Aluminum rear diffuser install
Registered User
Joined: Sep 2008
Posts: 2,419
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From: Canoga Park/ Northridge CA
Confirmed fits with dual HKS hi-power exhaust, was concerned that the extra chamber/canister would be too low but it fits perfectly, great piece. I do plan on redrilling holes where it attaches to the tie bar 'cause I want it to stick out like 4-5 inches from the bumper.
Very happy, looks awesome.
Very happy, looks awesome.
Registered User
Joined: Apr 2009
Posts: 529
Likes: 6
From: Little Rock, AR
My S is going on the boat to be shipped to Germany in a week. Once I get it there I plan to do an autobahn run with the diffuser on and off and see if the top speed changes at all since we are drag limited. This should give us a definitive indication of whether the diffuser helps aerodynamically, hard to do a definitive test on whether it adds downforce or not tho. I will be hitting the Ring fairly often as well tho so maybe I can do a run on there with and without as well.
anyone work for NASA?
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Joined: Apr 2011
Posts: 335
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Its going to be exactly the same as the AP1 installation.
I'm still trying to figure out a way to test the downforce on a moving car... I think if you size up the right belville washers and put them above the strut tower caps, you could use a dial indicator to measure deflection. All you would have to do is add weight to the front or rear of the vehicle to establish a gauge for compression vs weight then log the measurements at certain speeds and determine average deflections. You should be able to calculate a pretty accurate downforce from this number.
The ideal situation would include a laptop that could log speed vs this deflection value at a local 1/4 mile track, the 1/4 mile track is the flattest piece of concrete around that I know of and should give a good range of speeds and downforce measurements.
Sounds like a good test. Too bad no one has a wind tunnel. anyone work for NASA?
The ideal situation would include a laptop that could log speed vs this deflection value at a local 1/4 mile track, the 1/4 mile track is the flattest piece of concrete around that I know of and should give a good range of speeds and downforce measurements.
Joined: Jan 2010
Posts: 213
Likes: 14
just a suggestion but it would probably be more practical if you used a tension type force gauge, ideally youd have sensors on all the mounting locations to measure total down force. if you wanna be creative you can probably jerry rig a digital scale into a tension type force gauge.
Joined: May 2005
Posts: 1,881
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From: Pacifica/Elk Grove, CA
