my car feels floaty at 120mph
07-07-2003, 01:36 PM
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my car feels floaty at 120mph
On my commute to work today I decided to blow off some carbon and take my o3tt up to 115-120mph. There was no one else on this new, nice stretch of freeway, so this was "safe speeding". I was surprised how floaty the car felt. My E46 M3 didn't feel this floaty. Is my experience unusual or is this an expected feeling. New springs or coil overs are the best way to fix this, right? <img border="0" title="" alt="[Frown]" src="frown.gif" />
07-07-2003, 01:46 PM
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I've spoken to a few owners of C2's and they feel the car gets real floaty and begins to lift up at about 130.
Lowering the car should help dramatically
Lowering the car should help dramatically
07-07-2003, 06:19 PM
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The 'floaty feeling' is caused by increased airflow under the vehicle. The aerokit would decrease the volume of air under the vehicle while significantly increasimg the air pressure over the top of the vehicle. Your suspension suggestion does little to effectively alter the airflow. At best, a lowered suspension in and of itself, while lowering the volume of airflow, would increase its velocity. This would both increase aerodynamic noise [at approximately 3,600 Hz] as well as create some turbulence under the vehicle.
Think what your higher speed driving would have been like if there was a strong crosswind.
Think what your higher speed driving would have been like if there was a strong crosswind.
07-07-2003, 06:58 PM
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doesn't the standard tt come with an aerokit of sorts. Would exchanging the front spoiler really create that much more downforce in the front of the car?
07-07-2003, 07:23 PM
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</font><blockquote><font size="1" face="Verdana,Tahoma,Helvetica">quote:</font><hr /><font size="2" face="Verdana,Tahoma,Helvetica">Originally posted by pratt:
<strong>doesn't the standard tt come with an aerokit of sorts. Would exchanging the front spoiler really create that much more downforce in the front of the car?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">it's amazing what little change will do
<strong>doesn't the standard tt come with an aerokit of sorts. Would exchanging the front spoiler really create that much more downforce in the front of the car?</strong></font><hr /></blockquote><font size="2" face="Verdana,Tahoma,Helvetica">it's amazing what little change will do
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07-07-2003, 08:52 PM
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Porsche has both [CAD-CAM] designed and fabricated the $8,000+ Aerokit as a synergistic system which has been wind tunnel tested to 200+ miles per hour. Many of the other units sold by others have not been wind tunnel tested for best very high speed airflow and drag reduction. Drag reduction aerodynamically is a very difficult acheivement to be realized, when at the same time seeking external pressure increases. Additionally, Porsche has researched the harmonics created by the interaction of airflow to keep noise to a minimum.
One MUST use a wind tunnel , when designing such an AEROKIT system, to correctly quantify the: aerodynamics sought; drag reduction needed; and sound reduction desired. The 'poor boy' approach of other manufacturers might look good but can be counterproductive to those goals;and a purchaser would be paying not a dissimilar amount of money of the cost of Porsche's Aerokit for the privilege. I would always ask a aftermarket vendor if I could see the wind tunnel testing. If they did not have it I would get the Aerokit from Porsche.
One MUST use a wind tunnel , when designing such an AEROKIT system, to correctly quantify the: aerodynamics sought; drag reduction needed; and sound reduction desired. The 'poor boy' approach of other manufacturers might look good but can be counterproductive to those goals;and a purchaser would be paying not a dissimilar amount of money of the cost of Porsche's Aerokit for the privilege. I would always ask a aftermarket vendor if I could see the wind tunnel testing. If they did not have it I would get the Aerokit from Porsche.
07-07-2003, 09:30 PM
#10
Burning Brakes
I do not have any evidence or even a link for the following, but FWIW I recall someone on this forum saying that RUF and Gemballa have both performed wind tunnel tests of their aerodynamic add-ons.
07-07-2003, 09:54 PM
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Any legitimate manufacturer of aerokits should gladly provide copies of their wind tunnel testing and photographs taken. Mere statements that they have perfomed testing is not enough; they may be 'stroking' you. In reviewing the test reports, make sure that the velocity tested is the SAME OR GREATER than the ultimate speed you will be driving. Also, ask for 'smokers' [smoke trail] photographs showing the airflow pattern over, under, and around the vehicle. Additionally, any acoustic dynamic study performed, at stepped up air velocities, will let you ascertain if the unit will perform quietly on your vehicle.
Remember: Trust but verify.
Remember: Trust but verify.
07-08-2003, 07:17 AM
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I drove both M3 & 996tt up to 140mph couple times. M3 is definitely more floaty than 996tt, but M3 is quieter than 996tt at high speed. So you feel more comfortable to go fast. You just need to get used to the ride of 996tt.
07-08-2003, 09:08 AM
#14
Pratt
Your car should be rock-steady up to obscene speeds in bone-stock format. There is something wrong with your car (or possibly your perspective of what is happening) and you should have it tested and fixed by Porsche. Or you can follow the general advice here where you can just throw thousands of bucks at it and hope that sorts it out.
p.s. your car's older brother has seen 150+mph on several occasions, believe me you don't need an aerokit or front splitter or any of that nonsense.
Your car should be rock-steady up to obscene speeds in bone-stock format. There is something wrong with your car (or possibly your perspective of what is happening) and you should have it tested and fixed by Porsche. Or you can follow the general advice here where you can just throw thousands of bucks at it and hope that sorts it out.
p.s. your car's older brother has seen 150+mph on several occasions, believe me you don't need an aerokit or front splitter or any of that nonsense.
07-08-2003, 12:32 PM
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thanks for all the input everyone, I really appreciate it. I do agree with Christer that at 120mph my car shouldn't feel floaty. Maybe it's just my perception in comparison to my E46 M3.