4.2w / 14.4vdc = 291mA

You should be fine with the 4.2w device since most circuits are rated MAX 500ma..

Brett, I disagree with this. Relays are coil based devices that have a constant impedance. If the 4.2W device measures 350mA @ 12V then it has a coil resistance of 34.28 ohms. Then at higher battery voltage the coil will draw more current and use more power, not less:

current = 12.0 V / 34.28 = 0.350A , power = (12.0V)^2 / 34.28 = 4.2W
current = 13.6 V / 34.28 = 0.396A , power = (13.6V)^2 / 34.28 = 5.4W
current = 14.4 V / 34.28 = 0.420A , power = (14.4V)^2 / 34.28 = 6.05W

Do we know the ECU driving circuit transistor and it's power capability?

BTW I think I have a spare Apexi solenoid I can measure. It may work but I think they will be too expensive for most people.

[Vishnu]

I bought some 2 ohm 5 watt resistors for safety sake even though I'm hoping to run this without 'em, and they were just so damn cheap with free shipping. Hopefully all of the ports and sintered mufflers come in today like they're supposed to. If they don't I may be forced to wait until next week.

[Greg E]

Route the vent port into the rear intake pipe. It'll help increase response time from the solenoid.

[GTOJOE]

I just installed a perrin performance solenoid in place of the stock unit connecting port one to the rear Turbo intake hose and port 2 to the H joiner like the stock unit and left port 3 open. However this method should have a restrictor in-between the Turbo boost pressure port 2 but the stock system doesn't appear to have any restrictions in it. Is this because of the type of solenoid used from factory? I'm thinking of redoing it using the other method as a restrictor is not required. I did drive it as is though and boost seems to come on a lot faster.

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[Greg E]

I just installed a perrin performance solenoid in place of the stock unit connecting port one to the rear Turbo intake hose and port 2 to the H joiner like the stock unit and left port 3 open. However this method should have a restrictor in-between the Turbo boost pressure port 2 but the stock system doesn't appear to have any restrictions in it. Is this because of the type of solenoid used from factory? I'm thinking of redoing it using the other method as a restrictor is not required. I did drive it as is though and boost seems to come on a lot faster.

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There's no restrictor in the stock system. All you did was just mimic the stock setup with this new solenoid.

BTW this setup with a restrictor is how the EVO comes stock. They all ditch it for a 3-port for the reasons I mentioned above.

[RealMcCoy]

There's no restrictor in the stock system. .

???

The feed hose from the Y-pipe with the red stripe has a .030" restrictor orifice... That's how the solenoid can bleed off the pressure at the wastegates. Otherwise you're just stuck at wastegate boost with a variable boost leak.

[Greg E]

???

The feed hose from the Y-pipe with the red stripe has a .030" restrictor orifice... That's how the solenoid can bleed off the pressure at the wastegates. Otherwise you're just stuck at wastegate boost with a variable boost leak.

No shit! I never seen this pill inside that hose!

Might explain some things... :suspect:

[Jesters Deadd]

I have used the 35A-AAA-DDBA-1BA: 12v 5.4W for a week of dailey driving with success. I switched to the fp solenoid to test it.
My math says about 3.2-4W is the range we are looking for at 12V to meet stock spec. The system is capable of 5.1-6.25W at 15V.
The transistor is rated at up to 2A continuous draw. So it looks like we are well below the max at about 450 mA.
If someone wants to test the 5.4W valve more feel free. If you smoke a transistor testing it I will help you get it fixed, np.
I would suggest the 4W valve though. But I'm not selling my 5.4W Mac valve either. :)

@Greg did we forget to pull the stock restrictor pill out for testing? Haha

[smartaxel]

I replaced a lot of my hoses with new line when I bought the car. Is this the hose going from the pressurized Y-intake to that 4-way "t" that goes to the wastegate solenoid and wastegates?


???

The feed hose from the Y-pipe with the red stripe has a .030" restrictor orifice... That's how the solenoid can bleed off the pressure at the wastegates. Otherwise you're just stuck at wastegate boost with a variable boost leak.

[RealMcCoy]

I replaced a lot of my hoses with new line when I bought the car. Is this the hose going from the pressurized Y-intake to that 4-way "t" that goes to the wastegate solenoid and wastegates?

