opel

I need to install a 4 point roll bar in my FRC for hillclimbing. From what I have been able to find out on this forum and other places there's 3 main mounting locations for the main hoop on the C5. 1 the shelf, 2 the floor, 3 the frame between the floor and shelf. I know every one has there own opinion on what mounting location is the best/safest. I personally do not think the shelf or the floor in (stock form) has the strength to support the bar in the event of a rollover. I do believe with the right reinforcing all 3 locations would work fine. Yes I am interested in your opinions but more important I want to see pictures of how your bar was mounted, measurements between the uprights would be a plus.

This is the bar I installed in my C4 it was made to mount to the floor but the shelf is a stronger location on the C4. And it gave me more room.



This is a pic ( I copy from a post on this forum) of a cage mounted on the frame between the floor and the shelf.



Some other info you might want to know, my car (99 hard top) must stay street legal so I have to keep the stock seat belts.
I will be driving it on the street. I know it not recommended to drive a car with a bar/ cage on the street.
I don't want to cut up the interior any more than I have to.
At 6'1" 280 # the farther back I can get the seat the better. I will be using both the stock seat as well as a Sparco EVO2 seat.
Thanks for your help.
Dave

travisnd

Best way to do a cage in a C5 is to put the main hoop through the rear wall panel as shown in Kevin's picture. You have to pull the fuel tanks to do this and have a cage builder smart enough to make sure they'll go back in place. The rear wall panel is just flimsy metal so that's a horrible spot for the hoop. Coming down to the frame in front of the wall requres a side mout gusset setup and takes up valuable seat space.

Here's mine... I went so far as to pull the roof and remove the factory B-pillar halo bar.

el es tu

So far youre the only person Ive seen here who has expressed interest in hill climbs. If you dont mind me asking, what other modifications do you plan to do the car?

Im asking because Im still in the testing and planning stage for my car which is getting set up for the same thing (street legal but setup for hillclimbs and some track duty).

opel

travisnd,
I'm leaning towards the way you and Kevin mount your main hoop it looks like it's the strongest and gives me more room for when I run the stock seat. The Sparco EVO2 takes up a lot of floor space as it is, I don't know if I'll have room for a bar down there as well. Plus I never liked the side mount idea. I do under stand the shelf is way to weak in stock form I'm hoping some one might have a way to strengthen it up so it might be an option. Could you please post the measurements for your main hoop width down near the bottom were it goes into the wall?
Thanks,
Dave

el es tu,
There's not a lot of hillclimbers on this forum. Most of my road racing friends think I'm crazy for hillclimbing they won't go near it. A friend that wrote for Grassroots Motorsports said in a article some thing to the effect "that there's two types for hillclimbers those that have wrecked and those that will wreck. You have to be able to except that you car may be (and if you do it long enough will be) damaged/destroyed." With that said you don't have to go out looking to set records every time you run, you can just go out to have fun. My cars a 99 FRC it's a replacement for my last car, a highly modified 85 C4. I WAS going out looking to brake record in the C4 and did set my share and also had my share of mishaps ( mishaps is French for the driver f**ked up).
I spent so much time and money on the C4 that it kind of took some of the fun away. I'm not going to do that with this car. I autox it as well and will stay in AS for the autox the only mods will be those allowed in AS. The group I run with runs street tires only in stock, I like that idea. For the hillclimb's they don't have stock classes so I'm going to run in the ASP class. The only things I'll do for the Hillclimb is run the race seat and bigger rims with race tires.

What are your plans for your car.
Dave


PS
Some hillclimb videos.
http://www.youtube.com/watch?v=aRczwulMa-c
http://www.youtube.com/watch?v=IHs0_tWgL38

travisnd

Sure... I'll measure it this evening.

fatbillybob

I think you need to consider where your biggest safety threat is and design for that. I think picture 1 where cage feet are on unibody shelfs are weak and will punch through in a rollover. Picture 2 with feet on frame rail I call the Pheonix design. Lots of their C5/6 racecars in T1 are that way. This to me is best for rollovers and gives the most cabin room. It is a good design but my biggest threat and fear is getting T-boned on the drivers door in T1 racing. X-doorbars work by tensioning the A and B pillers. NASCAR bars work by shear mass putting energy into the A and B pillers. So when you have a curve in the NASCAR bars you loose some of the side impact integrity. So I stole this design from a Bimmer guy who posted his C5 build on CF and added the seat frame as a place to mount my seat to the cage (not floor) and house my harness anchors. I think the bimmer guys is the second best place to put the feet of a rollover hoop if that is your primary concern and only a 4pt is needed since it is primarily plated and welded to the same chassis frame rails that Pheonix uses just not in the best place.

