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-   -   Cheetah Engineering Underdrive Pulley ? (http://986forum.com/forums/showthread.php?t=27067)

mcfly777 12-02-2010 01:59 PM

Cheetah Engineering Underdrive Pulley ?
 
Has anyone used this one ? US$100 shipped.

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

thanks
Leo

manolo 12-02-2010 04:44 PM

Read this first before you proceed:

http://986forum.com/forums/showthread.php?t=24996

mcfly777 12-02-2010 05:07 PM

Many many thanks for the heads up. I will gladly pay more to support an honest person.

Leo

Lobo1186 12-02-2010 05:47 PM

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

ChrisZang 12-02-2010 09:24 PM

or this:
http://www.tarett.com/items/boxster~cayman-products/under-drive-pulley-udp-detail.htm

demick 12-03-2010 06:51 AM

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.

ChrisZang 12-03-2010 07:42 AM

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?

demick 12-03-2010 09:12 AM

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

mcfly777 12-03-2010 11:44 AM

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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