Jeff20B

Ah, you corrected yourself. I was wondering if you would catch it. Yep, the two pickups in the dizzy are very nearly 180° apart, depending on the LT split.



Hey, how do you think the VR sensor would perform if flipped over so the cores of each pickup coil are 90° apart? This sort of mod would be good for those out there who feel compelled to achieve trailing direct fire with a 2 tipped reluctor. It would be a good idea to mount on the shaft above the stock 4 tipped one (more room up there to build a bracket to hold both pickups precisely 90° apart). You'd have to butcher two dizzies and I haven't tried it yet because I don't feel the need to upgrade trailing (other than moving the plug wires to the leading part of the cap when going direct fire on the leading ignition), but there were a lot of people obsessed with it on the Mazspeed forum back in '03. Even RX-Midget modded an FC CAS and had ok results (no advance weights).



By the way, if you have one of those double ended, or 'DIS' style coils hooked to both plugs on each rotor housing, most of the spark energy goes to the trailing plug, right? It's the path of least resistance. Fellow forum user heretic could debate its effectiveness (or lack thereof, heh) much better than I could.

Lynn E. Hanover

You have to keep your eye on the prize. For the manufacturer it is to reduce costs.

So dumping the distributor as soon as possible is a big payoff in profits. A very costly piece to make.



Next we see the double ended coil from a motorcycle fireing both leading plugs.



Not because this is a great idea, because it is not a great idea. But because fireing both plugs on a housing at the same time does not work for emissions. If there were no emissions requirement there would be two double ended coils as I described above.



The double ended coil idea is there because it is cheaper to produce the car than installing two coils for leading and two coils for trailing.



So what is your prize?



Acceleration, cornering, reliability, looks?



The Kettering system uses 12 volts (this may not be true of the computer controlled stuff) (anybody know what voltage the 3rd gen and RX-8 run the coils?)

The primary windings are charged with 12 Volts DC. Inductive reactance resists the formation of a flux field because the expanding flux field generates a current that is the oppossite polarity of the battery. So the coil primary never sees 12 volts. In theory if connected to a battery that would maintain 12 volts for all of eternity, it would never get to 12 Volts.



So the leading coil fires twice per revolution, and it never gets to 12 volts. At 9,000 RPM thats 18,000 discharges per minute(twice per revolution). A V-8 at 9,000 RPM is 36,000 discharges (4 times per revolution).



So as the revs go up coil saturation time goes down and the spark energy available at the plug goes down.



If you detect a sag in power at full throttle and high RPM that goes away, or gets better when the throttle is pulled off a bit, it is probably secondary ignition voltage going down from short saturation time. So if the mixture is OK and you regap the plugs to .010" (ten thousandths of an inch) and the problem goes away, then it is

secondary ignition voltage sagging.



So now to the store for at least one and hopefully two MSDs.



It is accurate to say that one plug in the lost spark system will always be less effiecient than the other because of the polarity problem.



Depending on what model MSD you buy, the poor kettering coil will never again see that paltry 12 V primary voltage. When the trigger signal turns on the big SCR, 350 volts stored in a large capaciter is applied to the primary of the coil.



Now even the poor performing plug looks like a nuclear test. So even with short gaps

The MSD will reach through the plug boot and give you an electricity lesson you will not forget. You also want to keep your distance from the coil primary wires, now operating at 350 volts, and you don't want to try that either.



They draw about 9 amps at 9,500 RPM. And close to 100% of that energy is appearing inside the combustion chamber. That is great for starting a roaring fire.



This also good for lighting over rich and over lean mixtures.



Be sure to select a coil(s) from the approved MSD list. Many coils can't take 350 volts.



So the two pickup, single reluctor on the front pulley triggering two MSDs with two MSD blaster coils for each housing approaches ideal from the timing accuracy, energy delivered, reliability and HP point of view.



Wouldn't 4 MSD blaster coils in a line with 4" plug wires look great? There you go,



Looks too.





Lynn E. Hanover

j9fd3s

the newer mazdas split the + wire from the battery to about 5 wires. the black/yellow does the fuel injectors/ignition, the black/white does the emissions, theres a black/red that seems to run some of the brain boxes (abs, auto suspension etc), theres a black w blue, and something else.



so since the power to the coils doesnt go thru the ecu at all its gotta be 12v.



i'm not sure how the rx8 is wired up (but we just changed a harness for no reason so i can look) and they also went to a 4 coil ignition system. each plug gets its own coil

Lynn E. Hanover

The 4 coil idea seems to me the correct answer. Now the RX-8 people need to rig up (for off the road use only) MSDs to fire at least the leading plugs.



The newer coil on plug systems seem inviting. No plug wires at all. The MSD has no trouble fireing two coils in paralell so one MSD per rotor housing will do the job.



If the coils would hold up to the high primary voltage this would be a good option.



My Kia has a coil on plug with a plug wire to the next hole. So about half of it right and still very cheap.





Lynn E. Hanover

j9fd3s

sportage or sephia? those plug wires are about $10 retail, we did sell a couple of them per week. 2 of the dealerships i used to work at were mazda/kia. if you need kia stuff, we were selling to the wholesalers, shoot me a pm

Lynn E. Hanover

I had a performance problem with my 2000 Sephia just out of warantee. Left it at the dealer for a computer diagnosis. They found a bad plug wire and replaced both coils and wires and took out My new Bosch plugs and put in the new crap stock plugs, without calling me with an estimate of the repair. They lost the black screws that hold the cover down, and put in some zink plated screws from a Dormon box.



Thats $360.00 down the drain. The next time I take a car over there it will be to burn the place to the ground.



Thank you for the offer.





Lynn E. Hanover

j9fd3s

haha, whoops! our techs are doing well if they pull the right car in the stall

Cheers!

I wonder if those rx8 coils are better than lx92 coils.

j9fd3s

they are super small. i almost put em on the 20b, but i didnt want to be the ginuea pig

Cheers!

after re-reading this thread and Lynn E. Hanover remarks, it makes me wonder if my twol crane hi6 with two lx92 coils was the right way to go.



Damn it Lynn why did u have to make this post?