Multi-channel CDI
04-19-2008, 01:08 AM
#3
Best upgrade you can do for these cars. Will absolutely make a difference. Pro 10 is for single Plug engine, and pro 14B special is for Twin Plug engine. Both would use Distributor. For 6 coils (dual) you will need pro 16, 6 channel. You could use std Pro 14 and use only 3 channels and drive 2 Coils on one channel, but this would 1/2 energy.
Best to call Neil @ PD. He is US distributor who sells the most and gives the best support.
CDI is far better on these engines than Inductive. Supplies far greater chamber heat which gives better combustion. No issue with fouled plugs either.
The new 14B version is the single unit for twin plug engines. 6 Channel CDI's are big money, but the best you can have.
Best to call Neil @ PD. He is US distributor who sells the most and gives the best support.
CDI is far better on these engines than Inductive. Supplies far greater chamber heat which gives better combustion. No issue with fouled plugs either.
The new 14B version is the single unit for twin plug engines. 6 Channel CDI's are big money, but the best you can have.
04-19-2008, 11:30 PM
#7
Don,
Twin Plug engine would need the following. It will be an either or situation. Also, please ask neil what he thinks as well. He's the expert here.
6 Dual Coils (packs) would require 1 Pro 14 CDI, which is the 4 Channel variant. You would drive each dual coil with 1 channel of this 4 channel CDI with 1 channel spare. This is wasted spark. Same will apply for the Bosch 3x2 Coil packs. You could tie these together and drive them with a Pro 14 the same way. This way the CDI is driving 4 Plugs at once. 2 from each Coil assembly. 2 on compression and 2 on O/Lap. This is really lowering the spark energy, but still better than Inductive.
Or you could use a Pro 16 6 channel CDI and drive each pair together sequentially. This also will half the spark energy as you are driving 2 coils ( 2 plugs) with 1 output.
To be fully sequential and have the most energy you would require 2 x 6 channel CDI units, each channel driving it's own Coil.
Twin Plugs change alot.
I think I have got this right. Best to check. Neil will be able to give you the exact energy loss and the real difference between CDI and Inductive.
Twin Plug engine would need the following. It will be an either or situation. Also, please ask neil what he thinks as well. He's the expert here.
6 Dual Coils (packs) would require 1 Pro 14 CDI, which is the 4 Channel variant. You would drive each dual coil with 1 channel of this 4 channel CDI with 1 channel spare. This is wasted spark. Same will apply for the Bosch 3x2 Coil packs. You could tie these together and drive them with a Pro 14 the same way. This way the CDI is driving 4 Plugs at once. 2 from each Coil assembly. 2 on compression and 2 on O/Lap. This is really lowering the spark energy, but still better than Inductive.
Or you could use a Pro 16 6 channel CDI and drive each pair together sequentially. This also will half the spark energy as you are driving 2 coils ( 2 plugs) with 1 output.
To be fully sequential and have the most energy you would require 2 x 6 channel CDI units, each channel driving it's own Coil.
Twin Plugs change alot.
I think I have got this right. Best to check. Neil will be able to give you the exact energy loss and the real difference between CDI and Inductive.
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04-20-2008, 08:29 AM
#8
Nordschleife Master
Simon, to run CDI in waste spark mode, you'll need 2 pro 14s otherwise the ignition energy is cut in 1/2 for each of the plugs. Each Pro14 will fire one double ended coil serving a main spark plug and the "wasted" spark plug. I would never, ever run two coil off of one CDI unit since it isn't the way the system is designed to work and it cuts ignition energy.
The other option is to run two Pro10s and a 964/993 twin distributor. I much prefer this method over waste spark. I use a lot of the M&W equipement since they make the MoTeC units.
The other option is to run two Pro10s and a 964/993 twin distributor. I much prefer this method over waste spark. I use a lot of the M&W equipement since they make the MoTeC units.
04-20-2008, 12:14 PM
#9
Geoffrey,
I agree. But some do it. I know its not the way it should be. In the name of saving money, many will find a way.
