[Racerdad916]

Trackbird and I were talking the other day about some rumors floating around about the "New" NASA HPDE rules. My question is: To run a NASA HPDE event in 2011, if my car has a cage that is ERW not DOM, but is within design specs, will I be able to run? Same thing with fuel cell, seats etc. Before I finish the cage, it might be good to know if there are rule changes......

[Beach Cruiser]

I'm getting ready to start on the cage for my first gen car, I looked through the rule book, but could not find any reference to my question, so perhaps you guys can help. My car will be a street/track car. I want to make the cross bars in the main hoop removeable, is that allowed per the rules? Both NASA and SCCA. Second question is on the rear down bars, the rules state that the bars must be straight with no bends, is that the case? I've seen a lot of cars with rear bars that follow the roofline before bending down through the package tray. Third question, the front down bars, from the cowl to the front of the subframe, do they have to be 1 3/4? or would 1 5/8 be adequate?

I know, lots of questions, but you guys all have the answers! Thanks for any help.

[Blainefab]

I'm getting ready to start on the cage for my first gen car, I looked through the rule book, but could not find any reference to my question, so perhaps you guys can help. My car will be a street/track car. I want to make the cross bars in the main hoop removeable, is that allowed per the rules? Both NASA and SCCA. Second question is on the rear down bars, the rules state that the bars must be straight with no bends, is that the case? I've seen a lot of cars with rear bars that follow the roofline before bending down through the package tray. Third question, the front down bars, from the cowl to the front of the subframe, do they have to be 1 3/4? or would 1 5/8 be adequate?

I know, lots of questions, but you guys all have the answers! Thanks for any help.

First, some of the usual risk management stuff:

For a car that will see street duty, I don't recommend a full cage - ie one that extends forward from the main hoop. The halo is just too close to the occupants head to be safe without helmets, even with proper high density padding.

A 4pt rollbar - ie main hoop and bracing rearward, can be safe in a street car for front seat occupants if it is positioned rearward enough from the front seatbacks, and is padded with high density padding, and is set up to limit rear extension of the front seatbacks if the seat hinge mechanism should fail.

The rear seat in a rollbar/cage equipped car should not be driven with people in the rear seat - the steel on the sides and front of the seat can cause severe injury in even a minor incident on the street without a helmet.

OK, that said, the harness bar and diagonal in the main hoop can be made removeable, typically for access to store stuff behind the front seats. Care must be taken that there are no stubs or tabs pointing at the front seat occupants when the bars are removed.

The bent rear backstays are an artifact of NHRA and street use to clear the rear seats, before some folks figured out that beating heads on steel tubing was a bad thing. The RR folks have acquired, and appreciate that knowledge. Others, not so much.

Cage tube dimensions, material and design are highly dependent on the class the car will run in. If it is going to be HPDE only then the rules are more flexible but I encourage anyone caging a car to think ahead to the future - is there the slightest chance you'll want to race competitively? Or, maybe sell the car to someone who will? Meeting NASA/SCCA race cage rules in the initial build leaves options open for the future.

Beyond the required cage elements, tube sizing is open. Extra bracing underhood need not meet the general cage rules. If designed to be in compression and not bending it can be much thinner wall than the rest of the cage.

[Alien]

A 4pt rollbar - ie main hoop and bracing rearward, can be safe in a street car for front seat occupants if it is positioned rearward enough from the front seatbacks, and is padded with high density padding, and is set up to limit rear extension of the front seatbacks if the seat hinge mechanism should fail.

Alan, can you expand on this? I'm having trouble visualizing the bolded part. Are you saying the crossbar shoud be setup to "catch" the seats if they fail, or to allow for the seats to lay flat as they would if the rollbar wasn't even there. If the latter, wouldn't the main hoop have to be really far back?

My dad has been rearended by someone who fell asleep. He said him and a coworker were at a light, and the next thing they knew they were staring at the ceiling (sidenote: do stock seats fail as part of their design to absorb some of the impact?).

[Blainefab]

set up to limit rear extension of the front seatbacks if the seat hinge mechanism should fail.

Alan, can you expand on this? the crossbar should be setup to "catch" the seats if they fail,

My dad has been rearended by someone who fell asleep. He said him and a coworker were at a light, and the next thing they knew they were staring at the ceiling (sidenote: do stock seats fail as part of their design to absorb some of the impact?).

The crossbar should prevent the seat from passing thru the plane of the main hoop, and prevent the occupants head from striking the rollbar. The seatback should have a padded head rest (this became std OEM practice in the 80's IIRC) that stays between the head and steel. It should do this from any position of the slider.

Tech's std test on a car equipped with an OEM seat and a rollbar:
-slide the seat all the way forward
-release the recline mechanism and tilt the seat all the way rearward
-if the seat headrest passes under the rollbar bracing, that is a fail - no track time for that car.
-if the seat headrest is stopped by the rollbar bracing, that is a pass, if the bar is padded properly with HD padding, and meets the rest of the inspection criteria.

This post has been edited by Blainefab: Feb 17 2011, 08:43 PM