Road Racing - 2000 Trans Am NASA ST2 build

Just thought I'd throw this up here to show you guys what I'm getting myself into. It's going to take me a while to finish this because the garage this car lives in is across town from me. Either way I'm getting on it as much as I can. Got a new LS6 long block with a Pro Systems 780 cfm carb going on top. A tick built stage two T-56 going behind that. Now I'm just hoping the stock rear will hold together until I can get a 9 inch in there. Thanks for looking.

Kyle

Nice cage. Looks well built.

Curious about your reasoning and thought process where you attached the rear down bars.

The cage builder felt that was a more structural location than aft of the shock pick up point . With the cross brace it'll keep the two plains from trying to converge together. If he brought the down tubes aft of the shock pick up points he was afraid there wouldn't be enough metal to keep the frame rails from coming together. It was that design or actually cutting a hole in the stamped sheet metal to get to the inside portions of the frame rail under the car. ST2 rules say we can't cross the planes of the factory floor or modify them in any way except for exhaust clearance. He was nice enough to throw in two horizontal bars from the main hoop to the down tube terminations on both sides.
Where did you terminate yours?

I'm not familiar with the 2000 Firebird but when a roll cage attaches to a unibody floorpan, the door bars should attach to the rocker-panel or door sill structure. This prevents the roll cage from poking through the floorpan in a forward flop.

The current SCCA rule books allow for connecting the driver's door bars to that structure but not the other side door bars.

The cage builder felt that was a more structural location than aft of the shock pick up point . With the cross brace it'll keep the two plains from trying to converge together. If he brought the down tubes aft of the shock pick up points he was afraid there wouldn't be enough metal to keep the frame rails from coming together. It was that design or actually cutting a hole in the stamped sheet metal to get to the inside portions of the frame rail under the car. ST2 rules say we can't cross the planes of the factory floor or modify them in any way except for exhaust clearance. He was nice enough to throw in two horizontal bars from the main hoop to the down tube terminations on both sides.
Where did you terminate yours?

Interesting concept. I need to look at that closer.

Having similar concerns, a floor plate is welded to the floor bove the spring pick up point. It's where the weight of the car is supported. The plate is welded to the edges and incorporates the layers of metal that make up the pan, tub, upper spring perch and upper shock mount.

The main hoop is welded to a plate the incoporates the floor pan, the door sill, floor pan and right above the front mount of the lower control arm.

The braces you have that triangulate the main hoop and rear down bars are a great idea and make the back half stupid strong, including a side impact.

Placing a second main hoop cross bar just above the trans tunnel helps with side impact and makes a great place to attach a de-coupled torque arm.

Love race car porn ... Keep the pics coming.

awesome cage, love the white, keep the progress pics coming once you get more work done. :nod:

I'm not familiar with the 2000 Firebird but when a roll cage attaches to a unibody floorpan, the door bars should attach to the rocker-panel or door sill structure. This prevents the roll cage from poking through the floorpan in a forward flop.

The current SCCA rule books allow for connecting the driver's door bars to that structure but not the other side door bars.

We talked about this as well. He did a C5 cage right before my car and did exactly what you're talking about. As you've pointed out my car is uni-body and the C5 is body on frame. He connected into the rocker-panel area because that's actual structure in the C5.

The NASA rules are similar to SCCA. He didn't want to do just the driver side and then leave all the pressure to follow up the passenger side. I will still be retaining a passenger seat in the car because I'm an instructor and usually have a body in the right seat for ride alongs. So to try to keep the car from folding up nose to tail, he connected a bar from the front down bars into a reinforced mount on the firewall on both sides. Essentially we've centered on reinforcing to main tub of the car leaving the front and rear crumple zones to take all of the force in a collision.

The builder is a bio-mechanics engineer (or something along those lines) He is always afraid of over-caging a car and leaving the only the soft things to move around i.e. internal organs.

Here's a picture of the halo bars. This is something he's done on all his cages for a while now. Especially if you plan on having passengers. As opposed to the normal diagonal bar, this design maintains the most amount of distance from drivers and passengers head. That and I think it looks pretty trick.

Good looks roll cage...

Cage looks great! Amazing how similar it is to Brian's cage even down to the white paint! Let me know when you want some more help, or if you're stalled you can come help on my car.

Looking good, please keep this thread updated! What are your plans for brakes and aero? Going to become a front breather?

Progress is being made, slowly but surely. Rear hatch installed with hood pins as I removed the latching system. Steering column and dash panel fab'd up. Rear tank installed with return line setup for the carb. (with the factory FPR removed... right Beach Cruiser ?!?! haha)

Plans on aero right now are a front air dam and a NASCAR style rear fin. Would love a real "wang" just can't swing that kind of money. But trying to compete at ST2 speeds, aero is a must. Brakes are going to remain stock with cooling ducts for now. The problems with pad knock back with the c-clipped rear axles and the front hubs that start to fail after one weekend are a major hold back. Can't mount 4 pot calipers with all that movement going on. A 9" will take care of the rear and theres a group of guys over on FRRAX.COM working on a front hub setup right now. Car is currently a front breather with the radiator boxed in.

