infernosg's S5 N/A Build

[infernosg]

I'm tempted to redo my engine harness wiring. The "Wiring 101" thread has me worried. I've got corrugated plastic loom and electrical tape all over the place. I fear my CAS trigger wires are too close to the alternator and spark plug wires. The power wire to my IGN-1A coils is 16 AWG splitting into four 18 AWG wires, which may be too small. I've made a lot of decisions before I had the final layout complete and now I'm not super happy how everything turned out. So the question is do I unwrap everything, strip the interior and start over?

[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

[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?

[C. Ludwig]

I probably did tell you to ground everything to the engine. After talking with Lance at Pantera EFI, who is kind of the grandfather of these coils used in performance applications, we changed the way we wire the coils to ensure consistent operation. We now take pins D and E directly to the battery.

Yes, 14g mil-spec wire. I'd use 12g if I were using automotive hookup wire.

[infernosg]

Originally Posted by C. Ludwig

I probably did tell you to ground everything to the engine. After talking with Lance at Pantera EFI, who is kind of the grandfather of these coils used in performance applications, we changed the way we wire the coils to ensure consistent operation. We now take pins D and E directly to the battery.

Yes, 14g mil-spec wire. I'd use 12g if I were using automotive hookup wire.

Maybe my pinout is different but it says pin E is 12V power. I assume you're combining the ECU and battery grounds and keeping the one engine ground? So with the Sprint RE I'd just connect those two to the ECU sensor ground, which goes to the battery and everything should be fine? While on the subject do you recommend following Haltech's recommendation for ECU grounds? That is, one to chassis and the other to battery - (sensor ground). Since I'm rebuilding my harness I might as well make sure I do it right this time.

[C. Ludwig]

A - ECU signal
B - signal ground (rotor housing)
C - signal ground (rotor housing)
D - primary ground (battery negative)
E - primary power (battery positive)

Pin B is the one that's not real important. The AEM instructions say ECU signal ground, but the rotor housing is fine. It's primary use is for OE mis-fire detection, which we obviously aren't using.

I do wire the Haltech as their instructions say. Power ground to the chassis and signal ground to the battery.

[infernosg]

I guess this is no longer needed. Everything going forward will be documented here: http://rotarycarclub.com/rotary_foru...551#post266551

[N.RotaryTech]

Holy Transmission Rebuild Batman!

[scarsofcarma]

Great build thread! I'm currently planning for a hybrid miata/RX7 transmission swap into my FB so your transmission rebuild pics will be invaluable for me I'm sure. How long till your car is driveable do you think?

[RETed]

Just to keep the discussion going in a single path, I'm closing this thread.

As mentioned before, the project has been slightly redirected here:
http://rotarycarclub.com/rotary_foru...d.php?p=266551


-Ted