MicroSquirt.com read only forum (Jan.15,2018)

hey everyone, I just have a fiew questions to be answered before I pickup my MS2. I have a Blown (mechanicaly) Injected 468, and am looking to convert the mechanical injection for driveability, I have already figured that a set of 16-32#injectors on top of the blower would work nicely in a bank fire situation, I am wanting to run a water temp, air temp, IAC, and O2 sensor.........but that is the easy stuff, my main question is that I have a Magneto, so there is no way I can pull any kind of Hall or VR sensor off of it to time the injector firing, I have checked into crank triggering, but I thought I would get someone elses opinion before attempting something of this nature. I also will be running a magneto tach signal converter for my tach ( I didn't know if there might be a way to pull the signal off of that).

wow, that's a question. I haven't even heared that word outside of "x-men" in over a decade. wish I could be of more help friend.

A Tach converter should work fine as long as it provides a clean
O to 12 volt square wave output ,
this is what most Tachs want , MS wants it too .

It's a long way from the top of that blower to the cylinders ,
(I'm guessing you are running a "Rootes Style" Blower)
is this a "DRAG ONLY" setup ? then you'll be OK , if it's got to run on
the street you would be better off putting those injectors
under the blower , you will get much better idle and off idle control .

What is your expected idle RPM ? if you are in the 1800 to 2000 range
injectors on top are OK , otherwise put them on the bottom even if
you have to build a spacer to mount them in .

If you mount them on the bottom , and expect a civilized idle for the
street , you will also have to have a Fuel Pressure Regulator that is
referenced to the Vacuum/Boost under the Blower that can withstand
the amount of Boost you are running , these are readily availible from
Turbo Kit manufacturers , they have a Stainless Steel diaphragm .

If you are running an extremely choppy cam
(over 280@006 and 110 or less Lobe Centers)
MS has the ability to run in "Alpha-N" Mode where it uses
only TPS and RPM to inject fuel . Rather crude , but effective .

What kind of fuel are you running ?
Do you really NEED that Mag ?
Or is it for "Carrisma Points"
You would have far superior ignition control if you changed over to
Ford EDIS with an MSD Box .
This would also provide the Tach output you are looking for .
This would require mounting a 36 tooth wheel behind your front pulley
and mounting a VR Sensor next to it .

...................Jim

I don't really "need" the mag, but it does clean up alot of extra stuff, and I'm already setup to run the mag......so I figured why waist the money on another distrubitor, and throw away what I have already sunk into it. it is along way for the fuel to travel, but with mechanical injection, that's where the injectors are, and they don't atomize the fuel near as well as electronic......Idle RPM....I haven't the slightest clue as to where would be good, and the cam, I would have to go searching through my paperwork, it has been a while since i put it in..........also, this is just a mild motor for me to just put around on till I can get a much healthier one built....I'm looking at 750 hp out of this one, I really would like to more than 2500 hp out of the next one......and that will require a mag to run, so I am also trying to plan ahead. so basically what you are saying is that I can drive the injectors through the tach signal converter? or will that just be telling the MSII how fast it needs to be firing the injectors? in a perfect situation, the MSII will fire 1 of 2 banks per revolution of the crankshaft.....or should I have it fire at 180 degrees of each crank revolution? to do this could I use a basic crank trigger wheel with just 2 teeth 180 out on it?

oh, and i forgot, yes this is a "roots style" blower, and this will definatly be going on the street.

You need to save that Mag for your Alky/Nitro motor and get a used HEI ,
put an Accel Coil on top of it , and run it with an MSD-6 .

No Module needed in the HEI , just the pickup coil (VR Sensor) , this will
make MS very happy , then MS will control the MSD and control Ignition Advance .
You probably have this stuff laying around in your garage ,
it will work MUCH better than a Mag .

A Crank Trigger Wheel would be very nice , it would eliminate the slop in
the distributor timing , but it's not needed .
If you have one , definately use it .

You don't need to worry about the number of magnets or teeth , MS can
can fire every 90 , 180 or 360 degrees , and can alternate injector banks
or fire both injector banks at the same time .
You have to determine which setup you will use by the size of your injectors , or ,
determine the size of the injectors by how often you want to fire them .
How to calculate this is fully covered on the MS website .

Using your Mag ,
you will be giving up ALOT of engine control , driveability AND power .
Not to mention getting about 5 MPG ,
having to changing your plugs twice a week , and
having your radiator blow lunch regularly .

Also , a Mag sometimes will get funky at cranking and idle RPM ,
it may or may not have a stable output at low RPMs , this could cause
all sorts of headaches when driving a Fuel Injection Computer with it .

Somebody will probably give you 2 or 3 hundred dollars for that Mag . ,
you can spend that money on a Wide Band 02 Sensor and be way ahead .


...................Jim

I'm not exactilly sure, but I don't think the HEI will fit behind my blower, is there a smaller distributor that will work? and how would the vacuum advance work with it? I want the timing to retard with the boost, and that would require a MSD 6-BTM box also.

As you have a working Magneto setup then leave it right there. Suggesting you change it out just on Megasquirt's behalf does not sound like a good idea to me.

How does your rev counter get driven? You may be able to tee into that wire for the Megasquirt tach signal. Otherwise a simple crank trigger setup may be in order - 4 bolt heads and a VR sensor is all you need. For fuel only they do not need to be that precise either. It doesn't even need to be 4 really either, but if you are adding some then that makes the numbers work on a V8.

James

I have a MSD mag-tach signal converter to produce the signal for the tach, VERY easy setup, small box, and just a couple wires.......and I checked, and an HEI definatly would not fit.......actually my mag barely fits in there.

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