sen2two

i already have the Jacobs FC1000 ignition system...



http://www.fcignition.com/ProductDetails.a...;minselection=1



i want to stay with them for the coils...what do you think of these???



http://www.fcignition.com/ProductDetails.a...;minselection=2



also, would i need 4 of them??? (just making sure, im new to ignition systems)



the stock FD coil set has 3 coils? im looking at mine and these 3 "things" the middle on has 2 plugs in it. and the outers have one each. and a mini harness connecting all three together. now just how would i get 4 different coils working together???

Lynn E. Hanover

Nobody has an opinion on your ignition system.



Perhaps that is a vote for never heard of it. Jacobs has been around for a long time. I bought one years ago

and tried it on the dyno, and got identical results as a $19.00 Chrysler (points eliminator) ignition module from the 70s. So I gave it away. It was also no worse than the Chrysler stuff, but no better.



The dyno is a sort of indelicate down at the one HP level, so it could be that there was a very small advantage to the Jacobs, and I couldn't see it.



This data is from 30 years ago, and probably has nothing to do with the unit you have.



I have never seen a Jacobs product on a race car. Again, I may be in the dark on this, and maybe everyone in California is using one, and the wave of popularity has not swept this far East yet.



MSD and Mallory HiFire is all thats used in any numbers. On the dash of every NASCAR vehicle is a pair of MSDs. They even have a special plug for NASCAR units. The GM racng Division sells MSDs painted blue.

See a pattern here?



Find the specs for the Jacobs and look for 150 milijoules per spark. If it is less than that, or they will not give you the data, do something else. That 150 number is what the Mallorys and MSDs put out, and is enough energy to kill you.



The MSD units for fuel dragsters and funny cars, puts out enough power to kill you and all of your friends.



Depending on the Model of MSD or Mallory, the coil will be fed between 350 volts and 550 volts. Some coils will not last long doing this, and a list of coils that will hold up is available on their web sites.



These systems capacitive discharge systems use about one amp per thousand RPM.



So line up the specs side by side and make your pick.



The odd coil linup on the FD engine is confusing at first look. The problem is that some money could be saved by having three coils to run 4 plugs instead of 4 coils. Since they can do it........they do it.



In the car biz, cost to manufacture is everything. No profit........no cars. So a few years back the car companies noticed that those pesky motorcycle people had been lighting two plugs with one coil on two cylinder engines. And anything like that is like a magnet to car people. So now we see the lost spark system being used everywhere.



Lost spark is what again?



A regular coil is called an auto transformer. There is a primary winding of heavy wire to use much current, and a secondary winding of fine wire, to allow more room in the coil because the secondary has 10 to 20 times the length of wire of the primary. That is called the turns ratio. The higher the ratio the higher the secondary voltage.



Not that the coil has two connections for primary wires but only one secondary out let. In the olden days where I come from, the coil was supplied power from the ignition switch, and the points would open the circuit to get a field collapse to generate a high voltage to fire the plug.



It is called an auto transformer because one end of the primary and one end of the secondary are connected inside the coil. To complete a circuit, the return path for high voltage is the whole car. Ground straps to the block and so on to the shell of the plug. And back to the grounded side of the battery.



In a piston engine of 2 cylinder or more, 4 stroke engine there will be one cylinder in the exhaust stroke when one cylinder is being fired. So a coil with both ends of the secondary windings available are connected to those two plugs, and when the coil is fired to light one cylinder at the right time, the other end of the secondary is firing the plug that in imersed in exhaust gasses. Since this has no effect on performance, the spark is wasted, or lost.



So, the Mazda uses the lost spark system on the leading spark plugs. Because it is cheaper to use one coil rather than two. Works just like piston engine coils doing the same thing.



Why are there two coils for the trailing plugs if leading has only one? (You might ask).



Unlike the piston engine, the rotary will have an apex seal between the two plugs in the housing not being fired. (he wasted spark end of the coil) A spark from a double ended coil would fire the charge in the off housing way too soon and damage the engine. So the wasted spark idea will not work for the trailing plugs in the rotary.



So, there are individual coils for each trailing plug, and the controller fires these only one time per revolution. While the leading double ended coil fires twice per revolution.



Easy isn't it?



Lynn E. Hanover

heretic

I try to stay out of discussions involving Jacobs electronics. They tend to turn into religious arguments between people who say to use the MSD because it works and it works great, and the people who get suckered into the Jacobs marketing crap.



IIRC, Jacobs is the company that would have you believe that differing running conditions need different spark outputs, because a too-strong spark under light running conditions can actually extinguish the flame kernel. There was also a lot of techmological jargonese involved, too. It all smells heavily of BS.



