Just curious on the Alternator specs required for my car. What are the requirements and specs I should be looking for?

 

Andrew, the X-Type battery for US cars is a 120 amp unit with an internal rectifier and is externally excited (ie, excited from the ECU/ECM). There is no reference that I can find that relates the alternator to a style type (ie, like a lot of Ford products use what is called a "3G alternator" which is a set bolt pattern, amperage, etc). This is where you are going to have to pay attention and make sure that it is specifically stated that it is designed for use in a jaguar.

Of interest, the alternator spins at 2.8 times the speed of the engine. This is needed to allow the alternator to produce sufficient output at idle. With this being said, an alternator does not output 100% at idle speeds. It actually can only output about 60% of rated. As the engine RPMs come up, the percent output will rise till you reach the maximum which will occur normally in the 1500-2000 RPM range.

If there is something that you are after, let me know.

 

https://www.jaguarforums.com/forum/x...nation-202162/

 

Thanks thermo and dell for the responses. Also yeah I'm likely going to be after a new alternator thermo. Trying to keep it as low budget orientated as possible though. I was looking around a bit on ebay and a lot of the alternators were rated at 100 amps and not 120 amps like you stated. Also was also looking at just getting the main pieces to rebuild my current one but once again it was hard to verify what was oem and falling into spec and what was more generic and not meant for my car. So I guess the question becomes is could you direct me towards a correct alternator or even correct replacement parts to rebuild my existing one.

Thanks again

Andrew

 

Andrew, look on E-bay. There are a lot of new alternators there for around $140 (not reman units). There are also used units starting at about $50 and going up from there. You want to stay away from the 100 amp units as those are for the diesel variants. watch the specs and look for the 120 amp units. if they say something like 160 amps or "upgraded output", stay away from those. Some members here have gotten those units and overall, they have not had good luck with them.

You can also look at places like Autozone,they have 3 listed. One I would stay away from as it is a 100 amp unit. But, the other 2 are reman units with a limited lifetime warrantee. One was $120 (plus a $40 core) and the other was $133 (plus a $50 core). If you have a friend that is military, you can get 10% off. Or, pay attention to a sale and see what you can get off then. I am sure Advance or Napa will have similar units. It may be a cheaper way to go so you are not having to pay for S&H.