Yes, that's the one...

[99 vr4]

Brett, I disagree with this. Relays are coil based devices that have a constant impedance. If the 4.2W device measures 350mA @ 12V then it has a coil resistance of 34.28 ohms. Then at higher battery voltage the coil will draw more current and use more power, not less:

current = 12.0 V / 34.28 = 0.350A , power = (12.0V)^2 / 34.28 = 4.2W
current = 13.6 V / 34.28 = 0.396A , power = (13.6V)^2 / 34.28 = 5.4W
current = 14.4 V / 34.28 = 0.420A , power = (14.4V)^2 / 34.28 = 6.05W

Do we know the ECU driving circuit transistor and it's power capability?

BTW I think I have a spare Apexi solenoid I can measure. It may work but I think they will be too expensive for most people.

Ugghhhhh - Of Course! (Face-Palm) I should have caught that as I was typing that the math I had was wrong. . . . . . too much Tramadol will clog the ol' brain. Yes, constant power applies to certain electrical mechanical devices but NOT coil based devices which are constant impedance. Thank you for pointing that out.


I have used the 35A-AAA-DDBA-1BA: 12v 5.4W for a week of dailey driving with success. I switched to the fp solenoid to test it.
My math says about 3.2-4W is the range we are looking for at 12V to meet stock spec. The system is capable of 5.1-6.25W at 15V.
The transistor is rated at up to 2A continuous draw. So it looks like we are well below the max at about 450 mA.
If someone wants to test the 5.4W valve more feel free. If you smoke a transistor testing it I will help you get it fixed, np.
I would suggest the 4W valve though. But I'm not selling my 5.4W Mac valve either. :)

@Greg did we forget to pull the stock restrictor pill out for testing? Haha

The transistor in question is an N-ch MOSFET.

The data sheet rates the maximums at both TA= 25°C/77°F (TA = Ambient Temperature) and VDS = 1.0v (VDS = Drain to Source Voltage, 1.0v is near the minimum voltage necessary to apply to the gate to “turn on” the MOSFET):

ID (dc) ± 2.0A (This is the 100% ON rating)
ID (pulse) ± 4.0A (This is the pulse @ Pulse Width ≤ 10ms, Duty Cycle ≤ 50%)

Now since this is at VDS = 1.0v, you have DE-RATE for higher voltages. At 15vdc (close to the maximum voltage our cars should see):

ID (dc) becomes ± 0.1A (or 100 mA)
ID (pulse) becomes ± 0.6A (Pulse Width ≤ 100ms, SINGLE Pulse)
ID (pulse) becomes ± 2.5A (Pulse Width ≤ 10ms, SINGLE Pulse)
(This was taken directly from a graph on the datasheet)

And since this is at 25°C, we again have to DE-RATE for heat. At TA= 60°C/140°F (probably the max we will see) you have to de-rate again by 70% (This was taken directly from a graph on the datasheet):

ID (dc) becomes ± 0.07A (or 70 mA)
ID (pulse) becomes ± 0.42A (Pulse Width ≤ 100ms, SINGLE Pulse)
ID (pulse) becomes ± 1.75A (Pulse Width ≤ 10ms, SINGLE Pulse)

Now factor back in the duty cycle of 50% and we have de-rate yet again . . . but that math eludes me.

I would say it is safe to assume that the OEM solenoid probably had a margin of safety built into it for out of tolerance parts. Usually, a 50% margin is built in for safe keeping and product longevity. But there is no way to be sure what the Mitsubishi Engineers did here. Additionally, we have to take into account the pulse width that is being utilized and the junction temperature which is directly affected by both the ambient temperature and the temperature being generated by the ECU.

I would think that the 500 mA would be the absolute maximum that we would want, but again, anything around the lower 400 mA is preferred.

And of course if anyone smokes a MOSFET, it is easily repaired as long as there is no damage to the PCB or damage back through the system to the CPU or DAC, and yes that can happen as most of the MOSFETs are direct driven from the CPU or the DAC chip. But again I have spare CPU and DAC chips if need be.

Jim?

[smartaxel]

Thanks! Was there a section in the manual showing which lines have restrictors in them? Or, do you know of others I may also need ot check?


Yes, that's the one...

