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Hello, I have been searching around for a while it seems like and I keep running in circles it feels like. I have came across ton of info about 70, 80, and 100 amp alternators for the MR2. I have only found people talking about the 90amp on fourms but no definitive facts. I know it exists because I can find remanned units for sale at 90 amps.

One thing I know for sure is that power steering and non power steering are different. I have a 97 MR2 GT with power steering.

I know I have a Denso alternator, but I can't seem to make out a serial number. Would anyone happen to know if this is a 100amp alternator or 90amp alternator? Or does it even matter? I am specifically looking at remanned usdm 90amp alts on rock auto and was hoping that would suffice.

I will be checking if I can get it rebuilt, but I would like to know the facts need be. Any help would be appreciated. Thanks!
 

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if you have a power steering model you will need a 100amp alternator as soon as you use anything Radio, headlights, heater, especially if your running any extra fans you will notice a drop in amperage. I have a 91 jdm with P/S you will bent over for parts and prices, get a OEM alternator, I whent through 4 aftermarket brands, longest lasting was 2 months. Even oem are remanufactured but better chance of getting one that will last.
 

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Here are the part numbers for the JDM GT/GT-S along with the Amp output. The only one that is 100A is the REV1. REV2 had 2 alternators and REV3-5 had 1 part number.

JDM GT/GT-S Alternators. They usually have the larger body and larger bracket.
69175


This is the JDM G/G-Limited list for a Manual car. Mine is a 1990 manual G-Limited and has a small alternator and a smaller bracket. The body is like a Celica so I use Celica alternators. Only difference is the pulley has an extra rib on the pulley than the MR2 but still works.
69176


This is the JDM G/G-Limited list for Automatic cars. They tend to use a larger alternator if they have power steering. Like the GT/GT-S models that always had power steering.
You will note the Japanese characters say 'Power Steering'.
69177


If we look at the G/G-Limited bracket part numbers it also states Power Steering denoting a bigger bracket.
69178


Same part numbers as the GT/GT-S models.
69179
 

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Discussion Starter #4
Here are the part numbers for the JDM GT/GT-S along with the Amp output. The only one that is 100A is the REV1. REV2 had 2 alternators and REV3-5 had 1 part number.

JDM GT/GT-S Alternators. They usually have the larger body and larger bracket.
View attachment 69175

This is the JDM G/G-Limited list for a Manual car. Mine is a 1990 manual G-Limited and has a small alternator and a smaller bracket. The body is like a Celica so I use Celica alternators. Only difference is the pulley has an extra rib on the pulley than the MR2 but still works.
View attachment 69176

This is the JDM G/G-Limited list for Automatic cars. They tend to use a larger alternator if they have power steering. Like the GT/GT-S models that always had power steering.
You will note the Japanese characters say 'Power Steering'.
View attachment 69177

If we look at the G/G-Limited bracket part numbers it also states Power Steering denoting a bigger bracket.
View attachment 69178

Same part numbers as the GT/GT-S models.
View attachment 69179
Wow thank you a ton! I really do appreciate it!
 

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Discussion Starter #5
if you have a power steering model you will need a 100amp alternator as soon as you use anything Radio, headlights, heater, especially if your running any extra fans you will notice a drop in amperage. I have a 91 jdm with P/S you will bent over for parts and prices, get a OEM alternator, I whent through 4 aftermarket brands, longest lasting was 2 months. Even oem are remanufactured but better chance of getting one that will last.
Do you have cruise control and traction control? I am pretty sure I lack a few extra electronics that were included and that's why I think the 90amp exists for the 93+
 

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My car doesn't have those options but it has power steering, power windows, power folding mirrors, 7 speaker sound system.

Most JDM cars didn't have cruise or traction control. I know of a few that have cruise control here in NZ but only 1-2 that have traction control fitted.
I know one that has both fitted and this is a 07/92 GT so would have had the 90A fitted.
 

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Discussion Starter #7
My car doesn't have those options but it has power steering, power windows, power folding mirrors, 7 speaker sound system.

Most JDM cars didn't have cruise or traction control. I know of a few that have cruise control here in NZ but only 1-2 that have traction control fitted.
I know one that has both fitted and this is a 07/92 GT so would have had the 90A fitt
Okay, so currently my thinking is check and see if I can get my alternator rebuilt. If not do you think this Delco reman would suffice from rockauto? I think it was remanned from a Denso but not too sure on that.

 

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All I know is that the OEM unit lasted 18 years and my 'new' reman unit died 7 times in 7 different ways over 11 years. Good thing mine is small and I can pull it out the top without having to take off the bracket or drop the subframe.
 

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Getting hard to find a decent replacement for these now.

Already been down the replacement path here.

Best to rebuild your existing alternator with a new rectifier diode pack, brushes and new bearings. The aftermarket ones can be rubbish and only last 6 months. Its a total mission getting it in and out of the car so I suggest its a job you only want to do once.
 

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Discussion Starter #12
Getting hard to find a decent replacement for these now.

Already been down the replacement path here.

Best to rebuild your existing alternator with a new rectifier diode pack, brushes and new bearings. The aftermarket ones can be rubbish and only last 6 months. Its a total mission getting it in and out of the car so I suggest its a job you only want to do once.
I took my alternator to the only local shop I could find, and they couldn't rebuild it due to not being able to get the parts for it. Ended up purchasing the Delco 90amp from rock auto. Hoping it will be somewhat decent
 

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Rebuilding an alternator with some parts is quite easy. The brushes, voltage regulator and diodes are easy to replace.
Bearings and the rotors are a bit harder. One thing I don't have access to is proper testing equipment for testing the voltage regulator so can be hard to tell if that has failed. Unless the brushes have melted into it and you can see it. :cautious:

Oh the joys of MR2 alternators. Keep them clean and dry is the best thing for them.
 

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Discussion Starter #14
Rebuilding an alternator with some parts is quite easy. The brushes, voltage regulator and diodes are easy to replace.
Bearings and the rotors are a bit harder. One thing I don't have access to is proper testing equipment for testing the voltage regulator so can be hard to tell if that has failed. Unless the brushes have melted into it and you can see it. :cautious:

Oh the joys of MR2 alternators. Keep them clean and dry is the best thing for them.
Yeah, I understand that there's no magic to alternators. I just don't have the expertise to find the proper parts to rebuild it within a decent time frame.

I think my plan is to just use this Delco alt, and try to find some place that will be able to get me the parts, or some place that will be able to rebuild it even if it's not local. At least I'll be able to drive the car in the meantime.
 

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... One thing I don't have access to is proper testing equipment for testing the voltage regulator so can be hard to tell if that has failed...
I don't think that there is any equipment necessary. If it makes the correct voltage, then the regulator is working. If it holds up under load, that proves the diodes and brushes. There is a terminal that you can short to force it to full output, which is a similar test to load.
 
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