Roll Cage Design

Post by **RWD_NissanMan** » 28 Feb 2006 18:58

Here are some shots of the BNR32 project we are currently working on - thought some of you might be interested in this. This will be used as a track car only. Just got the car back from getting the cage put in. It is really "state-of-the-art" in current cage design - all of the tubing is chrome-moly alloy that is TIG welded and then MIG'd to the chassis.

Post by **RWD_NissanMan** » 28 Feb 2006 19:02

And a few more shots from different angles...

Post by **RWD_NissanMan** » 28 Feb 2006 19:05

And a few more.....

Post by **RWD_NissanMan** » 28 Feb 2006 19:05

... and of course we need to have a window net

Derek · Post by **Derek** » 28 Feb 2006 19:15

Was that done by Ronnie O'Brien> (that could be spelled wrong). I know the cage in my dad's Z was done by him in Chromoly and Sprogl didn't want to pass it through Targa tech (as I am sure you know, Targa rules stipulate mild steel ONLY). Does Ronnie do any pre/post heating or normalizing? From my knowledge of Chromoly it is essential to normalize the welds or they can be quite brittle. Looks great though!

Post by **RWD_NissanMan** » 28 Feb 2006 19:33

Yes, it is Ronny's work - you have a knowledgeable eye!! Actually, I had a long discussion about how to TIG chrome-moly with Ronny last night when I picked up the car. Basically, the whole thing about normalizing welds in chrome-moly is somewhat of a wive's tale. Chrome-moly tubing was introduced for the aircraft building industry back in the '60's. In those days, they did not have the modern TIG & MIG technologies we have today, so everything was welded with gas welders. This is where they developed the technique of "normalizing", which is to preheat the tubing to a very high temp, weld, then allowed to cool. Today's TIG systems do not require normalizing since the control and penetration of the weld is so much better. Ronny uses rod for the exposed areas around tubing welds, then uses a MIG with steel wire for bonds of the cage to the chassis sheet metal.

I know of the problems that your Dad had with the Targa rules. Problem is, the rules are following CARS (rally) and they don't reflect current race car building technology. I suspect that it is because there are very few people building rally cars in Canada that are truly competent welders and able to work with chrome-moly - so they insist on only mild steel and the resultant heavier weight. The cage we have done here is for CASC race rules and won't ever be used for Targa.

Post by **Byron510** » 28 Feb 2006 21:17

Bob, is this the "parts" car that you acquired over the pacific?

Good to see it in one piece again. I thought that one was destined to be wrapped in 240Z sheet metal?
Byron

Derek · Post by **Derek** » 28 Feb 2006 22:25

I'm willing to trust Ronny on this one -- he certainly knows what he's doing. My dad ended up getting it through Targa spec based on the fact that is it a road-race legal cage. Along those lines, the Z's going to be vintage raced this summer. I will be back in Ontario for the VARAC weekend at Mosport in June to go lapping and crew for my dad and bro.

Here's the Z's chromoly cage:

Post by **510rob** » 01 Mar 2006 00:13

This article has interesting information about TIG-welded 4130 chassis...
http://www.auto-ware.com/ubbthreads/pri ... &type=post

(Not to be a stickler for details, but the TIG process was first developed in 1942 by Pavlecka and Meredith at Northrup Aviation, using motor generator supplies (implying AC-only))

Oh yeah... those are both really nice looking cages!

Yellowcar · Post by **Yellowcar** » 01 Mar 2006 08:27

Nice work! So many triangles... I've alwya wondered about the tradeoff between weight VS stiffness.
Where do you reach the point that you have added so much weight to acheive superior stiffness that you are actually slower

Post by **510rob** » 01 Mar 2006 10:56

...but perhaps more safe?

Post by **defdes** » 02 Mar 2006 06:56

The "box section" in the middle of that Z is interesting, I've not seen that detail before...

Post by **RWD_NissanMan** » 02 Mar 2006 11:14

Byron510 wrote:Bob, is this the "parts" car that you acquired over the pacific?

Good to see it in one piece again. I thought that one was destined to be wrapped in 240Z sheet metal?
Byron

You are right!! This is the parts car I bought in Japan last April. In order to get it here, we only had to dismantle it and didn't have to cut it up. Once we got it here, we decided to scrap the idea of using the drivetrain to build an AWD 240Z - it just looked like it would take too much time and money to be a worthwhile project after we got all the measurements taken. Decided to build it up as a track car and sold off my HUGE pile of 240Z stuff to Greg Whitehead in Toronto.

Post by **Byron510** » 02 Mar 2006 11:25

If you're just into a competition car, you no doubt made the right decision! It's so nice to work with something that doesn't, in the least way, involve rust repair or thin metal.
This'll be a neat project. When it gets old enough, will you be able to register it here in Canada? Or does this have to happen upon entry only?
Neat project. Will you be keeping us updated here, or will this be on another forum?
Byron

Post by **RWD_NissanMan** » 02 Mar 2006 13:33

Byron510 wrote: When it gets old enough, will you be able to register it here in Canada? Or does this have to happen upon entry only?
Byron

No, it will never be eligible for registration in Canada since it was brought in as parts. Vehicles imported that will be licenced and insured to drive on public roads must be registered at time of entry and have a new VIN# assigned. This car will never be eligible to run something like Targa because all of those vehicles have to be licenced and insured like any other rally car.