The MSD, on the other hand, works, and works great.

sen2two

damnit.....i think i got cought up in the Jacobs BS. i seen they sell it at RX7.com and some one had mentioned it was used on a few of the fastest FD's in the country. but i havnt seen it.



but now i think i should sell of the FC1000 and build up an MSD full system...



can someone do me a favor of making a list for me what i need. or maybe a recomendation as of what i should use.

(as i said im new to ignition systems)



basic list of what my build is...will be street driven but im reaching for 600WHP.

13b-rew

Apex-i PFC

half bridge

RX8 e-shaft and stat gears lightened REW rotors

Precision T60-1 Turbo

1000cc and 1600cc secondarys

howracer

'as usual lots of spot on info from Lynn...



i spent alot of time researching ignition as i run methanol in addition to pump gas on my 88 pounds per minute twin T04 setup.



and it is true that, like discussing oil, lots of opinions and a modest amount of data. we are talking about a bunch of black boxes.



Summit does have data on their site. i assume it comes from the manufacturer.



i was looking for the ultimate ignition and here's what i came up with:



stock trailing ignition coils

two Jacobs FC 3000 ignition amps

two MSD 8253 coils

a custom made (from the universal set) set of MSD Superconductor wires

two EGK 8725 10.5 plugs leading, B10EGVs trailing



each amp runs one leading plug thru it's own MSD coil. the amps are in the rear package compartment behind the driver.



with this setup i can easily fire 9.0 AFRs of 70% pump and 30% methanol.



here's why i picked the Jacobs amps...



-------------Jacobs FC 3000--------MSD DIG6+-------Crane HI-6-------MSD 6A----FC1000---------------------------------------



CD VOLTS---------535----------------535---------------450----------------470----------500-----



OUTPUT------------145Mj-------------135----------------120----------------115----------125



unlike the other amps, the FC3000 has a circuit that senses acceleration and goes to full output. the rest of the time when you are just driving around you aren't frying your plugs. i have 5000 miles on the setup and it has been very plug friendly. i run 10.5s leading on the street and 10s trailing.



coils



again, using Summits data nothing can touch the MSD 8253.



check out the spark duration.... 450uS.



none of this stuff is cheap but if you want to make 600 rwhp you need good systems so you take them out of the project riskwise.



oh, as to few people running Jacobs, that may be true but one of the few people is Ari Yellen and he has taken alot of scalps...



good luck,



howard coleman

TYSON

If you're replacing the entire ignition;



http://www.mwignitions.com/

Lynn E. Hanover

There you go...........All of your home work done for you. Now sell the car and you will have enough money

for a great system.



Lynn E. Hanover

sen2two

thanks very much...



should i need another FC1000 and run 2 of them? or an FC3000 or even 4000??? or is one FC1000 sufficient for what im doing?



what should i be looking for when shopping for coils??? i see the jacobs c-4 coil has 60,000 volt, while the MSD 8253 has only 44,000. plus they would match my Ignition amp also...



i see your way more experienced than i am in this. but at 1 third the price, and more voltage...it looks to be a great choice. (jacobs C-4 coils)



what makes a coil a great choice besides that everyone else uses it...???



and why would i want to use the stock trailing coils? simplicity, price, or there just better???

heretic

Even this is not always enough information. I had an MSD setup years back and loved it. I sold it to a friend of mine, figuring that I could get another one when the time was right. When that time came, the local rep for a company who shall remain nameless (not MSD, not Mallory, not Crane, not Jacobs) told me to try their box, since it had higher spark output than the MSD, was a few bucks cheaper, and used dials for the rev limiter instead of "pills" (plug-in resistors). Taking his word for it, I went with his product.



First clue was that the box was less than half the size of the MSD. Second clue was that the power lead was supposed to be connected to the old coil positive instead of directly to battery (MSD's current draw will spike to hideously large numbers). Third clue was that all of the wires for the unit were about 16 gauge and aluminum core.



The box would not reliably fire the leading and trailing coil at the same time, either with stock FB coils or MSD coils. After converting to the leading-only direct fire setup, the box lasted about five thousand miles before blowing up. Before failing, the engine felt "flatter" than it did before, power suffered, and fuel economy suffered. Those problems went away after converting back to good old fashioned transistorized ignition.



The MSD is en route as I type this. The millijoules number is lower than all of the competition, but none of the competition compare as far as real world ability to create huge fat sparks in the engine, under any conditions, no matter what hare-brained coils scheme you have saddled it with.