Alternator bracket for 90 amp alternator

[Davy MacLean]

I understand you need a different type of alternator bracket if you wish to upgrade the 45 amp alternator to a 90 amp from a golf or similar anyone make these off the shelf or can someone make me one please?

Also as I plan on fitting a couple leisure batteries would I be OK in fitting an alternator from a diesel golf or will that be too high a charge?

[Red Westie]

Too high a charge? these older type Bosch alternaters are all regulated at around 14volts (13.9 - 14.2) however there charge rate (how many amps they kick out) varies (45/65/90 Amp hour) the bigger unit having the ability to charge all these batteries faster.
As long as you can get this larger alternater properly mounted and aligned you are fine, make sure you use an appropriate belt (I think the 90's have a slightly wider profile belt...10mm instead of 9.5?) but check.
Martin

[kevtherev]

I understand you need a different type of alternator bracket if you wish to upgrade the 45 amp alternator to a 90 amp from a golf or similar anyone make these off the shelf or can someone make me one please?

no modifications required when using a 90 amp off a 2.1

[NeilC]

Bear with my limited knowledge of alternators here, but do higher-rated units sap more power from the engine for their higher output or are they merely more efficient?

[ajp]

If your fitting it to a 1.9 you should be able to put it straight in but you will need an 1100 belt instead of a 1050. The 1050 won't fit around the pulley ( unless you want to find a way of threading the belt on then mounting the alternator... I didn't!) But the 1100 needs the bracket all the way out as fair as it will go to get the tension. One pinched finger and a fair bit of swearing soon had it in place and working.

[kevtherev]

Bear with my limited knowledge of alternators here, but do higher-rated units sap more power from the engine for their higher output or are they merely more efficient?

No not sapping unless your trying to heat the sea
they just have more windings and magnets and stuff.

[Red Westie]

In theory the bigger/higher output alternator will take more turning when under load (charging heavily discharged batteries) turning mechanical energy into electrical energy....thats why the belt squeels from cold (everything turned on ie: lights, heated rear window, blowers and the alternator working hard to replace the discharge in the battery) and thats why higher output units tend to have a slightly wider/stronger belt. However, the difference in engine performance would be negligable. It is also worth noting that the alternator is self regulating (it only charges as much as it is needed) so when the batteries are fully charged it has little resistance to turning.
Martin

[NeilC]

Thanks for the responses. I will keep my eye out for a beefier alternator when I go scavenging!

[Davy MacLean]

I understand you need a different type of alternator bracket if you wish to upgrade the 45 amp alternator to a 90 amp from a golf or similar anyone make these off the shelf or can someone make me one please?

no modifications required when using a 90 amp off a 2.1

Would be fitting it to a 2ltr air-cooled would that still fit on with out making a bracket?

[CovKid]

http://www.relitech.com/90alt.htm - all you need to know. Thats what I did.

[Davy MacLean]

Seen that is it an alternator from say the likes of a Mk2 Golf if it's the top one it's from a 1.8 ltr 88-93 passat would htat be a 70 or 90amp



or can a later one from a MK3 upwards be used like this?