MS2 to control 4agze supercharger

phydeaux · Post by **phydeaux** » Wed Aug 16, 2006 7:52 pm

I think I've got this halfway figured out but I could use a little help. I'm pulling the turbo etc off from my 4agte mainly because I've misscalculated a few things and I lack the time/fabrication skills/money to get the conversion finished by the time I need it to be. Anyhow I'm putting the supercharged parts back on mainly because I know they fit and work and the car will still be fun to drive. Enough with my reasons, on to the question. The 4agze used a magnet clutch, similar to an a/c compressor, to engage/disengage the supercharger when needed. I want to get the ms2 to mimic this operation. Should be easy enough to do, just use one of the extra outputs to control a relay. I'm already using fidle to control the fan so it'll problaby be one of the leds. Whats hanging me up is the variables to activate the port. The stock ecu turned the s/c on when there was <8" of vac in the manifold and kept it on until there had been >10" for more then 5 sec. The 5sec delay was to keep the s/c engaged durring shifts, I don't see anybody needing 5sec to shift but anyway... I understand how to setup the port to activate at 8" and how to set the hysteresis to keep it on until it drops back to 10", but how can I add the 5sec (or perhaps shorter) delay. I think something in the hardware would probalby be the best solution for this, mainly because I don't feel like hacking code. Is there a circut or somthing that I could build in the proto area that would keep the relay energized for a few extra seconds after the pin has turned off? I'm not 100% sure this is needed but unless someone is able to reason me out of it I'd like to set it up this way.

andy

Bernard Fife · Post by **Bernard Fife** » Fri Aug 18, 2006 6:51 pm

phydeaux,

That's a tough one. The spare port settings in MS-II don't have any built in timer mechanism. If you clutch has a switch on it, you could use that and a relay (and a diode or two) to keep the supercharger clutch activated during shifts.

Lance.

phydeaux · Post by **phydeaux** » Mon Aug 28, 2006 7:08 pm

My clutch switch does have a relay but I'm not sure how thats going to work with out activating the supercharger every time I push the clutch which I don't think I want to happen. Is there any way to perhaps build a timer circut that would hold the supercharger relay open few seconds, either in the proto area or externaly. I'm an electronics newbie when it comes to engeneering things like that.

andy

sparkandfuel.com · Post by **sparkandfuel.com** » Mon Aug 28, 2006 7:44 pm

phydeaux wrote:My clutch switch does have a relay but I'm not sure how thats going to work with out activating the supercharger every time I push the clutch which I don't think I want to happen.

I believe Lance was referring to the supercharger clutch, not the drivetrain clutch.

Lance; does MS-II have any sort of hysterisis in the works that you know of? otherwise, MS-I with MSNS-E firmware has hysterisis on some outputs that will work fine for your needs.

phydeaux · Post by **phydeaux** » Tue Aug 29, 2006 7:54 am

I think the MSII does have hysterisis on its outputs, but nothing that would work for this. I really need something to do time and the msII only lets me work with the inputs. I looked over msns-e and you're right, it does exactly what I want. But I have the msII already and would like to use it if possible. I originally chose the msII based on what I needed to run the motor with a turbo so I never took any of this into concideration when I was planning. I haven't had the time to look at whats in beta for the msII, is there anything thing like this in the pipe? Perhaps it'll be in msII-extra when it comes out. Or maybe I'll get off my duff and try to remember how to write c again. Plenty of options, I'm sure this'll eventually get figured out.

andy

randomtask1 · Post by **randomtask1** » Tue Aug 29, 2006 8:12 am

why not just run it so it turns on the relay at 25% throttle, thats what i was planning to do with mine. i would also be running a switched relay on that relay so i can manual turn of the supercharger when on the freeway. i have the SC switched already, but im afriad that the ECU does not compensate for the missing air.

phydeaux · Post by **phydeaux** » Tue Aug 29, 2006 9:31 am

I had been thinking more along the lines of 80% throttle with a large hysterisis to keep it open until it drops back to 30% or so, or perhaps basing it on map like it was stock. No sense running the s/c when its not needed, these things arn't exactly long lived. I don't think having the clutch off when shifting is going to do much more then wear it out faster. I'm not sure how much inertia the rotors have so it may not even be an issue if it doesn't loose too much rpm freewheeling for a second. I won't know any of that until I get the thing running but I would like to have it setup like this any way. I'm going to setup an override switch to turn it on full time as well so I may just have to use that for a while.

andy

phydeaux · Post by **phydeaux** » Sun Sep 03, 2006 7:08 am

I think I might have found a solution. I found this circut googling around and I think it might work for my problem.

http://ourworld.compuserve.com/homepage ... elay_i.gif

It looks like I could build that in the proto area and run the fidle output to it, then power the supercharger clutch off the fidle relay on the relay board. They're talking about a 15s delay there but I should be able to change the values and get the 5s delay I want.

any thoughts?

andy

phydeaux · Post by **phydeaux** » Mon Sep 04, 2006 6:02 pm

I took a look at that circuit more and it seems that it won't quite do what i want. That circuit needs a 12v input to operate, but the driver for the fidle supplies a path to ground so I'm going to have to change something somwhere. I have rather limited electronics skills but here goes my idea. I was looking at the circuit diagrams of the v3 board and I was thinking about building the delay into the existing driver circuit. I'm not sure how it would interact with q20 and r39 though. I understand those are for overload protection or something like that so I could eliminate them and be careful if need be. Here is the modification I'm thinking

I'd move r19 to the proto area, add the diode and capacitor in front of it, then jumper the circuit back to where r19 was on the board. I believe that the idle-1 pin of the ms2 gives +5v so I will have to recalculate the value of r19 and the capacitor to work with this.

Will this work? or am a completely wrong?

I'm too tired to try to figure out how to calculate the values now, and I'm not even sure I'll figure it out when I'm awake so if someone could help me out with that too it would be appreciated.

andy

phydeaux · Post by **phydeaux** » Tue Sep 05, 2006 5:29 pm

Ok I attempted to run the numbers, and I came up with some values which I have no idea if they are right or not.

I assumed that the relay draws 133mA (90ohm coil at 12v)
And if I read the spec sheet right (I have no idea how to read spec sheets so I googled it) the ztx450 has a gain of 100 so I figure I need a base current of 1.33mA.

I assumed before that there is 5v at the processor port and I guessed I have to subtract 1.4v from that for the 2 diode drops and came up with a base voltage of 3.6v.

I then figured the resistor should be about 2.7kohm (3.6v/.00133A)

Then manuipulating the delay time equation from the site I linked before, time = 3 * R * C, with a time of 5s I figured I should need a capicitor of about 617uF.

Am I completely off base with this? I'd like to start playing with it on the stim but I don't dare try it until I'm sure I at least won't fry the processor.

Playing with it more and using 1000 for the resistor value (whats already in r19) and a 1666uF capacitor I could also get a delay of 5s (I think) and the base current would be 3.6mA. Is that another way of doing it or am I as confused on this as I think I am?

I realize that I've gone pretty far off topic with this and it doesn't really deal with the msII directly any more. If this thread would be better suited in another forum please move it there or perhaps bring it to the attention of someone who may be able to help. The car is almost back together and I'm chomping at the bit to get it going.

andy