[Jimvr4]

I would say it is safe to assume that the OEM solenoid probably had a margin of safety built into it for out of tolerance parts. Usually, a 50% margin is built in for safe keeping and product longevity. But there is no way to be sure what the Mitsubishi Engineers did here. Additionally, we have to take into account the pulse width that is being utilized and the junction temperature which is directly affected by both the ambient temperature and the temperature being generated by the ECU.

I would think that the 500 mA would be the absolute maximum that we would want, but again, anything around the lower 400 mA is preferred.

And of course if anyone smokes a MOSFET, it is easily repaired as long as there is no damage to the PCB or damage back through the system to the CPU or DAC, and yes that can happen as most of the MOSFETs are direct driven from the CPU or the DAC chip. But again I have spare CPU and DAC chips if need be.

Jim?

Can you post up the MOSFET data sheet? These devices are usually pretty robust. The ON resistance is typically what determines power handling, the lower the better. And much more power can be handled in a pulse environment vs continuous as you point out.

[GTOJOE]

???

The feed hose from the Y-pipe with the red stripe has a .030" restrictor orifice... That's how the solenoid can bleed off the pressure at the wastegates. Otherwise you're just stuck at wastegate boost with a variable boost leak.

I hope mine is still there. Like below it may have been replaced. I haven't replaced it but when other people work on our cars things can end up in the wrong places etc. So if I go away from the bleed method I will have to remove this. IS there any other hoses with restrictions in them?


I replaced a lot of my hoses with new line when I bought the car. Is this the hose going from the pressurized Y-intake to that 4-way "t" that goes to the wastegate solenoid and wastegates?

[hated]

.

The stock FPR solenoid is showing a lot of promise...So far just me and Adam are running it.

Taking volunteers?

[Greg E]

Taking volunteers?

Sure. Swap the FPR pin with the BCS pin at the ECU. Disconnect the vac lines from the FPR solenoid and the regulator and hook the regulator to the boost/vac source directly.

The FPR solenoid has 3 ports. One of them is capped. The capped port goes to the intake. The perpendicular goes to the waste gates. The last port goes to the y-pipe.

Remember to lower the WGDC to 45-50% for the first pull. Also remember to zero out the boost corrections table (this will disable the corrections feature).

Have a ball. :)

[99 vr4]

Can you post up the MOSFET data sheet? These devices are usually pretty robust. The ON resistance is typically what determines power handling, the lower the better. And much more power can be handled in a pulse environment vs continuous as you point out.

PM sent

[Jimvr4]

The transistor in question is an N-ch MOSFET.

The data sheet rates the maximums at both TA= 25°C/77°F (TA = Ambient Temperature) and VDS = 1.0v (VDS = Drain to Source Voltage, 1.0v is near the minimum voltage necessary to apply to the gate to “turn on” the MOSFET):

ID (dc) ± 2.0A (This is the 100% ON rating)
ID (pulse) ± 4.0A (This is the pulse @ Pulse Width ≤ 10ms, Duty Cycle ≤ 50%)

Now since this is at VDS = 1.0v, you have DE-RATE for higher voltages. At 15vdc (close to the maximum voltage our cars should see):

ID (dc) becomes ± 0.1A (or 100 mA)
ID (pulse) becomes ± 0.6A (Pulse Width ≤ 100ms, SINGLE Pulse)
ID (pulse) becomes ± 2.5A (Pulse Width ≤ 10ms, SINGLE Pulse)
(This was taken directly from a graph on the datasheet)

And since this is at 25°C, we again have to DE-RATE for heat. At TA= 60°C/140°F (probably the max we will see) you have to de-rate again by 70% (This was taken directly from a graph on the datasheet):

ID (dc) becomes ± 0.07A (or 70 mA)
ID (pulse) becomes ± 0.42A (Pulse Width ≤ 100ms, SINGLE Pulse)
ID (pulse) becomes ± 1.75A (Pulse Width ≤ 10ms, SINGLE Pulse)

Now factor back in the duty cycle of 50% and we have de-rate yet again . . . but that math eludes me.

