Direct Fire... converting back

[Speed Raycer]

Ok all, it's been at least 2 seasons now since I've had my RX on the track, so forgive me if I've lost some memory for the details...

My 1st gen had been converted by the PO to direct fire using two MSD's... one on the leading, one on the trailing (trailing is not direct obviously... MSD just replaces the ignitor)

Since the distributor must distribute the spark per the rules, I'd like to convert back but still use the mSD's. My memory is a little fuzzy on how ignitors work and how the direct fire operates.

Should I modify the cap/rotor to still use direct fire, just routed through the distributor cap? Legal?
Should I rewire the MSD's to basically act as ignitors?
Should I just ditch the red boxes and rewire a stock system back in?

[lateapex911]

I'll watch this with interest, although I admit to being boggled just by the terminaology, LOL

Word is that the MSD adds power. But I need to learn why and how.

[dick elliott]

Scott! Go to the MSD web site and order their instruction book. It shows both single and dual MSD hook up for a rotary. Lots of good racer stuff in the book.

[mustanghammer]

You can wire the MSD so that it connects to the ignitors or have it connect to the pickups (no OE ignitors) in the distributor. An MSD 6A has two methods of input - the instructions for the MSD box will detail how to do this.

That means it is possible to use both MSD boxes and run everything through the cap.

[cpa7man]

Does anyone have actual dyno results showing that the MSD's really do add power? I purchased an MSD unit but have never installed it. Some of the ep guys don't use it, as a matter of fact the fastest 12a does not.

This link might be helpful. http://www.mazspeed.com/msd.htm

[Karl Bocchieri]

To do it correctly you need 3 MSD boxes 2 for leading 1 for trailing. I was crusing all the RX-7 sites and it's a little different with 1st and 2nd gens but most people said the signal from the ignitors was DIRTY and that the signal direct from the distributor/crank angle sensor was better. There was also some talk about having to use aftermarket coils. I dont think I have seen any of the front running ITS Mazdas use anything other than stock coils and ignition.

I think the hot setup would be a coil on plug setup. Paul Yaw was working on something on his web site but I havent been there lately. Something like the coils off a late model 6.0 LS1.