MSD 6AL/Capacitive discharge, what's been done?

[ShiRen]

I've been searching high and low this afternoon for ignition mods, but the search doesn't like 3 letter words so "msd" and "6AL" are out. Has anyone used one in these cars? I'm actually trying to reverse engineer one, I just need confirmation how its hooked up and such. The manual is pretty vague on the workings of the ignitor, but it seems to be just a transistor, aka spark voltage is really flipping low. If I can get the information squared away I'll start building immediately and post it all in this thread. I've seen a few impressive engine control mods done here, but yall are pretty much are all fuel injected or obd1/computerized, my goal is to be as basic as possible and I know for a fact that the circuit in the 6AL that would be used for a carbed 3g is pretty simple and only needs the core components of whats in that box. In other words, I'm not paying $250 for some secret sauce.

Edit: I'm actually not 100% sure how well this will work, there's a few obstacles that must be overcome: tachometer output, spark duration, transient response, current draw. These are just all unknowns, but what I do know is I can charge a capacitor and get the full 45kv out of my MSD Blaster 2 coil.

Here is some of the sources I have been looking at:
http://web.tiscalinet.it/giordy/ECU/msd6a_02.pdf
https://www.homemade-circuits.com/how-to-make-capacitive-discharge/
https://www.elprocus.com/capacitor-discharge-ignition-cdi-system-working/
https://www.preludepower.com/forums/showthread.php?t=233619

[Shane86]

Look into mega jolt

[ShiRen]

Look into mega jolt

Megajolt is crank fired ignition. I think its really cool, but its not what I want to do. Somebody else is doing it right now, I would like to keep my mechanical distributor over a computerized system, and its more than I want to spend, probably moreso than a 6AL after coils. Megajolt is also a wasted spark system afik, if its based off Ford EDIS, distributors best pont is that they are direct fire per say, they only fall flat against distributorless direct fire because there is only 1 coil to charge vs 4 though. A capacitive discharge system such as the 6AL can out perform a wasted spark system given that your coil is heavy enough, the downside is there is a lot more wear, low rpm can suffer, and peak rpm (youll never reach it with an A20) is reduced. Distributor uses 1 coil for 4 cyl, wasted spark uses 1 coil for 2, distributorless direct fire uses 1 for 1, the coils can only charge and collapse so fast.

[InAccordance]

I have a thread in the Performance section of my megajolt conversion. Still a work in progress cause other shit keeps breaking and I work 5 days and I still have to daily the car but I'll get it done one day...
Oh, and I'm carbed.
I had an MSD box on the Prelude I had but frankly I dont even remember how to wire them up. Been 12+ years ago lol. Do know it works though.

[InAccordance]

Look on Preludepower.com. Pretty sure there is an MSD box how-to write-up somewhere there. I remember using it back then. I do remember it being pretty simple to wire even for a FI car. I used a Blaster SS coil and 11mm plug wires, it worked pretty well.

[ShiRen]

I have a thread in the Performance section of my megajolt conversion. Still a work in progress cause other shit keeps breaking and I work 5 days and I still have to daily the car but I'll get it done one day...
Oh, and I'm carbed.
I had an MSD box on the Prelude I had but frankly I dont even remember how to wire them up. Been 12+ years ago lol. Do know it works though.

Don't worry, I am watching that, its really cool.
I think I know how to hook it up just from reading pages 24-3, 24-9, and 24-12 in the manual but I will check around there too

[Shane86]

Megajolt is crank fired ignition. I think its really cool, but its not what I want to do. Somebody else is doing it right now, I would like to keep my mechanical distributor over a computerized system, and its more than I want to spend, probably moreso than a 6AL after coils. Megajolt is also a wasted spark system afik, if its based off Ford EDIS, distributors best pont is that they are direct fire per say, they only fall flat against distributorless direct fire because there is only 1 coil to charge vs 4 though. A capacitive discharge system such as the 6AL can out perform a wasted spark system given that your coil is heavy enough, the downside is there is a lot more wear, low rpm can suffer, and peak rpm (youll never reach it with an A20) is reduced. Distributor uses 1 coil for 4 cyl, wasted spark uses 1 coil for 2, distributorless direct fire uses 1 for 1, the coils can only charge and collapse so fast.

I completely understand. I'm one of those OBD1 fuel-injected guys so I am really not too much help. I do know the blue wire from your stock coil is rpm signal and the black with yellow striped is 12 volt power source. But that's fuel injected

[ShiRen]

I completely understand. I'm one of those OBD1 fuel-injected guys so I am really not too much help. I do know the blue wire from your stock coil is rpm signal and the black with yellow striped is 12 volt power source. But that's fuel injected

Yeah, there is actually 2 blue wires... For some reason Honda used only used 4 colors for 6 or 7 wires in the ignition circuit, its really convenient :wtf:
One is tach, the other is the pulse from the ignitor, the one coming from the distributor is the pulse. I think I have gotten that much figured out, but I am contemplating on revising the ignitor as well being as it looks like its becoming obsolete.

