KahnBB6

iTrader: (5)

I'm getting a lot of voltage sag (bouncing down to 12.3V or so briefly a few times last night while at low speed in a parking lot) from the OEM Denso 93-98 Supra TT Auto 100-Amp alternator and I think it's time for an upgrade replacement with some newer technology.

I'm not looking for much and I prefer OEM and was set on the Tundra/Sequoia/GX470 130-Amp alternator upgrade which requires some minor modification to those alternators to work on a JZ engine.

That information can be found here:

https://www.supraforums.com/threads/...ngines.683340/
https://www.supraforums.com/threads/...&daysprune=365
https://www.supraforums.com/threads/...#post-10493306
https://www.clublexus.com/forums/per...upgrade-2.html


This video has a very good visual example of why a certain part of the Tundra/UZ 4.7L alternator needs to be trimmed slightly to be mounted correctly. Apparently one of these guys says the extra ear on the side does not present any obstruction issue and can be left alone... however in the main SF thread it is said that it should be trimmed off so as not to interfere with the JZ crankshaft pulley/damper.


.......



However.... I then came across this info and video in the big SupraForums thread on 130-Amp OEM alternator alternatives for 1JZ/2JZ engines:


https://www.supraforums.com/threads/...#post-13911342

Notes from the SF thread post on this:It seems that this is a fairly recent thing that someone has tried as another alternative OEM Toyota/Lexus/Denso alternator upgrade. Has anyone here given this a shot?

It seems the big differences between the Tundra/etc. 4.7L 130-Amp alternator swap is that this 2003-2010 alternator has the common JZ oval plug which means no re-pinning into another connector is required and also there seems to be an extra ear(?) that has to be shaved off according to this video if I understood it correctly. Also the video suggests that the accessory belt pulley is the same as the common JZ belt pulley which has to be swapped over on the Tundra alternator.

Just the same as with the Tundra alternator swap there is a little bit of mounting ear material that has to be shaved down by a few millimeters and depending on the car the alternator will be used in an alternator fuse rated high enough to cover the new output may be needed (unless the car just won't ever draw that much maximum current).

The advantage with any of these is primarily much improved amperage and therefore voltage output at idle. I'd just like to confirm whether or not the 2003-2010 Lexus SC430 130-Amp alternator has the same newer technology that makes the Tundra / Sequoia / GX470 4.7L alternator appealing.

Has anyone here tried this '03-'10 SC430 130-Amp alternator swap instead of the Tundra alternator swap?

Ali SC3

iTrader: (10)

I don't have first hand info but it sounds plausible, I think its worth a try if it has the right connector and pulley already.
The 430 has a lot of electronics and the folding hard top, so I would think they had a beefed up alternator on it at some point.

KahnBB6

iTrader: (5)

This is what I was thinking as well. The physical modifications to the alternator are the same as what is required with the 4.7L Tundra / Sequoia / GX470 alternator and in this case the pulley and connector need no modification. Same 130-Amp rating and presumably with the same better internal design as compared to the old OEM JZ alternator technology which puts out only 20 Amps at idle.

The SC430's did originally come with 100 Amp alternators (no idea what their at-idle output was) for model years 2001-2002 but they got 130 Amp units for 2003-2010. I don't remember what model year it was but a friend of mine had an SC430 and he often had issues with the battery and electrical system due to failed alternators due to the very over-taxed electrical system in those cars. If I had to guess I'd say the 130 Amp units for 2003+ probably cured that.

For our purposes with our JZ SC's and some more fans and electronics than they all came with stock these sound like a really good upgrade if the DIY work doesn't scare anyone off.

The only downside I can think of is what street or core rebuild value any of these alternators might have used when it comes time to getting another one but I'm not too worried about it as I'll get a Toyota/Lexus reman from a dealer. Everyone who responds in those threads only has good things to say about the similar Tundra alternator upgrade.

KahnBB6

iTrader: (5)

Ali, one further question about this: in most of the pertinent threads I have read that the universal "Big 3" electrical wire upgrade for the alternator-to-battery-positive, battery to chassis ground and the engine block to chassis ground is recommended with aftermarket high output alternators, many of which go to 150, 170, 200, 240 Amps and higher.

