400a to 200a conversion

[Maxjeep1]

I can’t wait to do this! I have set money aside 3 times and everything around is braking. I’m glad it worked out for you.

 

[Retiredwarhorses]

I was over thinking it. I measured everything with the 400a still mounted in the truck and the 200a not installed. They do not align perfectly and I was worried about the rear bracket not sitting flush and side loading the alternator tab. I talked to Steve at RWH and he assured me it all works out and to just install it with everything loose and then snug it all down. I did and the 200a is now installed and making power in the truck. I forgot just how much more space there is with the 200a vs 400a under the hood.

Extra benefit #1: The 200a has the over running pulley so the truck doesn't "chirp" every time I shut it off now.

Extra benefit #2: With the larger pulley on the 200a, my tach now reads correctly.

Thanks for everyone's help/suggestions (especially Steve at RWH). I apologize if I made a bigger deal out this than it actually was. You guys are great.

Never a problem, we just had to make sure you had everything, so based on that conversation on the phone I was confident you Just needed to install it all as I’ve done numerous times, it would all fall right into place.
And yes….your post install observations are spot on and of course one of the many reasons to go the 200 route.

 

[Retiredwarhorses]

May I add, there is a pulley kit that uses a fixed pulley on the 200amp that allows you to use the 400 serp belt, or if you are able to remove your old fixed 400 pulley you can reuse that….but you will lose the lower rpm indication previously talked about because it’s a smaller pulley.

 

[Maxjeep1]

May I add, there is a pulley kit that uses a fixed pulley on the 200amp that allows you to use the 400 serp belt, or if you are able to remove your old fixed 400 pulley you can reuse that….but you will lose the lower rpm indication previously talked about because it’s a smaller pulley.

So you are saying if you reuse your 400amp pulley that your tach will be off?

 

[Retiredwarhorses]

So you are saying if you reuse your 400amp pulley that your tach will be off?

it’s already off…so it will stay “off” LOL

 

[Retiredwarhorses]

The reason for a smaller pulley is to have a higher output of amps at idle, the 400amp puts out 180amps at idle, almost what the 200amp puts out at max rpm’s.

 

[Coonass77]

So you are saying if you reuse your 400amp pulley that your tach will be off?

More info in this thread:

Tachometer Inaccurate?

I have a 2006 M1165, 6.5 turbo, 60mph speedo and a tachometer. My problem is that the tach rpm reading is wrong. The tach shows idle at 950rpm, but my handheld rpm meter shows 700rpm. And with the engine speed set and showing as 2000rpm on the tach, my handheld meter is reading 1500rpm. I...

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