roll bar bracing/strengthening - NJFBOA - Home of New Jersey's Camaros and Firebirds

sweetbmxrider · 01-09-2010, 03:02 PM

does anyone have some good info or links on strengthening a 6 point in an f body? i had purchased a wolfe bolt in 6 point with the rear bars that go to the wheel wells but am not pleased with that and plates for the attaching point. also just looking for overall info into tying the bar into the frame structure. the main hoop sits on the floor pan and that seems kinda weak even though its a unibody car. was considering tying them into the subframe connectors.

thanks

Mike · 01-09-2010, 03:16 PM

So are you trying to turn it into a weld in? Or just make better bolt in points? I have a picture of a mustabg that rolled with a bolt in bar and when it hit the roof the bottoms of the main hoop punched through the floor

sweetbmxrider · 01-09-2010, 03:25 PM

sorry yes it is going to be welded in. i believe i saw that pic, didn't he not have plates under the bars or something?

LTb1ow · 01-09-2010, 03:50 PM

Lots of plates, and I guess you could drill the unibody and tie into the SFC.

sweetbmxrider · 01-09-2010, 05:03 PM

well the front bars mount over the top of the subframe. the roll bar comes with plates to mount under the main hoop and rear bars. i am talking about strengthening where the rear bars and hoop mount and tying them into the subframe/connectors rather then welding them on the floor pan/sheet metal

transmaro93 · 01-09-2010, 05:26 PM

im sure we can figure out a good way to strengthen that up... your not concerned about the cage it self but rather just the mounting points welding and bolting to sheetmetal... when its on a lift one day we should take a closer look at it...

1QWIKBIRD · 01-09-2010, 07:55 PM

Go here:

http://www.blainefabrication.com/projects.html

There are multiple shots of 4th gen bars, not drag stuff, but still you see lots of pics of how the attachment points are handled.

Basic idea is you want the plate which is fit and welded to the floor to be in at least 2 different planes. This adds considerable strength to the plate. Most shots you'll see show the rear bars landing over top of or very close to the shock mounting points in the rear. The stock floor is reinforced in this area. I don't think you need to go through the floor to try and land on a subframe connector if the plates are properly executed and the welding is done properly.

sweetbmxrider · 01-10-2010, 09:06 AM

wow, those are some sick cars on there. thanks! we did see that where the shocks mount it is reinforced. i almost think i should get the over the rear seat bars instead, they seem to sit in a better location.

also, i don't mean going through the floor and attaching directly to the sfc, but using a brace bar with a plate welded under the car under the main hoop then welding it to the sfc.

when you say the plate should be on two different planes, you mean like this?

all of the welding will be done by a certified welder.

1QWIKBIRD · 01-10-2010, 10:01 AM

Yeah and this based on what I have read and seen and been told. If you can wrap the plate onto two different planes, you add siginificant strength to the structure and lessen the chance that the plate will punch through the floor or simply tear away from the floor.

Another solution if you cannot get the plate to wrap onto two different planes is to drill a hole in the center of the plate, maybe 1/2" in diameter, then weld the center of the plate to the floor as well. Ideally this rosette weld (I think that is the proper term?) would fall directly under where the bar lands. This increases the weld area and also helps to keep the plate from pulling on the floor solely at the perimeter of the plate and acts to distribute load on the entire area of the floor under the plate, not just the edges.

sweetbmxrider · 01-10-2010, 10:05 AM

ok I was thinking since it is a bolt in kit, either bolting it in as well as welding or welding around the bolt holes.

1QWIKBIRD · 01-10-2010, 10:15 AM

Quote:

Originally Posted by sweetbmxrider

ok I was thinking since it is a bolt in kit, either bolting it in as well as welding or welding around the bolt holes.

