V8kilr

yea ur right,dont know what i was thinking,must have been tired.

V8kilr

lets get back to this.

Dyno

Not much. Using an MSD with stock cap and rotor, my dyno results were: ~1hp for direct fire, ~1hp for side fire plugs. 2 hp total improvement over MSD and stock cap/rotor. Probably hard to say it was an improvement if you take into account all the things that could make the dyno read 2 hp different. Did lean the mixture out ~0.5 lambda though. I have no idea how much of a difference it is over a stock ignition with no MSD. As always, your mileage may vary....

SilverRocket

I've seen lotsa people claiming 10hp from ignition, but as far as my opinion goes this is mostly cause their stock ignitions are in awful shape to start, and then they replace with brand new nice stuff. From what I've heard, most of the benefits are driveability, cold starting, slightly smoother revving, etc. I also remember hearing a lot about MSD's were actually a bad idea on the high end of the rev range, which is all I frankly care much about anyways. Dig up some old threads written by Jeff20B, I think those are where all this was discussed. Bottom line from what I've seen and the fast cars I've personally witnessed, is that Mazda's stock ignition system is excellent if in nice condition.

If it's significant power gain you're interested in, you'd be much smarter to look into aftermarket carb setups, porting and fuel mods rather than blowing all kinds of cash on ignition. Of course if already have everything else, an ignition setup is a nice piece to complete the car. That's just my 2 cents.

mar3

iTrader: (8)

After seeing that, maybe I won't bother with direct-fire...

SilverRocket

Keep in mind I haven't actually done the mod, it's just my opinion from what I've seen and read over the last couple years. But as we know, 10 guys on here can have 10 different opinions lol.

I've heard lots of "it starts easier, it idles smoother, etc." but not really much in the way of substantiated power increase information. I would like to see a dyno comparison of a stock system in perfect condition vs. direct-fire MSD in perfect condition. My guess is that top end power would be very similar. Even a quartermile run comparison would be nice, but it would only be valid if done on the same day and same conditions.

Remember though, if easy-starting, low rev drivaebility and minimizing emissions is what's important to you, I'd think the MSD would a good idea. I just don't see how anyone's gonna get considerable power gains from it, if their stock system is in good shape.

I remember reading that the advantages of the MSD are negated by around 3k rpm on the FB. I really should be writing an essay right due tomorrow right now lol, or I'd try to dig it up.

Barwick

heh oops.. the stupid forum cleans out extra spaces.. here, one more try..

(ignore the periods, they're for spacing)
(asterisks * dictate a plug firing)

Rotor 1
.\... ---Trailing Plug
..\
../
./...*---Leading Plug

Rotor 2
.|...*---Trailing Plug
.|
.|
.|...*---Leading Plug

See, on rotor 1, the leading is firing at the same time as the other rotor's leading plug, that's the waste spark.

Now on the next firing cycle:
Rotor 1
.|...*---Trailing Plug
.|
.|
.|...*---Leading Plug

Rotor 2
.\... ---Trailing Plug
..\
../
./...*---Leading Plug

V8kilr

the whole reason im interested is because i already have all the stuff to do it,
i was asking some q's about something else and someone said
"you are direct fire right?you have all the stuff to do it"
i said "huh?"
and went investigating,mostly i have a huge improvement over stock with a much much smooter idle,and smoother sounding engine,
they mostly compair to the sound of a 2nd gen and 3rd gen.

SilverRocket

Well then by all means go ahead lol. I said what I said with respect to what Dyno posted.

RXcetera

The reason why most people have a smoother idle and smoother acceleration after dropping in an MSD is because they adjusted their timing in the process. With a good condition stock distributor, new plugs, a timing light and a properly adjusted carb, any FB can start in a flash and idle/accelerate perfectly smooth...

mar3

iTrader: (8)

So is it your opinion, also, that direct-fire is not worth the cost? What's your setup, now? Stock or direct fire?

RXcetera

Mine? On the 83, Stock distributor and King coils (basically chrome stock ones), aftermarket NGK wires and stock plugs. I also have my timing set to RB specs and I'm not using any vacuum advance. I can easily reach 8000rpm and I've never had a problem with misfiring or backfiring. My idle with Nikki carb was perfectly smooth at 700rpm but it's lumpy at 1000rpm with the Dellorto.

My Savanna has breaker point ignition... but that's a whole different story...

For me, I've never seen a necessity for direct fire or MSD.

RotorMotorDriver

iTrader: (1)

Woah, FJ, it all became suddenly clear, thanks man ! I was thinking just like V8Killer for a little while there, not knowing about the direct fire setups. I had the leading/trailing part down, I understood all that and they way it works stock, but what V8Killer was saying made sense to me. But what I forgot about is that since the rotors are out of phase with eachother, the plugs would be firing a different times anyway . Thanks alot...I get it now

~T.J.

PS - After reading this, I too see no reason for Direct Fire to be on the top of my mods list either.

peejay

I love my MSD! I just can't figure out where in the heck I'm gonna mount the coils on the new car... my MSD bracket will fit easy (just have to clean up the edges so it's not so ugly, and re-paint it silver to match the car) but the coils in the old car are mounted where the A/C compressor is in the new car. And I refuse to remove A/C that is still functioning... I'm not very heat tolerant anymore... the 40-50lb weight penalty is a fair trade-off to avoid being stuck in a hospital for a couple days again!