I would say it is safe to assume that the OEM solenoid probably had a margin of safety built into it for out of tolerance parts. Usually, a 50% margin is built in for safe keeping and product longevity. But there is no way to be sure what the Mitsubishi Engineers did here. Additionally, we have to take into account the pulse width that is being utilized and the junction temperature which is directly affected by both the ambient temperature and the temperature being generated by the ECU.

I would think that the 500 mA would be the absolute maximum that we would want, but again, anything around the lower 400 mA is preferred.

And of course if anyone smokes a MOSFET, it is easily repaired as long as there is no damage to the PCB or damage back through the system to the CPU or DAC, and yes that can happen as most of the MOSFETs are direct driven from the CPU or the DAC chip. But again I have spare CPU and DAC chips if need be.

Jim?

Brett, Thanks for sending the datasheet for the MOSFET.

I don't have the circuit to look at so I'll make an assumption. The assumption is that the circuit controls the FET using a 0V / 5V switch from a register or similar. This voltage drives the Gate of the FET. The FET has its Source grounded thus the FET is turned on when VGS is at 5V and the FET is turned of when VGS is at 0 volts.

Now if this assumption is correct, the solenoid is connected between the Drain and Battery. When the FET is turned on (VGS=5V) the Drain voltage is forced close to the Source voltage. If the coil resistance is low enough then VDS will approach the minimum which is 0.7 volts. Now with the battery voltage running near 14.5V the solenoid will see 14.5-0.7 or 13.8 volts across it and it will be energized. When the VGS is switched back to 0V then the Drain voltage will float high near battery voltage and the solenoid will be off. Note the ON resistance for the FET is approximately 0.3 ohms when VDS is at 0.7 volts.

Now for power handling. In the energized case we have 13.8V across the solenoid. Let's assume the solenoid has 34.3 ohms resistance, then the current is 13.8/34.3 or 0.402 Amps. So, the coil itself has a power dissipation of 13.8*0.402 or 5.5 Watts. But, the MOSFET power is not nearly that high. It's power drain is I^2 * RON which is (.402)^2 * 0.3 or .05W in this case. The absolute max power handling is 2W on the datasheet and we have to derate it to 60% at 60 degrees C which is still 1.2W continuous. I haven't even considered this is a pulsed application which uses even less power.

Let's look at a solenoid of only 20 ohms. For this low resistance the current is 0.69 amps. Coil now draws 9.52 Watts but the FET only has 0.143 Watts. Bottom line is the FET's very low ON resistance is making sure that the FET is never stressed for delivering power to the coil.

We only need to worry about the solenoid power handling itself, not the ECU FET driver circuit.

BTW if anyone cares, the Apexi AVC-R solenoid has 35.1 ohms resistance. It is a perfect choice for the boost solenoid. It's probably a relabeled MAC solenoid.

[GTOJOE]

???

The feed hose from the Y-pipe with the red stripe has a .030" restrictor orifice... That's how the solenoid can bleed off the pressure at the wastegates. Otherwise you're just stuck at wastegate boost with a variable boost leak.

Can someone post a pic of this factory hose? because almost every aftermarket y-pipe comes with a new vacuum line to replace this one. Even the 3sx one. The one I have is identical to this [but bought on ebay]. I didn't replace the stock line but I did extend it using a piece of the blue silicon line they supplied with it. I can't see any red stripe on the original line. So I have to assume someone changed it at some point?

http://www.3sx.com/store/comersus_viewItemBundle.asp?idProduct=30805

http://www.3sx.com/store/catalog/ypipe-chrome-blue-01-600l.jpg

My setup.
http://i299.photobucket.com/albums/mm289/1STGENGTO/20130416_151948_zps5248d3e2.jpg

[GTOJOE]

Double post.

[GTOJOE]

OK I took a pic of the hose that goes to the y pipe because it has a red section right at the bottom. Is this the restrictor?

http://i299.photobucket.com/albums/mm289/1STGENGTO/20130417_111019_zpsbdc547f4.jpg

Sent from my GT-I9300 using Tapatalk 2

[smartaxel]

Yep, that's the hose (or looks to be). If you squeeze it a bit, you'll feel the restrictor near one end of the hose.


