I have spent weeks looking at how to satisfy my tuners needs to achieve 13.8-14.2v reliably at the computer as well as guaranteeing that I am charging my battery properly. I tried everything including speaking with auto-electricians, motor re-winders and have come up with the following solution. What I found was re-winding the factory alternator meant the battery was discharging until higher in the rev range and even then it was unreliable voltage. So here is a step by step guide on how to replace it with something that works and see the results at the end. The donor alternator from a Nissan Patrol, part number ALT110718G from Auto Electrics Australia, for roughly $450. (http://rides.webshots.com/photo/2084237790049183497DTRNqv) A few comparison photo's of the factory vs. the ALT110718G (http://rides.webshots.com/photo/2712853800049183497epWyFX) (http://rides.webshots.com/photo/2865154670049183497MpcUsX) Make sure you ask for the plug too, so you can adapt it to the current harness. (http://rides.webshots.com/photo/2885117820049183497IvOivj) Check where your Sense (S) and Light (L) goes on the current one and match it to suit the wiring for the new alternator as shown in my sketch of the plug. (http://rides.webshots.com/photo/2357374690049183497LJnYzV) New plug wiring diagram (http://rides.webshots.com/photo/2600174120049183497xijvrW) To make the alternator fit the front rib on the engine block needed to be ground back a few millimetres as well as grinding back one side of the spacer. As you can see in the coming photo's, the body of the alternator is much fatter than the factory one meaning there is little clearance between the body of the alternator and the spacer / engine block mount. (http://rides.webshots.com/photo/2310120660049183497rATjHU) (http://rides.webshots.com/photo/2002690930049183497KneoTU) (http://rides.webshots.com/photo/2035926890049183497wcbNFV) This gets you up to the point that you can get the alternator into the engine bay now, some adjustments may need to be made if you have not ground off enough. The next stage I figured you can either keep the factory adjustment bracket and put on a shorter belt, or keep the factory belt (4PK850) and make a longer bracket which I opted to do because I work in a steel shop. As you can see, it floats in mid air with nowhere to mount with factory belt. (http://rides.webshots.com/photo/2161154400049183497usnxkn) See comparison of 2 brackets, the factory one is the shorter of the two. I am able to supply dxf's for anyone who is keen to try this. (http://rides.webshots.com/photo/2908007030049183497sTxkHM) (http://rides.webshots.com/photo/2883130550049183497hVSisJ) See new bracket fitted with mount bolt in: (http://rides.webshots.com/photo/2581574910049183497JScrCB) (http://rides.webshots.com/photo/2955610600049183497UChHkt) I found on the alternator that I purchased the spacing was 1-2mm longer than the factory one so I put in an additional washer between the engine mount block and the spacer block. Overtightening of the alternator can otherwise cause the cast mount arms to snap. This will be for you to check before tensioning the bolt on the engine block. It is critical to get the belt tight and in line also otherwise it will slip when cold & revving. Voltmeter test at Battery, 14.0v at idle. I also tested it with a clamp meter and found I was getting 10amps of charge (not discharge) with all accessories on (air con, high beams, stereo etc) at idle. Some original photos have not been recovered yet.

Good job, looks neat and tidy. Quick question, after you had the alternator re-wound it couldn't supply enough grunt to power everything? It did before? but didn't after the re-wind?

The factory alternator is only 70amps so once you start running lights, a decent stereo, fuel pumps, thermo fan(s), air con etc it just wasn't coping and my tuner was complaining about unreliable voltage. It was rewound up to 85amps but this meant at idle the battery was discharging and was still not making reliable voltage.

I wouldn't of thought the rewind with the larger copper would of affected it unless.. well it make sense could not fit as many turns on stator thus more revs required to get it to output. I think there is an high output alternator available, not sure if it was a BT1 spec thing or not, but my old white girl had a 130amp sucker on it. None the less good job and probably a much more efficient alternator to boot.

There was obviously an issue with the old Bosch alternator . Unless you're running a big stereo , i find it hard to believe that an 80a Bosch alternator was struggling to charge your car . Interesting conversion , people usually go from a Hitachi to a Bosch as they're so expensive to rebuild .

I read the thread below and spoke to this company when i started my research, you are spot on about getting less turns and therefore requiring more revs to make the power and that is why these guys no longer wind up the factory alternators. The link also discusses where all of your amperage goes to when you upgrade things. http://www.calaisturbo.com.au/showth...ght=Alternator (http://www.calaisturbo.com.au/showthread.php?t=131563&highlight=Alternator) Maybe there was an issue with my original alternator, but the conversion gives 110amps and is working well so I thought I would share anyway. I think there were other alternators used throughout the vl including on the bt1's, but I couldn't find any new replacement alternator that would bolt straight in.

My original alternator couldn't cope either when running twin thermos 3fuel pumps head lights etc it would drop aswell, I had 12 volt look after me with upping the amps too 100 and something can't remember exact number now runs perfectly!

See I did learn something at uni You could also of over spun the alternator but they don't like revs at the best of times. I know the bloke that owns my BT1 now and next time I am over his place I will have a squiz and see what the alternator is was etc. A BT1 nut may know off the top of their head. Quote: Originally Posted by TROPPY [View Post] I read the thread below and spoke to this company when i started my research, you are spot on about getting less turns and therefore requiring more revs to make the power and that is why these guys no longer wind up the factory alternators. The link also discusses where all of your amperage goes to when you upgrade things. http://www.calaisturbo.com.au/showth...ght=Alternator (http://www.calaisturbo.com.au/showthread.php?t=131563&highlight=Alternator) Maybe there was an issue with my original alternator, but the conversion gives 110amps and is working well so I thought I would share anyway. I think there were other alternators used throughout the vl including on the bt1's, but I couldn't find any new replacement alternator that would bolt straight in. Some original photos have not been recovered yet.

Just use a gtr alternator, they're 90 amps, if your drawing more than that in a Vl maybe u should take a look at urself

Silly suggestion but why not fit a rb25det alternator has higher rating exact same mounts, adjuster, pully etc all need to do is put two spade terminals on it for regulator which your doing anyway to fit the patrol alternator?? This what i did on my calais worked a treat and charges at idle if needed ie fully load from air cond lights etc...

How many volts at the battery should i have at idle to make sure its charging correctly?

Anything over 12.8v is charging. Check it with engine stopped then again with engine running if goes up it charging..