I'll take some pics tomorrow and post them up. Thanks for the interest guys.

I thought the rebuildable hubs were already in production and being used? Look into a Car Of Tomorrow (COT) wing, much cheaper than APR (which gives NASA members big discounts btw) and other wings and very functional. I can probably get you a contact of someone who has one or can get one..they run about $500 and of course need to be rigid mounted to frame or with welded pads to solid unibody floors to prevent unwanted flex. With the speeds of ST2 I don't see how stock calipers are going to work, even with something like carbotech xp16/xp12 pads

Also, why carbeurated and not fuel injected?

Rebuildable hubs where made a while back by a member on Frrax. They where crazy expensive (700$ a piece) and have had a failure. They looked exactly like the stock units and retained abs (don't need). The ones being designed now use a machined plate to mount a spindle and hub unit from the 3rd gen cars. Very economical and the 3rd gen hubs have been tested. Waiting on these is the only reason I'm still retaining stock brake components. There isn't much that's going to work well with the amount of pad knock back I'm dealing with.

That's an interesting idea with the COT wing. Any reason you see it couldn't be mounted to the rear deck?

Ran into a bit of a snag trying to get the motor in the car. Broke the little "ear" on the bell housing to tranny mating surface. Between the two holes for the throw out bearings hydraulic lines...

A carb.... well... I can try to come up with some legitimate sounding reasons but it really boils down to I wanted to try it out.

hahahaha, no additional info needed on the carb then :)

Cool, wasn't aware of those hubs. I still think fronts should be looked at closer, that or you need A LOT of cooling to them and probably want to run SRF fluid

Deck mounted wings are never really a good idea. they are not nearly strong or stable enough when producing high downforce forces at speed. You want the wing to be as rigid as possible with no play. The more play it has or can create on its own (by being at speed, hitting curbings, etc all will wear on the mounting equipment and deck lid itself thus weakening it) the less efficiency it serves as an aero piece. Other problems are when it's not rigidly mounted and you slide into a wall, tire barrier or have some rear contact of some sort, it can cause the forces from the wing to be redistributed to the trunk lid it's mounted to causing a lot more damage than you really should have had. Don't get me wrong though, a lot of people do it with Corvettes (HPDE only typically) and their deck lid is not as strong as an fbody, it's just not optimal as you want all the air on and over the wing and not being disrupted by a moving/vibrating/flexing wing

I think I can build you some "stands" inside the trunk area that we can attach to the base of the wing to with hood pins and sandwich the deck lid in between, that way you have a solid connection to the unibody from the wing. We can try and tie it into the cage, but I'm thinking that is going to be to far forward to do without adding a bunch more steel. Food for thought.

A carb.... well... I can try to come up with some legitimate sounding reasons but it really boils down to I wanted to try it out.

Not to mention that he sold the motor and all the FI stuff to me for my 1st Gen build!:cheers:

I think I can build you some "stands" inside the trunk area that we can attach to the base of the wing to with hood pins and sandwich the deck lid in between, that way you have a solid connection to the unibody from the wing. We can try and tie it into the cage, but I'm thinking that is going to be to far forward to do without adding a bunch more steel. Food for thought.

Chris likes this :D and ya, cage isn't necessary, on frame cars you want them rigidly connected to the frame similar to this

http://a5.sphotos.ak.fbcdn.net/hphotos-ak-snc6/217189_10150175999452910_836377909_6755427_922546_ n.jpg

otherwise to a reinforced section of unibody :) having a 2nd mount is often recommended to keep forces from pulling it back/away and bending it's base mount..i suppose that could be to the trunk lid, but I think a better option is the rear "trunk" wall; again, reinforced...or you could run forward to the down cars on the cage, but that's not a good use of space

found this little guy: http://cgi.ebay.com/ebaymotors/REAR-CARBON-FIBER-WING-NASCAR-COT-CRAWFORD-SCCA-ROAD-RACING-IMPORT-RALLY-/180702142714?pt=Race_Car_Parts&hash=item2a12afe0fa

Item number: 180702142714

not sure if the guy I know can sell one for much cheaper

Not to mention that he sold the motor and all the FI stuff to me for my 1st Gen build!:cheers:

:cool:

Yeah, I think we can make something work. Kyle is local to me so I think we can make something work when he's ready. Not to jack his thread, but here's a link to my build thread for my 67 RS. http://www.lateral-g.net/forums/showthread.php4?t=16169

Thats what I was thinking Mills. Cut two channels in the rear deck lid so as it opens and closes it will clear the vertical supports. The two frames in the rear are pretty wide and nice and flat. A project to look into after the car rolls under it's own power. It's this or go with the standard NASCAR rear lip about 10" tall.

Just thought I'd throw a couple of pics up to keep this going...

mmmmmm carb....

looks really good bud!

At post 18 related to rear wing, good information>>http://www.fulcrumaero.com/