If it's one complaint I've had with Toyota (atleast late 80- early 90) is the wiring. It seems they went out of their way to use the smallest wire they could find.
I had good results with the supra, and thought I'd do the 80.
All measurements taken at the battery with my Fluke meter
First test:
13.94V warm idle all accessories off
13.09V headlights on
12.86V while rolling down window
I took off the terminals and fully cleaned and retested. Same results. Just wanted to be sure that didn't make a difference.
I changed to marine style terminals as they were better suited for adding connections than stock. I ditched the goofy wing nuts in favor of a real nut.
I cut off the puny negative battery terminal to body wire. I sanded down the area and added a new ground. I soldered a new terminal to the factory ground from terminal to engine bracket that used to be integrated into the factory terminal.
Second test:
14.10V warm idle all accessories off
13.92V headlights on
forgot to test window
From there, I ran a new cable from the positive terminal to the alternator. This was the only pita job. It's hard to find a route to keep it from heat and sharp edges. I ran it the same basic path as stock. Instead of through the space between the radiator and support I ran it further down and through the opening behind the headlight. It was just too tight of a fit for my taste the other route. I added an ANL fuse right off the battery and connected it to the new terminal. I attached the fuse holder to the back side of the battery box.
Third test:
14.20V warm idle all accessories off
14.18V headlights on
14.08V window down
The headlights are noticeably brighter and no longer do they get brighter off idle when you rev it up. The windows are faster for sure, and can actually roll them both up at the same time and it not take 2 weeks.
I used Flux 4awg wiring for the job. It has a very high strand count so it is super flexible and has a very thick jacket. I also used E2 split style terminals. I like them much better than the cheaper solid copper lugs from Autozone.
I still have the engine to chassis wire to add, just ran out of time. I doubt there will be much difference but it's the last part of the system.
All in all I'm very happy with the results. ~$100 worth of parts and a night of labor.
*Last note, the PO replaced the factory alternator with a non OEM. It isn't a cheapy Duralast, but not certain of the brand. There may be a better output still with an OEM alternator.
I had good results with the supra, and thought I'd do the 80.
All measurements taken at the battery with my Fluke meter
First test:
13.94V warm idle all accessories off
13.09V headlights on
12.86V while rolling down window
I took off the terminals and fully cleaned and retested. Same results. Just wanted to be sure that didn't make a difference.
I changed to marine style terminals as they were better suited for adding connections than stock. I ditched the goofy wing nuts in favor of a real nut.
I cut off the puny negative battery terminal to body wire. I sanded down the area and added a new ground. I soldered a new terminal to the factory ground from terminal to engine bracket that used to be integrated into the factory terminal.
Second test:
14.10V warm idle all accessories off
13.92V headlights on
forgot to test window
From there, I ran a new cable from the positive terminal to the alternator. This was the only pita job. It's hard to find a route to keep it from heat and sharp edges. I ran it the same basic path as stock. Instead of through the space between the radiator and support I ran it further down and through the opening behind the headlight. It was just too tight of a fit for my taste the other route. I added an ANL fuse right off the battery and connected it to the new terminal. I attached the fuse holder to the back side of the battery box.
Third test:
14.20V warm idle all accessories off
14.18V headlights on
14.08V window down
The headlights are noticeably brighter and no longer do they get brighter off idle when you rev it up. The windows are faster for sure, and can actually roll them both up at the same time and it not take 2 weeks.
I used Flux 4awg wiring for the job. It has a very high strand count so it is super flexible and has a very thick jacket. I also used E2 split style terminals. I like them much better than the cheaper solid copper lugs from Autozone.
I still have the engine to chassis wire to add, just ran out of time. I doubt there will be much difference but it's the last part of the system.
All in all I'm very happy with the results. ~$100 worth of parts and a night of labor.
*Last note, the PO replaced the factory alternator with a non OEM. It isn't a cheapy Duralast, but not certain of the brand. There may be a better output still with an OEM alternator.