However with these 130-Amp 6-phase OEM Tundra 4.7L and SC430 OEM 4.3L 130-Amp 6-phase alternator upgrades I don't see everyone also doing a Big 3 upgrade to their charging and grounding system wiring.

Would this be asking for trouble to not apply the wiring upgrade or is this such low amperage output that the stock alternator, battery and engine ground wires in our SC's is sufficient to safely hold the maximum current draw/output from one of these factory UZ 130-Amp alternators? I certainly don't want to be on the edge of what the SC's wiring can handle but I'm not sure if that is the case or of concern when only going up 30 Amps from an OEM 2JZ 100 Amp 3-phase alternator with older stator technology.

I know that in Japan there were some factory 1JZ-GTE cars that came with 130-Amp OEM alternators (which we never got in the U.S.) but for all we know their charging systems may have had beefier wiring and it's unknown whether or not those particular alternators were the old style 3-phase or the newer style 6-phase designs.

t2d2

iTrader: (8)

From what I've seen, you always (*) upgrade the charge cable when going to a higher output alternator, but the ground wire is usually sufficient (**).

(*) Unless the jump is small and the original cable was over-spec'd.

(**) Unless the jump is large.

Ali SC3

iTrader: (10)

Isn't that cable from alternator to battery the same thickness of the battery to starter cable? can't remember off hand but I thought they were all the same size.
If they are all the same size then you probably don't need to upgrade it, should be at least like a 3-4 gauge thickness. I think toyota "slightly" overbuilt the battery cables.

The battery to starter will use way more amps than the alternator to battery but for a short period of time (think cold cranking amps of your battery).
The alternator to battery will be a fraction of the amps but more continuous. I would think the stock wire is fine to handle the extra amps, but an extra ground strap from the engine or around the alternator to ground wouldn't hurt as its now generating more amps overall (the alternator pulls power from the ground side and pushes out the positive side, so you don't want a bottleneck at the ground).
Really you are still going from about an 80 amp max output to a 130 amp max output which isn't crazy different, even though the 130 makes more power across all the different load ranges.

I am guessing stock is like a 3-4 gauge wire, and should be fine actually, but you could always go to 2 gauge from alternator to battery for extra overhead or even all around (0 is a bit overkill and mostly for battery relocation but would work also). and throw in an extra good ground strap on the block there or upgrade the factory one isn't a terrible idea if you are having electrical issues.

If for some reason the factory stuff is smaller than 4 gauge, then yeah go at least 4 gauge thickness but if you plan to run heavy electronics then I would say while you are in there might as well go to 2 gauge.

KahnBB6

iTrader: (5)

Just an update. I ended up going with this 2003-2010 SC430 alternator upgrade and so far it works very well.

I detailed my install in a short DIY post in my build thread. As a basic improvement over the factory JZ 3-phase alternators I think it's pretty good!

https://www.clublexus.com/forums/bui...l#post11075036

scsexy

iTrader: (1)

I've got an is300 alternator on my sc300 with is300 fans it all works great =)

KahnBB6

iTrader: (5)

scsexy, was its OEM Lexus part number 27060-46300-84? Or Denso P/N 2100506? I see that either one of those for the 2001-2005 IS300 comes up as a 100-Amp unit. Do you know if it's a 3-phase type alternator or a 6-phase design with better idle output characteristics under full load than the 100-Amp Supra TT Auto factory Denso alternators? That was my main problem and motivation for considering either the 2003-2010 SC430 alternator or the 130A and 150A versions from the Tundra and Sequoia.

It sounds like it's working for you very well! And of course it's designed to bolt right in to any JZ engine with no case modification.

Ali SC3

iTrader: (10)

That is good to hear it is working out well, I think you chose the best oem type one especially since it has the right plug already

KahnBB6

iTrader: (5)

Thanks Ali! Yeah, I'd recommend this specific alternator if all someone with a JZ engine needs is the 6-phase design for far better amperage output potential at idle with just a bit more maximum amps capacity.

Although the 150A version with the different plug found on some Sequoia's/Tundra's might be best if someone needs all of that and even more max amps.

Maybe one of these will be what you'll use on your next SC build?

Ali SC3

iTrader: (10)

After seeing your results I will be using this alternator when the time comes

KahnBB6

iTrader: (5)

And thus the anticipation begins