A1 90 Amp Alternator Retrofit

From: Paul Ilenda
To: Jan
Subject: Artice for VW Site
Date: Sat, 13 Jan 2001 19:08:31 -0500

Jan - heres something I posted on the NG. Alot of people are asking about it... Theres been alot of talk about this lately so I figured I'd post all the info you'll need to do this. Pay attention, Im dropping you pearls here... This project was for an A1 GTi w/Yorks square style a/c compressor. My a/c worked great but drew so much current it would eat up the tiny 65 amp alternator every 20k miles. It would have been nice to keep the a/c, but it wasnt possible to mount in a 90 amp alternator and keep the a/c without MAJOR reconstruction. There's alot of ways to do this but here's a tried a true method.

What you will need :

Bosch alternator from 92 GTI w/ac - 90 amp. Its probably common to many A2's w/ac, but this is the one is used.
Crank pulley from a non-a/c Fox. Again, it may be possible to use one from other A2's or A1's, but a Fox is easy as pie to find in the wrecker yard. Get the 4 little hex bolts holding it on.
Water pump pulley from Fox - with or without a/c, doesnt matter. Get the 3 hex bolts holding it on (spares for when you strip one).
A2 alternator, power steering, a/c bracket - get this from any A2 - there all the same. Grab all the bolts + get the alternator tensioner arm. If it bolts to the head in 2 places and your head only has 1 mounting location, dont worry - it still will works. you can also grab the tensioner from a non-a/c A1.
Get a 1065mm x 3/8" belt. Read the size off the belt, not the package it comes in. Its different most of the time, esp. with Gates belts.
Go to Pep Boys and get two 4 gage battery straps 49" length. These are the ones that just have a flat eyelit at both ends.
Go to Radio Shack and get some end eyelits to crimp/solder on to a lead.

Now the fun part.

Remove the alternator - return for core ( they wont check and see its not a 90amp).
Drain the lines of freon, then remove all parts of the a/c. All brackets, stiffeners, everything. Maybe someone knows of an address for the as$hole who designed this and we can all mail to his house? If not, rejoice in satisfying sound all this crap makes as it hits the bottom of the dumpster.

Now, take off the a/c crank pulley with all those stupid shims, remove the crank pulley, and take off the spacer on the crank - all you should have left on the crank is the cog which the timing belt rides on.

Remove the water pump pulley. Install the Fox crank and water pump pulleys (h2o pulley dished in towards inside of engine)- yah, they will be close, but not touching. They should line up very close. Install the A2 alternator bracket - bolts right in (and you have provisions for power steering pump mounting and A2 a/c compressor mounting, some other day).

Install the 90 amp alternator and the tensioner arms.

Put the belt on, should be perfect (ed. note. that belt size took 4 trips to the store to get it right, and its the only size that will work).

Now you need to cut off the clip that attached to the old alternator - has 2 red wires + 1 blue. Take the two red ones, and run them into 1 eyelit, then solder them to the eyelit. Take the blue one and run it into another eyelit and solder it too.

Now take 1 of the 4 gage battery straps you bought and connect it to the big positive terminal on the alternator. Also put the 2 smaller red wires on this terminal as well. connect the blue wire to the terminal right underneath the + terminal on the alternator.

Run the 4 gage back to the battery + terminal in a way that wont piss you off during oil changes, ect... Use zip ties liberally.

Last, run the second 4 gage off the negative battery terminal down to the A2 alternator bracket and ground it using one of 13mm holes you arent using. this will ensure your rusted out A1 is getting proper battery ground.

Thats it, fire it up man. I'll send this to Jan's page so we can bury it once and for all.