Aerodynamic effects of different spoilers
07-28-2009, 12:03 AM
#16
Rennlist Member
I have a factory aero kit on the TT....came originally with the rather wide front spoiler that lasted all of about three weeks before the speed bumps ate it.
I switched over to the FVD type of front lip sold by Sunset Porsche for around $270 rather than try to stay with the $800 OEM one.
Recently, I found that the C4S lip, which is raised in the center to give more ground clearance....will also fit the 996TT...all the slots line up perfectly and it pops right into place and requires only two phillips screws at the ends to hold it into place.
My question revolves around what the consensus of opinion would be regarding the aerodynamics of using a C4S design in lieu of the FVD design which has the same width and down pitch all the way across. The factory aero lip is a good 3/4 inch wider than the FVD type....and the C4S design eliminates the down pitch in the middle for better clearance I guess. You can't run a rear spoiler without the front due to the front going light on you at high speeds, but what's the consensus about a modified front lip like the C4S....with top speeds around 150.??
I'm not looking to break any speed records, just wondering about aerodynamics of investing in the less expensive lip since I seem to go thru about one or two a year. The C4S lip is only arout $140...
I switched over to the FVD type of front lip sold by Sunset Porsche for around $270 rather than try to stay with the $800 OEM one.
Recently, I found that the C4S lip, which is raised in the center to give more ground clearance....will also fit the 996TT...all the slots line up perfectly and it pops right into place and requires only two phillips screws at the ends to hold it into place.
My question revolves around what the consensus of opinion would be regarding the aerodynamics of using a C4S design in lieu of the FVD design which has the same width and down pitch all the way across. The factory aero lip is a good 3/4 inch wider than the FVD type....and the C4S design eliminates the down pitch in the middle for better clearance I guess. You can't run a rear spoiler without the front due to the front going light on you at high speeds, but what's the consensus about a modified front lip like the C4S....with top speeds around 150.??
I'm not looking to break any speed records, just wondering about aerodynamics of investing in the less expensive lip since I seem to go thru about one or two a year. The C4S lip is only arout $140...
08-01-2009, 07:56 PM
#17
Instructor
Join Date: Jan 2005
Location: Reno, NV
Posts: 117
Likes: 0
Received 0 Likes
on
0 Posts
Car has stock front and rear spoilers and I had it up to 199 indicated. It's definitely aero neutral, or very little down force. Light feeling but not unstable or dangerous. Would feel a little more secure with more front aero for sure. Had a modified Mitsubishi Evo VIII MR and that car made lots of downforce and felt completely planted at 175mph. Aero makes a huge difference but only north of 100mph can you tell.
08-01-2009, 08:07 PM
#18
Drifting
Thread Starter
Join Date: Feb 2006
Location: Elk Grove, California
Posts: 2,647
Likes: 0
Received 2 Likes
on
2 Posts
I just went and measured the difference between the factory front lip that came with the rear aero kit and the aftermarket lip....the factory lip measures a full 3 inches at its wides point, the aftermarket lip measures 2 1/4 inches.
It's going to take the engineers on this forum to tell me what that might equate to in terms of downforce lost, and even then, it's probably subjective without actual wind tunnel or field testing....the designs are pretty much identical with the exception of the wider lip on the factory one.
I have only had it up to around 140 with the narrower lip, and couldn't tell much, I didnt sense any lightness to the front, but I was doing a straight run. I imagine the real test comes in the turns and changes in attitude, acceleration etc....
Guess I'll just keep it "south" of the century mark.
It's going to take the engineers on this forum to tell me what that might equate to in terms of downforce lost, and even then, it's probably subjective without actual wind tunnel or field testing....the designs are pretty much identical with the exception of the wider lip on the factory one.
I have only had it up to around 140 with the narrower lip, and couldn't tell much, I didnt sense any lightness to the front, but I was doing a straight run. I imagine the real test comes in the turns and changes in attitude, acceleration etc....
Guess I'll just keep it "south" of the century mark.
