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View Full Version : 5th gen celica OVERdrive Pulley: Where to find?



Shadowlife25
01-23-2010, 08:46 AM
I suppose a pulley from another model would work but most all the offerings I have found are solely for newer vehicles. (1zz/2zz/scion Xa/Xb)

Anyone have a lead on this?

klapa
01-23-2010, 04:58 PM
I guess you mean a smaller diameter alt pulley?

Maybe some other cars shared the same alt and had a different size pulley?

For example - the cars with auto trans pulley has a different P/N than the cars with manual trans - maybe the diameter is the only difference.

I had long ago wanted a duplex pulley for my Mopar V-8 and ended up having one made out of spun aluminum - cost $200 tho.

klapa
01-23-2010, 08:58 PM
Actually,

I was interested to find out about this so I looked around a little more and also measured the pulley diameter on both my cars - manual and automatic trans.

Both pulleys are the same diameter - 8 cm - I guess the reason for the different part number for each is the the alt rotor P/N is also different between the two maybe a different rotor shaft diameter.

I also came across this little write up which may explain why the smaller pulley didn't seem to add much at idle for the high output alt.

http://www.alternatorparts.com/more_alternator_power_at_idle.htm.

acidice333
01-23-2010, 09:08 PM
I dunno about the newer models but you could always messure :)

See if the diameter is smaller, if so, see how many grooves there are on the pulley (most likely 5?)

Shadowlife25
01-23-2010, 09:32 PM
Yeah Steve, it's a 5 groove.

Klapa, following your link to read up now. ;)

Shadowlife25
01-23-2010, 09:34 PM
There are several ways to get more power at lower engine speeds. If you only require a little more power at lower engine speeds you may be able to use a smaller pulley. The smaller pulley turns the alternator faster at lower speeds thus making more power. When using a smaller pulley care should be taken not to over rev the motor. If you over rev the alternator with a smaller pulley the alternator can fail. I have seen internal and external fans explode and go through the hood of the vehicle with a $10,000 custom paint job.
The best way by far to obtain more power at lower engine speeds is to install an oversize alternator. The physically larger alternators produce more power at lower engine speeds and are much more reliable at higher outputs. Installing a higher output alternator that is the same size as your original alternator will not give you more power at idle unless they use a special rotor stator combination.


Very interesting.

klapa
01-23-2010, 10:31 PM
I have some experience with all this - not because I have big boomer stereo in my car but because I lived on 25 acres of land in an RV for about 7 years and I did not have power - I had a big bank of marine/rv batteries I would charge up.

I got a high output alternator for my 3/4 ton Dodge pickup - it was 100A which was a big deal then cuz the stock alt was only rated at 40A.

That new alt was at least half again bigger size than the original - and I'd bet maybe twice the weight too.

As far as the stuff flying apart - I doubt that would happen - tho I had a friend that lost a fan blade in his Wyllis pickup - darned thing went right through the hood! Made a really nice looking vent.

I'll post a couple of other things about this back on that HO alt thread - because I really still don't understand why an HO alt is needed just to run a stereo.

Shadowlife25
01-23-2010, 10:42 PM
It isn't solely for the stereo. It is for the entire electrical system. :)
Many times there is a component that will cause a large drain when engaged.
In my particular case, it is the OEM foglamps in my AllTrac. They drain gobs of power.
The fan (heat/a/c) is another one put on "high".
So many accessories...

I just need to rebuild ALL the wiring. It is honestly likely due to age and internal resistance being built up in the wiring.

klapa
01-23-2010, 11:25 PM
It isn't solely for the stereo. It is for the entire electrical system. :)
Many times there is a component that will cause a large drain when engaged.
In my particular case, it is the OEM foglamps in my AllTrac. They drain gobs of power.
The fan (heat/a/c) is another one put on "high".
So many accessories...

I just need to rebuild ALL the wiring. It is honestly likely due to age and internal resistance being built up in the wiring.


Well - that was going to be my "point" so you have saved us all some time!

It's the wiring and any switches (relays) in the path that's the most important for high current loads - and for lights don't forget the sockets themselves. Any resistance in the path to the load reduces the voltage at the point of the load - which in turn causes the load to need more current.

That guy in the HO alt thread seemed to have the best luck after changing the wiring for his 1kW audio amp to 4AWG. Still - 4AWG seems a bit "overkill" to me as audio is not a "constant" load like a light would be - i.e. if you've got it "turned up to ten" then you'll be pulling 1kW every time you've got a big bass "boom" - but in between there is silence (the nature of audio) and nearly no power - thus the AVERAGE power over time is much less than 1kW and this is what you use to size your wiring - the current required from the average power.

For lights - it's completely different - they draw the wattage 100% of the time - so the average power required IS the combination of the power required by the light bulbs themselves.

I would think a full run of 10 AWG would do even for the audio amp - so long as careful attention is made to the connection terminals - which is always where most problems occur.

The most likely problems with connections are improper/suspect termination of the connectors (crimp terminals not tight or expanding with heat) and also the connector itself - the most common "faston" spade terminal not having good spring pressure on the mating terminal.

With a low-voltage system you will always have a larger current for a given power level vs. a higher voltage system - thus the wire size and switch resistance in the path is more critical. Thus for such you should always plan to solder all your connectors, only use high quality connectors, and finally to run the largest wire size you can.

In any case - it is always best to draw the "equivalent circuit" of your path from the battery to the load - keeping in mind that current is always a series circuit - and thus you might have 4AWG from the battery to point A - and 4 AWG from the light to point B - but if you have 20 AWG from point A to B - then you effectively have a 20 AWG circuit all the way.