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FD alternator conversion and FD alt questions...

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Old 10-08-03, 10:55 PM
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FD alternator conversion and FD alt questions...

Ok since I ruined my other thread with flames I don't want that one to keep on going.

Here goes:



Jarret and I have both had a problem with the FD(93+) alternator not charging avoe 12v when you start the car. To get proper charging you need to rev up the car past a certain RPM point. Mine being ~2k rpms. Jarrets theory is that since the FD alternator's stock pully is much smaller compared to the FC style pully that we use when we convert/upgrade that it slows it down enough for it to NOT charge. He also thinks that it is a FEATURE of the new alternators to not charge untill they reach a certain RPM. At which point Jarret heard an audible CLICK from the alternator that came right at the time of the volts rising to FULL charge.

I would like to hear more details and info about the FD alt and anything relating to this.

Santiago
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Old 10-08-03, 11:02 PM
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Eet fase

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Not sure about your problem, but mine reads a little above 14 volts when the car is idling ~800 RPM. Always has ever since I installed it. I did not wire up an external relay or anything like that either.
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Old 10-08-03, 11:08 PM
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My theory:


Basically, I feel that the change in alternator pullies causes the alternator to come online slower. Some alternators will not start generating voltage until a certain rpm is reached.

With Santiago's AWS disabled (as I assume it is), the alternator probably isnt spinning fast enough until he revs the car. Then the alt comes online. NOW, I could be wrong, thats why its called a THEORY.

Jarrett
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Old 10-08-03, 11:35 PM
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I was thinking about an OVER drive pully. That is to make it go faster right? Just get a dual sleeve OD pully and drill it out to fit the FD alt. I mean as long as it is still relatively the same size as the FFD one it should have no reason to granade right?
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Old 10-08-03, 11:39 PM
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...94% correct.

 
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What I wanna know is why my alternator which I bought from autozone puts out 13.8v from idle and 14.3 cruising if they suck?
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Old 10-08-03, 11:44 PM
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voltage and amperes are different. think of volts as a standard and amperes ae how much you can run. More amperes means more **** you can handle like stereos, e-fans, etc.
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Old 10-08-03, 11:44 PM
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Originally posted by Makenzie71
What I wanna know is why my alternator which I bought from autozone puts out 13.8v from idle and 14.3 cruising if they suck?
Try it with your headlights, heater, wipers, and electric fan going.

Then you'll say "Ahh yes! 70A = Teh Gh3y!"
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Old 10-08-03, 11:47 PM
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...94% correct.

 
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mine's more along the lines 90A...maybe more...I can't remember for certain...I never had any problems with all those running. Before I replaced it things were a bit dim and when my subs bumped you could watch the needle move...lol
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Old 10-08-03, 11:49 PM
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S4 alt is 70A S5 is 80A and S6+ is 100A+
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Old 10-08-03, 11:51 PM
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...94% correct.

 
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yeah...I know...but mine's rated higher...I can't remember for certain...I'll have to check out the sheet when I get home but I'm almost certain it's higher than that...
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Old 10-08-03, 11:53 PM
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lol, all of you. I got my alternator rebuilt and upgraded and it puts out 14.7 with my highbeams on (aftermarket headlights) 400watt stereo bumpin...with everysingle thing on it doesn't go under 14 wipers, fan, whatever!!

Why spend that much money on an FD alt i got mine rebuilt and upgraded for 50 bucks canadian
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Old 10-08-03, 11:56 PM
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where do you go to do that?
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Old 10-08-03, 11:56 PM
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I didn't want that because people always talk about how its not trust worthy to rebuild them or get remans
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Old 10-09-03, 12:08 AM
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Yeah but you could be in a situation like mine where you have multiple S4 alts. You can rebuild one and carry the other for a spare when traveling too far from home...
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Old 10-09-03, 03:51 AM
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i didn't spend as much money as you its a Bosche replacement...

Its a 70amp alternator but we tested it and it put out i think... 93?
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Old 10-09-03, 12:23 PM
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The FD alt is just better man. It is a min. of 100 amps and Tony tests them out and says that some pump out 130 but the avg. is 125ish IIRC. The FD alt is made better you can tell that just by doing a side by side comparisson.
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Old 10-09-03, 12:38 PM
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You know that behaviour is completely normal, right? Low voltage prevents huge current draws from the battery just after it has finished cranking the car...
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Old 10-09-03, 12:43 PM
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I don't see why it should be normal since both my old FC alternators didn't do that. I had ONE problem with my second FC alt that was similar to this but was caused by a loose cable. I have already checked ALL of my work twice and re-done some of it. no change.

Even if it idles for 10 minutes without me reving it it WILL NOT go above 12v. 10 min. after cranking is not good to have 12v now is it?
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Old 10-09-03, 12:59 PM
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All my FC alternators (and I have gone through a lot of them ) have done this. If you really think it's bad, I'm sure Tony will swap alternators with you. But the result will be the same.

When you start your car, it should idle up to 1500 anyway until it warms up.
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Old 10-09-03, 01:02 PM
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Are you sure you even wired the altenator right? I've one of Tony's alt and it charges at idle nearly 15v. Only problem I'm seeing is when I put a load on it at idle all that juice drops to the high 12's. But I'll get that solve when I actually have time to test it out.
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Old 10-09-03, 02:20 PM
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Originally posted by Aaron Cake
When you start your car, it should idle up to 1500 anyway until it warms up.
Only if the AWS is still active, and the thermowax is still installed.

IIRC, the TB mod disables this feature. And I believe it would be safe to assume that Santiago has done the TB mod.

Jarrett
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Old 10-09-03, 02:28 PM
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Yeah, I'm aware of that. If you completely strip the throttle body, this gets disabled. It is easy to do the "throttle body mod" without pulling all this (useful) stuff off...I would also assume he did the "complete" mod, removing yet another necessary system from his car.
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Old 10-09-03, 02:45 PM
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How is the thermowax useful?

Well, for you Canadians, I imagine its quite useful. Down here in Tucson, its worthless...
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Old 10-09-03, 03:44 PM
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Well, for one, it starts the alternator off. Lights off the main cat (if equipped) a lot faster. Makes the car easier to drive when it's cold, etc.

Also keeps dumb newbies from flooring the pedal when the car is still cold...

I don't have a problem with the thermowax per say, but I do have a big problem with people just taking random stuff of their car because they are uninformed on it's function, don't understand the consequences, and somehow believe it will give them power. Like wiring the ports, removing emissions, removing charcoal canister, PCV valve, etc. etc.

Really, there is absolutely no good reason to remove the thermowax unless it is broken.
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Old 10-09-03, 04:32 PM
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True,

And mine is still installed....

Last edited by J-Rat; 10-09-03 at 04:34 PM.
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