Increasing Body Rigidity

[Shuie]

Does anyone make a sheet metal stiffening kit for the rear shock tower area? I know there are 911 rocker stiffening panels and a number of 914 chassis kits out there. Are the rocker stiffening panels any benefit to a coupe or are they only helpful for cabs & targas? I guess none of this stuff would be too difficult to fab if you have access to a sheet metal brake. Is 20gauge sheet stock big enough for the shock tower reinforcements?

[Bill Verburg]

Local fella by the name of Geoffrey is prepeping a race 964, he has posted some nice pics here well worth looking at.

[Shuie]

The seam stitch welds make a lot of sense. Where are the chassis stiffenning panels a good idea? the rockers, floor to rocker joint, and the boxed sections seem logical to me. Where are the main areas that can be improved on without going to a full cage tied to the suspension points?

[911SCfanatic]

Excellent thread! To echo others, I would like to see pics of the reinforced areas. I'm particularly interested in all the mods/reinforcements that can be done just short of a full blown cage.

[Jeff Alton]

Doc, your cars suck!! just kidding, nice pics. A little more than I had in mind for my barely streetable street car! But now I am thinking full cage......

Jeff

[john_colasante]

Factory Cup cars are seam welded in the "weak spots" and the cages are welded to the A/B pillars.

[widebody911]

Aftermarket cab sill plates:

[RideShoot&Drink]

Originally posted by 911SCfanatic
Excellent thread! To echo others, I would like to see pics of the reinforced areas. I'm particularly interested in all the mods/reinforcements that can be done just short of a full blown cage.

ditto...

[RideShoot&Drink]

Maybe sligtly off topic, but does somebody know who makes that type of roll bar for cabs?

[randywebb]

Thom - I can see how the sill plates would help a cab or targa resist buckling (like that pic someone posted of a trage bent into a Z in a crash). But do you think it will help a coupe any? Doesn't seem like it... and doesn't seem that it would help with torsional twist either - only when the front & rear are pushed up and towards each other, bending horizontally at the car's center.

[widebody911]

Originally posted by randywebb
Thom - I can see how the sill plates would help a cab or targa resist buckling (like that pic someone posted of a trage bent into a Z in a crash). But do you think it will help a coupe any?

I doubt it.

[rdane]

Had an interesting discussion on this subject today with a guy capable of doing it "all".

His comment was , "if I wanted to stiffen the body, first thing I'd do is remove the gutters and weld the 3 biggest sheet metal panels on the car together. The rest of the small stuff just makes specific parts of the uni body stiffer. Full cage being one of the few exceptions. Only reason Porsche didn't always do it (chop & weld the gutter) on the earlier cars was the racing rules (then) wouldn't allow it."

He went on to speculate that removing the rain gutter now isn't that common because the majority of "tuners" (guys capable of doing frame reinforcements and full cages) rarely get into doing body work, fiberglass body parts being added as the norm after a full cage.

"The cage is needed any way so most stop there...2/3s of the way to being finished."

Any of the professionals care to comment on that thought process?

[patkeefe]

Are you speaking of the rain gutters on the roof above the doors?

[Shaun @ Tru6]

subscribe to see the pics. I'll be doing the sill plates that Thom posted later this summer, also seam welding the the A-pillar base, and anywhere else I can. The plates are tacked together every inch or so by the factory, on some of the spaces in between the plates are separated by a full 1/8 inch.

[patkeefe]

Shaving rain gutters

OK, after looking at this, I understand the rigidity issue with the gutters. Rdane's car looks pretty good there.

[RoninLB]

Originally posted by Tyson Schmidt

I'll take some pics of my car on Monday that'll show you the weakest point on the 911 chassis, and how to strengthen it.

if you took the pics already ok, if not that's ok also.

I only want to rear coil-overs and I'm looking for a nice mod +, just in case my street coupe has a more exciting future.

it's one of those "while you're in there" things.

thx

[RWebb]

Originally Posted by jluetjen

PatKeefe;
We'll let you off on this one. It's come up a number times, often regarding Targas and Cabs. Mark Donohue's book -- The Unfair Advantage says that the coupes have a torsional stiffness of about 2000 lb-ft per degree. Given the race tires of the time, he thought that that value was more then adequate.

Jon - your embedded links are no longer working.... wonder if it is due to the new server Wayne just installed....

[Walko]

Tyson
Did you end up taking those pics.
I know this thread is quite old but I am researching the best way to strengthen my body whilst keeping it looking stock for the racing class I will be competing in.

Michael

[sc_rufctr]

This thread should be a sticky...

[911pcars]

A lot of discussion on the subject, with photos:

Structural Reinforcement

Sherwood