Techinical Bulletin--ST/TT B-pillar Cage Notching 3-12-18

[Greg G.]

TECHNICAL BULLETIN 3-12-18

B-pillar Notching for Cage Placement

 

ST1-4

6.2.1 Chassis and Body Modifications to Production Vehicles

1h) "B" pillars of the unibody may be notched to accommodate the placement of roll cage door bars provided that the notched area is welded to the bar(s) that intrude into the B-pillar.

 

ST56.1.3.2 Chassis and Body Modifications

1h) "B" pillars of the unibody may be notched to accommodate the placement of roll cage door bars provided that the notched area is welded to the bar(s) that intrude into the B-pillar.

[Fair]

Thanks for this clarification/change. This allowance really helped us cage a 4 door EVO X. This was for a customer's TT car that needed to go to ST.

This car came in with a welded 4 point roll bar, but the top was shorter than the roof (and his helmet), and it was pretty narrow - several inches inside the B-pillar. We cut all of that out and skinned the roof for a carbon panel, too.

We made the main hoop to where it almost touched the roof skin (3" taller) and moved the seat back, as well as the hoop. We made it about 6" wider than the old 4-point's main hoop that came out as well. That added some protection laterally.

With the main hoop and rear structure in place it was obvious that the factory B-pillars would be in the way of the upper door bars.

With the doors gutted and the door bars kicked out to the door skin, we had over a foot of room from the door bars to the driver.

But there was no way to get the upper door bar to the main hoop without notching the B-pillar. If we went around the B-pillar then the rear door hinges wouldn't fit, and opeing the back doors (to access cool suit cooler, ballast, etc) was a LOT more work.

We ended up using two lower door bars - one that terminates on the B (see above) and another lower bar (see below) that slides inside it, at the floor (not near his body).

This is how the "ladder" structure of the door bars went together on both sides, giving the driver ample "crush" space and snaking around the B-pillar underneath. Just the bar up by his elbow & arm he needed the "notched" routing through the B.

The B-pillar notch was welded to the cage, of course. And we got NASA approvals at every step of this cage build, including the change to the CCR listed.

In the end the customer was happy, the tech inspector was happy, the rear doors could open and close normally, and the car was much safer than before.

Thanks,

[Greg G.]

Very clean build!  Must be nice having that much room in there for the driver. 

New Forums are great with the easy photos uploads, too!

[TurboShortBus]

Ah, yes...a textbook example of how to turn a 7 month old tech bulletin update into a watermarked shop plug / build thread.

Mark

[Tansar_Motorsports]

Greg,

What about a car like the RX8, which does not have a true B Pillar.

The rear suicide doors on my car are notched, to make clearance for the nascar bars, but are not welded to the cage, since the rear doors are still functional.

[Greg G.]

 Doors can be notched. The reason the rule was written is because the B pillars are part of the frame. 

[DavidSinger]

Actually, because of the photos added to this old tech bulletin, Google popped this thread up in a totally separate search I made.  Any professional builder who wants to post photos as useful (to me anyway) as these are should be allowed to watermark his work.  All of us have to watermark the cars we build so they are allowed to race NASA.  Oh, and please take all the oompeting watermarks off before you unload, thank you.  Name recognition is all part of the game.