T3 megasquirt II conversion

[clintonddk]

This is a diagram that was sent to me to show how to build a 5v pull up. This is for a wasted spark set up for a four cylinder engine. You would build one for spark A and one for spark B.

[Devastator]

If you want to stick with the coil and dizzy, you can get a higher output coil fairly easily. In fact, I have one for sale.

[Max Welton]

Understood and thanks. At this point I'm just trying to change the ignition triggering device, not get a hotter spark. That can come later.

Max

[Piledriver]

In that case you should already have the single ignition driver.
(is probably what you are using now?)

Bad news: It still needs a 1K ohm resistor pullup from 5v to the output pin to control the logic level coils, as the transistor needs a signal to "pull down" to fire the coil.
Good news: The setup moves ~all the ignition noise out of the ECU.

I don't have a 3.57 board to send you a picture, but Matt at DIY autotune probably can.

[Max Welton]

In that case you should already have the single ignition driver.
(is probably what you are using now?)

What I'm using now is the stock distributor (w/Compufire trigger) and coil. The ECU is not presently controlling the ignition.

Tonight I will pull the MS out and see if I can make sense of where the ignition driver is (or is not). I bought mine a while ago and it may be slightly different than what DIY is now selling.

Max

[Devastator]

What I'm using now is the stock distributor (w/Compufire trigger) and coil. The ECU is not presently controlling the ignition.

I think Pile is indicating that you are getting your tach signal from the dizzy, so, driving the coil should be fairly simple to do.

[Max Welton]

What I'm using now is the stock distributor (w/Compufire trigger) and coil. The ECU is not presently controlling the ignition.

I think Pile is indicating that you are getting your tach signal from the dizzy, so, driving the coil should be fairly simple to do.

Yes.

Now... hand me that piano!

Max

[Piledriver]

What I'm saying is the v3 (and even the V2.2 units) boards can be bought preconfigured with a ignition driver onboard.

If it exists, you are ready to rock with a std coil, but if you want to control a logic driven coil it needs a 5v pullup resistor/jumper.

The ign1A is a great coil, i hope to be able to buy a full set of them when I grow up.

There is a picture floating around a a twin tower version, a pair would get you waste spark, and lots of it.

[Devastator]

The ign1A is a great coil, i hope to be able to buy a full set of them when I grow up.

I sure like my IGN4.
You will have to set all of your advance numbers in MS2Extra to a very low number if you chose not to lock your dizzy before switching over.

[Max Welton]

OK, big picture time.

Can somebody tell me if I do or do not have an ignition driver? And if not, where would it go?

And let's pretend I am an electrical idiot.

http://www.maxwelton2k.net/squareback68 ... G_7845.jpg

http://www.maxwelton2k.net/squareback68 ... G_7848.jpg

http://www.maxwelton2k.net/squareback68 ... G_7849.jpg

http://www.maxwelton2k.net/squareback68 ... G_7852.jpg

I will stand by to take additional pictures as needed.

Max

[Piledriver]

Referring to: http://www.msextra.com/doc/ms2extra/build_manual.htm

See the empty spot on the far right marked Q16?
That's where your high current coil driver would go if you had one.

I suggest setting the pullup up using a jumper, so you can drive a std coil OR a logic controlled coil using the same output, simply by removing or installing the jumper.

The good news it that it's almost certainly very easily done, but I personally cannot coach you on how to mod a 3.57 mainboard for the pullup as I have not done it.

OTOH, someone surely has.

I suggest you search a bit on the msextras board and if you can't find it, post up.

If you decide to send it off to DIYAutotune or Mario et. al. I'd suggest possibly setting up both the LED drivers so you can go waste spark later.

[Max Welton]

Thanks Pile!

Max

[Max Welton]

So while I am mulling over the attractive idea of simply having somebody modify my ECU ...

http://www.symtechlabs.com/catalog/mega ... -p-47.html

... I got a question about locking the distributor.

Why?

If I leave an 009 in place (and this is assuming I don't go straight to a 2-coil wasted spark setup), it will only be to point the rotor at the correct cylinder. The mechanical advance will still serve to keep the rotor in the neighborhood of that contact in the cap. Actual ignition timing will be handled by the ECU, triggered by the VR sensor.

Just trying to wrap my fragile mind around this.

Max

[Piledriver]

...Consider: ... the mechanical advance moves the whole upper section of the shaft, points cam (or magnets) as well as the rotor. If it was ONLY the rotor advancing, it would be OK, but it isn't.

I suppose you could do something interesting with a djet distributor, but it's easier to safety wire the tabs where the springs of the advance mechanism were, or are...
(for that matter, you could do a "wheel" in a modified distributor and go waste spark, or iirc even full sequential if you used the right pattern)

Don't forget to still oil it occasionally.

You may want to make a slightly wider brass tip and solder it on the rotor...

You will be able to ask for far more timing than the distributor can physically deliver, but even the stock setups could put ~35-45 degrees advance in between the mech. and vacuum.

[willo357]

if your running a missing tooth wheel for CAD you dont need to worry about locking the dizzy. Infact it is usefull if the rotor advances as it helps keep it inline with the dizzy cap-out as RPM increases.

Remember if you have a toothed wheel for CAD the dizzy simply sequences the spark. it is the most simple method and provides perfect spark for normal running conditions. Usually Q16 is the high current transistor bp373 thingy for spark output A