1 (edited by ndbarber 2017-05-09 07:44 AM)

Topic: Adding bars to the top of a roll cage for more height?

Hey there!

I've spent some time searching on the forums but haven't found any examples of the solution that we want to do, so I figured I'd better ask before spending a couple hundred bucks to have a shop do some bending and welding for us.

My team got a '86 Nissan 300zx. Which ends up being a pain for taller drivers (and for the mechanic, hiyoooo). Hoping to get a few inches of clearance above our heads by welding a pair of exo-cage bars that run perpendicular to the A-bars on the top of the car. I'm wondering... Will this be kosher and will it pass tech?

Something like this maybe:
https://docs.google.com/drawings/d/1Zd2tsU0NqvlIiuowJcV6Zwe2S9Zu-q1ySChQ-kDGipY/pub?w=923&h=631

Some extra context:
We want to put in a new seat w/ sliders and cushioning worth a nickle, but we've run into a clearance issue with our current cage. I see a lot of posts about building a fresh cage and getting the height by going above the roof of the car with an exo-cage, but I don't see much about modifying current cages and if that'll pass tech.

Re: Adding bars to the top of a roll cage for more height?

Most common is to add a "roof bar" which either runs front to back at the center of the windshield bar and main hoop that bends up to touch the roof. Or the same idea but diagonal.

I could see what you've proposed working, but it needs to be blessed. Email HQ and get their input since they are the ones that make the final call.

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Re: Adding bars to the top of a roll cage for more height?

I have seen this done but the bars went from the header bar back to the main hoop.  We are in the same boat as you because we have drivers ranging from 5'7" to 6'4".  Our solution is to raise the mounting point of the slider off the floor with a 1" x 2" tube welded to a 1/8" steel plate we are putting down on the floor pan and then the back of the sliders are on the floor.  That gives us about 2" +/- of height difference with the seat all the way forward to all the way back.  Plus, out tallest driver will take the padding out of the bottom of the seat to give him a little more clearance from the bar.  BTW, we are not doing an exo cage.  Hope this helps

Skip "Mongo" L.
Team DadBod

Re: Adding bars to the top of a roll cage for more height?

Solution #1: Do a bent center bar that joins header bar and main hoop. It's ok to have one with a kink in the middle or on the ends. It won't be much but it'll give you an inch or so of extra clearance, which might be all you need.

Solution #2: cut out the floor from rocker to trans tunnel and from rear footwell to pedal box bend (not sure if fuel/brake lines go there, so be careful with that). Cut off the reinforcement that runs down the middle, weld a 2x1" steel square tubing perimeter (like this stuff , re-weld it. If there are fuel/brake lines, make sure to make an indent in the floor for them to keep them outside but inside the floor plane (shallow c-channel should work), and keep them covered with a welding blanket while you work. Weld strips of 1/8 steel as reinforcements for your seat mounts.

#2 is a bit of an effort but that's how I'd do it.

K Car Stalker

Re: Adding bars to the top of a roll cage for more height?

TheEngineer wrote:

Most common is to add a "roof bar" which either runs front to back at the center of the windshield bar and main hoop that bends up to touch the roof. Or the same idea but diagonal.

I could see what you've proposed working, but it needs to be blessed. Email HQ and get their input since they are the ones that make the final call.

Thanks, I'll go ahead and email HQ with the idea and see what they think... We've thought about the front-to-back centered bar, but because the current cage is damn near right up against the roof, we didn't think it'd buy us much unless we drilled through the roof anyway... which we don't mind, but seems like an awful bit of trouble considering the car is a T-Top and right/left main bars are exposed already.


moose72 wrote:

I have seen this done but the bars went from the header bar back to the main hoop.  We are in the same boat as you because we have drivers ranging from 5'7" to 6'4".  Our solution is to raise the mounting point of the slider off the floor with a 1" x 2" tube welded to a 1/8" steel plate we are putting down on the floor pan and then the back of the sliders are on the floor.  That gives us about 2" +/- of height difference with the seat all the way forward to all the way back.  Plus, out tallest driver will take the padding out of the bottom of the seat to give him a little more clearance from the bar.  BTW, we are not doing an exo cage.  Hope this helps

This does help, I think that may be how we end up mounting our seat's sliders regardless of how we get more clearance out of the cage.

firegremlin wrote:

Solution #1: Do a bent center bar that joins header bar and main hoop. It's ok to have one with a kink in the middle or on the ends. It won't be much but it'll give you an inch or so of extra clearance, which might be all you need.