OK I took a pic of the hose that goes to the y pipe because it has a red section right at the bottom. Is this the restrictor?

http://i299.photobucket.com/albums/mm289/1STGENGTO/20130417_111019_zpsbdc547f4.jpg

Sent from my GT-I9300 using Tapatalk 2

[Unlogic]

Here is a photo of the restrictor:

http://pics.unlogic.se/3000gt/projekt/IMAG2574.jpg

The hole in it is really tiny.

[Jesters Deadd]

There is also a restrictor in the stock wastegate solenoid. I pulled out the restrictor from the bottom nipple and the car was hitting 14-15 psi without changing the wastegate duty cycle in the code.
I tested it on a stock 98 and it ran great no knock and great afrs with the stock tune on chrome v2.
I tuned it a little and the car is now pushing 18 psi and falling to 10 psi and no knock. Good afrs. Stock fuel system.

I also put a MAC/AEM valve on a car to replace the stock solenoid. It was working great however it makes a very loud clicking sound at random during idle.
May have been a bad valve. We need more testing with it.

[Greg E]

The valve works fine. They all sound like that. It's annoying...

[Jesters Deadd]

The valve works fine. They all sound like that. It's annoying...

Really? It's sounds really bad like a super loud lifter tick.
If thats the case I wouldn't use those valves.
Greg when you were testing with your stock 98 did you remove the wastegate solenoid restrictor?

[Greg E]

No I didn't.

Yes they are *that* loud. Ever notice how the stock solenoid pack has rubber insulating the mounting bracket to the firewall? Guess what that's for?

[RealMcCoy]

If you still have the stock intake pipes, mount the solenoid by tying it to the rear intake pipe with a large zip tie. You'll never hear it again.

Also very well hidden down there...

[Greg E]

If you still have the stock intake pipes, mount the solenoid by tying it to the rear intake pipe with a large zip tie. You'll never hear it again.

Also very well hidden down there...

Not a bad idea. I was thinking of mounting mine on the intake plenum itself (the 98/99 cars keep the purge solenoid mounted there). It's a good spot because its half way between the turbos and you can cleanly setup equal length vac lines.

[FluffyCow]

Im getting confused. To use the fpr solenoid as a bcs do i need tonuse the stock wastegate solenoid too? Right now I have just the fprs wired to bcs wires, bottom line to throttlebody pipe, horizontal to WGs, top to atmosphere. Didnt feel like fighting with the intake piping to go top to rear preturb.

[Greg E]

I never made any posts about using the stock FPR solenoid. Only mentioned that I'm testing it. Until then, no one has my graces to use that setup.

[Jesters Deadd]

I gave the ok. I use it on my car it works.
Make sure you put clamps on the nipples. Mine blew off at 25 psi.
But the stock wastegate solenoid works good too if you pull the restrictor out of it.

[Kx1984]

is it better to use ecu based boost controller over the aftermarket ones?

cant decide if i should get a vr4 ecu to replace the SL

[FluffyCow]

is it better to use ecu based boost controller over the aftermarket ones?

cant decide if i should get a vr4 ecu to replace the SL

Ecu will keep power around the same spot but may lower boost. Aftermarket sets boost and might nake car run like shit ib some weather.

[99 vr4]

Brett, Thanks for sending the datasheet for the MOSFET.

I don't have the circuit to look at so I'll make an assumption. The assumption is that the circuit controls the FET using a 0V / 5V switch from a register or similar. This voltage drives the Gate of the FET. The FET has its Source grounded thus the FET is turned on when VGS is at 5V and the FET is turned of when VGS is at 0 volts.

Now if this assumption is correct, the solenoid is connected between the Drain and Battery. When the FET is turned on (VGS=5V) the Drain voltage is forced close to the Source voltage. If the coil resistance is low enough then VDS will approach the minimum which is 0.7 volts. Now with the battery voltage running near 14.5V the solenoid will see 14.5-0.7 or 13.8 volts across it and it will be energized. When the VGS is switched back to 0V then the Drain voltage will float high near battery voltage and the solenoid will be off. Note the ON resistance for the FET is approximately 0.3 ohms when VDS is at 0.7 volts.

