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Me like track days
Join Date: Sep 2003
Location: Kirkland, WA
Posts: 10,209
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VALVE caps - yes valve stem caps - some observations
Wheels are typically balanced with the valve stem caps OFF.
One could insist they be balanced with them on. The metal caps weigh a fair amount - as much as a wheel weight added to my wheels. Balance? Some stress on the valve stem? The Carrera GT has silver plastic valve stem caps. Use plastic?
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- Craig 3.4L, SC heads, 964 cams, B&B headers, K27 HF ZC turbo, Ruf IC. WUR & RPM switch, IA fuel head, Zork, G50/50 5 speed. 438 RWHP / 413 RWTQ - "930 is the wild slut you sleep with who tries to kill you every time you "get it on" - Quote by Gabe Movie: 930 on the dyno |
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07-16-2005, 12:50 PM
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Registered
Join Date: Mar 2004
Location: US
Posts: 1,621
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Plastic is lighter. From a performance standpoint, it will, in theory, allow the wheel to accelerate quicker (a very minute amount, for a wheel/tire weighing 25 kilos, and the cap a couple grams). And, it will help keep the wheel in balance. I say go plastic. Its not a hard swap back anyways.
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07-16-2005, 01:05 PM
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I've heard that some pelican member is working on carbon fiber versions that will withstand the rigours of track use, yet save precious weight where it matters most.....
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1970 914-6 street"evil cockaroach" 1970 911 Targa "ST" Jade Green IROC Tribute (ready to race) |
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07-16-2005, 01:26 PM
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Crusty Conservative
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You have to compare the weight of the stem/valve/cap assy to the material removed from the wheel to insert the stem.
And allow, of course, for the decreasing radial location of the stem, valve and cap in some way. probably an integral in there somewhere... 
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Bill 69 911 T Targa, 2.4E w/carbs (1985-2001) 70 911 S Coupe, 2nd owner (1989- 2015) 73 911 T Targa, 3.2 Motronic (2001- ) |
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07-16-2005, 01:34 PM
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Registered
Join Date: Mar 2001
Location: Marysville Wa.
Posts: 22,431
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you often see marks on the rim made by the heavy metal cap being slung out centrifugally (sp?). better have stem supports if you use them.
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https://www.instagram.com/johnwalker8704 8009 103rd pl ne Marysville Wa 98270 206 637 4071 |
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07-16-2005, 02:00 PM
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Registered
Join Date: Nov 2004
Location: Greater Metropolitan Nimrod, Oregun
Posts: 10,040
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Naturally the weight of the valve caps is already posted on this board in an old thread - search it up if you want.
I wold not run high speeds with a metal cap unless I had a metal stem, or used the supports for the rubber stems. Metal stems are all over the place now - seems every tire shop has them.
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"A man with his priorities so far out of whack doesn't deserve such a fine automobile." - Ferris Bueller's Day Off |
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07-16-2005, 02:28 PM
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Slackerous Maximus
Join Date: Apr 2005
Location: Columbus, OH
Posts: 18,165
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I have come to the conclusion that 911 ownership is no longer a hobby, but rather a dangerous cult, turning seemingly normal people into performance crazed lunatics.
Whats next? Not eating for 24 hours before driving to cut down on weight? No wearing shoes? Better not wear those contacts....extra .0023 grams.
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2022 Royal Enfield Interceptor. 2012 Harley Davidson Road King 2014 Triumph Bonneville T100. 2014 Cayman S, PDK. Mercedes E350 family truckster. Last edited by HardDrive; 07-16-2005 at 08:29 PM.. |
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07-16-2005, 02:29 PM
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Crusty Conservative
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JP Montoya removes his watch and has his lead mechanic hold it for him while he is on the track. when asked, his reply was; excess weight.
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Bill 69 911 T Targa, 2.4E w/carbs (1985-2001) 70 911 S Coupe, 2nd owner (1989- 2015) 73 911 T Targa, 3.2 Motronic (2001- ) |
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07-16-2005, 02:54 PM
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Diss Member
Join Date: Jul 2002
Location: SC - (Aiken in the 'other' SC)
Posts: 5,020
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Quote:
Take an enema 1 hour before grid!  It beats drilling lightening holes in the ignition key. --- Hey Craig, I make sure they balance the wheels with the valve caps on. (I use the cheap Dorman metal caps because they are thin.) BTW - Thanks for the video. --- Oh, and if I need that last thousandth of a second... ...don't wear underwear!  (and make sure you don't have an 'accident'.)
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- "Speed kills! How fast do you want to go?" - anon. - "If More is better then Too Much is just right!!!" - Mad Mac Durgeloh -- Wayne - 87 Carrera coupe -> The pooch. |
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07-16-2005, 03:52 PM
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Registered
Join Date: Nov 2004
Location: Greater Metropolitan Nimrod, Oregun
Posts: 10,040
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I'd rather drill holes in the key...
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"A man with his priorities so far out of whack doesn't deserve such a fine automobile." - Ferris Bueller's Day Off |
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07-16-2005, 05:48 PM
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Information Junky
Join Date: Mar 2001
Location: an island, upper left coast, USA
Posts: 73,189
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Quote:
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Everyone you meet knows something you don't. - - - and a whole bunch of crap that is wrong. Disclaimer: the above was 2¢ worth. More information is available as my professional opinion, which is provided for an exorbitant fee. 
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07-16-2005, 06:02 PM
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Back in the saddle again
Join Date: Oct 2001
Location: Central TX west of Houston
Posts: 55,985
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Quote:
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Steve '08 Boxster RS60 Spyder #0099/1960 - never named a car before, but this is Charlotte. '88 targa  SOLD 2004 - gone but not forgotten
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07-16-2005, 07:44 PM
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1970 Porsche 911S 2.2l MFI