Yeah we don't need much, we're just looking for a few good inches to help out with visibility and with the taller drivers. I forgot to mention the visibility issue we've got right now with the car. Other than the tallest guy, everyone else has to sit on cushions/tarp/phone-books to get their eyes over the dashboard enough to see.

firegremlin wrote:

Solution #2: cut out the floor from rocker to trans tunnel and from rear footwell to pedal box bend (not sure if fuel/brake lines go there, so be careful with that). Cut off the reinforcement that runs down the middle, weld a 2x1" steel square tubing perimeter (like this stuff , re-weld it. If there are fuel/brake lines, make sure to make an indent in the floor for them to keep them outside but inside the floor plane (shallow c-channel should work), and keep them covered with a welding blanket while you work. Weld strips of 1/8 steel as reinforcements for your seat mounts.

This is something I don't think I even considered for our car. "Can't raise the roof? Drop the floor." I think it would hurt our visibility too much right now since we can barely see over the dashboard. Shame, really, because that sounds like a real badass way to fix this problem.

Re: Adding bars to the top of a roll cage for more height?

If you would like, I can email over a sketch of what we are doing for the seat.  We found at www.speedwaymotors.com (not a shameless plug) universal sliders and plates you can use to get everything set.

Skip "Mongo" L.
Team DadBod

Re: Adding bars to the top of a roll cage for more height?

Thanks, but we've already got a seat and sliders. Bit of a story behind that... uhh... We're the guys that showed up to Joliet in July last year without a cage in the car, and no fabrication skills to really speak of on the team. We all learned a lot that weekend though. Honestly probably no better place to build a lemons car than track side at a race.

Anyway, on topic: Our car got thrown together super last second at Joliet last year and ended up buying a seat off another team to replace ours because our seat was too big.

8 (edited by firegremlin 2017-05-09 11:55 AM)

Re: Adding bars to the top of a roll cage for more height?

Another possible solution that should help if your cage is just too low:

- cut the cage off (as close to the spreaders as possible)
- lift it up until it hits the roof
- add a roof center bar so that it's so tight that it also hits the roof
- weld 4x6 1/8 plates back to the stays
- box them with 1/8 plate back down to the floor.
- option: cut off the rear stays and redo them using original spreaders.

Make sure that you can cut enough clearance to actually hit the roof and that there aren't gonna be any other surprise issues, but this should be way faster than pulling the cage and doing it again. Coupled with the roof center bar you should get a good amount of clearance.

Extra bonus is that you can move the cage over to driver side a bit for more driver room. Every 1/4 inch counts!

K Car Stalker

Re: Adding bars to the top of a roll cage for more height?

I solved that problem by putting the top the cage above the roof.  The Delsol is already a targa top car, so the roofline wasn't hard to work around.

http://www.murileemartin.com/UG/LSD17/503-_MG_5058.jpg

Kinda hard to do when the cage is already in the car.  I've seen bars done above the roof line from a left/right or halo cage - but they were not done as front and rear bars, but left and right side bars.  Conveniently gives the driver something to grab onto as they exit.

I've also done a clearance bar in the middle of the halo.  That is the bump you can see in the Bee's roof line:

http://www.murileemartin.com/UG/LSD17/442-_MG_4934.jpg

(I built both those cages)

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Re: Adding bars to the top of a roll cage for more height?

http://www.roadkill.com/wp-content/uploads/2017/01/Rollcage6_Helmet3.jpg

The MGB-GT that runs in the Midwest is my standard go-to for an example.

Also, you may or may not find this helpful:

http://www.roadkill.com/learn-safety-ge … ns-racing/

Eric Rood
LeMons Contributor for www.roadkill.com
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