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Ignition systems

Discussion in 'Technical Q&A' started by Professor, Aug 8, 2005.

  1. Professor

    Professor Rookie

    May 30, 2005
    16
    England
    Full Name:
    Andy
    I have a 1982 Mondial QV European spec. I want to replace both Digiplex boxes. Does anyone have any ideas about sourcing, pricing and performance of aftermarket ignition systems? I am based in the UK.
    Many thanks
     
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  3. CliffBeer

    CliffBeer Formula 3

    Apr 3, 2005
    2,192
    Seattle, Washington
    Full Name:
    Cliff
    My father replaced the std. (and troublesome/expensive) distributor/points/coil system on his 308gt4 with a very nice ignition system from Electromotive (www.electromotive-inc.com). This system has separate coils for each cylinder/plug and a programmable ignition advance curve. Also, the spark produced is very, very strong - probably two or three times the voltage of original. Installing these aftermarket ignition systems successfully will require some engineering understanding and decent DIY skills, so, not for the feint of heart.
     
  4. Nick

    Nick Formula Junior
    Sponsor Professional Ferrari Technician

    Oct 31, 2003
    505
    Full Name:
    Nick Scianna
    #3 Nick, Aug 9, 2005
    Last edited by a moderator: Sep 7, 2017
    I have been doing ignition direct coil kits for 308's for years using electromotive engine controls, The new set up is called the XDI. I supply a complete kit with brain box, coil packs, relays, ignition wires, sensor, sensor bracket & custom trigger wheel & tac black box & full tech support. The system arrives set up so the car starts right up. It is a very reliable set up. There is more info on my website on it & you can also call me for more info. Here is a link.

    http://www.nicksforzaferrari.com/forzaferrariwebsite1_009.htm
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  5. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
    Full Name:
    Russ Turner
    #4 snj5, Aug 9, 2005
    Last edited by a moderator: Sep 7, 2017
    I also wearied of my Marelli repeatedly crapping out, so using an adapter from Norwood's (board sponsor) I simply used a Mallory Unilite billet electronic distributor with an MSD and hot coil. Very simple, DIY friendly, inexpensive, proven reliability and easy to install. Has been very effective and met my requirement for reliable ignition performance. Starts every time, no more single bank ignition. Adaptable for any 308/328. I documented the conversion in FChat Tech section.
    best
    rt
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  6. TomDial

    TomDial Rookie

    Aug 6, 2004
    36
    Europe
    Full Name:
    Chris
    The Digiplex is a very good system. Any alternative would be a downgrade in overall performance. It gives a strong spark and has well proven advance curves for any load situation.
    Try to restore before throwing it in the bin if it is still some kind of working. Cleaning, drying and conserving the circuit with silicone oil and grease or sealing it in special electronic sealing paint will help it run forever. The wires are easy to diys rebuild if you are able to solder.
    If you cant do this, don’t think about fitting any other, different system. Even if you get it running at once, it is very difficult to restore the advance curves. Wrongdoing at this point can give you expensive engine damage or heavy power loss.
    Not anything Ferrari fitted to these cars was complete garbage.
     
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  8. pma1010

    pma1010 F1 Rookie

    Jul 21, 2002
    2,559
    Chicago
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    Philip
    An opinion: Any well sorted system should be fine. The ability to "tune" the advance curve can be helpful. There are (reportedly) some advantages to the spark integrity of crank fired versus cam triggered systems but whether these are meaningful for NA street applications is a question.

    A perspective: Giovanni @ Autosprint in Chicago has been modifying 8 and 12 cylinder Ferraris for years with MSD / optical "distributor" which (I believe) fits in the "traditional" housing. He reports no fails and owner happiness.

    A datapoint: I bought one of Nick's kits (the earlier HPX) a few years ago and it has run flawlessly outside of a short spell when I didn't connect up one of the grounds well enough connected on re-installing the engine after some engine-out work. Once identified it has again run flawlessly.

    Seems like you pay your money / take your choice.
    Philip
     
  9. Professor

    Professor Rookie

    May 30, 2005
    16
    England
    Full Name:
    Andy
    Many thanks for your comments so far. However, many of the systems mentioned that retro-fit 308's don't fit the later QV308s or Mondial QVs with the Digiplex ECUs. I have tracked down a couple of Digiplex boxes in the US but they have the number: MED 805A. My boxes have 803A. I understand that 803A are to Euro spec. Will the 805A boxes work or will they reduce power etc. or not be compatable with the euro spec injection etc. Any other suggestions welcomed. Surely someone must have utilised the original Ferrari TDC and tacho sensors to fire up a modern ECU at a reasonable price!
     
  10. DGS

    DGS Four Time F1 World Champ

    May 27, 2003
    41,988
    MidTN
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    DGS
    I'd guess that the biggest difference between the 803 and 805 units is the ignition curves -- linked to the different cam timing between US and euro cars.

    If you're looking for a "plug replacement", you should probably keep looking for an 803A -- and retain a concours point or so, while you're at it.

    Modern ignition systems will have a completely different ignition curve. Some are programmable, but most won't be able to match the horrendously complex curve built into the Marellis.

    Most "aftermarket" ignition systems are generic -- there's a limited market for 308 unique ignition systems. So it will take a bit of tweaking -- and a knowledge of theory -- to fit one to any car.

    And aftermarket systems are listed "for racing". This means two things: The curves are simple power curves, without all the complexity built into the Marelli for emissions. And there are no internal diagnostics -- it doesn't check if the sensor inputs are working. Of course, the old Marellis also lack internal diagnostics, unlike modern OEM ECUs.

