Fitting Underdrive Pulley to Cayman S

PCGB Member
  • Total Posts : 557
  • Joined: 2012/04/29 14:12:25
  • Status: offline
Chris_in_the_UK PCGB Member
2014/05/11 20:45:12 (permalink)

Fitting Underdrive Pulley to Cayman S

Hi folks - finally got down to fitting the RSS Underdrive Pulley I bought during my recent US road trip and visit to Sharkwerks.

For those who are not familiar with this modification it is a pretty cost effective way of releasing some horsepower and torque.

Here is the Planet9 version of what I did but using a different pulley to the RSS one I used.

1. This pulley's and belays are accessed from behind the seats - just pull them as far forward as they will go and tilt them towards the windscreen.

2. Remove the luggage bar - this has a couple of torx screws so you need the relevant bit - then pop out the retaining stud and carefully remove the carpet and sound insulation combo.

3. There are several bolts and a couple of nuts that need removing from the aluminium access panel which can then be removed - the edges of the panel are very sharp as this is a pressed item at manufacture - I smoothed these of before I replaced this.

4. Once tha access panel has been removed then the pulley's and belts are visible. Use a socket on the tensioner pulley to ease this off against it's spring and the belt can be removed.

5. RSS provide a 'stop' bolt for the pulley that is to be replaced (the bottom one) and you just need to used a socket wrench to rotate the engine to line up one of the holes in the pulley with the boss on the engine that has a locking hole in it. Once you have done this the centre bolt can be undone - normal thread orientation, just a bit tight.

6. Once the pulley is off, you need to cut approx 5-6mm off the locking boss so the smaller under drive pulley does not foul it - despite how it sounds, it's no big deal (honest). I found it easier to remove the nearest idler pulley to give easier access (visible by the vacant boss in the last picture).

Here is a comparison of the pulley sizes - black one is the RSS under drive pulley.

RSS state that the standard drive belt is ok to use with their pulley, but the chaps at Sharkwerks recommended a slightly shorter belt which I grabbed at the same time I picked up the pulley.

And a final (cr@p) picture of the pulley in place.

As regards how it drives........

Not had time yet! All runs ok so looking forward to seeing how this feels - ran out of time doing the engine mount work (see my other post).


1 Reply Related Threads

    Guest of the Club
    • Total Posts : 62234
    • Joined: 2015/06/29 11:09:45
    • Status: online
    Guest Guest of the Club
    Re: Fitting Underdrive Pulley to Cayman S 2016/05/02 21:58:58 (permalink)
    Can you recall the type of bolt supplied to affix through the old pulley into the block - M6, M8? I am just about to embark on this task ;-)
    Quick Reply: (Open Full Version)
      Enter the random characters shown
    Submit Post
    Jump to:

    Posts made and opinions expressed are those of the individual forum members

    Use of the Forum is subject to the Terms and Conditions


    The opinions expressed on this site are not necessarily those of the Club, who shall have no liability in respect of them or the accuracy of the content. The Club assumes no responsibility for any effects arising from errors or omissions.

    Porsche Club Great Britain gives no warranties, guarantees or assurances and makes no representations or recommendations regarding any goods or services advertised on this site. It is the responsibility of visitors to satisfy themselves that goods and/or services supplied by any advertiser are bona fide and in no instance can the Porsche Club Great Britain be held responsible.

    When responding to advertisements please ensure that you satisfy yourself of any applicable call charges on numbers not prefixed by usual "landline" STD Codes. Information can be obtained from the operator or the white pages. Before giving out ANY information regarding cars, or any other items for sale, please satisfy yourself that any potential purchaser is bona fide.

    Directors of the Board of Porsche Club GB, Club Office Staff, Register Secretaries and Regional Organisers are often requested by Club members to provide information on matters connected with their cars and other matters referred to in the Club Rules. Such information, advice and assistance provided by such persons is given in good faith and is based on the personal experience and knowledge of the individual concerned.

    Neither Porsche Club GB, nor any of the aforementioned, shall be under any liability in respect of any such information, advice or assistance given to members. Members are advised to consult qualified specialists for information, advice and assistance on matters connected with their cars at all times.

    © 2017 APG vNext Commercial Version 4.6
    Silverstone Auctions
    Oracle Finance
    Archant Dialogue

    Cornbury House
    Cotswold Business Village
    London Road
    Gloucestershire  GL56 0JQ

    Call us: 01608 652 911