Paradox_Racing

I have been brainstorming, and trying to come up with a way to run zero split trailing timing with a first gen ignition system. The only things I can come up with is either a flying magnet crank trigger system, or a 2nd gen crank trigger/decoder. Problem is, with the flying magnet design, you would need two seperate crank triggers (One for each rotor) which is not very cost effective, and very difficult to accomplish because both crank wheels would have to attach to the E-shaft, but could not be right next to each other; and as far as I can tell there is no simple way of adapting a 2nd gen cas to work without the factory ecu. I want to do this because I would like to control my spark from my EMS, but it is not designed to do rotary engines. I am running an MSD direct fire setup from a 6a box, I could control the leading ignition from my EMS but not trailing, because you can't utilize wasted spark on the trailing ignition. Any ideas?

rotarygod

iTrader: (1)

It's simple to change the split on a distributer. Nothing special to it at all. All you do is loosen 2 bolts that hold down the trailing vacuum advance pot, move it inward until split is at 0 and tighten it back up. Check out the factory service manual page on adjusting timing. You'll see how to do trailing.

http://www.rotaryheads.com/PDF/1st_g...erformance.pdf

3rd and final 7

iTrader: (9)

there a system for the mag pickup on the eshaft but i dont know what its call i ll look it up in a Rx7 performance book i got. its called, quote from mazda Rx7 Performance Handbook Pg 93 lower RH corner."Electromotive it uses a multi coil setup so that one coil ca re-energize b4 it is called on to fire the plugs again.with this ignition you can throw away your distributor, and for that matter, your coils. The stock Rx7 dizzy relays on on a gear to turn a rotor, which in turns distributes spark. The Electromovtive system senses the rotation of the e-shaft directly, and fires accordingly. " that what that says honestly its going to take time and money to get it perfect.

3rd and final 7

iTrader: (9)

disregaurd what i said! RG's sounds better

Paradox_Racing

I'm not trying to adjust the trailing split, I know how to do that. I am trying to find a way to tell MY EMS what the crank angle is, so it can tell the one or two MSD boxes when to fire. I'm basically trying to get rid of the dizzy altogether if at al possible.

3rd and final 7

iTrader: (9)

you can run a megasqurit with the CAS from a 2nd gen if you wanna get rid of your EMS and the MS will only run you about 200 or so bucks!

Paradox_Racing

Not a chance, I love the control the Commander 950 gives me, but I was possibly thinking of moddifying a mega suirt to act as nothing but a translator for the cas, and sending it's signal to the EMS ECU. Don't know if that'll work yet though. I need to do a little more research.

rotarygod

iTrader: (1)

Why can't you just run the MSD direct fire mod and then add a second box on the same circuit to run another set of plugs? You wouldn't even need the cap and rotor anymore, you'd have zero split, and you'd have your MSD boxes working. If you do it this way you'll still have ignition advance. If you were to use a 2nd gen cas without an ecu, you'd need to use an ignition box that could adjust timing as opposed to something simple such as 6A which can be used with the above setup. If you used a cas with no ecu and only a 6A type of igniton box, you'd have a fixed advance.

Paradox_Racing

I can't fire the trailing plugs in a wastes spark config.

rotarygod

iTrader: (1)

Good point.

rotarygod

iTrader: (1)

OK how about this idea. Open up the dizzy. Each pickup wheel has 4 teeth. Luckily there are 2 of them and 2 sensors, one for each wheel. Instead of using 1 for leading and 1 for trailing, you will need to rewire it to use one for one rotor and one for the other. You will need to grind off 2 of the teeth from each wheel. Make sure the teeth on the top wheel are the opposite ones from the bottom wheel in other words the ones that are 90 degrees off from the opposing wheel. Hopefully you follow this. Then you can run one MSD to the top wheel and another MSD to the other trigger wheel. Using this setup, each ignition box wil only fire one every 360 degrees as the dizzy turns at half the engine speed. The opposite trigger wheel has the teeth in the middle of these so it fires 180 degrees off of the other wheel but also every 360 degrees. Then you wire up a leading and trailing from one rotor to the coils of one box and the leading and trailing of the other rotor to the other box. I hope that makes sense but you'd still have the advance built in if you did this. It seems like it would work but I've never tried this so I'm not sure. I don't see why it wouldn't though. There would be no more wasted spark and you'd still have leading and trailing firing with no split. If you think about it, this sounds alot like th flying magnet system you mentioned above. It has a pickup for each rotor and is run off of the crank.

Paradox_Racing

You know that just might work, and I have a spare dizzy to try it on. I'll take a look at it tommorow. Thanks for the idea!!

