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Discussion Starter · #1 ·
Hello everyone.

I'm a noob here (as far as joining), but have had my '94 LX Wagon for
about 2 yrs now. I've gotten lots of GREAT info and advice from this site,
so THANKS much.

My question is:

If I were to install a 50% undersize crank pulley to add a little more power
and hopefully reduce some of the engine drag caused by using the AC,
would there be any long term adverse effects to the alternator and/or
AC compressor from spinning more slowly?

Thanx

- - escortozone
 

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you can buy a ZXTuner alternator ODP, which will help resolve the issue there. Can't help you on the AC compressor, as I removed mine long before I put the 50% crank UDP on.
 

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The only adverse effect you will see is the empty spot in your wallet that would otherwise bee occupied by beer money. Otherwise it makes no difference whatsoever ... no matter what the hype is. No one has ever offered up a dyno chart to prove up on all the seat of the pants claims. The guy that sells them used to claim 14Hp ...lol.

Spend your $$ on something else.

That is a great price on that pully too.
 

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^ This is coming from a person that has never had one. I have the 25% and noticed and a difference. I have much more power with the A/C on. As a matter of fact, the difference with the A/C on and off is almost unnoticeable now with the UDP. It pulls harder as well.
 

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Thanks for the link. I just ordered one. I have been disappointed with my lights and fan dropping down at idle.

I disagree that they don't work. Besides being 3 pounds lighter meaning less mass, the engine doesn't have to work as hard to spin the accessories thereby reducing the parasitic drag. The more accessories you drive e.g. p/s a/c, alternator, the more you recoup.
 

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madmatt2024 said:
^ This is coming from a person that has never had one. I have the 25% and noticed and a difference. I have much more power with the A/C on. As a matter of fact, the difference with the A/C on and off is almost unnoticeable now with the UDP. It pulls harder as well.
Really? Did your crystal ball tell you this ? .... but who's keeping track :D

A motherhood and apple pie issue ... let's see the dyno charts instead of "it pulls harder". This is sort of like the cam pulley making a HUGE difference on a stock engine. I have 90+ dyno runs that proves otherwise ... but then who's keeping track .. :D

Actually, the Escort/Focus guy selling them used to claim they netted a 14 Hp gain which was a crock and he got called on it. So now it is just the parasitic drag reduction. It certainly helps but it is almost zip and the ECU probably cuts the compressor out at WOT anyway.

Someone give me the net result from the reduction in the rotational mass. I'd say it is immeasurable as a practical matter.

But hey ... if it feels good buy 2 of them. I have one but only to slow down the alternator a little.
 

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Discussion Starter · #8 ·
Thanx for all of the replies so far!

I think what I'm understanding is that if one changes to a UDP on the
crank, then the alternator will need an overdrive pulley, right?

Then, what about the AC compressor? Will it spin fast enough for the AC
to work correctly? I'm an admitted wuss when it comes to a hot interior
in the summer.

BTW, I'm not looking for a substantial increase in HP as a result of this,
just to reduce (as much as possible) the unbelievable drag on the "go"
when the AC is turned on.

Thanx again!

- - escortozone
 

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I don't think you need an overdrive pulley for the alternator unless you are like me and don't want the electrical systems, fan, lights, etc to dim at all. If you never sit in traffic or don't mind the temporary drop you would be ok w/o one. I don't have any summer driving experience with the UDP and a/c. I seldom use a/c anyway. I would think it will be ok at speed but might drop some at idle.
Another fix might be a higher capacity alternator. I haven't thought that one thru yet.
 

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Discussion Starter · #10 ·
To madmatt...

Seems like you've got what I am looking for.

Do you notice a difference in cooling level at idle? I'm in the Chicago
area and sit in traffic quite a bit. If not, maybe I'll just go for the 25%
UDP.

Thanx
 

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Discussion Starter · #11 ·
Another stupid q...

Do any of you know of a UDP supplier for a 91-94 1.9l other than
escortfocus.com (they are out of stock on both 25% & 50% UDPs
right now)?

I noticed the harmonic studs on escortfocus' UDPs and no Ford UDP on
e-Bay (right now, at least) seems to have those.

Thanx
 

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The A/C should still function properly with the UDP. The only thing you'll notice is a low volt reading on the battery if you have a booming sound system. If your car is all stock electrically, it shouldn't be a problem. But it never hurts to keep the amps up that are coming out of the alternator.
 

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Escortfocus is the only supplier of CVH UDP's. My A/C works fine at idle. Looking back I probably should have gone with the 50% but hey, I'm happy with the 25%. Anything is better than stock.
 

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Discussion Starter · #14 ·
Thanx to all!

Guess I'll just have to wait 'til Escortfocus gets the UDPs back in staock.

Already ordered the alternator ODP, thanx Madmatt for the link.

Think I'm all good.
 

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My alt ODP is very light. Definitely weighs the least out of that, stock, and the AEM true power pulley. Pic for reference:



Mine is the ZXTuner alt ODP.
 

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I got it from ZXTuner. Don't remember the price off hand, but I believe it is still on thier site.
 
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