Rennlist - Porsche Discussion Forums

Notices
Racing & Drivers Education Forum
Sponsored by:
Sponsored by:

PCA Club Racing adds Spec Boxster Class

Thread Tools
 
Search this Thread
 
Old 05-09-2008, 08:45 PM
  #31  
jrgordonsenior
Nordschleife Master
 
jrgordonsenior's Avatar
 
Join Date: Oct 2004
Location: Vacuuming Cal Speedway
Posts: 7,306
Likes: 0
Received 7 Likes on 5 Posts
Default
Originally Posted by Gary R.
Why safer? I can't imagine the fiberglass lid being anything but destroyed in a rollover but would like to hear your take on it.
That's my conclusion too. I'm installing a roof net and window net before my next race to eliminate the arm restraints and for general safety. I want to run without the roof so the roof net would be mandatory...
jrgordonsenior is offline  
Reply Like
Old 05-10-2008, 02:05 AM
  #32  
JW in Texas
Three Wheelin'
 
JW in Texas's Avatar
 
Join Date: Jun 2001
Location: Just North of "Big D"
Posts: 1,639
Received 2 Likes on 2 Posts
Default
Structurally, probably no difference but from a debris stand point, I think we are better off with the roof on.

Originally Posted by Gary R.
Why safer? I can't imagine the fiberglass lid being anything but destroyed in a rollover but would like to hear your take on it.
JW in Texas is offline  
Reply Like
Old 05-10-2008, 05:11 AM
  #33  
seege
Addict
Rennlist Member
 
seege's Avatar
 
Join Date: Oct 2003
Location: Rancho Mirage, California
Posts: 630
Likes: 0
Received 0 Likes on 0 Posts
Default
I'd bet the aero is much worse with no top, anyone got a wind tunnel?
seege is offline  
Reply Like
Old 05-10-2008, 09:41 AM
  #34  
Gary R.
Rennlist Member
 
Gary R.'s Avatar
 
Join Date: Dec 2004
Location: Valencia, Spain
Posts: 15,583
Received 271 Likes on 165 Posts
Default
Originally Posted by JW in Texas
Structurally, probably no difference but from a debris stand point, I think we are better off with the roof on.
I actually like the way they look with the top on but would imagine vision is much impaired as opposed to topless.
Gary R. is offline  
Reply Like
Old 05-10-2008, 12:54 PM
  #35  
Ray S
Ironman 140.6
Rennlist Member
 
Ray S's Avatar
 
Join Date: Apr 2002
Location: North Carolina
Posts: 13,794
Received 10 Likes on 9 Posts
Default
Originally Posted by seege
I'd bet the aero is much worse with no top, anyone got a wind tunnel?
From personal driving experience (in my 986), I would bet you are correct.
Ray S is offline  
Reply Like
Old 05-10-2008, 05:05 PM
  #36  
jrgordonsenior
Nordschleife Master
 
jrgordonsenior's Avatar
 
Join Date: Oct 2004
Location: Vacuuming Cal Speedway
Posts: 7,306
Likes: 0
Received 7 Likes on 5 Posts
Default
Originally Posted by seege
I'd bet the aero is much worse with no top, anyone got a wind tunnel?

Yea about a mile from you house in the middle of the desert....
jrgordonsenior is offline  
Reply Like
Old 05-10-2008, 07:00 PM
  #37  
JW in Texas
Three Wheelin'
 
JW in Texas's Avatar
 
Join Date: Jun 2001
Location: Just North of "Big D"
Posts: 1,639
Received 2 Likes on 2 Posts
Default
That & it's much cooler. First thing I noticed in the Boxster is how damn hot it gets inside compared to the Cup. The curve @ the back of the window & the smaller opening must really impede airflow into the cockpit. Plus you have a hot box sitting right behind you

