Chassis Stiffening

[JimB]

Hi guys,

Does anyone know what exactly was done to stiffen the 996 chassis throughout it's life? I race my 1999 tub as a 2004 so any changes that were made during that time I could apply. Actually, I'm required to apply. I know thay made them stiffer but I don't know how they did it.

Thanks,

Jim

[Loren]

I don't have the tech books for MY99, 00, or 01 but in MY02 the front axle cross member was secured at its rear fastening to the body (arrow) with two bolts instead of one.

[JimB]

That looks pretty hard to duplicate. Got anything easier? Just kidding. Thanks for the info. I'll look it over tonight.

Jim

[viper501]

I think I've seen somewhere that there were additonal gussets welded into a couple corners of the inside of the pasenger compartment. I don't remember exactly where they were nor where I saw that information.

[umn]

Hi guys,

Does anyone know what exactly was done to stiffen the 996 chassis throughout it's life? I race my 1999 tub as a 2004 so any changes that were made during that time I could apply. Actually, I'm required to apply. I know thay made them stiffer but I don't know how they did it.

Thanks,

Jim

Hi,

Amongst other things, they changed the side members, seat moulds and roof frame from MY2001 to MY2002, which increased the stiffness of the chassis by 25% for the coupe and 10% for the cab. They also fitted an extra tube to make the chassis stiffer against side impacts. I've attached the text of the Technical Service Information. It's in German, unfortunately I haven't got a copy of the English version.

Cheers,

Uwe

Rohbau

Umfangreiche Verstärkungsmaßnahmen im Schweller-, Dachrahmen-, und Sitzmuldenbereich steigern die Biegeund

Torsionssteifigkeit nochmals um 25% bei den Coupe-Fahrzeugen und um 10 % beim Cabriolet.

Neben den Kotflügeln, die vom 911 Turbo übernommen wurden ist der Rohbau durch die Modellpflegemaßnahmen

in verschiedenen Bereichen geändert.

Die B-Säule wurde zur Aufnahme des neuen Gurtstraffers und Gurtkraftbegrenzers überarbeitet. Im Tunnel- und

Sitzmuldenbereich ist zur Querverstärkung ein zusätzliches Rohr mit Seitenabstützung verbaut. Im Tunnelbereich

wurden Änderungen zur Aufnahme des neuen (Tiptronic S) Getriebes durchgeführt. Damit entspricht die

karosserieseitige Aufnahme der Getriebelagerung der des 911 Turbo.

Im seitlichem Dachrahmen ist ebenfalls ein Verstärkungsrohr verbaut.

Edited March 20, 2006 by umn

[dphil66]

As a practicing Engineer, I can say that duplicating what the factory did on your older tub will be difficult at best. I would guess that Porsche could compile all the changes to components, assemblies, material specs, and processes from your MY to 2004, but this could be a week-long project for at least one Porsche engineer working full-time on it. I'm assuming you'd want specifics like whether they went from cold-rolled to HSLA on a particular component, what their material specs are, what their welding processes are, what adhesives at what temperatures and cure times they use...it could be done, but to truly duplicate an '04, you'd need access to all that kind of information. Knowing them, it would probably be much more than adding a couple of gussets made of hot-rolled steel here or there.

[JimB]

Thanks for the info guys. Phil I know what you are saying but it's certainly not beyond Porsche to add a brace or a weld here or there to stiffen things up. I have an 02 cab so I'll do a little hands on research one of these days and post the results.

Thanks,

Jim