Smaller alternator issue completed(pics)

[Rickamurphy]

Ok, I'm going to try this and see how it goes. First I'm going to get some measurements on the "early" 944 ALT jsut to be sure, but if still too big I'll go with the ENIAC setup. I'll report back when underway. Everything except the ALT is off already and out to various shops for service.

[CO951]

I was thinking about doing this. What is the stock alternators amperage output? I was thinking it was less than this one's. If it is less, has anyone thought of using the pully that comes with this alternator so it will turn slower and have less of a load on the engine? Or would the difference in load be to little to be of significance?

[ArthurPE]

usually 3 wires

the big terminal should be red and goes to the starter/battery
the 2 pins:
one is a ground (brown or bare)
one is for the idiot light in the cluster (black)

usually
you need a wiring diagram for the nissan

meter (ohms) each pin to the case...that will tell you which is ground...the other should be for the idiot light

[m73m95]

If you want to use the Nissan quest alternator used in this thread, then all the install instructions are here, including how to wire it to the 944.

[eniac]

Originally Posted by CO951

I was thinking about doing this. What is the stock alternators amperage output? I was thinking it was less than this one's. If it is less, has anyone thought of using the pully that comes with this alternator so it will turn slower and have less of a load on the engine? Or would the difference in load be to little to be of significance?

I used the stock 951 alt pulley since the one that came with the Quest alt had one rib less.

[eniac]

btw, here's a long term update. ~25,000 miles and over 2 years later it is still working fine and I haven't had to touch it. Recently, I do get some belt squeek for a few seconds after a hard start with the blower, radio, and lights on so I think it's time to retension the belt. That's it.

No issues at all with this setup.

[eniac]

Originally Posted by ArthurPE

usually 3 wires

the big terminal should be red and goes to the starter/battery
the 2 pins:
one is a ground (brown or bare)
one is for the idiot light in the cluster (black)

usually
you need a wiring diagram for the nissan

meter (ohms) each pin to the case...that will tell you which is ground...the other should be for the idiot light

Page 3 has the wiring, here it is again.

[CO951]

I wasn't asking about the wirring! I was asking about how many amps the alternators can produce. I was thinking the stock was 110amps. How much more is the Nissan one rated?
Did you have any pics of the mods you made to the alternator housing? I know the hole was drilled out, but I didn't quite understand where the area that was ground down is.

[Brian Broderick]

Originally Posted by eniac

So there it is, a 1997 Nissan Quest alternator that is a great match which some minor work to fit in a 951. This alternator is rated at 110amps with 70 amps at 1100rpm and peaks 130amps at 6k rpm. It came a with a nice little dyno sheet, lol. The back of the alternator sits much farther forward which is also much farther away from that hot alternator killing turbo.
.

Post #1

Most alternator run a 2-3 to one ratio so 6K rpm at the alternator is 2-3K rpms on the Engine.

[jlturpin]

Read his signature as well, just above the photo he posted.

BTW, I had a zanzibar red boxster S, it was a cool color.

[jlturpin]

Here is a photo of the Nissan alternator installed on my engine out of the car. I do have a larger pulley I am going to use to hopefully retain the stock belt.

[eniac]

Originally Posted by Brian Broderick

Post #1

Most alternator run a 2-3 to one ratio so 6K rpm at the alternator is 2-3K rpms on the Engine.

Originally Posted by jlturpin

Read his signature as well, just above the photo he posted.

BTW, I had a zanzibar red boxster S, it was a cool color.

Originally Posted by jlturpin

Here is a photo of the Nissan alternator installed on my engine out of the car. I do have a larger pulley I am going to use to hopefully retain the stock belt.

Thanks for posting a pic. Difficult to do with mine since it's in the car. I had to get a different length belt but with the pulley from the Porsche alt I was able to keep the same 6 rib width belt.

[m73m95]

OK, so I'm attempting to do this. I don't know if there are different casings for the nissan alternator or what, but I am having to cut away a TON of the mount. I've almost got it now but GOD DAMN! I've cut the slot for the alternator bolt, and I've sanded away 1/2 the mount on 90% of the alternator area.

The pully shaft doesn't have a woodruff key. Its on there tight (impact), but I hope it doesn't slip.

The write up on installing this is right on, there is just more to do than you'd think. Maybe the NA mounts are a little different than the turbo mounts? Maybe my alternator is a bit different? Who knows.