[Shane86]

Good luck with it I hope you figure it out

[Oldblueaccord]

The big thing is multi spark at the lower RPMS. On performance cars esp with large camshafts with over lap this really fights misfires.

Problem with MSD is there quality is junk and there so many Chinese knock offs I wouldnt bother running it.

Summit racing has a multi spark box that claims made in America and is the same design as all the other multi spark boxes.

[ShiRen]

The big thing is multi spark at the lower RPMS. On performance cars esp with large camshafts with over lap this really fights misfires.

Problem with MSD is there quality is junk and there so many Chinese knock offs I wouldnt bother running it.

Summit racing has a multi spark box that claims made in America and is the same design as all the other multi spark boxes.

Right, and my goal is to actually replicate the capacitive discharge system. 500v to the coil, 125mj spark. I don't think multiple spark will really benefit me with the stock cam and it will really suck to build from scratch.

[InAccordance]

On stock cam with stock induction, nah probably wouldn't do much. Throttle response would be more snappy though.

[ShiRen]

I have a set of bike carbs I am going to put on when I get another intake manifold to chop. One could only wish you could even still get cams, though I guess I can regrind

[Shane86]

I have a set of bike carbs I am going to put on when I get another intake manifold to chop. One could only wish you could even still get cams, though I guess I can regrind

There's quite a bit of options for cams. Delta, Colt, Webbs, crane, bisimoto

[InAccordance]

Webcam has some in stock the last I looked.
Are you looking for a stock carb manifold?

[ShiRen]

I think I am going to go to delta with a second cam, webcam shows a ballpark of $400 for a regrind, so I don't think they have a stock. I sent delta an email request for a quote.

Id love to find a cam gear too, Bisimoto still sells valve springs, but I think in the past year he stopped selling cam gears, or maybe Im dreaming. Id like to look for other valve spring options anyhow, I just happened to see them.

As for the cdi progress, I only need to find out what I need for a transformer, then I can order components and get it mocked up

[InAccordance]

I still kick myself for selling the cam gear I had years ago. Took part in a group buy in preludepower but the car was totalled before I could use it. Held onto the gear for a while but ended up selling it cause I didn't think I get another A motor years later...

[ShiRen]

Id love to know what the difference is vs some of the other honda cam gears

[InAccordance]

Size mostly.
I think sohc d series are larger round vs the dohc stuff being smaller diameter.

[ShiRen]

I hoped ot wasnt something like that, if it was the inside diameter being different I think I could make do. Im assuming f series is larger too.

[ShiRen]

Well I didn't want to abandon my cdi project, but I saw an auction on ebay for an msd 6200 6A last night for $60 shipped, I just won the auction. I'll crack it open and make sure its ok and the components are in spec once I get it. If anybody is super upset that I'm not building an msd equivalent cdi I can still I guess, but I'm assuming building one from scratch is a bit above the level of what most guys will try to make and run on their car. I'll still post the innards of the 6A and the testing, as well as the installation. Still need to make my arduino cruise control too, I bought a few arduinos to get started on it, but its so easy to control the speed on the highway it hasnt bothered me recently lol

[InAccordance]

Nice deal. Thought about getting one for the megajolt but figured it's already wasted spark so wouldn't really do much.

[ShiRen]

Sounds like a good way to melt down a stock ford coil lol. Hey if you feel extra froggy you can always ditch the megajolt for something like a megasquirt and go coil on plug... 370z coils would look mint dangling between the exhaust ports.

[InAccordance]

Could.. but this my first time doing this so got to learn on something simple lol
Maybe in the future if I ever want to go ITBs and full on FI

[ShiRen]

Itbs on an a series... You know at that point you may have fallen off your rocker, but who am I to judge because I was thinking a coil on plug setup would work good if youre running a big draw through turbo

[InAccordance]

It's been done before. They make dcoe style itbs and I already have a dcoe intake so actually wouldn't be all that hard. Worst part would be wiring up all the electronics required for FI
That and cost. Be an easy 3 to 4 grand for everything you'd need. I've got about 1500 in my carb setup so I'll stick with that for now lol

[ShiRen]

Man there's all sorts of psychos driving these cars, glad I'm driving one too, makes me feel like part of a cult, I mean clan. And you don't have to wire up any fuel injectors for your megasquirt, hell that'd be sacrilege in my book.

[InAccordance]

Well I just mean FI in general, various sensors and such.

[Hondanator]

Ive got a msd 6al on my 84. Ill double check but i think i got mine wired both Blackand yellow to red both blue to White, orange to coil positive black to coil neg.

[ShiRen]

I figure I should tune back in on this. I wired up that 6A a long time ago, I don't think I had any problems with wiring it. It was either exactly the same as that or I already knew what wire was what because of my hairbrained attempts at electrical engineering. If anybody needs to know which wires go where, I am sure I can look.