REVHED

I did this ages ago with a stock dizzy. You need to grind two lobes of the reluctor and move the trailing pickup so its 90* from the leading.

wecycle

I have been working on two ways to do the full DFIS on a first gen.

1 Set the T pickup to 0 split, remove two lobes from the reluctor. This will fire the two original ignitors in an alternating sequence through the two original coils. One to each rotor T plug with less than a foot of secondary wire with the coils mounted to the dr. strut tower. Add a second reluctor above the first. The L pickup is extended up 3/4" to align with the added reluctor. This fires the L plugs in a wasted spark setup through a GM HEI module and dual outlet HEI coil mountes on the strut tower, again with less than one foot plug wires. I bought an Accel coil and module. This eliminates all high voltage through the distributor and retains full vacuum and centrifugal advance without the need for an ecu control.

2 Set the T pickup to zero split. fire two dual outlet GM style coils . One with both outlets connected to the L & T plugs of rotor 1 and the other with both outlets connected to the L & T plugs of rotot 2. This will give you simultaneous firing of both plugs in each rotor while retaining centrifugal and vacuum advance.

For either of these strategies you can retain the distributor cap with no secondary wires or cut off the top and epoxy a flat top to clean up the look.
The simultaneous firing of both plugs may yeild 3% power increase and probably will require slightly reduced initial timing due to the faster rise time for chamber pressure. I have the cap made but have not finished the guts of this modification.

REVHED

I don't see how either of those setups will work correctly by what you described.

wecycle

What part needs clarification?

On version 1 a ballast resistor on the stock coils might be a good idea to avoid overheating the ignitors. The HEI has dwell and current limiting built in so it will not need a ballast resistor. This version is a little harder to build.

Version 2 is likely to produce slightly more power but also more emissions.
Version 1 should cost about $100 while version 2 would run about $160. This version is very easy to build.

rotarygod

iTrader: (1)

I'm second guessing myself right now and hope I wasn't getting confused with the 2nd gen cas system. I still think the idea can be made to work though. Does the dizzy have only 1 trigger wheel inside? I know it has 4 teeth. I'm wondering if it has 1 wheel but 2 pickups on it? I forget. If it does you still remove 2 teeth and make sure that the pickups are 90* apart. That will still work the same. If it does have 2 trigger wheels then it is as I said the first time. I can exactly remember as it's been a while since I've had the dizzy open but you should be able to make it work either way.

rotarygod

iTrader: (1)

This confuses me as well. For setup #1 are you wanting to add another pickup for a total of 3? I still don't see how removing 2 teeth will cause it to alternate back and forth between rotors. If you removed 2 teeth and had 2 pickups spaced 90* apart, then you'd basically have what you want for the trailing. Then you'd need to add an additional pickup to another wheel that still has 4 teeth to retain wasted spark on the leading plugs. That's what I understand out of what you said and the only way I can see that working.

Scenario #2 as you describe it won't work as you'd have wasted spark on leading and trailing. You can't have wasted spark on trailing.

REVHED

Yeah, I was wondering about what you said. The stock dizzy has two pickups and one wheel with four lobes.

wecycle

No. I fire both L & T plugs in rotor 1 then both L & T plugs in rotor 2. I.E. zero spilt or simultanteous firing of both plugs per rotor. One dual outlet HEI coil per rotor triggered by a two lobe reluctor. The former trailing pickup is set to zero split and the leading pickup fires the plugs in rotor 1 while the trailing pickup fires the plugs in rotor 2.

wecycle

[QUOTE=rotarygod]This confuses me as well. For setup #1 are you wanting to add another pickup for a total of 3? I still don't see how removing 2 teeth will cause it to alternate back and forth between rotors. If you removed 2 teeth and had 2 pickups spaced 90* apart, then you'd basically have what you want for the trailing. Then you'd need to add an additional pickup to another wheel that still has 4 teeth to retain wasted spark on the leading plugs. That's what I understand out of what you said and the only way I can see that working.

This setup has two reluctors and three pickups. The top 4 lobe reluctor fires the leading in a wasted spark pattern. The lower reluctor has two lobes and with an added pickup at 90 degrees from the first fires the trailing alternately through the original coils. One coil to each trailing plug. This retains the split and also vacuum and centrifugal advance.

REVHED

The only way that will work is if you grind two lobes off the reluctor and have the pickups 90* from each other. Otherwise you'll be firing the L and T of each rotor every 180* in effect having wasted spark on both L and T.

wecycle

Right! That is why I said using a two lobe reluctor.

REVHED

Ahh, I missed that.

It just didn't seem very clear in your first post that's all.