96 corolla alternator swap?

Hello everyone! I have a 96 Corolla 4A-FE 1.6L and I have some high tech equipment in it that draws quite a bit of power. When I have my gadgets on the engine idles rough on stop lights. When I turn everything off it seems to be just fine. I was wondering if this could be solved by swapping the 70AMP alternator that is in it with the 80AMP one that is used on the 7A-FE 1.8L engines and of course the main concern: is this safe for the 4A-FE 1.6L engine and it's electrical components? Thank you in advance!

Reply to
Mick
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Go see a local auto electric rebuilding shop, and see how big they can go with an alternator that will still fit in the space available and onto the same mounting points - you might find something that drops and plugs right in like factory.

An alternator swap to gain only 10 amps of hot charging current is a waste of time, see if they can find something in the 100A to 120A range for you.

The engine can handle it fine if it's EFI, the computer can bump up the idle as needed to compensate for the extra load.

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Reply to
Bruce L. Bergman

I would highly suggest not going to 99% of those electronic shops out there that rebuild alternators, you're almost always going to end up with a dead alt at some point or all kinds of other electrical problems . You might be able to swap it out for the higher amp alt from the same car if it is the same engine, you may need the higher amp alt bracket, though.

If you do want to have your alt rebuilt I suggest these guys:

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Reply to
Josh

I started using a mkII supra 7mgte alternator, the mounting brakets are a bit diffrent I use a stock pully and this alternator. I have not had one problem with it soo far, my car stays up in the higher rpm band majority of the time 7000-10500rpm I was buring out the autolight Autozone replacements about one a week.

The supra one comes in two styles the 100amp and a 80amp. Try using a smaller pully on it finding a smaller pully can be done by looking at other corolla models from previous or next generation's.

Keeping the rpm up in the alt will keep the lights from diming and the car from stressing. Obviously when the alternator is spinning at higher rpm's its going to die much quicker. I have a 4ag in my car which is basicly the same bottem end "block you have" in your car. Soo I figure if you use the supra alt remember this...There will be a slight modification to the adjustible alternator bracket on your car I had to reem the slide adjustment bracket out soo I could fit my belt on of course getting a smaller belt can be a remede for that also.

Reply to
Myrone Bagalay

PS...GO JUNK YARD HUNTING anything made by nippon denso from 1985-1993 should work bring your sample alternator soo you can compare the alternator shells for mounting purposes, and plugs.

Reply to
Myrone Bagalay

Besides the physical size issues that may or may not be present, there is no reason why you couldn't use an 80A alternator instead of a 70A. The question is, will 80 be enough?

All of your stuff is rated in watts, but the alternator and battery are rated in amps, so you have to do the conversion. Divide the total watts by the voltage (12) to arrive at the needed amps. I would round up in all cases.

Frankly, I am not sure how much stuff you can actually put on a Corolla, that the Corolla can haul around town, and exceed the output of the alternator. I suppose you could put in a subwoofer and power amplifier that take more power than the engine produces, and add blender to make margaritas ...

In any case, add the wattage of the all of the accessories and divide by 12. If the result exceeds 80, then 80A will not be large enough. Bascially, 80A will provide enough juice to run 960W of stuff. The odds of running everything at once is usually pretty slim, so you could reasonably run perhaps 1200W of stuff from an 80A alternator, but you can't run all of this stuff at once, and I think that any loads greater than this will leave you in pretty much the same place as you are today. For example, you have added the monster sound system and upgraded the lighting up front; you may find that you can't run the stereo at night because the combination of the sound system and the lights exceed the power output of the alternator.

What you are noticing is that the loads are drawing down the available voltage because they exceed the power that is available. When the power demand exceeds the output, the voltage drops. Power and voltage are related, and when the demand exceeds the supply, then voltage is sacraficed. You notice the votlage drop as rough running at idle. Frankly, if you were drag racing with the subwoofer blaring, you should notice that your 1/4 Mile speeds should drop off as well.

Just because you have an alternator that can produce 120A does not mean that the wires will get cooked. What happens is that the individual loads on the car have certain demands, and they have these demands whether the alternator can meet them or not. If the alternator makes 70A, but the loads demand

100A, then the voltage will drop to about 8.5 in an attempt to provide the amperage. Obviously, a circuit getting 8.5V, that wants 12V, isn't going to work very well. But, if the alternator can produce 120A, but the loads only demand 100A, then there will be plenty of voltage to run everything.

Reply to
Jeff Strickland

Thank you for the info. This was very insightful!

Best regards, Mick

Reply to
Mick

There is a reason, and that is the brackets may be changed, unless you know something I don't. The alternator casing as far as I know are different and used different brackets. This is the case with my 90amp on my '94 5sfe mr2, which uses a different bracket than some of the other alternators made for the same year, same engine and same car.

If you do go to a junk yard looking for an alternator be sure to take the bracket with you.

Reply to
Josh

I have no clue as to the physical attributes of the higher output alternator. I was trying to explain how to decide if the new alternator was going to meet the electrical needs, or not.

Reply to
Jeff Strickland

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