Now for power handling. In the energized case we have 13.8V across the solenoid. Let's assume the solenoid has 34.3 ohms resistance, then the current is 13.8/34.3 or 0.402 Amps. So, the coil itself has a power dissipation of 13.8*0.402 or 5.5 Watts. But, the MOSFET power is not nearly that high. It's power drain is I^2 * RON which is (.402)^2 * 0.3 or .05W in this case. The absolute max power handling is 2W on the datasheet and we have to derate it to 60% at 60 degrees C which is still 1.2W continuous. I haven't even considered this is a pulsed application which uses even less power.

Let's look at a solenoid of only 20 ohms. For this low resistance the current is 0.69 amps. Coil now draws 9.52 Watts but the FET only has 0.143 Watts. Bottom line is the FET's very low ON resistance is making sure that the FET is never stressed for delivering power to the coil.

We only need to worry about the solenoid power handling itself, not the ECU FET driver circuit.

BTW if anyone cares, the Apexi AVC-R solenoid has 35.1 ohms resistance. It is a perfect choice for the boost solenoid. It's probably a relabeled MAC solenoid.

Thanks Jim. Your assumptions are correct. Even with all that, I have identified that Mitsubishi has replaced the FET with a beefier modem which is capable of 4 a max and has a higher rating for duty cycle (yes it is a duty cycle). This FET is on all newer ECU's and as soon as my current stock is depleted (or sooner) I will be beefing up this circuit. This will make the choice of a boost solenoid not an issue...

[Greg E]

Thanks Jim. Your assumptions are correct. Even with all that, I have identified that Mitsubishi has replaced the FET with a beefier modem which is capable of 4 a max and has a higher rating for duty cycle (yes it is a duty cycle). This FET is on all newer ECU's and as soon as my current stock is depleted (or sooner) I will be beefing up this circuit. This will make the choice of a boost solenoid not an issue...

Meaning you can run a solenoid that won't need resistors mounted inline? That's a good idea!

[Jimvr4]

Thanks Jim. Your assumptions are correct. Even with all that, I have identified that Mitsubishi has replaced the FET with a beefier modem which is capable of 4 a max and has a higher rating for duty cycle (yes it is a duty cycle). This FET is on all newer ECU's and as soon as my current stock is depleted (or sooner) I will be beefing up this circuit. This will make the choice of a boost solenoid not an issue...

Brett, Could you PM the datasheet for this new FET?


Meaning you can run a solenoid that won't need resistors mounted inline? That's a good idea!

I don't see why any of these solenoids wouldn't handle the full 12V across them :confused:

[Greg E]

Brett, Could you PM the datasheet for this new FET?



I don't see why any of these solenoids wouldn't handle the full 12V across them :confused:

I'm not an EE, so hardware terminology is still very foreign to me, but it's my understanding that it's not a good idea to use aftermarket solenoids due to the amperage draw they demand from the ECU driver. The EVO guys never looked into upgrading the hardware on the board, they just wired a few resistors inline to keep the draw within spec.

[Italo Grasso]

I gave the ok. I use it on my car it works.
Make sure you put clamps on the nipples. Mine blew off at 25 psi.
But the stock wastegate solenoid works good too if you pull the restrictor out of it.

Hey Adam, what DC are you using to get 25psi?

[FluffyCow]

I'd need to check mine but I slightly increased it(I wanna say between 25 and 30) and I'm peaking at 15 before I hesitate. There's a boost leak I have yet to find on my car, though.

Peaks at 15,falls off to 12ish around red line in first.

Since this is the bcs thread, I have a bcs-related question. How do I go about tuning out the richness from open atmosphere bov?

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[Greg E]

You set the BOV back to closed loop like stock. ;)

Not a BCS issue. :p

[FluffyCow]

Pfft. If I wanted recirc I'd buy a recirc bov. :P

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[Greg E]

You shoulda wanted to bought one. :lol:

[Ange]

with this new info about the variable boost solenoids the need for the lcdbc is kind of half-lost isn't it ^^

But I like it anyways. Because of the live info you get from the ecu. and it looks sweet.

[mb3000]

Pardon my electrical ignorance, but is the 35A-AAA-DDBA-1BA: 12v 5.4W safe to use with factory wiring, etc?

[Jimvr4]

Pardon my electrical ignorance, but is the 35A-AAA-DDBA-1BA: 12v 5.4W safe to use with factory wiring, etc?

It is my opinion that stock wiring can handle far more than a 5W device. This is based on the MosFet data sheet provided by Brett.