Originally Posted by Gary R.
I actually like the way they look with the top on but would imagine vision is much impaired as opposed to topless.
JW in Texas is offline  
Reply Like
Old 05-10-2008, 09:25 PM
  #38  
jrgordonsenior
Nordschleife Master
 
jrgordonsenior's Avatar
 
Join Date: Oct 2004
Location: Vacuuming Cal Speedway
Posts: 7,306
Likes: 0
Received 7 Likes on 5 Posts
Default
Originally Posted by JW in Texas
That & it's much cooler. First thing I noticed in the Boxster is how damn hot it gets inside compared to the Cup. The curve @ the back of the window & the smaller opening must really impede airflow into the cockpit. Plus you have a hot box sitting right behind you
Jay I haven't noticed that, well yet anyway.... Did you have sealed windows in your cup?
jrgordonsenior is offline  
Reply Like
Old 05-10-2008, 10:52 PM
  #39  
sbelles
I'm in....
Rennlist Member
 
sbelles's Avatar
 
Join Date: Mar 2004
Location: Here some and there some
Posts: 12,104
Received 257 Likes on 172 Posts
Default
Originally Posted by seege
I'd bet the aero is much worse with no top, anyone got a wind tunnel?
I'm betting drag is higher with the top on. There is also a good chance there is less lift without the curved top on. I't could just be me but I've run faster lap times with the top down.
sbelles is offline  
Reply Like
Old 05-10-2008, 11:19 PM
  #40  
Brinkley
Pro
 
Brinkley's Avatar
 
Join Date: Feb 2007
Posts: 734
Likes: 0
Received 0 Likes on 0 Posts
Default
No wind tunnel, but I have noticed that high speed stability in fast corners (say Bishops Bend - Sebring) feel better with the top on. I have a fiberglass top with lexan rear window. I believe this helps airflow over the top and down over the rear deck and wing.
Brinkley is offline  
Reply Like
Old 05-11-2008, 12:21 PM
  #41  
JW in Texas
Three Wheelin'
 
JW in Texas's Avatar
 
Join Date: Jun 2001
Location: Just North of "Big D"
Posts: 1,639
Received 2 Likes on 2 Posts
Default
No. Open with non-vented quarter windows.

Originally Posted by jrgordonsenior
Did you have sealed windows in your cup?
JW in Texas is offline  
Reply Like
Old 05-11-2008, 12:52 PM
  #42  
insite
Three Wheelin'
 
insite's Avatar
 
Join Date: Oct 2004
Location: Lesa, Italy & Atlanta, GA
Posts: 1,517
Likes: 0
Received 4 Likes on 4 Posts
Default
Originally Posted by sbelles
I'm betting drag is higher with the top on. There is also a good chance there is less lift without the curved top on. I't could just be me but I've run faster lap times with the top down.
drag is lower with a closed top. the turbulence caused by the air flowing over the top of the windscreen and into the cabin is significant. anyone who's taken a boxster on a long trip knows that the gas mileage improves about 15% with the top up.

there MAY be less lift, but there is certainly much more drag.
insite is offline  
Reply Like
Old 05-11-2008, 01:52 PM
  #43  
sbelles
I'm in....
Rennlist Member
 
sbelles's Avatar
 
Join Date: Mar 2004
Location: Here some and there some
Posts: 12,104
Received 257 Likes on 172 Posts
Default
Originally Posted by insite
drag is lower with a closed top. the turbulence caused by the air flowing over the top of the windscreen and into the cabin is significant. anyone who's taken a boxster on a long trip knows that the gas mileage improves about 15% with the top up.

there MAY be less lift, but there is certainly much more drag.
If the windows are up there's no question. Not as clear with the windows down.
sbelles is offline  
Reply Like
Old 05-12-2008, 09:58 AM
  #44  
Ray S
Ironman 140.6
Rennlist Member
 
Ray S's Avatar
 
Join Date: Apr 2002
Location: North Carolina
Posts: 13,794
Received 10 Likes on 9 Posts
Default
Originally Posted by sbelles
If the windows are up there's no question. Not as clear with the windows down.
I'd disagree. In my experience fuel mileage and acceleration suffers (both indications of higher drag) when the top is down (with or without the side windows up).
Ray S is offline  
Reply Like
Tags
Back to Subforum
Racing & Drivers Education Forum
View Next Unread
Dyno numbers on my track car, finally...




Advanced Search
Quick Reply: PCA Club Racing adds Spec Boxster Class


Reply Closed Thread Share
Forum Jump

All times are GMT -3. The time now is 06:19 PM.