Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

Weld in roll bar install

 
Post new topic   Reply to topic    924Board.org Forum Index -> General Discussions
View previous topic :: View next topic  
Author Message
Kenodog  



Joined: 25 Jun 2003
Posts: 2584
Location: Vancouver,B.C.

PostPosted: Sun Oct 06, 2019 11:22 am    Post subject: Weld in roll bar install Reply with quote

Hey homes and homies. Anyone that's had a weld in roll bar can you tell me did you cut holes in the sloping sheet metal in front of the rear wheel arch to access the sub frame or did you weld it directly to the flat bit ? The fellow doing the install says he needs to cut it and pass the bar through to the support underneath but this seems very wrong to me....

Any help is always appreciated

Me
_________________
1979 Euro 931, Olive
1981 931, Sabine
2014 Mazda CX-5 (Kinderwagon)
2008 GS500
2016 DR650
2019 KTM 790 Adventure
Back to top
View user's profile Send private message Send e-mail MSN Messenger
TJC  



Joined: 04 Apr 2010
Posts: 762
Location: Central-ish Arizona, USA

PostPosted: Mon Oct 07, 2019 1:46 am    Post subject: Reply with quote

Can't address your application directly without seeing a photo or diagram of your roll bar but the roll cage in 924-005 did not pass through the floor at any point and had reinforcing pads welded to the floor in places where it attached. Is yours a kit from someone or is your fellow making one up?
It also didn't pick up on the wheel housing but was welded to the floor in the rear seat area and then went all the way to the back of the hatch compartment. Check out my web page for photos.
Also the 4 point bolt in, (could be welded as well), roll bar I had in my 924S, (an Autopower if I remember correctly), didn't "pass through" the body. Sorry, no photos of that one.
_________________
'95 BMW 318i/5 ..."Pearl"
'80 Porsche 924 Turbo..."Pogo"
'81 Porsche 924 Turbo...Parting!
'87 Porsche 944 NA... "Liebchen"
'02 Porsche Boxster..."Sunbeam"

Still on the Prowl!

www.ttrs1.com
Back to top
View user's profile Send private message Visit poster's website
Carrera RSR  



Joined: 08 Jan 2010
Posts: 2022
Location: Somerset, UK

PostPosted: Mon Oct 07, 2019 4:06 am    Post subject: Reply with quote

I’m sure many ‘specialists’ will have their own way of doing it. But for EMC Motorsport in the UK whom built many, many 924/944/968 race cars weld spreader plates and mounting boxes to the sill, rear seat slope and wheel arch as per ....

jpg-3 by stevenmcooper, on Flickr

And

jpg-4 by stevenmcooper, on Flickr
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
Fifty50Plus  



Joined: 28 Feb 2008
Posts: 1107
Location: Washington DC area

PostPosted: Mon Oct 07, 2019 7:56 am    Post subject: Reply with quote

SCCA rules don't allow cutting holes in the floorpan but welding in the plates like Carrera RSR's pics is the perfect way to install a cage.
_________________
1979 924 NA race car
1982 924 NA race car - Sold
1982 924 Turbo almost a PoS
1981 924 Turbo a real PoS, new engine
1982 924 Turbo nice body, blown engine
1972 911 E race car - going to Vintage
Various 944s to become IT-S race car
Back to top
View user's profile Send private message
MikeJinCO  



Joined: 08 Jun 2010
Posts: 936
Location: Maysville, Colorado

PostPosted: Tue Oct 08, 2019 1:09 am    Post subject: Reply with quote

I have the HanksVille hot rods Spec944 cage from Denver and it goes in like Carrera's with addition of 1/8" pad with a lip on the main hoop, which is probably there but I didn't see it in the pic. It took some hammer work on the roof ribs to get it in there, it is a very tight fit. Every connection point to the body has a chassis reinforcing pad.
_________________
Mike
Poco a Poco, #033 '78 Vintage racer, SCCA Dp-81
'77 924
cricketdesigns.com
Back to top
View user's profile Send private message Visit poster's website
macBdog  



Joined: 16 Aug 2004
Posts: 1111
Location: Brisbane, Australia

PostPosted: Tue Oct 08, 2019 6:19 pm    Post subject: Reply with quote

CAMS (governing motorsport body) rules in Australia say to do it like this:






_________________
1979 931 with a 350 chev
1973 911E with EFI
p-talk wrote:
I'm still convinced the word 'Porsche' makes people crazy in all kinds of ways
Back to top
View user's profile Send private message Visit poster's website
924RACR  



Joined: 29 Jul 2001
Posts: 8346
Location: Royal Oak, MI, USA

PostPosted: Sun Oct 13, 2019 10:57 pm    Post subject: Re: Weld in roll bar install Reply with quote

Kenodog wrote:
...The fellow doing the install says he needs to cut it and pass the bar through to the support underneath but this seems very wrong to me....


Sorry, been on vacation.

The above statement tells me your welder doesn't know 924/944s. That flat section IS the structure.

But he can still do a good job, just needs to learn his subject a bit more.

That flat part is correct for a solid tie-in. At the very least, a flat plate to help spread the load under the end of the tube will help. As shown in the ref Aussie pics (red car).

