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Discussion Starter #1
Has any one done this to scavenge some extra horsepower that normally end up getting used spinning the water pump and alternator at standard speed?

I have seen underkit pulley kits, just wondering if you have done it and if you think that it was worth the money and hassle?

96ProjectBronco
 

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FSB warrior
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96PROJECTBRONCO said:
Has any one done this to scavenge some extra horsepower that normally end up getting used spinning the water pump and alternator at standard speed?
96ProjectBronco
:twak :twak gain 3 HP but reduce cooling and lower the amps our alternator can put out and the amount of pressure the PS pump puts out therefore reducing its effectiveness offroad;) Sounds great.

Search next time. If you did you would have noticed that we think its not such a good idea.:wacko
 

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Wrenching for a Livin'
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Pull(ies) does it actually replace? I mean if its a smaller pulley on the alt. shouldn't it increase its output?
 

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Discussion Starter #8
1.5% horsepower increase for 180.00 bucks. That doesn't sound all that good. I think that I will spend money on polyurethane bushings instead and remove some clunk.

Does anyone else get sick of hop ups that don't live up to their hype?

Thanks

Ninety-SixProjectBronco
 

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Satyr of the Midwest
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96PROJECTBRONCO said:
Does anyone else get sick of hop ups that don't live up to their hype?
Such is the world of high performance. Fortunately, we have internet forums such as this very fine establishment to put the manufacturers' claims to the flames. :D I am eternally grateful that it's here, otherwise I'd be kinda stuck on a few issues and ideas for my rig, and I wouldn't be able to help fellow BKO'ers out, either.

Back to the question, underdrive pulleys help very little. Unless you're like me and you have access to a lathe or CNC mill to make new ones yourself (and even then just for looks), I'd save the cash for something effective like exhaust, 4x4 repairs, etc.
 

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96PROJECTBRONCO said:
1.5% horsepower increase for 180.00 bucks. That doesn't sound all that good. I think that I will spend money on polyurethane bushings instead and remove some clunk.

Does anyone else get sick of hop ups that don't live up to their hype?

Ninety-SixProjectBronco
Last time I saw one I think it was around $40 on eBay.

In any case, they do live up their hype (a few extra HP); however, since there is no such thing as a free lunch, that may effect cooling, PS, or the alternator.
 

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I've always used an underdrive crank pulley on all my prior Mustangs and even my current Cobra.

However, I will never use the "underdrive" alternator or water pump pulleys... The aftermarket underdrive water pump and alt pulleys are larger in size than the stock pulleys, thus "underdriving" those accessories, which is not a gain at all and only creates cooling/charging issues.

The underdrive crank pulley is actually smaller than the stock pulley, so essentially you are increasing the rotational speed or centrifical force of the engine's crank - which can and does net to a small HP gain, but nothing to get overly excited about.

The 1993 Cobra used a REAL "underdrive" water pump pulley which was actually the smallest water pump pulley that Ford produced for the Mustang 5.0's. The pulley is only about 2.5"-3" in diameter and it actually does work in the effect that it spins the water pump FASTER than if it had the regular "stock" 5.0 water pump pulley. I have used these 93 Cobra water pump pulleys with great success on my prior 5.0 Mustangs (86-93's). However, this pulley is not available for the 1994/95 Mustang 5.0's, due to the pure fact that the center hub and bolt pattern on the 94/95 water pump is quite different as opposed to the 1986-1993 5.0 water pump...

If the bolt pattern and center hub on the Bronco 5.0/5.8 water pumps is the same as the 1986-1993 Mustang 5.0's - then you too could use the 1993 Cobra water pump pulley to speed up the pump's flow rate and cooling capability. This can also be used with an underdrive crank pulley without any detrmental affects - and it will not affect yor charging capabilities either. IF using the smaller 1993 CObra water pump pulley, you WILL need a shorter belt (and also if you run an underdrive crank pulley, you will need a shorter belt and MAY have to reroute the belt in the opposite manner as it would normally be routed).

You can get the 1993 Cobra water pump pulley by searching eBay OR you can contact Jim D. @ http://www.performancepartsinc.com/main.htm

Adding an underdrive crank pulley will net you some HP gains and if ONLY using an underdrive crank pulley, you will not affect your alt or water pump output capabilities at all.

:)
 

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aurgathor said:
that may effect cooling, PS, or the alternator.
Theres no MAY about this. Crawling threw the desert at 2,500 RPM's at .5MPH: overheat in about 10 minutes. Spinning the stock C3 pump slower... is gonna be like manual steering and your headlights are gonna dim if you run anything more then 2 55W halogens or a 140W amp.
 

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The Anti Yam!
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Cobra Jet said:
The 1993 Cobra used a REAL "underdrive" water pump pulley which was actually the smallest water pump pulley that Ford produced for the Mustang 5.0's. The pulley is only about 2.5"-3" in diameter and it actually does work in the effect that it spins the water pump FASTER than if it had the regular "stock" 5.0 water pump pulley.
Then it's not an underdrive pully, it's an overdrive pully.






Cobra Jet said:
Adding an underdrive crank pulley will net you some HP gains and if ONLY using an underdrive crank pulley, you will not affect your alt or water pump output capabilities at all.
Using a smaller than standard (Underdrive) crank pully is still gona slow down the Alt and P.S. pump, even with your overdrive water pump pully. Without the overdrive water pump pully it still slows that down too.

Non of this may be a problem on a Mustang.

But Mustangs dont often sit sidways stuck in a rut trying to turn a 35" tire sideways so it can climb out wile powering itself and extra offroad lights at night.

That does however happen to a truck every now and again.
Depending on the owner of course.
 

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I looked at doing this and could not find one positve responce when it comes to 4x4 use. As such, truck would never see the dirt, or be in heavy stop and go low speed driving in the summer... Go for it......

But I would like to find some folks that really have used them... THey sell them, so someone has to be buying and using, and happy about it, as I'm not seeing used ones all over ebay....
 

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884lps said:
But I would like to find some folks that really have used them... THey sell them, so someone has to be buying and using, and happy about it, as I'm not seeing used ones all over ebay....
They are generally used on any car/truck that turns high rpms regularly (drag cars, road racers, Auto-X, etc.). All they do is reduce the parasitic losses of the auxillary equipment at all rpms by spinning them slower. ;)
 

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I had an under drive crank pulley I used for 90K miles while pulling a travel trailer in 3rd gear (lockout od) at 2500 RPM. I just took it off this fall because alt turns too slow for winter driving. I've never had water pump, steering pump or alt problems. But I agree with the neg comments about using them while off-roading.
 

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Lick my balls
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I would remove the clutch fan and hook up an electric fan before installing that pully kit.
 

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The Anti Yam!
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jam0o0 said:
could an underdrive pully be made fo rthe AIR system? the silly emitions thing? or is that pully already huge i can't remember.
For the smog pump?
Why would you want to?

It uses absolutly no power.
 
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