Fiat Dino Tacho

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Re: Fiat Dino Tacho

Postby alh » Thu May 21, 2015 11:26 am

Stefan2000 wrote:Adrian, that makes sense. The guy producing the 123 ignitions lives around the block for me so i'll might discuss with him what is possible and what not. If i understand you correctly the downside of this ignition is the maximum current output from the coil in combination with what the circuit board of the 123 could handle. So a higher output coil might raise your output but could damage the circuit board?
Temperature problem might be less of a problem in a fiat dino compared to a Ferrari dino because it right there with it's nose in the wind??? (well ofcourse it's behind the radiator) I can monitor the temperature from the 123 on my laptop and so far it never exceeded 60 degrees or something while driving.
Your right about the coil current, i can also monitor it on my laptop and it is somewhere inbetween 3 and 4 Amp's
I do drive the BPR7EIX Plugs.
Do i need a special zener diode, i see that for a 12V you can have 0W to 5W
http://www.dil.nl/Search.aspx?SearchFor=zener&QuickAbort=True
Thanks for the interesting reply!


Ideally the 123 would be able to drive a Bosch 0 221 119 334 coil with a maximum of 6 or 8 Ampere coil current. From what i remember the 123 circuit board uses a standard ST Powermesh IGBT transistor which can easily handle >20A coil current at engine room temperature, so technically it should not be a problem to use such a setup.

You can use a standard 1-2 W zener diode. BTW, you could also reinstall your Dinoplex and connect it to the 123 (black wire of the 123 to [D] wire of the Dinoplex, tacho wire also to the [D] wire). That way the 123 would handle the ignition advance, and the Dinoplex manages the spark. The tacho should work without modification/zener diode in this setup.

You only need vacuum advance for family cars ;-) The main advantage is fuel economy and a bit of engine drivability at low RPMs with a high load and lean mixtures, but for a sports car with carbs where the air/fuel mix is usually set up a bit on the rich side there is no real gain to use vacuum advance IMHO.


Good luck,
Adrian
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Re: Fiat Dino Tacho

Postby Stefan2000 » Thu May 21, 2015 3:31 pm

I'm quite sure it would have around the same amount of HP with the dinoplex system. But at least it shows that the 123ignition is not inferior quality and capable of doing the job unregardles of whatever output it creates. But i do admit that if the Original dinoplex creates 45kV and the 123 ignition 20kV i would like to perform the 123 somewhat similar in that way as well. But i didn't know there was a substantial difference in coil output between the 2, also part of the learning process i bought it for in first place :D

I'm going to discuss it with the guy from 123 ignition if it is posible to run the bosch coil you mentioned. Great advice and i appreciate the technical explanation, really interesting.
Would be a nice setup to attach the 123 ignition to the dinoplex but than i'm going down a path i promised myself not to go, experimenting with the Original dinoplex.
I will make the zener diode/resistor tacho adapter instead and see if i can get it working properly that way.

Well i kind of like vacuum advance, i think if you can run more economically it's always a good thing. But most of all without vacuum advance you always have to program a relatively conservative graph just based on WOT. While with everyday driving i drive about 0.1% of the time with wide open throttle and i could most likely have some 10 degrees more advance resulting in a more agressive engine and better drivability with just normal use.
I will test it soon without vacuum advance and with vacuum advance to see if it really makes some difference or not, if not we leave it for the family cars :)
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Re: Fiat Dino Tacho

Postby Stefan2000 » Mon May 25, 2015 5:25 pm

Adrian, do you know what's the primary resistance of the bosch coil you mentioned?
The bosch red coil (or beru bz109) has around 1.6Ohm and i've been reading at the 123ignition website not to use coils below 1 Ohm. It seems that below 1 Ohm the solder joints are the weakest point but it's just something i read on the internet so it's not verified by them yet.
Now i could try to find a coil with around 1 Ohm (like the beru bz 115) to boost the output a bit.
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Re: Fiat Dino Tacho

Postby alh » Mon May 25, 2015 7:13 pm

The primary resistance of Bosch 0 221 119 334 is 0.8Ω. The lower the resistance = the faster the coil charges so you have more energy available at high RPMs.
Keep in mind that the Bosch red coil is specified for points and coil setups where it has to be used with the external ballast resistor (1.8Ω), so the overall resistance is about 3.6Ω (equals 3.3A at 12V).
Using the Bosch red coil without ballast resistor will overheat and damage it in the long run. The Beru BZ115 is also specified for a points and coil setup and requires a ballast resistor based on the specs by the manufacturer.