[mb3000]

Awesome, just what I wanted to hear.

[D.I.P.]

So after reading through all 7 pages an not understanding all the technical stuff that was discussed it seems to me that it is ok to just run the 35A-AAA-DDBA-1BA: 12v 5.4W Solenoid with no resistors at all. Just wire it in, plumb it up and good to go? Can somebody confirm this for an electronics dummy like myself? :)

[Greg E]

Lol!

Yes.

[99 vr4]

Actually, I have been bench testing a GM 1997152 on a MODIFIED ECU . . . this boost solenoid draws more than 1/2 amp!!! This is a CHEAP 3 port that can be had for about $30 with the pigtail!

I will begin driveability testing tomorrow and if all goes well, I will certify that all of the Clone2 ECUs will support this and a LONG list of boost control solenoids! Basically, if you can find a vacuum solenoid, it will work with the Clone2 ECU and be covered under the warranty!

[Vishnu]

Spiffy, I may need upgrade my current Clone.

[Bleu]

Sub'd Looking at one of these valves for my standalone.

[99 vr4]

Testing all weekend.. Actually tuning and dialing in. The Clone hardware change handled the high current 3 port BCS like a champ!

Photos and a write up coming soon.

[CoopKill]

and what about us Clone1 one chaps?

[99 vr4]

I am still working on a solution for the Clone1 guys. This will probably be in the form of a swap out. You send in your old Clone1, you get a new Clone2 for a small fee to cover processing!

[Vishnu]

This will help in cleaning up my overall wiring. The less jumpers and extensions the better imo.

[D.I.P.]

So what Pins are people using to wire up this solenoid? Where are you tapping into a 12V source? Im hoping i can tap into a 12v source under the dash somewhere. Am i correct in that 1 wire goes to a 12V source and the other to pin#41(Turbo Wastegate Solenoid) on the 98-99 ECU harness in order to get signal and be able to control the BCS?

[99 vr4]

Technically speaking BCS gets 12 volts from the mfi relay and the ECU acts as a switch to ground. There is 12 volt available under the hood where the stock plug is for the stock BCS

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[D.I.P.]

I see so i could just tap into the stock BCS plug wiring for the 12V source and then run a wire into the cabin to ECU pin #41?

[99 vr4]

Or use both wires on the stock BCS plug....

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[D.I.P.]

Or use both wires on the stock BCS plug....

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GENIUS!!! lol i shall now go browse through the Service Manual to find a pinout of said plug! Thank you sir!!

[99 vr4]

One black wire one white wire. It does not matter which is which as the solenoid does not care. .. There is no plus or minus for solenoids UNLESS they have internal blocking diodes. ..

Use 1/4" male quick connects I.e. spade terminals to plug into the stock plug. ..

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[D.I.P.]

Excellent this will make it extremely easy, thank you!

[FluffyCow]

Looks like I'm stuck as I have a Jesters' chromeECU. Are there any aftermarket solenoids that work better than an for solenoid with my ecu?

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[mb3000]

Why would you be stuck? Also, why not just run the MAC solenoid?

[Greg E]

Looks like I'm stuck as I have a Jesters' chromeECU. Are there any aftermarket solenoids that work better than an for solenoid with my ecu?

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Huh?? The jesters ECU does ECU controlled boost just the same. The only thing with the Jesters is you have to use the MAC solenoid posted in this thread or one of the other stock solenoids.

[FluffyCow]

Huh?? The jesters ECU does ECU controlled boost just the same. The only thing with the Jesters is you have to use the MAC solenoid posted in this thread or one of the other stock solenoids.

Was under the assumption that the mac solenoids out-drew what the ecu could provide without burning it out

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[99 vr4]

The 4.3w is probably ok... The 5.4w is iffy. ..

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[BucknVr4]

The 4.3w is probably ok... The 5.4w is iffy. ..

Any long term results with running the MAC 35A-AAA-DDBA-1BA 5.4w with Jesters ECU or has it been decided this is taboo? I like the idea of having the option of switching boost ctrl from my LCDBC to my Jesters Chromed ECU without having to change valves.

[Greg E]

I know of one person running this solenoid for close to 6 months now with his Jesters ECU and no issues. Take it for what it's worth.