Originally Posted by rotarygod

You could use them on PAST rotaries ('86- until Renesis) because the leading plugs in both chambers always fired at the same time as the other. This was referred to as wasted spark mode since the additional firing by the plugs was on the exhaust side of the apex seals. The MSD box (or any other) was fed a signal from the leading output of the ignition system. The MSD box fired a pair of coils simultaneously to the leading plugs. In order to fire the trailing plugs off of an MSD, 2 more boxes were needed for a total of 3 ignition boxes! Since the trailing plugs fire independently of the other one, they can not be run off of the same box as each other. Neither trailing plug fires at the same time as the leading plugs either. The created the need for 3 boxes to fire at 3 independent times. On the old distributer equipped RX-7's, 1 box could be used before the distributer since the distributer seperates the firing sequence internally. Those cars could also be converted to the later system by picking up the leading plugs signal before the ignitor in the ditributer. This signal could be run to an MSD box and then directly to 2 leading coils. The leading coils ran off of the MSD and the trailing plugs still fired off of 1 coil through the distributer. This is how I run my 1st gen RX-7 and it is superior to the distributer system. This now takes us to the RX-8.

At this time I have not heard of anyone using an MSD or equivalent on the Renesis. There are some main problems which make it harder on this car than on the previous rotaries. First of all, the coils are very small and get very hot. A few people have already burned them out just playing with spark duration. We aren't even talking about running more juice through them. They would probably not live very long. It is my opinion that new aftermarket coils should be used if an MSD type of system is to be used. The next problem is that all 4 plugs fire independently of each other. No more wasted spark mode. This means that we either need 2 boxes for only the leading plugs or 4 boxes total if we want to boost the entire system. We also need 4 new coils. I don't know where anyone is going to fit all of this under the hood yet alone be willing to pay for it. I'm fairly sure it can be done but it would not be cheap and would be a big hassle. A hotter spark may help the poor little trailing plugs light off the engine faster and help the flooding issues some.

I hope that shed some light on the subject.

Originally Posted by Dookie_Rx-8

whats the benifit?

Originally Posted by Charles R. Hill

The thing that bothers me somewhat is the current claimed to be generated by such a system. 500 amps? You can weld with that. As a matter of fact, Crown Amplifiers used to weld with their power amps at trade shows to display the durability of their products. Since the secondary side of an ignition system typically runs with 35-50K volts at less than 1 amp I am wondering what the operating voltage is in the Direct Hits set up. Over the past few years current manipulation has been used, again in the audio industry, as a way of meeting the needs of certain loads placed on power amps. This puts the burden of supply voltage/current back on to a good electrical supply in the first place. Prior to current-drive we used voltage to deal with the loads and that placed the onus on well-designed circuits in the amp itself. This is a relative comparison because ignition systems and audio power amps do exactly the same thing(as do all other electrical circuits); modify voltage and current to satisfy the needs of a particluar objective. In the automotive world, be it audio or ignition, we are dealing with extremely limited power supplies, such as 12 volts and an ultimate limit of maybe 125 amps because that's all a good alternator will kick out. This is also why the automotive industry is experimenting with a 48v electricasl system. I'll stick with more traditional means to get a "hotter" spark, thank you.

Good to hear from you again, Haze. How's my grammar?

CRH

Originally Posted by Charles R. Hill

The DirectHits concept goes way back to the '60's if not earlier. The idea is to use a storage capacitor on each spark plug to drain the factory coil of all of it's available voltage on each revolution and discharge that voltage on each ignition cycle. This places a huge load on the ignition coil. Similar technology is used in audio apps. where caps are used to store voltage for those low frequencies that drain the power amps of their voltage, too. The response in such audio systems is to have several batteries and a couple of H.O. alternators to restore the power in those caps ASAP. To use this type of ignition system requires one to change from resistor-type plugs to non-resistor plugs, hence the problem finding a proper application for the Renesis. Non-res plugs also tend to be very noisy and cause EMI which may disturb the operatrion of the radio or, worse, the ECU and other sensitive electronics. I think the Nology plug wires operate on roughly the same principle and that may have been why some have had problems with them on the Renesis.

Of course, I could be way off base here. In that case, never mind.

CRH

Originally Posted by rx8pilot

You're probably right...it would be up to the stock output of maybe 125 amps. i think the 500amps you were reading is the max..depending on application and power supplied.. even so..a spark at 120 amps or so would be alot greater than stock....right? lol

Originally Posted by rx8wannahave

So Dr Lou, are you guys going to make some for the RX8? I have to go check out the website but what type of power and fuel economy numbers are you seeing? What I mean is, what is the improvement...in real life application.