[MacktheKnife]

That’s great news! I would definitely run a relay rather than trying to feed it with just the DPO. Very curious to see how much current it draws and how much heat it generates running a full 12v through it. If it works out I’ll do it that way as well and stick the DCMD on the shelf for a future turbo build.
On my 108 I’m actually running 4 4-channel ignition controllers I robbed from VW Passats in the junkyard bolted to a piece of aluminum plate so they don’t overheat. On the S55 W111 I built I’m running a pair of Holley 4-channel ignition controllers with each output firing both halves of a coil. I’m setting up my C123 the same. I’d imagine the Haltech coil drivers are at least as good as the Holley ones so you shouldn’t have any issue running 2 coils off one channel. The Holley ones were marginally cheaper.

 

[ctravis595]

Let me know what you find out, I had just ordered a variable dc voltage machine before reading your post

 

[Brento]

Ok this is my finding, pin 1 confirm is motor negative and pin 4 motor positive. When the power is applied can clearly hear valve open and power peaks to around 110W, then after a minute or two it slowly falls back and stabilises around 80W which is 6.15A at 13V. So I’m not sure if it can cope being held like this for extended periods of time, after a few minutes the motor is warm but the only way to tell perhaps is if I leave it for a considerable amount of time say 15 minutes and see what it feels like? In the rear world situation it would be getting a rest quite often particularly if it was set to close at say 25% or even 0 MAP?

 

[ctravis595]

I believe you’ll need to connect 12v, ground and then also two more wires for the position sensor inputs

another guy had the same idea, again in the megasquirt world. Seems his issue was the valve was not quick

 

[ctravis595]

doing more searches on the megasquirt boards shows Mercedes’ bypass valves are not typically just a 12v, ground and a varied <5V signal … but I’ve not seen anyone successfully control the valve with the polulu board either. One person mentioned they successfully controlled their bypass valve with their megasquirt as a solely on/off mechanism… this may be our only option

 

[Brento]

The valve is super quick. I’ve proved today that it is easy to either have fully open or closed by applying 12V to the motor. We are not using the valve as boost control so to control proportionally is not really required. I just don’t know if the current draw is too high for longevity of the valve, this is what we must establish other wise it is simple for the Haltech to operate it either fully open or closed against a multitude of conditions.

 

[ctravis595]

The valve is super quick. I’ve proved today that it is easy to either have fully open or closed by applying 12V to the motor. We are not using the valve as boost control so to control proportionally is not really required. I just don’t know if the current draw is too high for longevity of the valve, this is what we must establish other wise it is simple for the Haltech to operate it either fully open or closed against a multitude of conditions.

I am also worried about overloading the unit. The highest rated pololu module is only rated for 30-40amps. I think that is 30-40amps continuous duty, where as we would only need to shut our valves occasionally under boost, and we could also upgrade the heatsink/cooling of the module to maybe handle the load better

I personally do want to use the bypass valve as boost control if possible. For my setup I am trying to find a way to tie the supercharger, map sensor, and bypass valve to the ecumaster det3 piggy back module on a 2005 e500 4matic wagon. The piggyback has 4 programmable outputs, so I was thinking one for a secondary fuel pump, one for the bypass valve trigger, one for the intercooler pump.

The piggyback has pwm/5V programming options I’ve just not used it before, and would like to have all of my options “sorted” so I don’t have to keep taking the supercharger off while I experiment with the bypass valve. It may be easiest to use the valve as an on/off valve, and maybe I can bleed off boost in a more traditional way

another thing we may want to consider is the difference in amperage/load during bench testing and during real world testing. The supercharger should be putting significant force against the butterfly of the bypass valve during normal operation. Perhaps we only need 30-40amps to close the valve only when the supercharger is building boost and pushing the butterfly closed.

Similar concept to opening/closing doors on a windy day. Once we have figured the bypass valve out I can figure out if I can get away with a $260 piggyback or if I have to go through the traditional route if virginizing an e55 ecu for my application

 

[Brento]

I think you may have misread the load figures, it is drawing just over 6 amp to keep the valve shut. When under boost the top would be seeing vacuum and the underside pressure so I’m not sure if this would have much effect on reducing the load on the motor or not. There would be also significant amount of heat being directly applied to the bypass motor from the engine itself I.e. 80 to 90 degrees C so I don’t think a heat sink would help as you would be trying to radiate the engine heat.

