I've read through quite a few threads about installing a higher amp alternator from an MR2 turbo, specifically the 1991 model with power steering. No thread I've seen has provided instructions with photos to help the visual learners, so I thought I'd give it a shot. The alternator itself is rated at 100 amps, while ours are only rated at 70-80 amps (depending on the model year). The part number is DENSO 2100184 and I bought it from Rockauto http://www.rockauto.com/en/moreinfo.php?pk=870504&cc=1276837&jsn=352 . My main reason for doing this is because at night time, especially on a cold night and it's raining, when I have several electrics running (wipers, headlights, heater) at idle,all the lights would dim; my voltmeter would run under 12V. So leading up to that, I thought that I might as well change out the alternator since it's been in use for almost 30 years(if the previous owners have not changed it out), and redo the ground wires from the chassis to the engine and transmission. Also, my car is an 87T, so your findings may vary.
Just general photos to show the difference between the two alternators. The bigger one is obviously the MR2 alternator. Removal of the alternator is fairly simple, 12mm for the adjustment portion, a 14mm for the main bolt, 10mm for the stud bolt and remove the round plug in the rear. The pulleys are different, so you will have to reuse your old one. A 21 or 22mm socket with an impact gun makes quick work of that.
Placement of the wiring on the old alternator. The round plug will plug back in no problem, the only slight difficulty that you'll have is the other wire that attaches to the stud.
I used a 3/8 drill, vice grip and a wooden block to enlarge the hole.
After that, it's just re-tightening what you took off. Since the alternator is larger, you will have to squeeze it in with the PCV hose that's running from the block to the head. Haven't gotten around to driving the car as I'm installing a temperature based oil cooler system to replace the stock pressure based system. Personally, I don't think this upgrade is worth it if the stock grounds are extremely brittle and degraded; I would recommend redoing the grounds prior to this. I hope this helps you as I think it will help me once the car is running again.
Just general photos to show the difference between the two alternators. The bigger one is obviously the MR2 alternator. Removal of the alternator is fairly simple, 12mm for the adjustment portion, a 14mm for the main bolt, 10mm for the stud bolt and remove the round plug in the rear. The pulleys are different, so you will have to reuse your old one. A 21 or 22mm socket with an impact gun makes quick work of that.
Placement of the wiring on the old alternator. The round plug will plug back in no problem, the only slight difficulty that you'll have is the other wire that attaches to the stud.
I used a 3/8 drill, vice grip and a wooden block to enlarge the hole.
After that, it's just re-tightening what you took off. Since the alternator is larger, you will have to squeeze it in with the PCV hose that's running from the block to the head. Haven't gotten around to driving the car as I'm installing a temperature based oil cooler system to replace the stock pressure based system. Personally, I don't think this upgrade is worth it if the stock grounds are extremely brittle and degraded; I would recommend redoing the grounds prior to this. I hope this helps you as I think it will help me once the car is running again.