The REAL way to do these when building a custom car is:

- make the tubes too long when bending
- punch through the frame rail/rocker with a hole saw
- drop the tubes/hoop through the holes you just made in the rockers
- weld the a-pillar bars, halo and main hoop together, with the main structure of the cage dropped down so you can get to the top of the tubes to finish the welds all the way around
- raise the cage back up until its touching the roof
- trim the tubes to length, so you can JUST slip the mounting plate underneath the end of the tube, with the top of the cage still contacting the roof.
- finish welding the plates in place to the rockers, and the cage to the plates.

And that is how you build a cage that can survive a roll without even cracking the windshield!

As for that blue car reference - point and laugh with me at that center bar going to no-where in the middle of the main hoop cross-bar. Tubes need to end in nexus points; any loads imposed on that bar will go no-where. Hopefully your fabricator knows better.

That EMC cage in the blue car actually looks quite shitty to me. Note also the rear main hoop braces going to weak sheetmetal on the arches - no structure there to tie in to. Those tubes should go to the sides of the rear load floor; if you're familiar with the underside of the 924/944, you can see the frame rails you end up tying in to. Ideal IMO is to grab the very front edge/corner of the floor, since that's where the shocks mount, and if you're wanting to use coilovers, that'll help the load paths.

That said, the OG Racing cage in our 924 - which has survived too many visits to walls and frame racks - was tied in to the floor about halfway back, and seems to work decently.

I will say that the EMC cage does mount to the correct frame rail points on the boxes for the a-pillar bars and main hoop, so glad to see they got that right. I've seen far too many cages that blow right past these and go to the floor, which of course by contrast is pretty flimsy. Google "cage punch-through" if you want to see some scary pics.
_________________
Vaughan Scott
Webmeister
'79 924 #77 ITB racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Carrera RSR  



Joined: 08 Jan 2010
Posts: 2022
Location: Somerset, UK

PostPosted: Mon Oct 14, 2019 3:50 am    Post subject: Reply with quote

FYI. That EMC cage in the blue car is made by Safety Devices and is fully FIA approved. Supplied in pieces and welded in by EMC which are the go to 924/944/968 race preparers in the UK. It’s the same cage cage in my car but bolt in rather than welded in.
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
Cédric  



Joined: 27 Aug 2004
Posts: 1999
Location: Sweden

PostPosted: Mon Oct 14, 2019 5:05 am    Post subject: Reply with quote

It looks fairly good, but that tube attaching in the middle of the cross tube is such a basic mistake it sound weird that its a safety devices design.
_________________
´80 924 Turbo
Back to top
View user's profile Send private message MSN Messenger
Carrera RSR  



Joined: 08 Jan 2010
Posts: 2022
Location: Somerset, UK

PostPosted: Mon Oct 14, 2019 7:10 am    Post subject: Reply with quote

Cédric wrote:
It looks fairly good, but that tube attaching in the middle of the cross tube is such a basic mistake it sound weird that its a safety devices design.


Not sure that is a stock Safety Devices cross tube? Rest of the cage is. Other cars they have prepped have it, some don’t, so there must have been a reason?

https://www.porscheclubgb.com/forum/download.axd?file=0;511915&filename=rearcageshot.jpg

https://racecarsdirect.com/Advert/Details/85525/1993-porsche-968-race-car
_________________
1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
924RACR  



Joined: 29 Jul 2001
Posts: 8346
Location: Royal Oak, MI, USA

PostPosted: Mon Oct 14, 2019 10:43 pm    Post subject: Reply with quote

Well, once it's in, there's any number of ways a cage can be ruined...

And those rear braces are still relatively useless IMO.
_________________
Vaughan Scott
Webmeister
'79 924 #77 ITB racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype
Back to top
View user's profile Send private message Send e-mail Visit poster's website
TJC  



Joined: 04 Apr 2010
Posts: 762
Location: Central-ish Arizona, USA

PostPosted: Tue Oct 15, 2019 2:55 am    Post subject: Reply with quote

924RACR wrote:
Well, once it's in, there's any number of ways a cage can be ruined...

And those rear braces are still relatively useless IMO.


I was looking at that as well. It appears that some type of box/pedestal is welded to the inner wheel well and then the bars are welded to it. Seems to be just another piece to collapse before the wheel well does, but perhaps it's just the way I'm seeing it in the photo.
The bolt-in roll bar in my 924S that I referenced above had the rear braces attaching at the wheel well location too but to be honest it wasn't a real serious safety device. Sort of a "better than nothing, something to modify to attach shoulder straps to, boy racer" piece of work. Hell, it came with the car when I got it!!!

I do like the blue though!
_________________
'95 BMW 318i/5 ..."Pearl"
'80 Porsche 924 Turbo..."Pogo"
'81 Porsche 924 Turbo...Parting!
'87 Porsche 944 NA... "Liebchen"
'02 Porsche Boxster..."Sunbeam"

Still on the Prowl!

www.ttrs1.com
Back to top
View user's profile Send private message Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> General Discussions All times are GMT + 11 Hours
Page 1 of 1

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group