Ok, back to my sanding/grinding/cussing/bleeding..... I'll chime back in when its done.

[m73m95]

FOR THE LOVE OF ALL THAT IS GOOD AND HOLY.... I'M DONE!!

only took 10 hours... few pints of blood, words my kids have never heard before, and grinding, drilling, cutting, and should be welding (just to fill some unneeded holes lol)

Have not tried it yet. I still have the air box off. I'm installing the Rennbay headlight kit tomorrow (which is the reason I updated the alternator in the first place).

The bolt spread on my alternator is about half a hole to short, so I had to grind out the hole on the bottom alternator mount. There's only about 1/4" of material left on it, but its not in the direction the belt pulls, so it should be ok.

Also, I had to add a washer to the back of the pulley to bring it out some. Its a thin (maybe 1/16") 1/2" washer that I had to open up the hole on.

Its also not perfectly straight. Its 99% there, but we'll see how long the belt lasts. I don't know if its the case of my "remanufactured" alternator, or the mount on the car. The bolt goes in straight, so I can't figure out why its crooked, but it is.... a tiny bit.

Thankfully I didn't need to mess with the holes in the original mount, so if need be, I can put back the Porsche alternator............ and waste $200 on the Nissan one lol.... whatever.

I got the Duralast from Autozone. I think that might be where the differences are between this OP's write up and my debacle. Its got a lifetime warranty, but I think all my drilling and "fitting" might have voided that LOL. If I need to get another one, I'll buy it with cash, then get my core with cash, so they can't take my core money back when they see what's in the box

Goodnight all!

[eniac]

Originally Posted by m73m95

FOR THE LOVE OF ALL THAT IS GOOD AND HOLY.... I'M DONE!!

only took 10 hours... few pints of blood, words my kids have never heard before, and grinding, drilling, cutting, and should be welding (just to fill some unneeded holes lol)

Have not tried it yet. I still have the air box off. I'm installing the Rennbay headlight kit tomorrow (which is the reason I updated the alternator in the first place).

The bolt spread on my alternator is about half a hole to short, so I had to grind out the hole on the bottom alternator mount. There's only about 1/4" of material left on it, but its not in the direction the belt pulls, so it should be ok.

Also, I had to add a washer to the back of the pulley to bring it out some. Its a thin (maybe 1/16") 1/2" washer that I had to open up the hole on.

Its also not perfectly straight. Its 99% there, but we'll see how long the belt lasts. I don't know if its the case of my "remanufactured" alternator, or the mount on the car. The bolt goes in straight, so I can't figure out why its crooked, but it is.... a tiny bit.

Thankfully I didn't need to mess with the holes in the original mount, so if need be, I can put back the Porsche alternator............ and waste $200 on the Nissan one lol.... whatever.

I got the Duralast from Autozone. I think that might be where the differences are between this OP's write up and my debacle. Its got a lifetime warranty, but I think all my drilling and "fitting" might have voided that LOL. If I need to get another one, I'll buy it with cash, then get my core with cash, so they can't take my core money back when they see what's in the box

Goodnight all!

I happy to see others doing this as well... and makes it worth it to post a write-up rather then sell a pre-fabbed kit for this directly.

The only thing I had to do to the alternator is drill and retap one hole on one of the tabs and trim a "ring" off so the bosch pulley would fit on. I think it had a woodruf key but if it's tight you should not need one.

As for grinding the mount. You could cut a slot out of it but I wanted to keep as much material as possible. I tried a dremel which failed, then tried a cut off wheel which did a poor job as well. What finally made this easy was a decent angle grinder that ground through the mount like butter. Yes a lot of material needs to be removed however it's not enough to compromise the mount.

My alternator is dead on straight so maybe a hole is drilled slight angled on yours.

I plan to remove it this winter while doing some other work so I will take some pics of the mount I modified and add to this thread whenever I do it.

The spacing on this is so tight and close that tolerances among different factory mounts and brand alternators will make things more or less work to fit this correctly. As in any fab/custom work, it may take an hour or 3 weeks depending how well things fit into place...that's my experience. Just yesterday I had trouble with a different very simple mod fabbing something I have done on many 951's. For some reason it just didn't go as easy as the 15 other times.

To anyone else doing this...

Use an angle grinder!