Ok guys, is there any good reason to use an MSD ignition box with a stand alone, IE: fast, DIY, holley dominator? Im converting my carbed TTBBF to a FI set up with an MS3 and cant see any reason to use the current msd box I have. Ive talked to guys that use the ms3 with an MSD dizzy and use the magnetic pickup in the dizzy for the VR or crank signal for the MS3. If that is the case the MS3 has all and more bells and whistles than the msd digital 7 has... Would I need it for some ignition amplification?

 

If you're keeping the distributor, the MSD box would provide a hotter spark.

If you're going with something like a set of eight IGN-1As... no, they'll be plenty hot.

 

How will it provide a hotter spark?

 

It feeds the coil better/longer

 

i have a ms1 and a msd 7 programmable on a turbo 410 ci windsor. it is working good for me. if i did it again i would of gone ms3x with coil on plug.

 

If your ECU has an ignition module built in, it's almost certain to be an inductive type. This has the coil fed 12 volts and pulses the other end to ground. The amount of time the coil negative terminal is grounded is your dwell time. The more dwell time, the hotter the spark (up to the limits of your coil or ignition module). The trouble is, on a V8 with one coil, you have less and less time for dwell as the RPM comes up. Setups with eight coils don't have this sort of limitation.

An MSD box is what's called a capacitive discharge ignition. It contains a capacitor that it charges to around 400 volts. One end of the coil is held to ground, and it empties the capacitor through the other end to fire the coil. The capacitor has a short recharge time, so the spark energy doesn't fall off at high RPM. The downside is that it has much shorter sparks - the multi-spark thing is to make up for the short sparks being a problem at low RPM.

 

Thank you sir! That is what I needed to hear. Are there any good write ups on how to make a car with an megasquirt MS3X SEFI using an msd crank trigger and msd dizzy?

 

If using the wheel on its own, use the notes on Basic Trigger mode in the MS3 documentation, or our write up here:

http://www.diyautotune.com/tech_articles/using_megasquirt_with_msd_distributors.htm

If modifying the distributor to be a one tooth cam trigger, see the Generic Wheel notes instead.

 

So, I need to use the crank trigger as the crank sensor and cut the dizzy teeth off to use it as a cam sensor? Then set up the ECU accordingly? This is what I was thinking but thought there may be a different/better way.

 

you can't do something I did I use the genericwheel from DIY auto tune and then installed the top of a cam synchronizer from a 97 Explorer see my post on cam synchronizer there's a YouTube video there