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Old 12-02-2010, 02:59 PM   #1
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Cheetah Engineering Underdrive Pulley ?

Has anyone used this one ? US$100 shipped.

http://www.cheetahonline.com/products/n8040.html

thanks
Leo

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Old 12-02-2010, 05:44 PM   #2
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Read this first before you proceed:

http://986forum.com/forums/showthread.php?t=24996
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Old 12-02-2010, 06:07 PM   #3
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Many many thanks for the heads up. I will gladly pay more to support an honest person.

Leo
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Old 12-02-2010, 06:47 PM   #4
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Garage
is that just an UD pulley? if so here is a sight that offers one and he is a member here and has some real talent.

http://www.precisionchassisworks.com/boxster-underdrive-pulley.html
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Old 12-02-2010, 10:24 PM   #5
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or this:
http://www.tarett.com/items/boxster~cayman-products/under-drive-pulley-udp-detail.htm
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Old 12-03-2010, 07:51 AM   #6
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Also important to note that the original poster was pointing to a Power steering underdrive pulley (which is actually an oversized p/s pulley), which he lists at $100

Usually, when we talk about an underdrive pulley, we are referring to an undersized crank pulley, and that is what is others have pointed and compared to. Even Cheetah's underdrive crank pulley is $200 (which is similar in price to others).

Just trying to straighten out the apples/oranges comparison.
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Old 12-03-2010, 08:42 AM   #7
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thanks for the clarification, now I finally get it
the underdrive pulley which drives all accessories must be smaller in diameter to reduce the RPM for the pump while the pulley at the pump must be larger
Did I get it right?
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Old 12-03-2010, 10:12 AM   #8
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Yes, the underdrive power steering pulley is larger so that it will turn slower, and will only affect the power steering pump.

The crank underdrive pulley is smaller, and will turn all accessories slower (alternator, power steering pump, A/C compressor, water pump). This is why you get a power boost when you do the crank UDP, because you are reducing the losses of all of the accessories.

If you change both pulleys, you probably risk turning the power steering pump too slowly (but I don't know for sure).

Demick
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Old 12-03-2010, 12:44 PM   #9
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Quote:
Originally Posted by demick
Also important to note that the original poster was pointing to a Power steering underdrive pulley (which is actually an oversized p/s pulley), which he lists at $100

Usually, when we talk about an underdrive pulley, we are referring to an undersized crank pulley, and that is what is others have pointed and compared to. Even Cheetah's underdrive crank pulley is $200 (which is similar in price to others).

Just trying to straighten out the apples/oranges comparison.
Thank you Demick for the clarification. I wasn't aware that we were talking about a completely different pulley altogether.

Leo

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