infernosg's S5 N/A Build

[infernosg]

Originally Posted by RETed

Has the engine cranked and started yet?
That's the only way you can confirm if you need to redo the CAS wires.

What is the max current draw on those coils?
How long are the 18AWG wires?
Those coils can't be more than 10A each?


-Ted

Nope, engine isn't even rebuilt but the harness is "done." The engine is waiting on the rest of the car. CAS wires run across the top of the engine but they run parrallel to the IGN and main power cables for a short distance (<12 in.). After that they are at least 6 in. away from any high-voltage leads.

The only specs I can find on the coils say 19 A max but I think that's for the internal ignitor to the coil and not the external power draw. I've read a single 20 or 25 A fuse is suitable for four coils. The 18 AWG sections are short - 12 in. at most. The 16 AWG portion is the longest being something like 6 ft.

I don't want to get the car started and then have to redo the wiring within a year. I didn't use splices and taps anywhere but I'm sure I could have gone with better material.

[RETed]

Originally Posted by infernosg

Nope, engine isn't even rebuilt but the harness is "done." The engine is waiting on the rest of the car. CAS wires run across the top of the engine but they run parrallel to the IGN and main power cables for a short distance (<12 in.). After that they are at least 6 in. away from any high-voltage leads.

This actually sounds okay...
Only time will tell if it's effective or not once you start to crank the engine over.

The only specs I can find on the coils say 19 A max but I think that's for the internal ignitor to the coil and not the external power draw. I've read a single 20 or 25 A fuse is suitable for four coils. The 18 AWG sections are short - 12 in. at most. The 16 AWG portion is the longest being something like 6 ft.

If 20A is okay, max current would be around 10A...maybe 12A or 13A.
So we'll try and stick with 10A.
There are charts for reference for minimum wire gauge thickness versus current draw.
The 18AWG sections sound okay due to it's short run.
I would change the main lead to at least a 12AWG or even 10AWG.

I don't want to get the car started and then have to redo the wiring within a year. I didn't use splices and taps anywhere but I'm sure I could have gone with better material.

Well, everything can be updated.
It's a matter of how much you're willing to spend and labor...


-Ted

[C. Ludwig]

Originally Posted by infernosg

The only specs I can find on the coils say 19 A max but I think that's for the internal ignitor to the coil and not the external power draw. I've read a single 20 or 25 A fuse is suitable for four coils. The 18 AWG sections are short - 12 in. at most. The 16 AWG portion is the longest being something like 6 ft.

Four of the IGN-1As will draw around 5 amps at idle with a charge time of 4.5ms in direct-fire mode. As the revs go up and duty cycle increases, the amp draw will go up a bit to around 8-10 amps. This is on a 12V system. I've had one guy use these on a 16V total loss system and he had to build the circuit to support 30A max to run 4.5ms charge time. He's also getting a good bit more mJ out of the coil at that voltage and charge time than one would with a 12V system.

I build our harnesses with a 14G feed for primary + and - that's spliced down to 18G 10-12" from the coil. This is using M22759/16 wire. If I were using standard auto hookup wire, I'd probably go up one size.

[infernosg]

Originally Posted by C. Ludwig

Four of the IGN-1As will draw around 5 amps at idle with a charge time of 4.5ms in direct-fire mode. As the revs go up and duty cycle increases, the amp draw will go up a bit to around 8-10 amps. This is on a 12V system. I've had one guy use these on a 16V total loss system and he had to build the circuit to support 30A max to run 4.5ms charge time. He's also getting a good bit more mJ out of the coil at that voltage and charge time than one would with a 12V system.

I build our harnesses with a 14G feed for primary + and - that's spliced down to 18G 10-12" from the coil. This is using M22759/16 wire. If I were using standard auto hookup wire, I'd probably go up one size.

This is good information. I definitely think at least part of my harness needs some reworking at this point. Just to be clear you are using single 14 AWG power and ground wires for four coils that are split near the coils? I think it was you who also said to ignore the grounding instructions from AEM and just to ground everything to the engine. Would there be any benefit or detriment to following AEM's instructions?

I assume my wiring for the injectors is okay at 16 AWG splitting into 20 AWG? Injector Dynamics says their resistance values are in the 8.5-12 ohm, which gives a current of 1.23-1.65 A for a single injector. Multiple that by two and it's 2.45-3.29 A. Does that seem about right?