Drag Coefficient
03-25-2004, 07:28 PM
#1
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Drag Coefficient
Does anyone know the drag coefficient of a stock 993TT or a Nissan 350Z? The reason I am asking is a few days ago I parked next to a 350Z and my passenger commented that the Z had less drag coefficient than my 993TT but could not show me any numbers. Any help would be appreciated. Thanks Jim
03-28-2004, 05:20 PM
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993tt cd = .34
That number may be radically improved if you wish! mirrors are easily removed/replaced. dump the wipers front and rear.I also have A pillar fairings from Ruf and my Cd is closer to .29,albeit with the benefit of Ruf CTR front and rear spoilers. The a pillar fairings were good for several mph increase on the top end. Thanks to Steve Weiner for that tip!
R
R
03-28-2004, 05:44 PM
#5
Race Director
Rolans is right, as always.
My RUF BTR has the A-piller fairing (aero insert) and the tear-drop shaped carbon fibre side mirrors. The PO reported moving the top speed from 192 mph to 196 mph.
Here's a pic of the set-up.
CP
My RUF BTR has the A-piller fairing (aero insert) and the tear-drop shaped carbon fibre side mirrors. The PO reported moving the top speed from 192 mph to 196 mph.
Here's a pic of the set-up.
CP
03-28-2004, 07:13 PM
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Thanks Ruf-Racer and CP, those mods make a big difference. I just read that the 350Z drag coefficient is .30 which is real close, .29 is much better than .34 
Thanks again!!! Jim
Thanks again!!! Jim
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03-28-2004, 11:51 PM
#8
Nordschleife Master
I forgotten how to pull off those front wiper arms. I flipped the end cap up, removed the 13mm nut and washer, and expect that the arm will just pop off. Being the doofus that I'm becoming famous for, I'm afraid to pry anything too hard. Is there a trick to this?
03-29-2004, 12:31 AM
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OK Old Man
Steve,
My rear wiper assembly has been off for a long time. The front does have a hardware stackup but easily slips on & off. A small shot of WD40 won't hurt. how are ya?
R
My rear wiper assembly has been off for a long time. The front does have a hardware stackup but easily slips on & off. A small shot of WD40 won't hurt. how are ya?
R
03-29-2004, 12:37 AM
#10
Nordschleife Master
Roland,
Thanks... I'll give a little wd40 a try. I'm fine. Seriously thinking about running the TT at Willow with Tracquest on May 22. Have you been spending any time above 200 mph lately?
Thanks... I'll give a little wd40 a try. I'm fine. Seriously thinking about running the TT at Willow with Tracquest on May 22. Have you been spending any time above 200 mph lately?
03-29-2004, 08:20 AM
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From Paul Frere's book:
993 turbo
Cd 0.34
Frontal area 1.93 sqm
CdXS 0.656
CLf 0.01
CLr 0.03
CLf and CLr being the front and rear lift coefficients.
Sport Auto put a Lotec 993tt through the wind tunnel at 200kph and recorded 17kg of rear axle lift and a Cd of 0.339 (The Lotec car was stock bodywork but had 9X18 fronts and 11X18 rear wheels)
Ruf Racer,
Is that 0.29 figure a guesstimate or has a similar set up been tested ? 0.29 represents a massive improvement on stock for seemilngly minor mods ?
993 turbo
Cd 0.34
Frontal area 1.93 sqm
CdXS 0.656
CLf 0.01
CLr 0.03
CLf and CLr being the front and rear lift coefficients.
Sport Auto put a Lotec 993tt through the wind tunnel at 200kph and recorded 17kg of rear axle lift and a Cd of 0.339 (The Lotec car was stock bodywork but had 9X18 fronts and 11X18 rear wheels)
Ruf Racer,
Is that 0.29 figure a guesstimate or has a similar set up been tested ? 0.29 represents a massive improvement on stock for seemilngly minor mods ?
03-29-2004, 09:39 AM
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CP,
Does the fairing run the entire length of the rain gutter? Any idea how it is attached? Is it a Ruf part #? Sorry for all the questions. It's a great look and mph increase to back it up, very nice.
Thanks
Does the fairing run the entire length of the rain gutter? Any idea how it is attached? Is it a Ruf part #? Sorry for all the questions. It's a great look and mph increase to back it up, very nice.
Thanks
03-29-2004, 10:27 AM
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TB,
Cd @ .29 was a "calculation" done by rocket scientist type friend. Ruf seems to agree that number is close based on what he knows about similiar cars that have been tested. The faring extends to the roof line from the base of the A pillar. Moving from 205 to 211 either takes a bunch of power or smaller frontal area & lower Cd. We also tape the entire front end. The car is rock stable at the top end. It would go faster with a longer road but as you know we are power limited so getting past 211 takes a long time. the car just keep creeping. BTW,calculations done assuming 4500' ASl which is where we run most of the time.
R
PS
I have my notes archived somewhere,maybe I can dig them out if you are interested.
R
Cd @ .29 was a "calculation" done by rocket scientist type friend. Ruf seems to agree that number is close based on what he knows about similiar cars that have been tested. The faring extends to the roof line from the base of the A pillar. Moving from 205 to 211 either takes a bunch of power or smaller frontal area & lower Cd. We also tape the entire front end. The car is rock stable at the top end. It would go faster with a longer road but as you know we are power limited so getting past 211 takes a long time. the car just keep creeping. BTW,calculations done assuming 4500' ASl which is where we run most of the time.
R
PS
I have my notes archived somewhere,maybe I can dig them out if you are interested.
R
03-29-2004, 10:30 AM
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Originally posted by TB993tt
Sport Auto put a Lotec 993tt through the wind tunnel at 200kph and recorded 17kg of rear axle lift and a Cd of 0.339 (The Lotec car was stock bodywork but had 9X18 fronts and 11X18 rear wheels)
Sport Auto put a Lotec 993tt through the wind tunnel at 200kph and recorded 17kg of rear axle lift and a Cd of 0.339 (The Lotec car was stock bodywork but had 9X18 fronts and 11X18 rear wheels)
03-29-2004, 12:11 PM
#15
Race Director
Originally posted by KRA993tt
CP,
Does the fairing run the entire length of the rain gutter? Any idea how it is attached? Is it a Ruf part #? Sorry for all the questions. It's a great look and mph increase to back it up, very nice.
Thanks
CP,
Does the fairing run the entire length of the rain gutter? Any idea how it is attached? Is it a Ruf part #? Sorry for all the questions. It's a great look and mph increase to back it up, very nice.
Thanks
Roland's answer here is correct.
"The faring extends to the roof line from the base of the A pillar." Once at the roof level, it feathers out again and the rain gutter 'reappears'.
I believe it is glued in place, as I see no other visible means of attachment.
I do not have a RUF part number with me a this moment. I do have a RUF catalog at home some where, so I'll hunt for it. You may also search Weissach's site and see if it's there. I don't even know if that's a proprietary RUF part.
Since my car came with that in place, I don't have the details on it as I should. I know Viperbob installed them in his 993tt as well. May be he can also help out on this one.
CP