disasterman

All cages are not created equally. It takes more than good welding skills. The considerations involve where the supports are placed, type of support etc. A properly executed cage will improve the performance of the car by making it more rigid. I would highly recommend the following;

1. Collect photos of 944 cages and note who did the fabrication and when. Old cage work is usually not up more recent techniques. There are a lot of bad cages out there. I good set of photos from my car if you are interested. I firmly believe that my cage had direct impact on the handling of my car. Harder race suspensions require a more rigid chassis.

2. Interview the cage builder, share your favored techniques and discuss them. Do not just listen to the loudest voices.

3. Nascar bars are great but often executed with "s" bends which can be a weak point. Many cages extend the rear supports further back than necessary. You want to tie in at an area that will enhance your rear suspension.

4. I would not recommend a bolt in cage for racing.

tritone75

pm sent disasterman

2bridges

yep - spend the time doing your homework.

This is not a 951 roll bar, but takes advantage where many others don't.
Notice the crossbar at the down bars - on this car it ties the rear frame rails together at the upper control arm locations.

Anywhere you can stiffen the chassis/suspension you will benefit

As other have stated - the premade kits are a total compromise and can't be fit tight and are not tuneable.
The increased cost is absolutely worth the benefit to tailor to you - like harness bar heights fitted properly to your seats/shoulder height, etc,etc.

Oddjob

Not the best example of a cage/bar to show - that is not legal for most racing venues. Big problem is that the diagonal is not in the same plane and the main hoop, it has to connect at the foot of the main hoop; and the diagonal is disected by the crossbar, should be the other way.

2bridges

As stated this is not a 951 application.

Also the diaginal cannot be in the same plane as there is a fuel tank you would interesect. So you either mount the main hoop on the inside of frame and at a poor angle or on top of frame with main hoop and offset diaginal. This is SCCA legal on this platform.

Oddjob

Doesnt matter the application, rules are rules, and that is not legal for SCCA club or pro racing, NASA or PCA. Read any of the rule books. A roll bar is not legal in any SCCA racing class for production based sports cars. That particular bar may be allowed for a DE/Time Trial event, but not any door to door racing.

Page 102:
http://cms.scca.com/documents/2011%2...%20version.pdf

Page 56:
http://www.nasaproracing.com/rules/ccr.pdf

Main hoop would need to look like this:

2bridges

yep exactly. Pic is deceptive at this angle. The roll bar main feet are straight, it is the front diaginal that is angle forward to clear tank. If built as drawn you are attatching to the inside of the rail not the top of the rail.

When my life in on the line in the "big one" I want it on the top of rail.
We are getting way off topic. Suffice it to say I am not suggesting everybody build like this.

Here is a better pic to show the point I was trying to make for the OP.
By connecting the down tubes you can maximize stiffness

74goldtarga

Tritone, since your doors are already gutted it makes even more sense to go custom since a kit cage is going to want to clear the stock doors, you want nascar bars that go out into the door on the driver's side - I realize this has already been mentioned but I bring it up again as another reason why custom makes sense in your specific case.

tritone75

74goldtarga, the exact problem you mention with kit cages being for interior included...the previous owner of the car has a kit in it that was for an interior. Now, my head rises above the front bar since it is completely gutted...if the car turns over it turns over on my head first, then the bar. Custom cage- DONE! thanks for the perspective!

disasterman

These are some of my cage photos as requested. Note that this cage was built to comply with PCA rules. The car has been subsequently approved by both PCA and NASA.

333pg333

Along the lines of this discussion, what are the thoughts of the 'knee bar'? Our rules stipulate that it must be above the steering column now but this doesn't seem practical in many applications. Especially where a stock dash is being used.

74goldtarga

I have a stock dash, my knee bar runs behind it - you can see it through the air vents. At the time I thought I was building a PCA stock racer. Air-con and heat blow around it .

Oddjob

This is a problematic bend. PCA, NASA, or SCCA rules do not allow a bend in the main hoop diagonal.

The problem w/ running the main hoop along the b-pillar on a 944 is that there is not room for the seat and belt attachment, unless the driver is somewhat short. So cage builders like to bend the cross bar rearward and also, as in the this case, the diagonal to fit the seat. The legal solution is to move the main hoop about 4-6" rearward from the b-pillar, w/ no bends in the diagonal.

disasterman

Wrong, we showed the math and it was approved by PCA as well. I also had inspected by the SCCA for approval though I don't race in their series.

333pg333

That's the first thing I thought when I saw the bend but you've had it approved or pre approved which is even better. Congrats.