With the battery tray removed, we can see some corrosion to the front framerail brace from battery acid slowly leaking onto it over the past 30 years.
We can also see the A/C line that was cut to delete the air conditioning from the car to improve cooling the engine. This is a quick and cheap way to make an RX-7 run cooler, but this is not an acceptable solution for a daily driven car. We will be properly upgrading the cooling system and reinstalling air conditioning to the car in future articles.
Here we can see the positive battery terminal is connected to a 2-bolt cable that attaches to the starter motor. On the back side of the battery terminal-mounted fuse box are two more cables that connect to the alternator and the main power distribution box.
Note the random red wire that was added to the car to supply power to aftermarket gauges inside the cabin. This will also be replaced.
To remove the main electrical harness, we had to first disconnect the alternator power cable and 10-pin connector from the alternator. Next, we unbolted the starter motor, ground wires, and relay connectors.
With the main electrical harness removed, we cut open the corrugated plastic sheathing to take out the power and ground cables from the rest of the harness.
Then we re-covered the corrugated plastic with new electrical tape and added some “snake skin” electrical sheathing to other parts of the harness. With the thick power and ground wires removed, the electrical harness is now much smaller and sleeker.
12 comments
Great article. JP3 Motorsports makes a nice mount for the fuse block so it’s not zip tied or flopping around in the engine bay.
https://jp3motorsports.com/collections/mazda-fd3s/products/mazda-rx7-fd3s-battery-fuse-block-bracket-relocated-batteries
Awesome update. You always do such quality work. I can’t wait for the next one.
Didn’t see a fuse for the fuel pump at first glance (page 5, 1st pic ) Then I looked again.
FYI Lots of motorsports guys complain about those circuit breakers… they say they have had them vibrate open during operation. I’m running 2 on my car and haven’t had an issue yet.
I know that this is going to sound crazy, but recently I had a family member’s car serpentine belt fail and it ended up damaging the pulley. I was not able to source a new pulley in the location it was in, so we decided to try and run the car as long as possible without the serpentine belt (thus sans alternator, power steering, and AC). Fortunately, the battery was almost brand new and fully charged.
Interestingly enough, the car started and ran well for the 10 mile trip home! No issues whatsoever.
This makes me think that you could conceivably run a time attack car with the alternator removed!
Yes, this is totally crazy, but ‘racecar’, right?
Not only would you save a significant amount of weight, but you would reduce parasitic losses on the drivetrain. With a powerful enough lithium-ion battery, I am sure that you would have no issues running like this for one-lap.
Anyway, food for thought.
That is very common in SCCA sprint racing, especially in the smaller bore Prod and GT classes.
I don’t know about a modern racecar with all the electrical load. Our time attack car draws over 140 amps when everything is going full ti;t.
Was your classic to engine 2awg black ground wire able to reach north bolt holes with slack? Mine is very very tight and will not even bolt up
I think we relocated it to the 13mm bolt just below the brake master cylinder.
I have the same problem. The cable that comes with the kit is NOT long enough. Mine even came in a little bit longer at 16in. Pretty disappointing, gonna have to order another cable.
Yep, 15 inch is just barely too short in my set up (using Banzai motor mounts). Had to order a 17 inch cable, although 16 inch probably would have been ok.
What do you do if you don’t want to remove the Electrical harness and take out the old power and ground cables? Would like to leave them in there so it can be put back to original. Thank you
Would look nice with the JP3 Fuse Block Bracket.