Thru the dash is fine, but they should then go down the longitudinals.

 

Lets talk a little about 4130 cromo. This is used in light planes all the time and is not stress relieved. I have read a number of presumably good sources that says the thin wall of cromo in race rollcages does not need to be normalized and will maintain design strength. I have also read that when normalizing people basically heat red with a torch and let cool. The red is not really red but some other redish color that fingers an approximate temperature of the steel to change its properties upon cooling. This is allowed to room temp cool and thus stress relieve AKA normalize. The problem I have with doing this method is that it is subject to the art of the person doing it as opposed to sticking the entire work in a controled oven which of course cannot be done. So what is your guy's take on 4130 normalized vs. not normalized? I just don't know and could not really feel good about all the rumors so I stick with dumba$$ mild steel DOM tube.

 

I assume you mean verticle.

My question is: why?

If the a-pillar tubes can meet the floor or rocker there is no compelling need to bend the tubes. On most cars this is not possible, but on the 944, especially with a-pillar tubes away from the a-pillar, it is. Jon Milledge's cage recommendation for the 944 involves straight tubes here.

Remember, unbent tubes are stronger in most directions.

 

I was going to post the same thing. I can't remember where I first learned of this (perhaps here), but the FAA does not call for normalizing 4130 under a certain thickness. My little monkey brain seems to recall this is 0.250", but don't go by my recollection.

I think the FAA standards are good to follow here. There is no organization in racing that I know of that has studied this or made recommendations/requirements. Often the racing industry looks to aviation (more in the past than today), so this seems a good source to me.

 

My 15-second fly-by on this is that the connection between the top halo and the front down-tubes are at too acute an angle...you lose all the compression strength, and rely on what is basically 'sheer' in the event that you end up inverted.

I would not like to flip this car.

Of course, I'm not really big fan of flipping any car, but I would be particularly concerned about inverted motoring in this cage.

 

That cage is atrocious. Frontal impact I wouldn't trust the welds on the A-pillar tubes to hold. An impact on the fenders in the front would probably do the same thing because I'm gonna guess there is no bar across teh car at the firewall. They built the cage so far from the edge because they weren't confident enough in their skills to cut the roof off and do it right. I bet if you look closely you'll see burn marks on the door seals from where they were trying to weld the top of the apillar connection. If I was the owner of the car I'd probably go after the people who built the cage for giving me unsafe safety equipment. I can't see the mounts up close in the rear of the car very well. Are they bolstered or is it just welded to the OEM sheet metal.

 

Looks like there are suave little triangular plates to spread the love between the bent rear bars and the floor pan.

 

I still think this is a test and pulled up the NASA rules -- to me it looks like the diagonal may be a problem meeting the within 12 inch of the corner rule, 'One end of the diagonal brace shall attach to the corner, or horizontal part, or the main hoop above the driver's head, within twelve (12) inches of the driver's-side corner. The diagonal does not look like a one piece diagonal, but two pieces attached to the cross brace.

According to NASA rules the rear braces are definitely a problem in at least one way - 'The braces must not contain any bends.' That statement was bold and underlined.

Also 'Each mounting plate should have an area of not less than nine (9) square inches.' What can be seen of the Triangular rear mounting plates make me somewhat suspicious.

I believe someone showed up at John's shop and asked him to install a seat for him; hence, the Redline label on the seat mount. John was flabbergasted by the cage and posted pictures for our amusement.

 

There is zero need to remove the roof from a 944 to install a proper, tight fitting cage. My cage was built totally within the car with zero cutting of the coachwork. There is no place where the cage is more than 1/4" from any adjacent coachwork (and touching in many spots). It simply requires good planning and execution.

 

Yes an unbent tube is stronger, but the attachment point is also critical. It looks like the a-pillar tubes just go off to meet mr. firewall. It is a bit hard to tell from the picts tho'.

 

Mmmmmm...Nitrogen.....

My comment: there is no seat brace. Though not really a critique on cage design - I wouldn't want to back into a wall with that horizontal bar behind me and no support to prevent my back from attempting to bend around it.

And as others have said - all that stuff around the A-pillars look "sub-ideal."
-Z-man.

 

I agree that attachment point is critical. However, if the attachment is still the floor or rocker, at least that one part of the cage is OK (most of the rest is junk though).

 

Nitrogen.... bah..

Gimme nitrous. NO! Not for the car, for the driver!

 

Leifster... Dude!

I wouldn't joke with you, man!

 

OK... Here's what I thought of it;