For the intercooler pump why don’t you just run it continuously through a relay off the ignition? That’s what I was planning on doing, however I still have spare DPO’s from the Haltech and could trigger it off IAT temp, got me thinking now.

 

[ctravis595]

I think you may have misread the load figures, it is drawing just over 6 amp to keep the valve shut. When under boost the top would be seeing vacuum and the underside pressure so I’m not sure if this would have much effect on reducing the load on the motor or not. There would be also significant amount of heat being directly applied to the bypass motor from the engine itself I.e. 80 to 90 degrees C so I don’t think a heat sink would help as you would be trying to radiate the engine heat.

For the intercooler pump why don’t you just run it continuously through a relay off the ignition? That’s what I was planning on doing, however I still have spare DPO’s from the Haltech and could trigger it off IAT temp, got me thinking now.

thats good news, I must of been thinking of the wattage. Sounds like the pololu may work great for more precise boost control then

Regarding the ic pump i personally don’t like 100 different components turning on when the car is started/key is turned. I’ve been stranded before from too many consumers sucking down a weakened battery, during start up.

The outputs can be used for a second ic pump, superchatger clutch, bypass valve, methanol spray, etc. the options are nice to have on a modified car

 

[Brento]

Just a quick update on this, I can get the valve to close with as little as 6V and this has essentially halved the current. It does take a little longer to close like this but I’m talking like 0.5s total closing time still. So what I plan to do now is to run it PWM through the Haltech on Duty cycle so I can create an operating table still based on any input.

 

[ctravis595]

I am doing something similar, I ordered one of the mid range pololu modules, in the meantime I finished installing a m113k supercharger on my 2005 e500 4matic to sit better with my three other AMG’s.

From the owners manual of my piggyback, I am seeing I can choose at least two parameters for triggering the bypass valve

as we know, the bypass valve is held open with a spring. Some initial ideas, I am thinking I will use accel pedal position around 35-40% to command the valve closed and start building boost. I am theorizing from here I can rely on the pololu module to bleed off any boost over 7psi or so. Once the pololu arrives I can start to understand how it’s triggered and controlled best

The other parameter for triggering the bypass valve to close may possibly be engine load level, or to have the valve close when the intake manifold starts to sense 1+psi of boost pressure.

I feel this may be a counterproductive method because the valve will be bleeding pressure, before it reaches the placement of the map sensor on the m113k intercooler due to the bypass valve being upstream of the sensor. In other words the sensor may be slow to see 1psi and initiate the bypass valve because the bypass valve has already released some of that pressure by the time that charge air would reach the map sensor, and the supercharger is responsible for building 1+ psi in addition to the pressure being released from the charge air system

 

[Brento]

I think I will close mine on TPS also, probably 25 or 30%. Im not interested in tuning for fuel economy, it’s all about supercharger longevity and reducing heat soak for me.

 

[Brento]

Vacuum valves like fitted to LSA engines and also the Weistec one for the M156 supercharger kit operate on 0psi manifold pressure but they probably only do this as they don’t have a electronic input available.

 

[ctravis595]

I’ve gotten the pololu module driving the bypass valve on my bench, I’ve connected it via usb to my computer and I can use the program on the computer to control the bypass valve. Commanding the same desired position does not always produce the same result, hence why the pololu module excels as a motor controller, because it senses feedback from the positioning sensors of the bypass valve, to more reliably command the bypass valve. More like an oem ecu would control a standard throttle body

The two sensor inputs that I’m thinking of using on the pololu are either the analog voltage input with something like TPS. Or I found in the manual something about controlling the module with a PWM signal

through setting up my piggyback ecu system, I’m familiar with the fact it has programmable PWM tables, and dedicated PWM outputs as well. This frees up my other outputs on my piggyback module

 

[MacktheKnife]

Hey all, since we’re all working on the same engine, does anyone have an ignition table they’d be willing to share? A tune file or just a screen shot would suffice, I can figure out the rest of the tune from there. Also an engine wiring diagram would be a huge help so I don’t have to back probe the whole harness.

I’m trying to get my car on the road in time for a road rally in a couple weeks here, otherwise I’d be happy to take the time to back probe the harness and send it to a dyno, but time is against me. I’ve finished the whole driveline and built an exhaust and updated suspension and brakes, just wiring and plumbing to go.