Bluem

what msd ignition set-up should i run on a carburated 13b with a distributor???

APEXL8T

two MSD 6a. Cut vent holes in rotor cap.Used this setup for several years on IT car.

Bluem

any write ups on this ignition???

speedturn

iTrader: (1)

Here is one write up:

http://www.mazspeed.com/msd.htm
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In my opinion, the MSD is rpm limited. If you are running stock porting, it is fine, I use one on my street Mazda.

But for a hi-rpm peripheral ported race motor, I lost power above 8000 rpm with the MSD. Again, it is fine for stock porting, but maybe not the best for a PP race motor.

Dick Elliott

Order the MSD how to book from MSD (who else?) It tell how to hook up one and/or two MSDs to a RX-7. The book also has many pages of GOOD electrical info. DICK.

Alak

iTrader: (9)

Anyone ever run a second MSD on their 7's? I have the leading hooked up with a 6AL Box and it runs awesome. When I hook my other 6AL to the Trailing, I get pinging.

Syonyk

How do you have the trailing setup done with one MSD? It's two independent coils, and firing them at the same time WILL lead to pinging. I believe to do full MSD, you need 3 - one for the front combined coil, and one for each rear coil.

I'm also fairly sure that a MSD on the trailing coils doesn't do much, if anything. The bulk of the work is done by the leading plugs.

-=Russ=-

Doc Holiday

iTrader: (2)

I am curious, you say you lost power over 8000rpm with the MSD (I'm assuming to weak spark and random high rpm misifres). What sort of ignition setup do you run now to regain the lost power over 8000rpm?

Railgun

DIS-2 box

rotorbrain

they also make the sport compact boxes now that are supposed to have better response in higher rpms. . . and such.

i run a digital 6plus on my leading and WILL BE running a dis-2 on the trailing if the new coils arent good enough.

paul

mmonaco

I have had a horrible experience with MSD crap. I bought a DIGital 6 plus for the leading and the DIS-2 for the trailing with 4 coil blasters, i could not get it to spark at 20 psi for the life of me. It just kept breaking up. But it did work up to about 15psi flawlessly, but for higher applications i would go with something that is proven(second gen coils)

Thanks
Marc

Jaime Enriquez

I could never get the RevLimiter to work with my Carb 13B with a 6AL on the leading....anyone ever use the revlimit function...do I need two boxes or what?

Railgun

Here's the thing and a point about what I've been reading all over. Ultimately, voltage is going to be the key factor in this. I've asked what the winding ratio is on the stock FD coils. I'll ask what it is for the FC coils too. It may not be that MSD is crap, it may be that you're not using the correct product for the application. I'd also like to know how much voltage the primary side is seeing in stock trim.

For example, I'm running the stock coils with an AEM amp. That's 535v to the primary. I have no idea what the coils can do, but I need the amp at 15 psi else I get breakup. Here's the thing about the MSD box and coils. The MSD amp is rated the same, and the coils have a 100:1 ratio, but they're only rated to (depending on exactly what you have) 42-45kv. Technically, you should be outputting ~53kv since the output is the input by the ratio of the winding. Since you should be over what it's rated, I don't know what's happening.

I'll run into this issue next year as I intend to occasionally push 25 psi. We'll see what happens.

Perhaps you need the pro power coil (rated at 55kv)?

Keith13b

iTrader: (6)

I'm running twin Mallory Hyfire IV's with Promaster coils.

Noticible improvement, especially at high RPMs-

Built in rev limiters that work like a charm, too.

orange

iTrader: (1)

Have a look at this link.

http://www.smbaker.com/rail/msd6a.html

Bluem

thanx fot da link

rotaryengineering

The link that Orange supplied is good but, if your planning on running a P-Port for a full race application using the 1980 style distributor is not a bad idea. It does not use igniters on the distributor housing they are located externally.

This is just my preference:
I like the MSD 7AL running the MSD Pro Power Coils. My new ignition system I put together for my P-Port will be similar to the link Orange supplied but I will be running 3 MSD 7AL units/ 3 Pro Power Coils.

2 MSD 7AL/Pro Power Coil for each leading plug
1 MSD 7AL/Pro Power Coil for trailing plugs

This is not a cheap solution but, will definitely have enough ignition to support 11,000 - 12,000 RPMS.

Good luck with whatever setup you choose to run. There are so many setups people have write ups for us to choose from.

APEXL8T

My two 7AL'-2 with 6A