Practical ways to measure lift, downforce and drag on a 991 GT3 (?)
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Burning Brakes
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Practical ways to measure lift, downforce and drag on a 991 GT3 (?)
I've just posted a thread with a very similar title in the performance modifications forum, here:
https://rennlist.com/forums/performan...l#post13898932
(I wasn't sure where to post this, but then I realized that this will equally interest/disinterest owners of virtually any other 2 door Porsche, and maybe even some 4 door Porsche owners as well. And it seemed silly to have one discussion in the 991 forum, another in the 991 GT2/3 forum, etc.
On the other hand, the performance mod forum doesn't get a lot of traffic. Solution? Threads like this in a few forums to let anyone interested know to go to the performance mod forum.
Hope this is helpful!)
https://rennlist.com/forums/performan...l#post13898932
(I wasn't sure where to post this, but then I realized that this will equally interest/disinterest owners of virtually any other 2 door Porsche, and maybe even some 4 door Porsche owners as well. And it seemed silly to have one discussion in the 991 forum, another in the 991 GT2/3 forum, etc.
On the other hand, the performance mod forum doesn't get a lot of traffic. Solution? Threads like this in a few forums to let anyone interested know to go to the performance mod forum.
Hope this is helpful!)
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We're developing a data logger that when finished would allow you to measure the ride height sensors (shock potentiometers) to get a way to quantify aero changes on the car (lift and downforce). Drag is a little harder to quantify out in the wild. You need pitot tubes or other pressure sensors on the car ideally in a controlled environment like a wind tunnel... Or you need a precise method of measuring top speed at WOT over a fixed distance to back out drag...
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To measure drag its rather simple to do using a GPS datalogger.. Speed up to 200+ kph (the highest the speed the better) put the car in neutral and let it coast down to about 100kph. With a formula you can then calculate drag. The datalogger will measure slope of the road as well, important because you need to eliminate the road slope impact.
You also need to do a low speed rolling resistance test on the same road.. Same as above but low speed preferably 60kph to 30kph or so.
I did this recently with the 991Turbo and drag results were almost exactly the same as factory CDxA numbers in both normal and sport+ mode. If you search the 993TT forum we did these tests several years back also measuring the impact of the 993GT2 wing. Here is one but there is others..
https://rennlist.com/forums/993-turb...c-musings.html
For downforce and lift, you will need the help of sensors as Jamie above said. Downforce and lift data is however available for most cars from German Autobild/Sport Auto tests and others good publications.
You also need to do a low speed rolling resistance test on the same road.. Same as above but low speed preferably 60kph to 30kph or so.
I did this recently with the 991Turbo and drag results were almost exactly the same as factory CDxA numbers in both normal and sport+ mode. If you search the 993TT forum we did these tests several years back also measuring the impact of the 993GT2 wing. Here is one but there is others..
https://rennlist.com/forums/993-turb...c-musings.html
For downforce and lift, you will need the help of sensors as Jamie above said. Downforce and lift data is however available for most cars from German Autobild/Sport Auto tests and others good publications.
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Burning Brakes
Joined: Jul 2012
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Thread Starter
Burning Brakes
Joined: Jul 2012
Posts: 840
Likes: 16
Indeed, it's available for cars. But not for modifications. Even OEM mod's. Good luck, for instance, finding the drag and lift impact of the 991 aero kit with the duck tail. And there are gaps. One that annoys me is the original GT3.
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Burning Brakes
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@Jamie@dundonmotorsports welp, I'm doing this same work right now trying to figure out how to measure the ride height sensors. Did your research turn into something?