Direct Wiring Coil Packs

[GTSBoy]

I think you miss the point of what Stabby said. If you measure the same voltage up at the coils as the battery supplies (effectively what the alternator supplies given that to make this measurement you'd have the motor running) then the current is not high enough to cause a significant voltage drop, and so bigger wire won't help.

Assuming that the above is the result of the test. I would say that if everything is wired as per design and not faulty, that it should work that way, as the coils simply don't draw that much current. You'd need a bad connection or something to do it. And as I said above, you'd be better off fixing the real problem than patching it.

[battery]

I added a relay at the beginning of the coil pack loom and now I can run a larger plug gap. Ideally you would make an entire new coil pack loom but im lazy..

Its been a while since I did it but im pretty sure I tested before/after and there was a voltage difference..

[GTScotT]

If the original wiring is tarnished it WILL have higher resistance over it and current draw for the coils will be hampered.

I'm not sure what sort of resistance you will be looking for but you can definitely test it.

[Shoota_77]

I think you miss the point of what Stabby said. If you measure the same voltage up at the coils as the battery supplies (effectively what the alternator supplies given that to make this measurement you'd have the motor running) then the current is not high enough to cause a significant voltage drop, and so bigger wire won't help.

Assuming that the above is the result of the test. I would say that if everything is wired as per design and not faulty, that it should work that way, as the coils simply don't draw that much current. You'd need a bad connection or something to do it. And as I said above, you'd be better off fixing the real problem than patching it.

I'm sorry bloke but you need to read up on electrical 101. Voltage, Amps and Ohms are all relative to each other. You can't just measure the volts at 14.4V and say "she's all good mate". You have to measure 2 of the 3 variables before you can do the full calculation (volts = amps X resistance). Like I said, it is likely that it will measure the same as battery/alternator voltage as long as there are wires completing the circuit. When there is a resistor, short, etc in the circuit then it will likely read a lower voltage but not if say 8 of the 9 wire strands have broken through. If you measure the volts and the resistance or volts and the amps then you can use the electrical equation to work out if there is a drama, you can't use one of the three to presume everything is fine.

I think you're presuming that if the voltage is alternator voltage at the coils then it's fine but that's not true. If the voltage is fine but the circuit is crap (high resistance) then the amps will be crap. Example- 14.4 volts = 7.2 ohms X 2 amps would be horrible but it's still 14.4 volts. 14.4 volts = 1.44 ohms X 10 amps would be a whole different scenario right? It's still 14.4 volts but at a much higher amperage. Which circuit do you think is better???

If that still doesn't make sense then I'll shut up!

[GTSBoy]

Dude, You are the one who is wrong. If you have the circuit drawing current, and you do not measure a noticeable voltage drop, then the resistance is by definition low. You don't need to go all year 11 "I studied Ohm's Law in Tech Studies" on us.

If you have poor wiring/connections before the load (the coils), sufficient to affect things in a bad way, then you will measure a lower voltage at the coils whilst they are running. If you do not measure a lower voltage, THEN THERE IS NO f**kING PROBLEM.

I'm willing to bet I had a full understanding of Ohm's Law before you were even out of kindergarten. Let's just say that we're talking somewhere around 1980.......

[Shoota_77]

We (clearly!!) both think we're right so let's leave it there!

If you want to water your garden quicker, get a bigger hose!

That was my last pathetic attempt at winning the argument if I need to point it out.

Peace out!

[R31Nismoid]

Nothing wrong with a bit of passionate discussion and getting to the bottom of it.

It does make for interesting reading as long as people aren't trying to kill each other

[battery]

GTSBoy is correct...

If you Test the voltage under full load and there is minimal drop then you have a low resistance..

[MrStabby]

I'm sorry bloke but you need to read up on electrical 101. Voltage, Amps and Ohms are all relative to each other. You can't just measure the volts at 14.4V and say "she's all good mate". You have to measure 2 of the 3 variables before you can do the full calculation (volts = amps X resistance).

The way to show you have the biggest e-cock, is to mount the best argument. Here's my attempt to flop it out.

The current will be whatever V=IR says it is, when we complete the circuit. If we have 2 x 1 ohm resistors in series with our 14.4v power source, the current is 7.2 amps in our circuit. This means that if we look at one of the resistors in isolation, it is seeing 7.2 volts since V = 7.2 amps X 1 ohm. Now if we replace those 1 ohm resistors with 10 ohm resistors, the current is 0.72 amps, and if we again look at one of the resistors in isolation, V = 0.72 amps x 10 ohms = 7.2v again. So even though current changes significantly, we end up the same place. Resistors in series each step down the voltage, so if the voltage is the same we know that the resistance is zero by deduction. The current is a side effect during measurement. FWIW multimeters have a resistance in the megaohms, so when we're measuring the resistance of the coilpack loom, the current is tiny whether the resistance in the wire is high or low, because its in series and the meters resistance dominates.

Now, since the resistance of the primary solenoid in the coil is fixed, any resistance in the wiring to the coil will increase the entire circuits resistance, since its in series, and less current will flow the the coil and the energy at the spark plug will be lower. So we want the only resistance in this circuit to be caused by the primary solenoid, so we can get the max current in the circuit and max power at the spark plug.

HTH.

Oh and saying "go read electrical 101" was rude, and if you're wrong after saying something like that, it makes you look like an arrogant and incompetent jerk. Perhaps a case of Dunning-Kruger effect?

[Shoota_77]

You win, your virtual cock is much larger than mine.

Dunning-Kruger Effect? I think that's me every time I look at myself in the mirror.

I'm a car salesman, the key to being wrong is thoroughly convincing yourself that you're right which tends to have a contagious effect... Bloody internet just doesn't transmit contagions like face to face contact. I've been let down by technology.

If I'm wrong (and due to the weight of numbers building against my argument seems that I am) then I'll hereby bow out beaten.

If I've offended- sorry.

Over and out.

[MrStabby]

You win, your virtual cock is much larger than mine.

Whoa that was easy. You can tell by how vague my explanation is that I only sort of understand this stuff. A good way to know if you really understand something is to see if you can explain it in a clear and concise manner.

[Pezhead]

Hey guys, just catching up on my reading here.

A couple of things that people haven't mentioned.

1) Ensure you are using decent wiring. Core should be minimum 1mm if not 2mm. My CDI unit says that 0.75mm is adequate, but just looks too small to me.

2) Also I'd personally use a relay if you are going to hard wire the 12v source to the coils. It won't degrade any performance but will save you the next time you're turning a spanner near the coils.

Hard wiring is actually a old school hot rod tip from the days before electronic ignition. Cars used to run a resistor to drop down the 12v to more between 3 and 6 to fire the coil. This put less strain on the coil so it lasted longer. Funny huh!

[sickr33]

Does anyone know what wire or pin that is the feed (wire to battery with this mod)

R32 Gtr

I'm unable to test because in the middle of a build but would be easy to do now (car in peices)