85 amp alternator?

[heshan]

Guys,

My current alternator is faulty and am replacing it. Mechanic suggests putting a 85 amp alternator.

I'm worried my wires my get fried and also whether my battery would lose its longevity as it might get over-charged.

Any comments? Apart from this alternator being heavy on my engine, what other issues could it cause?

[assassin10000]

The voltage regulator will prevent it from over-charging in 99% of the cases (the 1% being if it fails, in which case it usually DOESN'T charge at all).

IIRC the 91 MR2 is a bolt in 70-80A alternator option. The 90/100 amp versions are a LARGER housing and won't bolt in.

I know I put a 91-92 80A alt on my engine just to see if it fit, and it did. I sold it 2 years ago to a guy who is still using it.

Mid 92/93 up they changed connectors so it would no longer be plug & play/Bolt-in installation.

Andrew

[heshan]

Thanks Assassin! Did you see any improvements in the car?

What benefits would I see with a high power alternator? Would it only be the ability to run more devices?

Also, would I feel a powerloss due to the size of the alternator?

[assassin10000]

It won't be a noticeable difference... except maybe if your lights dimmed at night with the stereo on or when it drops to idle it won't anymore. The alternator won't put more load on the engine unless the power drawn from it is enough that the voltage drops and makes the voltage regulator put out more amperage. The actual alternator itself is not that much bigger in size/weight IIRC.

I barely have a stereo, run all LED/HID lights... so I don't have any need for a high amp alt. It was a 'what if' type of thing for me.

Andrew

[heshan]

thanks guys.. I've upgraded to a 90AMP alternator and its working fine for now

Sometime soon I'll upgrade to a 60AMP battery as well