Even though the energy is lowered considerably, I feel its still far better than Inductive. At least the energy at the Plug this way is greater than Inductive.
BTW, if you run the Double headed Distributor, Neil has a special Pro 14 unit now that is designed to run 2 channels apired at the same time just for the twin Plugged Porsche engines. Saves alot of wiring and cleans up the engine bay.
Twin plugs really make a mess of things. Turbo applications make the Double Distributor a real mess around the Intercooler pipe. I think thats why neil has that rear mounted Distributor that fits in place of the Air pump, on top of the Turbo pump. You run the stock single Distributor at the front and another at the rear. Thats what he did on one of my old engines.
I still would rather go with Single coils. Just makes the CDI conversion a little expensive. 12 channels of Ignition. At least the coils were the type that fit direct to the plugs. Not sure the type. I think they were Denso from a Nissan. That cleaned up the engine bay some.
I have had discussion here about the merits of CDI over Inductive. I have seen the difference on the dyno, on starting, idle and on throttle response. I would never use Inductive on one of these engines.
I agree. But some do it. I know its not the way it should be. In the name of saving money, many will find a way.
Even though the energy is lowered considerably, I feel its still far better than Inductive. At least the energy at the Plug this way is greater than Inductive.
BTW, if you run the Double headed Distributor, Neil has a special Pro 14 unit now that is designed to run 2 channels apired at the same time just for the twin Plugged Porsche engines. Saves alot of wiring and cleans up the engine bay.
Twin plugs really make a mess of things. Turbo applications make the Double Distributor a real mess around the Intercooler pipe. I think thats why neil has that rear mounted Distributor that fits in place of the Air pump, on top of the Turbo pump. You run the stock single Distributor at the front and another at the rear. Thats what he did on one of my old engines.
I still would rather go with Single coils. Just makes the CDI conversion a little expensive. 12 channels of Ignition. At least the coils were the type that fit direct to the plugs. Not sure the type. I think they were Denso from a Nissan. That cleaned up the engine bay some.
I have had discussion here about the merits of CDI over Inductive. I have seen the difference on the dyno, on starting, idle and on throttle response. I would never use Inductive on one of these engines.
04-20-2008, 01:43 PM
#10
Nordschleife Master
An interesting thing about ignition systems. A few years ago in Formula 1, 1/2 the field was using CDI and the other half inductive. I prefer CDI for our level because they are racing bred systems whereas the inductive is simply a production version and they cannot even compare in terms of performance.
The way I tell the performance of an ignition system is how large a plug gap I can have without missing. On my old Turbo, I ran inductive becuase in 1996 when it was converted, that was the best option. I ran a plug gap of .045" at 1 bar of boost. After about .050" it would miss. Now an Electromotive system has difficulty with .025" of plug gap. My M&W CDI fires .080" on my current race car with no issues. From there, you can begin to see ignition timing differences between the different plug gaps and therefore the ignition system performance. You can definately see the difference on the dyno.
I'm running the small footprint Pro10s, one for each distributor. I wonder about the new single unit, how many caps are in there?
The coil on plug is difficult because they are inductive coils unless you go and get a racing system from Bosch, Tag McLaren, or Magnetti Marelli. Simply adding a 996 COP with a CDI unit is doing a disservice to the ignition system and the gains won't be there.
The way I tell the performance of an ignition system is how large a plug gap I can have without missing. On my old Turbo, I ran inductive becuase in 1996 when it was converted, that was the best option. I ran a plug gap of .045" at 1 bar of boost. After about .050" it would miss. Now an Electromotive system has difficulty with .025" of plug gap. My M&W CDI fires .080" on my current race car with no issues. From there, you can begin to see ignition timing differences between the different plug gaps and therefore the ignition system performance. You can definately see the difference on the dyno.
I'm running the small footprint Pro10s, one for each distributor. I wonder about the new single unit, how many caps are in there?
