E36 LSX alternator upgrade

[lovnbmws]

Took the car around the block last night for a little test spin... Half way around the car started sputtering and I couldn't get it over 2k. The next right turn and my lights got so dim I decided to turn them off to conserve power. That gave me just enough juice to make the last right hand turn into my drive way... My alternator is dead

I started looking into replacement alternators and I see a lot of the F-body guys upgrade to a higher output unit. I'll be running full accessories and a stereo so I figure a few more amps would probably be a good thing.

Has anyone replaced their alternator with something larger than the stock 105A CS-130?

Will a CS-144 fit?

Should I buy something off the shelf like a Powermaster or find a local shop to rebuild my stock unit with higher output?

Thanks!

[James39]

Check over on LS1tech.com, I'm pretty sure the truck alternators fit with f-body accessories with a little modification. I think I've read several posts referencing the design of the truck alternator is much better or less prone to fail, etc..

Escalades and other highly optioned SUV's and trucks came with either a 135 or 140Amp alternator. (standard truck alt is 105A)

I have one std. truck alternator if you need it, send me a PM

[JohnnyGe36]

I may be having the same problem, but i do lose power when i am driving like that. My car just wont start the next day, i got my new alternator to work for like 2 months then i went to a drift event the next day my car was dead. I don't have a power leak anywhere. I was reading about the truck alternators, people are saying you pull off the bottom bracket for it to fit the ls1's. I may be doing that this weekend.

[bimerok]

Did you connect the "exiter" wire (I think that's what it's called)? The one pin plug connector?

[JohnnyGe36]

Were you asking me bimrok? everything on my alternator is plugged in.

[lovnbmws]

I tested the exciter wire at lunch and it is not supplying power. I will be tracing down the issue this evening.

Where did you guys connect your dash alternator indicator warning light? I suspect I made this connection incorrectly which maybe causing the problem. My notes say to splice the warning lamp into the exciter circuit but maybe this is wrong...

[Kaane]

You can also convert your alternator to be self exciting. That way you don't need any signal from the ecu for it to work.

In order to do it you need to buy a new regulator.

GM part #D702SE.

I will be converting to it, one less wire to deal with.

[lovnbmws]

I found this link in my notes discussing how to make the warning light work properly


http://forums.bimmerforums.com/forum...r#post21547433

If I follow it correctly I should have wired the excite wire coming from the alternator to either the GM ECU C2-15 OR the BMW X20-25. I believe I spliced them all together so in theory if I disconnect C2-15 it should work... We'll see when I get home tonight

[BRAAP]

Cut and paste from other thread.

Didnt notice how you wired your ALT, please forgive me if it is already posted.

Few ways to wire it, personally I see only one way as it makes the most sense.

1) The only way for your dash ALT/charge light to function properly is to use it as the ALT excite wire, just BMW used it. That means not using the GM PCM wire to control the ALT, delete it and disable the armature DTC if it is enabled, (most truck PCM's it's enabled).

2) I have read here splicing the GM ALT excite wire to the BMW cluster ALT wire. To me this makes no sense and if the ALT dies yet the PCM still is sending power, the ALT light will not illuminate. It may glow very dimmly when the ALT dies but during the day it cannot be seen, this is what happened to Tongboy when his died, had to limp it back to shop and verify with a DMM.

3) Use the GM PCM to excite the ALT all by itself. I see no benefit in this route other you can have the PCM trigger the check engine light if the armature dies, but what's the point? Check engine light illuminates but you don't know why till you pull codes, the ALT light isn't wired in so it won't illuminate.

To me it's easier to wire and makes more sense to let the BMW charge light do the work as it will let you know immediately and supplies the proper voltage to the ALT so it will a long and happy life, it won't burn out prematurely due to being fed too high voltage, (many a destroyed GM ALT from people just feeding direct 12v). 20'000 miles on mine, even loaned to TongBoy when his ALT died while I was switching from 5.3 to 6.0L, works perfectly, ALT light illuminates during bulb check prior to engine start.

Hope that helps.

[JohnnyGe36]

This may seem like a stupid questions BRAAP, i am one of those idiots wiring the ALT directly with 12v power, and i have gone threw 2 ALTS already in 6 months. What did you have to do to wire it to the charge light? I am new to the wiring thing on the LS engine, kind of a newbie to this stuff. Is there a write up on it, been trying to look it up on here.

[bimerok]

Alt exiter wire to x20 pin 25?

[Mas280]

Some info here

http://www.norotors.com/index.php?topic=6897.0

[lovnbmws]

Got it straightened out. I had two problems

1) I did mistakenly connect both the GM PCM (C2-15) and the BMW light (X20-25) to the excite wire explaining why the light never illuminated even when the engine was not running

2) the excite wire was broken somewhere between the alternator and the main splice box.

Solution: I clipped the GM PCM wire and replaced the excite wire. Now the alternator light illuminates properly and the alternator is charging at 14v when the engine is running


WOW that Escalade alternator looks huge

So this photo taken installed in an RX7 with a custom bracket... I wonder how it would fit in an E36...

Pzary, is this the same alternator you were referring to out of an 06 Silverado?

[JohnnyGe36]

I have the 1998 Fbody ls1, i been looking up how to wire the alt to the charge light. But i hear there is a difference from 1999 fbody ls. I am using a Current Performance wiring harness and a PCM from a 1999 ls1 (got it on ebay from pcm seller) Is there something i have to do to get this to work, tired of blowing up alternators.

[Pzary3233]

That looked bigger I'll get a pic Tuesday... I'm out of town at the moment.

[cooler breeze]

To simplify for future reference;
simply wire the gm alternator excite wire to x20 pin 25?

[GG Allin]

To simplify for future reference;
simply wire the gm alternator excite wire to x20 pin 25?

The one question in this thread, asked twice that no one answered. I'd love to know.