Maybe the battery needs to be relocated to the back... yah that's it.... mount the MSD and the coils to a custom mount where the battery used to go. Heck there'd be room for a second MSD unit for the trailing (Just for the rev limiter function and the "ooh and aah" factor)

RotorMotorDriver

iTrader: (1)

Ok, question...MSD (or Direct Fire) consists of the coils and an ignition box right? The coils are for the same purpose as the stock ones just "better", right? And the ignition box is basically an "upgraded" electronic ignition then right? It takes the job of the distributor telling what plugs to fire when and what not, right? Ok...If all that is correct, and we have pretty much said that the stock distributor is capable of controlling the spark just fine, then wouldnt really the only "smart" upgrade be to upgrade the coils for a "better", "more efficent" spark? Im assuming that over the number of years that these cars are old, that the stock coils could be lacking something in performance after being used this long (like dying batteries in a flashlight maybe?)...I dont know much about this, I just understand the concept of how it all works stock (and how Direct Fire works now thanks to FJ), so forgive me if I look like a dumbass...

~T.J.

peejay

The MSD works totally different to the stock system. It supplies a MUCH higher voltage to the primary windings of the coil, as well as more amperage, and this results in enough spark energy to fire in practically anything. I never fouled a plug after putting the MSD in - you could probably have the spark plugs sitting in a jar of oil and they'd fire!

Also the MSD fires multiple times (up to about 3500-4000rpm), up to six times per spark event. So even if the first spark misfires, another one (up to five more!) happens and increases the chance of lighting it off. When does plug fouling occur? Low RPM! Beautiful!

RXcetera

You aint no dumbass lol. That's pretty much what I did... got some better coils and called it a day. Never really thought about my ignition system much since then... it's never let me down.

RotorMotorDriver

iTrader: (1)

I suppose that this could be considered a good thing, it makes sense to me, but my ignition works the way it is, why mess with it ?

~T.J.

PS - I was thinking about new coils, thats kinda why I asked...What would you guys recommend? Like I said, I dont know much about the products and what-not out there...

Northern 7

iTrader: (3)

I also love my MSD - you can go round and round on this one until every 7 owner has posted on this thread. The only way to clear up the opinions is to try both (it's a quick install) - if you don't see the improvements with the direct fire MSD, then take it back for a refund. Bottom line for me was this was the best money I ever spent on my car

On Peejays note on where to mount the BOX, you may laugh at this suggestion but I mounted mine in front of the rad on the opposite wall of my fab'ed cold air intake. Some will say it will get wet in this location, but if you silicone up the wiring outlets, you shouldn't have a problem. If you review the information that comes with the MSD, you will note that the biggest warning they provide is to keep it away from heat - that's tough to do under the hood of a rotary. The box will stay very cool in front of the rad and I've had mine there for 2 yrs without any problems - just an opinion

FJ

Glad some part of it helped. I wasn't sure what V8lilr was missing, so it was not a concise answer.
In case you missed my earlier correction, the 120* which appears in your quote of me is not correct. I spoke without thinking it through. The rotors are 60* out of phase with each other, not 120*. The rotor has 3 apex seals, 120* from each other. If the 2nd rotor was 120* out of phase with the first, you would always have apex seals, and rotor faces, aligned with each other. They are 60* out of sync. As long as I'm fessing up to inaccuracies, I also said the wasted spark happens "near the end of the exhaust cycle". I should have said "near the end of the chamber" during the exhaust, not at the end of the cycle. Sorry for any confusion. I'll try to be more precise next time.

May as well add my thoughts on direct fire: as the stock ignition has always worked well, I have other things to buy that will give me more bang for the buck than an MSD. But if I come across an extra igniter and coil, other than new, I will try direct fire not with MSD, but with http://www.geocities.com/cd23c/dlidfis.html , which is the direct fire setup I was referring to earlier regarding two igniters. It has to be a stronger spark, if not multiple sparks.

-John.

rotorhead

as far as stronger coils go, i found some accel coils in a local autoparts store. they're yellow, not too expensive, and put out around 40k volts. and i didn't notice a whole lot of a difference between those and stock coils. maybe a little bit smoother, and she always start on the first try, but no noticeable power gains from the seat-of-the-pants-o-meter

Directfreak

iTrader: (2)

LOL!

That is probably THE most commonly used meter around here.

V8kilr

whoa there,
lets recap on why a rotary has three cats and spits flames,and the exhaust is so damn hot,

its from the shape of the combustion chamber not being able to burn the fuel completely,
that is in the rb catalog.

so what can we do to help this???
ignition.

i believe the ignition system is one of the weakest parts of an fb's power source.

however some believe its already over kill on the later fb's

but if so then why did mazda switch over to direct fire on 2nd and 3rd gen rx7's???

thats just what i get out of already based facts.

V8kilr

you are the man!

just gave me a great idea that i will have to incorperate into my custom hatch.

one of those new sealed gel batteries in the back.plenty of space up front.

V8kilr

qoute by paul yaw

"
Distributors Suck
Now for the first generation. Distributors suck! Distributors require that the charge jump a .075" gap from the rotor to the cap before it can even fire the .055" gap of the spark plug. The gap in the distributor cap is easier to fire than the spark plug gap, because there is much less pressure, but it is still a really shitty way to make fire. Luckily it is relatively easy to convert the leading ignition to direct fire. I finally got around to doing this on my 13B, and then I was mad at myself for not doing it sooner.

Before the conversion, I was using an MSD 6A, with an Accele super coil. This is a lot of juice, so I was really surprised at the improvement after converting to direct fire. I called MSD to be sure that their box would fire two coils, and their tech guy said "Hell, it would probably fire a whole row of coils." I set it up with two stock coils for the leading ignition and was stunned at the results. The engine made more power everywhere in the powerband, and the driveabilty improved dramatically. I will never again run an MSD through the distributor."


thats was a quote from paul yaws web site.