420A How to: 420a Saturn Alternator install

okay im not sure if this is the right section for something like this but i cant post anywhere else related...

Ive read a lot about the saturn alternator install for the eclipse but couldnt find one thing about how to install one on a "2g 420a specific".
So i went ahead and mocked up one that i put in my car.i got this one for my car here: 91-97 SC/SL Series 1.9L

There are 2 issues when mounting it:

1)you need a little piece of metal wide enough for the tensioner bolt to go through and long enough to reach the tensioner and the mounting hole on the alternator(see pic 1)

2)you will need a spacer for the mounting bolt on the bottom of the alternator.

You must be logged in to view this image or video.

.
.

You must be logged in to view this image or video.

I used the same belt size listed for use with an AFX UDP.
As far as the wiring goes i didnt have to wire anything to the alternator.if you get one from the site i listed you will only need to connect 1 wire to the battery and that is all..as for the stock saturn alternators i do not know how the wire harness on them connects to the 2g 420a

 

[onefast2gdsm]

Have you noticed any improvements?

 

[Leonthefaded]

Nice simple writeup I like it

 

[Gruff511]

Have you noticed any improvements?

YES DEFINITELY! the stock alternator is a horrible. i dont know if its just me but ive gone through 3 alternators since i got the car and it sucks. the problem i had with the stock ones arent Voltage loss but rather they wouldnt charge the amps in the battery.and over time it got worse.
especially on hot summer days down here in south florida(95*) if i would turn the car off it wouldnt turn back on without a jump. and i would have to charge the battery everyday...

but improvements from stock! on this saturn alternator, well Mines* it is a 160amp and at idle im at 14.11-14.19Volts which is A LOT better than any factory alternator i ever had.
The 4g63t guys do this alternator swap because its a little more reliable than the factory alternator and is also more affordable buying them new compared to the ones actually made for our cars.

 

[dalesmitsu]

Nice write up. Could I use the stock udp, with this saturn alternator also what is the correct part number for the belt.

Im atx, thats why I ask about the stock udp. Havent seen a aftermarket UDP for atx just for mtx.

 

[Gruff511]

why cant you use the aftermarket UDP for our cars on an ATX?
but i am not sure as to what size belt will fit onto the stock UDP but i think the stock size belt will work since the pulley on this alternator is barely larger than the pulley on the factory alternator.

you can check out this article: http://www.2gnt.com/index.php?d=Accessory_Belt_Sizes

 

[DSM1G90]

Is there any issues with the ECU not having any voltage control for the GM alternator since Chrysler's alts didnt have an internal regular but depended on the ECU to do the control?

 

[Gruff511]

i only get a CEL of 41 & 46 which i dont see those as a bad issue since i know what its dealing with.

 

[97gst_spyder]

What wire did you hook to the battery? The larger red field wire?

 

[bduran1220]

heyy id love more info on this topic!!! my old ride was a 97 SC2 i miss her!!! and i had the alternator replaced on that car and i tried selling it CL but no luck so its just collecting dust in old car parts Box in the shop. id love to do something with it on my 97 gst spyder

wow i guess im on my own cant find nothing and this thread is more then a year old since origin

 

[Gruff511]

What wire did you hook to the battery? The larger red field wire?

Yes just that large +positive volt wire.

heyy id love more info on this topic!!! my old ride was a 97 SC2 i miss her!!! and i had the alternator replaced on that car and i tried selling it CL but no luck so its just collecting dust in old car parts Box in the shop. id love to do something with it on my 97 gst spyder

wow i guess im on my own cant find nothing and this thread is more then a year old since origin

Just search for "eclipse saturn alternator install" there has been A LOT of discussion on the saturn alternator on the 'GST' You will need to wire the alternators original plugs pigtail into your factory eclipse wiring harness to operate the alternator. And as for fitment you need to grind down a portion of the block to get it to fit properly.

 

[97gst_spyder]

Just so everyone knows. You can run a stock 4g63 alt on a 420a using the same method. It also has a built in regulator.

 

[DSMAvenger]

Is the 4g63 alternator better?

Chris

 

[Stmguy42]

Very good write up! I have a 95 talon tsi and I have issues with loud squeeling noise. I assume my alternator is on its way out because my battery will not stay charged.

 

[Gruff511]

Very good write up! I have a 95 talon tsi and I have issues with loud squeeling noise. I assume my alternator is on its way out because my battery will not stay charged.

I had the same problem before. I replaced the alternator and no more squealing

Is the 4g63 alternator better?

Chris

IDK but Ive read a lot about them failing and thats why a lot of 4g63 guys swap the saturn alternator in.

 

[Stmguy42]

If you could find the write up on the wiring I would appreciate it. What gauge wire is used.

 

[Gruff511]

Saturn Alternator Swap

Important Improvements Saturn Alternator Swap

The gauge wire depends on how many Amps the alternator is rated at. Im running a 160Amp Saturn alternator and my battery is in the trunk so i use a 1Gauge wire. smaller Amp alternators you can use 4gauge with no problems.

 

[silvreclips]

I think one of the biggest problems with the factory charging system is that the voltage reg in the ECU sucks. I have been running an UDP and with the lights and fans on the voltage would drop as low as 11.5 volts at idle. Once the motor reved a little it was back up to 13.5ish. When I swapped to fuel MS2 and running an external reg for the alternator the voltage has stayed at 14v regardless of electrical load or the engine speed. I should have ran the external reg a lot time ago. Im not sure if the higher output alternator is necessary.

 

[Gruff511]

Yeah I got the higher amp alternator because it wasnt that much more. But I do run my amp&sub all the time so it helps. And I went through a couple stock alternators in the past, they worked for a little then started making all kinds of crazy noises so I said Eff with the stockers.