Coil for non balasted system

B

bert4656

Member
Hi, I have purchased a standard Lumenition ignition kit for my p6 3500 and have discovered that my coil is a low resistance Bosch coil that I can’t use with this kit, it needs to be 3.0ohm and above, all I need to do is find an appropriate coil, I have found at Aldon Auto 2 Lucas sports coils for sale...

Lucas sports coil DLB110 1.5 ohm (for ballasted systems)
Lucas sports coil DLB105 3.0 ohm (for none ballasted systems)

I presume I can’t use the DLB110 1.5ohm because 1.5ohm is too low and needs to be 3.0ohm and above, but I’m wary of the "non ballasted system" coil. I don’t know what ballasted and non ballasted systems means, anyone know if I can use the DLB105 3.0ohm for "non ballasted system" coil? at least the 3.0ohm part is correct, and this is the only 3.0ohm coil I’ve found so far. Will a Coil for “non ballasted system” be bad for my car? Any help appreciated.
 
Hi Bert,

Unless Lumenition have changed the requirements, the combined resistance of the ballast resistor and the primary resistance of the coil must be 3 ohms and above. The original Lucas 16C6 coil has a primary resistance within the normal range of 1.43 - 1.58 ohms whilst the inbuilt ballast resistor is approximately 1.5 ohms.

Is your current coil a Bosch GT40R?

The ballast resistor is a piece of resistive wire which is incorporated within the wiring loom behind the instruments in some cars, whilst in others it is a large ceramic block that resides beside the coil.

If you have a ballast resistor in place, then the correct coil has a primary resistance of approx 1.5 ohms, so the the GT40R is perfectly correct and does not need replacing.

Ron.
 
oh wow thats good news. I knew you'd turn up :) yes my coil is a Bosch gt40r and there is no ceramic block near the coil, i didn't realise you had to add up the values, i did use a ohm meter on the negative and positive coil points and it is 1.7 and it has 2 radio supressors or something, like 2 small metal barrels bolted on one of the bolts with 1 black wire on each leading to the positive coil contact.
 
Good to go Bert :) The stated 3 ohm requirment is the sum total of the two, or when there is no ballast resistor in place, a coil with primary resistance of not less than 3 ohms.

The two small metal barrels that you describe are indeed capacitors which are used for attenuating white noise which would otherwise appear on the radio when switched on.

You'll notice a welcome improvement when you have the Lumenition up and running.

Ron.
 
Should I pull my dash out and check for the ballast resistor or should it be there? You've been a great help to me in the past months, thanks Ron.
 
I am pleased that I have been able to help Bert :)

No need to pull the dash out, you won't see the ballast resistor anyway as it is wrapped inside the loom with all the wires. If a previous owner had bypassed the ballast resistor, then using the GT40R (R for ballast resistor) would see more than the required voltage appear across the points and they would ultimately be damaged.

You can measure the voltage at the coil which will confirm that you have a ballast resistor in place. Turn the ignition key to position 2 and there should be approx 6.6V at the coil. Now switch the engine on and when idling at approx 600 - 650rpm there should be approx 10V at the coil. If there is no ballast resistor in place, then the first reading will be much closer to 12V.

Ron.
 
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