Targa wind roar

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PMMatthews

Original Poster:

5 posts

92 months

Friday 9th September 2016
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Hi,

I'm working with the PCGB 964 register secretary on an article for an upcoming issue of PP that explains how to make and and use a carbon fibre roof brace to cut-out the dreaded wind roar from a targa roof (in my case, on a 964, but I believe the roof design remained fundamentally unchanged from earlier versions).

The idea came from reading, on another leading Porsche forum, about a 964 owner in the US who made up a brace from a strip of carbon fibre, which he found to be very successful at reducing wind roar (he's recently confirmed to me that it's still working well). After digging around on the internet, I found the theory that the roar is caused by increasing aerodynamic lift on the targa roof as vehicle speed rises. The brace helps the roof frame to maintain its shape and in place despite the upwards force of the aerodynamic lift.

I tried my own brace, basically a carbon fibre rod cut to size and with rubber / nylon caps to prevent scratches on the roof frame, on the drive to Le Mans 24h this year and found I had no wind roar at speeds of up to 150kmph on the autoroute. The brace cost about £40 to make.

Before we go to print, I would like to hear the views of a few other Targa owners on their experience with the brace. My plan would be to loan out mine for a few days to other Targa owners for them to try. So I can explain how to use it, and to make sure you are happy that it will not damage your roof, I would plan to drop it off and collect it personally. For that reason, I'm looking for a few volunteers from the SW London / East Surrey / Thames Valley areas, please (I live near Sandown Park and commute to Reading). If you are interested, please get in touch.

Thanks,

Paul

PMMatthews

Original Poster:

5 posts

92 months

Monday 12th September 2016
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Thanks both of you for your replies. Perhaps, I can work out something so that one of you can try the brace (assuming the forecast for the w/e stays positive), but I'm afraid the Scottish test will have to wait for now!

PMMatthews

Original Poster:

5 posts

92 months

Monday 12th September 2016
quotequote all
Just for the avoidance of doubt, I'm not trying to 'push' anything at anybody.

There are posts on the various forums which explain how to adjust the targa roof so it is taught across the frame and so the frame fits tightly on the roof.

I asked a well-respected independent in London to adjust mine, but while this did make a difference to the speed I can reach before the roar starts, there has still been a noticeable benefit from using the brace.

Judging from other posts about solutions involving silicone sealant, draught excluder, additional rubber seals, etc I am not the only targa owner who wants a solution to this problem, though I did not want to try anything that would prove difficult to reverse at a later date. The brace is not fixed to the frame, it relies on tension alone (plus a bit of friction from the rubber / nylon caps) to hold it in place.

My experience has been that a brace is a really quite simple / cheap fix and it works with my roof. The aim in asking others if they want to try it before an explanation is posted in PP is purely so that interested readers can take comfort (hopefully) from the experience with more than just one roof (make that two, if I count the targa owner in the US who had the original idea).