fatbillybob

el es tu

I grew up in the country near some very twisty backroads, and just about the only thing to do out there was drive for fun. This is what really got me into hillclimb/rally.

At this point in my life, Id rather do it on a closed section of road, and since my c6 isnt a daily driver, it seemed like a good choice!

Plans are to make a street legal vehicle that looks like it came from the factory, and make it fun and reliable at high speeds on rough tarmac (backroads) and some light track duty.

So far Ive got the suspension dialed in almost to where I want it but its biased more for the backroads than smooth track. The brakes (likely AP or wilwood) wheels and tires (Bridgestone RE11 or Kumho XS) are my next thing before taking it to an event as my tires are worn and the brakes are on their way out so Im kind of in limbo.

Other modifications will just be for weight reduction and safety - gutting the sound deadening and possibly some carpeting, racing buckets and harness, fire extinguisher, and a half cage.


cool videos. I have had a hard time finding anything with vettes!

opel

I agree I think the frame location in pic 2 will be my best option. The first pic is of my C4 and the shelf in the C4 is a lot stronger than the C5.
Door bars or a full cage are not an option for me I need this to stay street legal as well as legal for AS autox. Hillclimb's are a timed event like autox one car at a time if I get hit in the door by another car some one really Fu*ked up.
At 6'1" I need all the head room I can get I don't think I would fit in the car if the seat was mounted on a cage like in your pictures, but if I had the room that would be the way to go.
Dave

opel

Any chance you had time to measure you bar.
Thanks
Dave

yooper

I am 6'4" and 250lbs and like what travisnd did with his cage. A few pictures from my build.

travisnd

Sorry about that... outside to outside of the main hoop is 54"

opel

Thanks guys keep them coming.

MySR71

If you want to keep the stock seat belts, be careful where you put the main roll hoop. You may have to position it a little further aft and/or lean it backwards slightly if you want it behind the seat belt pully that is up on the A-pillar.

C4B4the04

Here are a few shots of the Pfadt bolt in roll bar, one of the best I think.

http://s88.photobucket.com/albums/k1...04/Roll%20Bar/

Just pulled it to do a full cage this past week but hopefully this gives you some idea what is involved with a GOOD quality bolt in. Riv-nuts do NOT have nearly the strength of a good weld, obviously but this is as good as I think it gets for removable.



GL
Cassidy

travisnd

^ Wouldn't need a rearview mirror in that thing... nothing to see except bar.

opel

I contacted Pfadt about there bar, they could not tell me if it met the time trail 4 specs. If it did I was going to see if I could pick up a used one some were.
Dave

C4B4the04

If you know the specs on the needed bar, example would be wall thickness and tubing size, then you should be able to tell if it meets specs. Certain tubing is made a certain way, this is not my expertise but I think DOM (drawn over mandrel) is the one you want?

Cassidy

Pfadt Racing

Our chassis bar is 1.750 x 0.95 Chromolly and upon first glance seems to conform to the "American sedans May construct to these specs regardless of weight" caveat. If you've got specific questions you should email your local time trial association and get clarification. Ultimately they're the final word on whether or not the vehicle will pass inspection, but it does seem like it's good to go. Clear the material and wall thickness up with them to ensure that it's legal and good to go.

Keep in mind that our Chassis bar is fastened to the vehicle with RivNuts and in no way is implied as a replacement for a properly designed weld in cage on a race car. You could use it as a foundation for a cage and weld it to the structure. As our Chassis bar ships, a proper cage will provide a level of safety that our Chassis bar cannot. The main purpose of the Chassis bar is to have a bolt in solution for folks who want to properly and safely mount harnesses or camera equipment and still run their cars on the street.

Zip Corvettes

[IMG][/IMG]
[IMG][/IMG]