tcsracing1

sweet Gezus!!

beautiful build! Great example of how close the street and CUP cars are when you take their clothes off and dress them back up......

Are you going to keep a license plate on the car for ****s and giggles?

Antonov

Beautiful build.

With regard to differences of motor internals between Street and Cup GT3's, I believe that the streets cars have variocam, where as the cup motors have pinned camps. Though the variocam likely adds a few pounds, its probably worth the midrange advantage they offer.

mklaskin

Great looking cage. Who's doing the work?

Keep the pics coming.

Carrera GT

The concern with removing any structure is the risk of upsetting the integrity of the frame. Sometimes it can be hard to decide what's integral and what's there as a vestige of a manufacturing decision or other production engineering requirements. For example, if that cross beam were removed, would it tend to allow the tub to flex outwards (door sills moving apart) or inwards? If you can't answer that question with certainly, don't cut the pipe. If you wanted to experiment -- without access to the resources of engineers with considerable skills and experience ... literally people working at Porsche or accessible through Motorsports or their consulting services ... you could be bold and cut a 1 mm separation of the pipe itself with no further changes. I'd do this on a frame jig with pick-up point measurements on all four corners. Then weld in a strain gauge ("load cell") between the two halves of the cross beam across the "bifurcation" and get the car aligned and balanced, then take it to the track and set some best times. Then look at the data acquisition on the strain gauge across the two halves of the crossbeam. Then, I expect, I'd have a top flight fabricator reconnect the beam while the car was back on the frame jig to be certain I had exactly the same geometry and strength as before ... and make a note: "never do that again." : )

911SLOW

A voice of reasoning, much needed in times of radical decisions, but for this specific matter Porsche decided that in the presence of a bolt in rear roll cage said bar is not needed in the 6RS..
Cup cars of course also didn't have it..

Mike is a pioneer in this removal and we have to give him credit..
: )

996FLT6

^It's just a car but what a special car it is for me. Wasn't easy deciding to take that bar off but as John stated if not needed in cup or 996 rs- what's it for? My intentions is to race this car and ^ne dead weight is just dead weight. I'll be the 1st to tell u if my car splits in half if it gets tboned. 25lbs brick is a 25 lb brick plus also ^all the other stuff the street car has. I don't need it. Dont think neone wants to take out crash bumpers as well but it is what it is : ). Mike

996FLT6

Here's a pic of the said rear chassis bar. Look at it's design. In my eyes it offers very little protection in a t-bone scenario. If it happens what u think the force will be transferred? Me thinks the hoop part and that part is held by a single nut- in a t-bone scenario that bolt will shear off and hoop bends upwards. The sheet metal above and below wont prevent it from bending or snapping. Maybe itll except a 5mph hit much like those 5mph crash bumpers we have both front and back. If u really think this piece of bar does nething for rigitidy I suggest if u when u get a custom designed roll cage have your horizontal designed with a hoop and see where that goes in an incident- really poor design and only to meet minimal crash standards. Anyway enuf bandwidth with this. It's done and I'm willing to accept the full rollcage will provide the rigiidity plus moreso in place of that bar. I welcome opinions and that's why I live half my life in this forum. Regards Mike : )

RWK

strain guaging is obviously the ultimate diagnostic / design tool for chassis modifications.


taking a quick look at the orinetation and encapsulation of the bar in the metal formings, based upon its installed configuration, i would venture that if an axial force were to be applied into the bar, it would react against the drive train hump and ( be retained by) the shrouding tunnel also.

at the other end, if you squeeze the new cage against the a pillars, the pillars move before the cage ( prior to weld attachement of the A pillar to the sub box channel ( rectangle ornage tube) and upper dash support ( round black pipe) at the firewall. ( lookind g for pictures oif these attachement points.

btw: carbon Roof -(16-18#) at the top!

ATL Fahrer

I am not a structural design engineer (but I did stay at a Holiday Inn once) so I am probably wading into a topic that I know nothing about. Having said that, on page 52 of the "The new 911 GT3 - From the inner sanctum" hardcover booklet that Porsche prints, there is a diagram which shows the bodyshell structure of the GT3. Super high-strength steel (the green color on the diagram) is used very sparingly. The piece that Mike has removed, happens to be one of those areas.

I have to believe that it is not a vestige of an old design nor simply added weight. Its the most expensive steel that is used in our cars and I don't think that I would remove it.

CRex

^ I believe you're referring to this diagram which is repeated in the Gen 2 brochures. That bar is around where the label #4 is.

http://www.porsche.com/all/media/pdf..._MY10_PCGB.pdf

ATL Fahrer

That's the one.

aussie jimmy

good find. yeah the green steel looks important.
maybe the energy in a side impact is absorbed by the hoop, but as already mentioned, a good cage should suffice or be better.
remember andreas told savvy that he don't believe cages are necessary.......... - i beg to differ.......these cars are too fast.
maybe this lil' bar is a wunderbar!

ATL Fahrer

I wouldn't go that far. Good and properly designed cages MIGHT do the job. We, however, have no idea what was discovered in crash tests for this car. As far as I know, Cup cars are built on a completely different assembly line using specialized components. If this specific component was "deleted" in the Cup cars, the design engineers for the Cup cars had the benefit of talking to the guys that put the component in in the first place. We don't.

To say that a Roll Cage designed without express knowledge of the initial design will suffice from the OE spec, is a bit of a stretch - I think

aussie jimmy

cup cars have the proper cage, but the 6rs had the bolt-in plain jane cage.
you're right though, we are no experts in this field - just speculating.
hopefully rwk's cage fab person knows what he is doing?
it's looking pretty good.

RWK

Great pic, thanks!

Part #2 is the rectangular section tubing that I was refering to. The cage is connected to it in the front, via welded tubing, as seen in the pics.
We also connected it to the upper black dash support tube.

The work on this cage is being done by Eurotech in Framingham Mass. If any RL member local would like to see it, let me know,and I would schedule a time togo up to meet them. The car will be there another week or 2.

best
Bob