The coil on plug is difficult because they are inductive coils unless you go and get a racing system from Bosch, Tag McLaren, or Magnetti Marelli. Simply adding a 996 COP with a CDI unit is doing a disservice to the ignition system and the gains won't be there.
04-20-2008, 03:40 PM
#11
Agreed. I'm certainly not the person to give advice here, but something hat was very interested in was the plug gap verses the plug position. Try closing the gap and moving the plug into the chamber more. If you have the clearance. The less gap will give more heat by lowering the '''''''' whatevers. I don't know this stuff, but Neil is real good on Ignition. I know you you talk to him. Ask him. Most so called experts don't understand Ignition. These engines 930 Turbo's with the large chambers and Flat top Pistons really need all the Ignition help they can get. Those that have changed over to a good CDI system have found the difference. The basic 911 needs this to.
I do not know about he single unit. Best to ask Neil. I do know it's either more or bigger than the Pro 10.
I am not sure about the Coils either. I do know that they are similar to the Ferrite CDI Coils in inductance. The choice of whatever he uses fits the 911 with some small spacers for the Valve covers and they are the best types available. The Bosch ones that are sold are the same as the Denso types he uses and the Denso ones fit better.
Again, best to ask him as all I know is what I have seen, watched and been told.
Like you, he is a fan of CDI over Inductive for these engines. Dyno proof has shown this to be true.
I do not know about he single unit. Best to ask Neil. I do know it's either more or bigger than the Pro 10.
I am not sure about the Coils either. I do know that they are similar to the Ferrite CDI Coils in inductance. The choice of whatever he uses fits the 911 with some small spacers for the Valve covers and they are the best types available. The Bosch ones that are sold are the same as the Denso types he uses and the Denso ones fit better.
Again, best to ask him as all I know is what I have seen, watched and been told.
Like you, he is a fan of CDI over Inductive for these engines. Dyno proof has shown this to be true.
04-21-2008, 12:20 PM
#12
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I have a M & W Pro-14 CDI with six double ended coils and mount, with ignition wires that were used on the dyno only. I want to sell the set up but I need to confer with Geoffrey first.
04-21-2008, 09:58 PM
#14
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04-23-2008, 02:43 AM
#15
Don,
I stopped in at Neil's tonight and asked him about the CDI's. He told me he has ben talking to you about this. he told me you cannot drive 6 Dual Coils with 1 pro 14, but you can use 2 of them. he also told me that the Pro 16 is a better choice and less money.
Geoffrey, while I was there he gave me a real lesson in Ignitions. He showed me a system (parts) from a F1 engine from an 07 engine. It is Inductive. But very different Inductive compared to what we see as Inductive. Its more like CDI than Inductive. The Coils are charged with 600A. Each Coil is charged and fired 158 times per second. He told me that no after market ECU he knows of could do this. The ECU has to know exactly where the crank is within 1/10 of 1 degree at all times, to know when to charge the Coils. All this at 19000 RPM. Its no wonder there's so much current required. You have to charge the Coils 158 times per second. The Coils don't look very different but I'm sure they are very special.
I stopped in at Neil's tonight and asked him about the CDI's. He told me he has ben talking to you about this. he told me you cannot drive 6 Dual Coils with 1 pro 14, but you can use 2 of them. he also told me that the Pro 16 is a better choice and less money.
Geoffrey, while I was there he gave me a real lesson in Ignitions. He showed me a system (parts) from a F1 engine from an 07 engine. It is Inductive. But very different Inductive compared to what we see as Inductive. Its more like CDI than Inductive. The Coils are charged with 600A. Each Coil is charged and fired 158 times per second. He told me that no after market ECU he knows of could do this. The ECU has to know exactly where the crank is within 1/10 of 1 degree at all times, to know when to charge the Coils. All this at 19000 RPM. Its no wonder there's so much current required. You have to charge the Coils 158 times per second. The Coils don't look very different but I'm sure they are very special.