You'll be fine if you follow the destructions. What are you looking to do with the car? Drag race or something else?

sweetbmxrider · 01-10-2010, 11:47 AM

drag race, et as close to 10.0 when fully completed

LTb1ow · 01-10-2010, 12:26 PM

I think you know what you need to do... either do it like a regular weld in, or go big and do it extreme...

sweetbmxrider · 01-10-2010, 03:13 PM

heyyyy v6's are saweet! ok i lie

it is going to be welded in but the mounting areas leave a bad taste in my mouth. i would like to strengthen them so when i end up on my roof, i can tell people at the bar later that night how awesome it was.

LTb1ow · 01-10-2010, 03:20 PM

Make that puny Unibody into a steel master piece.

Mike · 01-11-2010, 02:31 AM

remember this is a tech section....

Pampered-Z · 01-11-2010, 10:28 AM

Just remember a 6 point bar is bacisally designed to protect you, not to streghten the frame. If you want to stregthen the car, you need to go from bars to a cage (10-12 point) and tie in the front and rear subframes. But, a bar will help some, although if you have swing outs it's not as strong either.

If you're not sure about welding it in then you need to get an NHRA rule book which details the size and thinkness of the mounting plates, welds etc so the car meets the rules.

sweetbmxrider · 01-11-2010, 10:57 AM

yeah i think i should grab a book and i'm really giving a 10 point conversion some thought. not to start an argument rather looking for an explanation, how does a 6 point NOT strengthen the frame? it ties directly into the front subframe and the rear bars attach over the top of the rear frame in most cases. i know a ten point will add more strength, but a 6 point will definitely stiffen up the car alot. i've read around and see people average about a tenth quicker simply adding a roll bar. then they have the subframe connectors that tie directly into the cage/bar for an even stiffer structure. this is what i am trying to do with what i have i guess. just looking for any additional pointers and tips to help the cause, like having the plate on two different planes.

WildBillyT · 01-11-2010, 11:12 AM

Quote:

Originally Posted by sweetbmxrider

yeah i think i should grab a book and i'm really giving a 10 point conversion some thought. not to start an argument rather looking for an explanation, how does a 6 point NOT strengthen the frame? it ties directly into the front subframe and the rear bars attach over the top of the rear frame in most cases. i know a ten point will add more strength, but a 6 point will definitely stiffen up the car alot. i've read around and see people average about a tenth quicker simply adding a roll bar. then they have the subframe connectors that tie directly into the cage/bar for an even stiffer structure. this is what i am trying to do with what i have i guess. just looking for any additional pointers and tips to help the cause, like having the plate on two different planes.

I think he may be talking about the purpose it was designed for. It is designed primarily for safety, with torsional rigidity and beaming stiffness as a side effect. Some of the 10/12 point setups are designed as part of the chassis and not an after-the-fact add on.

Just guessing though.

sweetbmxrider · 01-11-2010, 11:26 AM

ah very true

Pampered-Z · 01-11-2010, 01:42 PM

With a unit body car the bar/cage mounts to the floor pan not the frame, and with nothing going into the engine compartment the front subframe is not reinforce, likewise without bars going down into the trunk well you not supporting the unibody from twisting. Where in a a 10-12 point has a halo, front down bars, cross bar (under the dash) and bars that pass through the firewall to tie in the front of the car that makes it ridge. A 6-8 point bar is only to protects you from being crushed in a roll over or heavy side impact, what you want with a 10 second 130 MPH car. 9's and 135+ mph is 10-12 point cage. Under 7.5s funny car type cage/ Driver loops.

You really don't need to tie into the frame the way your thinking. look at the second pic, those bars are plate mounted. There are probably gussets under neither that attached the unibody to the frame rails, they don't actually pass through the floor pan. You have plates on both side of the sheet metal you brace off of.

Think ahead when you do your install. For my main hoop we used oversized plates so that if I ever need to we can add gussets to support the LSA mounting points into the cage. We also ran the rear bars into the trunk well. Again, we used plates that attached to the top of where the frame rails are and the plates turn down into the well. So if needed in the future I can add a cross brace for additional support.

