Replacing Alternator With More Powerful Alternatives - Help Needed

[Dose Pipe Sutututu]

Hi All,

Before you flame me, yes I have searched, and there's no conclusive information either on SAU and on Google.

I own a RB20DET from a R32 in my S13.

Problem: Alternator not charging properly, causing unneccessary engine stalling and a flat battery

Observations:

• When alternator is warm voltage drops to 12.5 volts from 13.5 volts (still very low reading)
  
• When all my 3xthermos kick in, car will hesitate and voltage will sit flat at 12 volts
  
• Alternator light does not turn on, i.e. alternator not 100% dead but not charging
  
• When car is revved past 3k voltage will bounce up to to around 12.7 volts which is still pathetic
  

I want to replace my alternator with something more beefy, as the stock RB20DET alternator only outputs a max of 70amps, which isn't enough provided the stereo & thermos alone would draw that much current. I was thinking either a RB25DET or a total aftermarket replacement.

I have read elsewhere that it is possible to use 120AMP Bosch alternators found in the cop car which is universal as per link:

http://www.calaisturbo.com.au/showthread.php?t=11447

apparrently all you have to do is switch the pulley over... and it will fit. Guys on the forum are saying VS commodore alternators fit onto RB30s, i.e. will fit on RB20 Rb25s someone please confirm?

And I've been reading that RB25DET alternators, rated at 90amps will fit RB20DET, but no one has confirmed that the rear plug will plug in or if there maybe some cutting and shutting required.

What do you guys suggest? RB25DET alternator will suffice? I'm just really concerned about it dying on me in summer with all 3x thermos kicking in, A/C on max, headlights on.

Cheers,

Johnny

Edited June 18, 2008 by johnnilicte

[_Scotty_]

I recently replaced the alternator on my RB25 with one off another nissan rated at 100Amp. Not sure exactly what it's off (possibly Z32?) but the part number is ARJ036. The standard one I pulled off was only rated at 80.

I don't know whether there's any difference in fitting to an RB20, but I'd be suprised if there is. Even if the plugs do need changing it's a pretty simple job for yourself or an auto sparky.