infernosg's S5 N/A Build

[C. Ludwig]

I always send them all to the rotor housing or head. It's convenient and works. Basically, two of the grounds are kind of along for the ride and won't influence performance. The high current (Pin D) is the one you need to have well sorted. If the block ground is marginal, (which it should not be!) then go to the battery. Better yet, ensure you have good grounding of the block to the battery negative post and then ground all 3 pins of the coil to the block.

[infernosg]

Originally Posted by C. Ludwig

I always send them all to the rotor housing or head. It's convenient and works. Basically, two of the grounds are kind of along for the ride and won't influence performance. The high current (Pin D) is the one you need to have well sorted. If the block ground is marginal, (which it should not be!) then go to the battery. Better yet, ensure you have good grounding of the block to the battery negative post and then ground all 3 pins of the coil to the block.

Grounding the block to the battery would be difficult (but not impossible) considering the battery is inside the car in the passenger's bin (grounded to the body). I have one engine ground on the rear iron that goes to the firewall that I was planning on using for the coils. Both ground points have the paint stripped and covered in dielectric grease. The battery ground is 2 AWG cable and the engine ground is 4 AWG. Would this be considered a "marginal" ground system? I could run the battery ground into the engine bay but I thought those were supposed to be kept <18", but I guess I could piggyback onto the body ground point. In the stock configuration the battery is grounded to the engine via the starter body, right?