01-11-2010, 02:21 PM

Quote:

Originally Posted by Pampered-Z

With a unit body car the bar/cage mounts to the floor pan not the frame, and with nothing going into the engine compartment the front subframe is not reinforce, likewise without bars going down into the trunk well you not supporting the unibody from twisting. Where in a a 10-12 point has a halo, front down bars, cross bar (under the dash) and bars that pass through the firewall to tie in the front of the car that makes it ridge. A 6-8 point bar is only to protects you from being crushed in a roll over or heavy side impact, what you want with a 10 second 130 MPH car. 9's and 135+ mph is 10-12 point cage. Under 7.5s funny car type cage/ Driver loops.

You really don't need to tie into the frame the way your thinking. look at the second pic, those bars are plate mounted. There are probably gussets under neither that attached the unibody to the frame rails, they don't actually pass through the floor pan. You have plates on both side of the sheet metal you brace off of.

Think ahead when you do your install. For my main hoop we used oversized plates so that if I ever need to we can add gussets to support the LSA mounting points into the cage. We also ran the rear bars into the trunk well. Again, we used plates that attached to the top of where the frame rails are and the plates turn down into the well. So if needed in the future I can add a cross brace for additional support.

what did your bar cost you?

1QWIKBIRD · 01-11-2010, 05:09 PM

Quote:

Originally Posted by sweetbmxrider

drag race, et as close to 10.0 when fully completed

If your goal is 10.0's then you should build for at least 9.90's and get the thing certified. This way down the road you'll have something of value that you possibly update as you go faster. Sounds like what you really need is a cage not a bar. And if you are gonna do it, do it in chromoly.....don't play around with mild steel at that level. Do it right. If that's not in the budget, then wait til it is.

Chris

Pampered-Z · 01-11-2010, 05:31 PM

Quote:

Originally Posted by JerzLT1

what did your bar cost you?

he he he, A good freind of mine is a welder/engineer and was going to put it in his car, then changed his mind. But he still wanted to install one, so I was his guinea pig installing it as he had planned for his car, back rails into the trunk well, the door bars mount into the front, this resulted in them not being very rigid as the weight would actually flex the floor pan so additional plates and riser supports were added up front as well.

It a basic S+W (8-point W/swing outs) with Steve's modifications. I bought it from him for what he paid for it and then I paid for the wire and gas for the welding. (Plus some beer and pizza). So let say i paid a 1/4 of what most people would pay!

It was a fun experience. We actually measured all the door gaps and such, put the car up on stands, let it sit for a week to see if any changed, then proceeded to weld everything in. Took us two weeks working mostly just the weekends.

Steve also did N2ODave's 12 point cage (same cage as mine with the added bars)

http://community.webshots.com/album/263592745zjeYOD

Quote:

Originally Posted by 1QWIKBIRD

If your goal is 10.0's then you should build for at least 9.90's and get the thing certified. This way down the road you'll have something of value that you possibly update as you go faster. Sounds like what you really need is a cage not a bar. And if you are gonna do it, do it in chromoly.....don't play around with mild steel at that level. Do it right. If that's not in the budget, then wait til it is.

Chris

Just remember once you go under 10's you need allot more stuff: Suit, nets, chutes, chassy cert., NHRA license.. Allot of money for parts that expire every couple years. Plus, if the car isn't allot faster then 9.90, once you add all the saftey requires you could be heavy enough to back in a 10.0 car! And Cromoly is also far more dollars for the material and the install. (I always get this backwards?) Steel-MIG, CM-TIG? I CM cage will be near double a Steel one in most cases.

sweetbmxrider · 01-11-2010, 06:23 PM

definitely some extra things to think about now. the most i see the car capable of is 9.5's and possibly 9.0's with the correct top end. it will be well under 150 so i won't need a chute. only the cage would need certing as far as i know. i already have pants and a jacket thanks to old man bill and the jacket is needed with any aftermarket power adder. 5 point can be re-certed every 2 years or sold on egay.

if i had known i would have been given this opportunity to have the cage welded in, i would have went chromoly 10 point right off the bat. for now i will just make do with what i have and limit the car to what it is allowed to run, if needed.

always appreciate everyones' inputs