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flosho · Posted: Wed Jun 22, 2005 2:41 pm Post subject: Just curious... Slalom Speed

What were the slalom speed for 924/931/924S and the skid pad numbers for these cars?
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Mike924 · Joined: 12 Aug 2004 Posts: 2601 Location: IoW UK

I don't know for sure, but I read somewhere that a motoring press test on the 924 gave the result of 0.85 g on a cornering force test.

If you remember your school days physics, you ought to be able to work out a cornering speed for any given bend radius!

I'll have a go myself when I get my brain in gear!
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1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd

'There is no substitute for a little grease under your fingernails.' - Chrenan, 924board.org

flosho · Posted: Fri Jun 24, 2005 3:33 am Post subject:

Well I was thinking about doing the skid pad test myself with my G-Tech meter. IT seems to be pretty accurate.
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-nick · Joined: 16 Nov 2002 Posts: 2699 Location: Cambridge, MA

Calculating skid pad numbers is going to be an impressive trick! Weight transfer, suspension geometry changes, slip angles, etc. make it just about impossible to calculate with any accuracy.

Anyway, the g-tech's seem to get somewhat reasonable numbers. Let us know what you get (and what tires you're running on!).

nick

CBass · Joined: 03 Nov 2002 Posts: 2807 Location: Vancouver, Canada

Keep in mind, any performance tests published for the 924 are on 25 year old tires. Rubber has come a long way since then.

Excerpt from Jim Pasha's suspension tuning guide
http://dspace.dial.pipex.com/town/pipexdsl/s/asco96/944t/SuspensionPreparation.htm

These improvements should, with quality tires, give you cornering in the low .9g range (The Porsche factory says that they achieved .872 on their skidpad on Pirelli CN36 tires with the same equipment and the standard alignment settings on the original 924).

"These improvements" being the factory 924 swaybars, a set of Koni or Bilstein adjustables, and lowering the rear ride height so that it's even with the front(US/Canada spec).

Now the question that comes to my mind, is what size tire were they using? Original size is a 185/XX/14, IIRC. A 225/45/16 would probably make for even higher skidpad numbers.
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'81 931 in various states of assembly

Mike924 · Joined: 12 Aug 2004 Posts: 2601 Location: IoW UK

Talking of G-Tech meters, this is what I use...

http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&category=30922&item=7979128278

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1985 Porsche 924 'Lux', Kalahari Beige (my ex)
1993 Porsche 968 Coupe, Midnight Blue, 6 spd

'There is no substitute for a little grease under your fingernails.' - Chrenan, 924board.org