Need to source 120A alternator

Need to source 120A alternator

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Discussion

Harry Flatters

Original Poster:

142 posts

257 months

Monday 27th June 2022
quotequote all
Can anyone please recommend a reliable make/source for a 120A alternator for my Chim 450.

The reason I need the uprated unit is that I have the Mk1 Imprezza PAS rack with an electric pump which can draw 70+ amps and the std 100A unit is not man enough, such that on the hottest day of the year, a week or so back, fried itself.

Many thanks....

dc400

124 posts

205 months

Monday 27th June 2022
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Hi. I bought this it’s about a year ago now.Don’t know if he will still have any as he said it was limited stock. Old stuff but unused.

dc400

124 posts

205 months

Monday 27th June 2022
quotequote all

phillpot

17,105 posts

182 months

Monday 27th June 2022
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A few people have now done the Subaru rack mod, including me, you're the first one I've heard of with alternator issues!

Are you sure the problem is not elsewhere, pump will only pull big amps like that under heavy load, much lower amps normally.

Harry Flatters

Original Poster:

142 posts

257 months

Monday 27th June 2022
quotequote all
I think under normal circumstances, you may get away with the 100a unit, however a respected auto sparks told me that with very high under bonnet temps it would probably be marginal and a 120a would just be a better belt & braces solution.

Zener

18,928 posts

220 months

Monday 27th June 2022
quotequote all
They certainly can draw some AMPs I have witnessed 50+ on OE fit euro-boxes when trouble-shooting previously , in normal use (moving/rolling) they are 25+

Belle427

8,857 posts

232 months

Monday 27th June 2022
quotequote all
Make sure your wiring sizes are adequate too, not sure where you tapped off for the power steering relay but as standard the cable sizes are inadequate.

Harry Flatters

Original Poster:

142 posts

257 months

Monday 27th June 2022
quotequote all
@dc400 - Thanks for the pointer, but all the NOS has gone on these.

@Belle427 - Will check the wiring size too.

I may have found a Denso unit - fingers crossed.

Polly Grigora

11,209 posts

108 months

Tuesday 28th June 2022
quotequote all
Does the car have a heated front screen?

The theory runs the practice and Mr Maths is always correct

Engine - 20 Amps Continuous

Lights - 15 Amps Continuous

Blower - 5 Amps Continuous

Engine Cooling Fans x 2 @ 10 amps - 20 Amps Intermittent

100 Amp Output Alternator will cover a 60 AMP PAS current draw when engine cooling fans are off and a 40 Amp PAS current draw when engine cooling fans are on

Going by the above calculations, a 120 AMP alternator is not required

Harry Flatters

Original Poster:

142 posts

257 months

Tuesday 28th June 2022
quotequote all
But 100 amp alt would not cover if the PAS pump draws 70+ amps (which my pump does), albeit intermittently. Also the high under-bonnet temps will have a mechanical (bearings etc) and resistance effect.

None of this takes into account the possibility that the 'fried' unit may well have been made of Chinese toffee.

I'm just going for belt and braces.

Polly Grigora

11,209 posts

108 months

Tuesday 28th June 2022
quotequote all
Ok then, 70 Amps seems very high during normal road use

Zener

18,928 posts

220 months

Tuesday 28th June 2022
quotequote all
Polly Grigora said:
Ok then, 70 Amps seems very high during normal road use
This ^ they can pull some current though GM vehicles often have an 80A fuse fitted so they knew something


Edited by Zener on Tuesday 28th June 13:46

trumpet1608

76 posts

193 months

Thursday 30th June 2022
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OEM quality alternator available from Rimmer Bros.

https://rimmerbros.com/Item--i-AMR2938P1

I bought one for my P38 diesel (same quality different part number) 3 years ago and have had no problems.

Trumpet

Harry Flatters

Original Poster:

142 posts

257 months

Thursday 30th June 2022
quotequote all
Thanks for that!

I managed to find a 'new-old-stock' Denso DAN016 on ebay. Hopefully arriving today.

Harry Flatters

Original Poster:

142 posts

257 months

Saturday 9th July 2022
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UPDATE:

New old stock Denso DAN016 fitted (getting the nut on that bottom bolt is a right pig!) along with a couple of minor repairs to dodgy wiring on the coil and all looks good - so far. PAS is back and no sign of alternator overload.

Many thanks for all the help & info.