I've been considering various means of stiffening the chassis of the 914 from the firewall area forward. It seems most people prefer the clamshell method on the outer longs, some prefer the inner long/firewall bracing of our very own engman, or some of course prefer the ever-true rollbar.

What about welding in cross bracing right beneath the targa top from one corner of the windshield frame diagonally across to the other side on the targa rollbar, creating an X? I know a very few, very rare 914's had a solid, welded in top with no targa. Wouldn't welding in bracing be similar? I know it wouldn't look as pretty with the targa top off, but I am just curious if anyone has done it.

Besides, I am honestly not a huge fan of the targa anyway and I seldom take mine off. Actually, in 7 months of owning my car as a daily driver I have never driven with it off and I live in So Cal. (I know, why even own the car, right? (':D', 'smid_4')
)

However, this is not a question about my strange anti-targa neurosis, whatever the nature of it might be (agoraphobia, perhaps?). Rather, it is a technical question about bracing, so...anyone have any ideas?

Last thought... The only reason I can imagine that this would not serve to profoundly improve body flex is that the windshield frame is not robust enough to provide support like this and would potentially start flexing itself. But then, why would Porsche install a few solid metal, immovable targa's on a few of their really high performance cars?

Thanks for your wisdom!

James

Will welding something/anything in help? Yes it will. BUT, the w/s is really not too strong and won't give you too much stiffness.

I think the 916 top was done to add some stiffening and to be a little different than a stock 914.

On your last question I believe that they put the solid tops on those cars because

of racing regulations.

Factory did it
heres some pics,
http://www.pbase.com/9146gt/image/28506758

You guys are always fabulous for info. Thanks much. I have this goal to be ready for a track event in December and I'm thinking that more rigidity is going to be a really good thing, since my car flexes like crazy when I take hard corners while driving "normally". I can't imagine how bad it would be on a race track.

So, I suppose it's rollbars or clamshells for me, since I just finished de-rusting my floorpan (thanks be to my sandblasting pot, por-15, and a long, long weekend) and the interior is all reinstalled. I don't consider it an option to take it all apart again so as to weld on inner supports. To bad. Wish I had done it while I had the thing all apart in the first place.

Thanks fellas.

James

I remember the first car I got a ride in a teener with the Engman kit.
Huge differance. As i rode in this car before and after the install.

it isn't race car tight. But much better than stock

My thinking is that a cage is by far the best way to go if you want rigitity.

A 914 without a cage is kinda like a shoe box with the lid remomed. It twists.
Put the top on the shoe box and the box becomes very rigid.

It's all about cosmetics and dollars VS rigitity.

Your call.......
regards,
Clayton

I disagree with the comments that just adding a solid roof wouldn't make much difference in the stiffness of the car, just compare a 911 coupe with a Targa (pretty much the same concepts). It definately would not stiffen the car as much as a well constructed rollcage, but would be a good idea for a street car if the top was not to be removed.

On the other hand, the removeable top is one of the nicest features in most of our minds. A nice sunny day and a country drive is true top down nirvana.

Jeff, I had a conversation with Mark Allin about this as we were considering doing it to my car. I eventually did it for the cool factor.

But, according to Mark and his research the factory did this NOT to add rigidity to the car...as the winshield frame is way too weak! Rather it was done after racing the GT's... as they found that as the car flexed the roof would unlatch itself and FLY OFF!

Like the balsa strips in the fiberglass lids that were there to control collapsing of the lids at speed the roof was just done to fix the problem.

If you are going to do this to the roof...you have to reinforce the windshield frame...when done in the same manner as the factory on the GT's it is not very pretty

Peter

WOW, how many other Porsche guys have a HUDSON in their garage????

one of these days I'd like to install the Engman kit, I've had one cage and maybe I'm getting too old, but it became a pain after getting in and out of the car a few times

I have always heard and have seen SOME first hand evidence that the lower outer windshield frame area will crack (even on street cars). The cracking is due to the windshield frame flexing while driving.

The stiffening shown in the pictures above was done to help prevent the cracking in the cowel area as well as to reduce windshield frame flexure.

When a windshield frame is fixed to (by means of weld tabs) the roll cage, it sufficient ly reduces windshield frame flexure and the associated cracking. I have seen a few 914-6 GT cars that had the top bolted in place, but those tops were very thin fiberglass and probably did not add much if any structural strength to the car.

I read that the 916 cars with the fixed steel tops were noticably more rigid than the 914 targa cars, but I have no information if there were any other structural modifications added to those cars or not.

just my $0.02

Adding reinforcement to the top of the car would be a improvement, but adding a engman kit to the areas where the car needs it (remember it is over 30 yrs old and has flexed a lot over that time) is the best bang for the $$'s that you can do......

(not stratplayer)