924Board.org

1st car · Joined: 23 Aug 2005 Posts: 57 Location: VA

Does a roll cage add allot off good body stability and what’s where’s the best to get from. Can my car still be street legal with it (I would think it would)?
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1979 924 sebring project car (first car)
and a 1996 saab 900 turbo SE

John Brown · Joined: 07 Nov 2002 Posts: 903 Location: Leesburg VA

Not so's you'd notice and really not recommended for a street car.
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John
80 931 - #931 44Cup
99 Escalade - tows track cars
gone but not forgotten: original 924.org car - 82

morghen · Joined: 21 Jan 2005 Posts: 9102 Location: Romania

i have an ideea....why dont we make a RACING section for the people who want to ask questions like this...and for peope who are into heavy mods with their cars.
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Supercharger and EFI kits
https://www.the924.com

teo · Joined: 07 Sep 2001 Posts: 637 Location: Hungary, Europe

1st car · Joined: 23 Aug 2005 Posts: 57 Location: VA

o sonds nasty
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1979 924 sebring project car (first car)
and a 1996 saab 900 turbo SE

CBass · Joined: 03 Nov 2002 Posts: 2807 Location: Vancouver, Canada

Pshh, there's lots of headroom in a 924! Seriously though, lap belts suck
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'81 931 in various states of assembly

rsp13-sideways · Joined: 09 Dec 2005 Posts: 14 Location: Fremont, CA

I have an autopower 6-point rollcage in my '89 240SX. You can put a rollcage in the 924 with no problems,

http://www.autopowerindustries.com/Roll_Cages.htm

If you're scared about crashing your head into the rollcage during an accident buy some padding, it's what I run.
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-1989 Nissan 240SX - Sil-eighty w/ GT2871R powered SR20DET making 410RWHP.

-1987 Porsche 924S

harnishclan · Joined: 10 Dec 2005 Posts: 30 Location: San Diego

Really no point, adds weight. And does not help handling. Only way to stiffen with a rollcage is to weld it in and along A-pillar in addition to suspension pickup points. Unless you plan on racing on the track or rolling on the street, it is just $800 worth of add on weight.
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Current: 81 924T, 82 924T, 87 944, 97 993, 04 Cayenne S.
Past: 83 944, 81 911SC Targa, 86 944.

rsp13-sideways · Joined: 09 Dec 2005 Posts: 14 Location: Fremont, CA

924RACR · Posted: Sat Dec 31, 2005 1:30 am Post subject:

No, he's right - unlike most cars out there, ours are very stiff to begin with, as befits a sportscar. I agree with everything harnishclan has said, except a proper roll cage for racing costs more like $2000 installed. The $800 bolt-in ones are only a start, and the Autopower ones suck in my opinion since they go to the thin sheetmetal of the floor - no structural integrity there, and on other cars they've been known to punch through the floor in extremely bad rollovers. I use an OG Racing cage, and it goes to the structural members in the 924 - the box sections of the sills.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

harnishclan · Joined: 10 Dec 2005 Posts: 30 Location: San Diego

rsp- kind of a harsh rebuke, especially when you don't back it up with any fact. The rollcages you buy and install are not going to help suspension at all. That is why in any of the three racing series I participate in, there are no points added for a rollcage, but none of them will allow you to go through to the front and tie in to the suspension pickup points. Or use bottom cross bracing along the floor pan. If you have a cabriolet, it might help, a little. But in a coupe there is nothing but weight added to a street car. And that is not even bringing in a discussion of DOT Spec tire limits of adhesion, which all of which a 924/944 chassis can withstand.
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Current: 81 924T, 82 924T, 87 944, 97 993, 04 Cayenne S.
Past: 83 944, 81 911SC Targa, 86 944.

rsp13-sideways · Joined: 09 Dec 2005 Posts: 14 Location: Fremont, CA

Perhaps I'm not 100% familiar with the 924/944 chassis'.

I run both my 1986 Corolla GT-S and 1989 Nissan 240SX at the track for drift and the biggest impact as far as stiffening goes (besides my inverted monotube coilovers) was my 6-point rollcage. Granted I didn't run Autopower instead ran Safety 21 (Cusco) but the handeling and the stiffness it added to the chassis felt like my car handeled on rails.

The mounting points on both my cars are obviously different than the 924/944 but they're all hatchbacks in essence. Thanks for the advice and sorry for being harse harnishclan......
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-1989 Nissan 240SX - Sil-eighty w/ GT2871R powered SR20DET making 410RWHP.

-1987 Porsche 924S

Peter · Joined: 04 Nov 2002 Posts: 379 Location: New York, NY

I have to respectfully disagree. A roll cage does add stiffness to a car whether bolted or welded. The major reason is that the chassis is tied into a box (cage) so-to speak, that minimizes torsion forces. See Chassis Engineering by Herb Adams published by HP Books for a greater analysis of this issue, specifically chapter 12 entitled Frame Design. Whether a driver notices the added stiffness depends on driver and usage. Of course, I am operating under the impression that persons who engage in these and other types of performance modifications are intending to prepare their vehicles for track events rather then for social occasions.
I have to comment about the negative perception of autopower roll cages. Although they mount to the floor, the installations that I have seen were welded to a steel“L” beam that is welded to both the longitudinal and the floor. I believe that this mounting is superior to welding to the longitudinal alone because the load is spread over (1) the top of the longitudinal; (2) the sides of the longitudinal; and (3) the floor, as opposed to only (1) the top of the longitudinal.
Furthermore, autopower roll cages are one of the less expensive roll cage brands available. However, that being said, for my desired usage I am budgeting for a custom cage.
-Peter

rat · Posted: Wed Jan 04, 2006 10:35 am Post subject:

While it may add stiffness, is it going to be something that youd notice in a street car? The extra weight, expense, and the look of the thing would be overwelming negatives in my car, even if there was some benefit in cornering, which i would question.

I find my mates car with full roll cage a pain, to the point where its almost pointless having doors, as its just as easy to climb in the window as over the roll cage. However his is a peugeot 306 whose tinfoil build i can see benefiting hugely from its addition.

harnishclan · Joined: 10 Dec 2005 Posts: 30 Location: San Diego

Unless you are on the very edge of R compound tires, there is going to be no difference in your handling characteristics by bolting (or welding) in a rollcage that does not tie in to suspension pick ups. Street tires will loose grip and slide before chassis torsional flex becomes a factor.
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Current: 81 924T, 82 924T, 87 944, 97 993, 04 Cayenne S.
Past: 83 944, 81 911SC Targa, 86 944.