I don't think the solder joints are the problem in a good design, it's rather the heat dissipation (and IGBT selection) which limits high current setups. You also need a good coil design with the right winding/core materials to ensure that the coil can store all the energy without going into saturation too early. Saturation means that the windings can no longer convert the electrical energy in a magnetic field so the excessive energy is transformed into heat (damaging the coil in the long run).
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Re: Fiat Dino Tacho

Postby Stefan2000 » Tue May 26, 2015 10:07 am

So if i want a safe system with a good coil able to create 45kV combined with dwell control, adjustable mapping and vacuum advance it would be best to hook my 123 ignition up to an MSD 6A. In this case the MSD and coil will create a good spark and my 123 will be used just for triggering. Also it would have the tacho output with a 12V square wave provided by the MSD box?
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Re: Fiat Dino Tacho

Postby alh » Tue May 26, 2015 10:36 am

Yes, but you could also connect the 123 to your Dinoplex with the same result (output, tacho). If 123 can drive the Bosch 334 coil you would need even less hardware.
P.s. MSD and Dinoplex do not require dwell control as they are capacitive ignitions. Dwell is only required by inductive (coil charged) ignitions.
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Re: Fiat Dino Tacho

Postby Stefan2000 » Wed May 27, 2015 1:34 pm

It indeed seems to be the IGBT transistor that overloads with less than 1 Ohm coils. The 123 ignition for v8 applications can handle up to 0.6 Ohm coils but it has 2 IGBT's parralel.
You kind of convinced (or made me convince myself) me to move over to a capacitive discharge system, also because than i will have my tacho output (where i started this thread for in the first place :D ). At the same time i really like the programmable curve and vacuum, standard cap/rotor etc from the 123 so i think i will go for the MSD with 123 option.
If i choose for this option, would you recomend the MSD blaster coil or the Bosch coil? I assume both of these coils are designed for a capacitive discharge ignition?
As far as you know, would i have any problems using a 123 just for triggering? From the MSD box do i need to use the magnetic pickup wires or the white wire that is normally used for the points? And from the 123 Ignition do i need to keep the blue one attached to earth and the black one attached to the white one from the msd, or the black and red one from the 123 to the magnetic pickup from the MSD?

Thanks for pointing me on the diffences between inductive and capacitive concerning the coils, after studying it makes a lot of sense that for inductive you need the right dwell to charge the coil enough but i did not think about the fact that with capacitive discharge the capaciter in the ignition itself is charged and blast around 500V right onto the primary side of the coil.

123 neg-earth.jpg
123 neg-earth.jpg (70.97 KiB) Viewed 2040 times


MSD 6A.jpg
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Re: Fiat Dino Tacho

Postby alh » Wed May 27, 2015 2:05 pm

Hmm, the 123 PCB i know has a STGB20NB37LZ IGBT in place, that one can handle 40A at 25ºC and 20A at 100º, pulsed 80A. A 0.8Ω could would be run at a max of 6-8A to avoid running it into saturation, so the IGBT should have no problem driving it even continuously.

For the MSD 6A please use the Blaster 2 coil (#8200 or #8202), the Bosch 334 coil is designed for a high power inductive ignition.

Connect the MSD white wire (points) to the 123 black wire, the 123 blue wire to earth and the 123 red wire to battery plus.
Connect the Dino Veglia tacho to the MSD grey wire (Tacho output).
Also source a 80Ω 5W resistor and connect it between the 123 black wire and 123 red wire, so there is some switching load for the IGBT.
That setup should work nicely together.

Good luck,
Adrian
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Re: Fiat Dino Tacho

Postby Stefan2000 » Thu May 28, 2015 7:58 am

Great!

This is the answer from the manufacturer of the 123 ignition:
Indeed if you mount a coil with less than 1 Ohm resistance the IGBT will get to hot and you will cook it together with a couple resistors (6x 1ohm parellel).
Mounting a coil with lower resistance is not going to have a huge affect on your peak current. The current through the coil is restricted. The restriction works a bit slow so if you mount a coil with less than 1 ohm you will still have the possibility of overloading the circuit.
I could find a replacement coil with around 1.1 Ohm for you but i think the benefits will be minor.
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Re: Fiat Dino Tacho

Postby alh » Thu May 28, 2015 10:26 am

I wonder why he said that the restriction works a bit slow, usually a current restriction limits the current as soon as the maximum peak is reached (within fractions of a millisecond), avoiding any overshoots. In a high performance inductive ignition you try to use a very low resistance so the maximum current is build up as fast as possible, allowing a full charge (dwell) even at high RPMs where not much time (around 1-2 ms) is left to fully charge the coil.

Can you ask him what maximum coil current is configured in the 123?
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