    I've been looking at replacing the Multiplex in my 328, but I've encountered a few issues:

    1) The built in flywheel sensors give only enough information to fire bank "A" or bank "B" -- they don't provide enough information to trigger individual per-cylinder coils. (The 328's heads almost beg for individual "stick" coils.)

    2) The 328's distributors are useless with a stick coil system, so something would have to be done about those oft-leaking seals. I'd thought to covert the distribs to cam position sensors (solving (1) above), but nobody makes off the shelf units, and, while computers are the easy part for me, I'm not the neatest mechanical fabricator in the world.

    3) The flywheel sensors give (as far as I can make out) 144 pulses per rev -- or about 2.5 degrees per pulse. This is nowhere near sufficient resolution, so the computer would have to use time to extrapolate between pulses. But that's just programming. ;)

    4) Any modern computer with enough address space to replicate a Multiplex map would also have more than enough CPU cycles to also drive an electronic port injection system ... without that big honkin' CIS barn door in the airflow. And a custom programmed EFI can add the internal diagnotics that the CIS lacks. --- But that means a quest for an EFI converted intake manifold -- those mechanical bits again

    5) A custom one-off EFI could drive stick coils, eliminate the CIS's air plate restriction, and add OBD to the system. But who would fix it if it broke? The average Ferrari shop wouldn't know the system, and dealer shops might flee in horror at the sight of it. (My friend and I added intermittant wipers to his '75 Alfa once. For weather proofing, we mounted the electronics in a plastic 35mm film can. The dealer, on seeing it, picked it up by the wires and looked at it as though he'd found a dead mouse under the hood. ;))

    6) The problem with system engineers is that we're used to having schedule deadlines to tell us when it's "good enough". Otherwise we keep trying to "tweak" the design to make it perfect, and never get around to building it. ;)
     
  11. hanknum

    hanknum Formula 3

    Nov 1, 2003
    2,050
    Santa Barbara
    Full Name:
    Henry
    Russ,

    What type of ignition wires are you using?
     
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  13. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    27,119
    Austin TX
    Full Name:
    Brian Crall


    The 805's were the single biggest reason for the power loss of the US version cars.
    Stay away.
     
  14. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
    Full Name:
    Russ Turner
    Taylor spirals, 8mm
     
  15. hanknum

    hanknum Formula 3

    Nov 1, 2003
    2,050
    Santa Barbara
    Full Name:
    Henry
    Are the spark plug extenders part of the wires? Are the 90 degree elbows also a part of the wires?
     
  16. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
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    Russ Turner
    We pushed the wire end through the well cover (difficult) where it then clip attatches to the stock extender as the original. The 90 degree ends at the cap come with the universal wire kit.

    I would really like to get rid of the extenders as well, if possible.
     
  17. hanknum

    hanknum Formula 3

    Nov 1, 2003
    2,050
    Santa Barbara
    Full Name:
    Henry
    I assume the "well covers" are factory Ferrari stuff? Your set up looks nice and clean.

    When I went to the Electromotive system (some 9 years ago) I was told to just disregard the extenders and plug the wires directly onto the spark plug. That's great, but a PITA to do. I put a little vaseline on the inside of the boot and then use a piece of 3" long tubing (that I have cut a slit in lengthwise) that I put over the wire that sticks out of the boot. This gives me a little rigidity to the wire so that I can press the boot onto the spark plug.

    I'd like to find a wire set (that is compatible with the Electromotive) that has the extenders already a part of the wires (and has the well covers). I think some wires that are designed for american hemis have this type of wire. This would make life much easier and "pretty up" the engine. IIRC, the Electromotive unit requires the wires to have a certain amount of resistance.

    Anyone have any suggestions?
     
  18. mk e

    mk e F1 World Champ

    Oct 31, 2003
    11,962
    The twilight zone
    Full Name:
    The Butcher
    Either a haltech or motec ecu will rear the OEM sensors and fire the stock distributors. Any other brand (I think) would require 2 parallel units, which would still work fine.
    Yeah, you need a cam position sensor for that plus the 2 crank sensors, I don’t know of any aftermarket ECU that will handle that. I added the cam sensor and 2 pins to the flywheel to get 4 pulses per rev from one either of the crank sensor and it seems to work well.

    Another option is waste spark. You fire the plug every time the piston comes up. That eliminates the need for the cam position senor. That is the standard electromotive set-up using a 60-2 crank sensor (a bolt-on from Nick), a ford 36-1 system could be used, or haltech and motec can do this as well, but again require a custom crank sensor 60-2, 36-1, of N/S/S/S magnets.

    That shouldn’t be true. There should be 3 sensors, 2 for ignition and 1 for the CIS. The CIS sensor reads the teeth on the flywheel…I had 106 in my head, but I guess it could be 144. The 2 that run the ignition are reading 2 pins on the back of the flywheel, so 2 pulses per rev.

    I think the better way to put it is ANY modern ecu has many times more than enough storage to duplicate the OEM maps, which are very primitive due to storage and processing limits of the day and the US versions are a bit odd to trying to meet EPA requirements. When I did my conversion, I used the Euro maps as a baseline, but still needed to interpolate a lot…I thing the OEM maps are 8x8 vs 32x22 on my ecu.

    From what I understand, doing the fuel is the easy part, it’s the ignition that’s hard. So there are several fuel only ECUs, but the only ignition only I know of is electromotive. You can use only the ingnition part of any ecu and but the efi at another time of never. Motec does have diagnostics as far as I know…I’m planning to switch to a motec M800 this winter, I’ll post something when I do.

    It’s been my experience that things that can break should be off-the-shelf, I would stay away from custom. If you really love messing with stuff, I guess a MegaSquirt will let you, but the hardware is a bit primitive…although way ahead of OEM.
     

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