Jerryg

Hi Guys

I’m at the beginning of my build, actually I’m still in the engine building phase so I don’t have the car yet. The engine is a 6.0l lq4 and I am using the stock wiring harness and PCM, with a LS6 intake so I will have to re-rout the harness. To help with this can someone please post a photo of where you mounted you PCM and an estimate of the length of the main wiring bundle between the PCM and the back of the engine.

Thanks
Jerry

SupaDupaSteve

Most I've seen are on the passenger side near the fuse box or further forward. Usually that's on NBs though. Mine is going inside but I had a custom harness made and redid all the factory wiring

GoKart

Are you running AC?

If not, there's room up in the passenger footwell where the large evaporator box would normally go. I used a couple of the factory studs protruding from the firewall to mount a bracket which holds the ECU. Very short wiring run and used the factory rubber grommet to pass the wiring through the firewall. Cleans up the engine bay as well.

charchri4

Jerry would you please update your signature showing what year and swap your car is so we know what you are talking about when you post? Edit your signature here (click)

You might check out this thread and look at all the under hood shots. Lots of guys put them under the hood and lots inside the car.
https://www.v8miata.net/area-member-...207/#post14581

Jerryg

I don't have the car yet but most likely it will be a NB. thank for the info

Jerryg

Thanks GoKart this is just what I was looking for. Any regrets with not going with AC?

Jerryg

Man this relay helps, it looks like there might be more engine bay room in a NB than there is in a NA is this true?

charchri4

For sure. The headlights take up less room and the inner fender/ shock towers are a different shape leaving a bit more room in the NB.

I would have put mine inside but the wiring was 6 inches too short and the donor had it under the hood so I figured it would be fine in the Miata too. 15,000 miles with no issues...

GoKart

I haven't had AC in the car since 2003, so no regrets here

The only time it sucks is when it's hot AND raining. If I daily drove the car I'd definitely consider AC.

The wiring on the donor car (GTO) was stupid long. I had to double over about 3' worth under the dash.