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Sorry assumed you had one but at least you're in the z family Looks like you got your hands full! Ill be doing a cage soon, was planning on dropping car off after new year but I just messed up the fiberglass rear hatch I was working on so I gotta start over from scratch :/.
Oh yeah, I have an 06 350z with a few mods. Although, Its my daily driver so I keep things nice and simple.
That's a bummer on the hatch. Fiberglass is tricky. In the picture, were you making a transfer mold or are you replicating the hatch in place?
What are you doing for a cage? The way you mentioned it, I assume you are taking your car to a race shop. Id like to know the price you got as well as specs.
In the picture, I was making a hatch in place... it fit fine then I added ribbing to it on the underside and fiberglassed it which caused it to contract because I didnt set it on the car... amateur mistake.
Taking my car to a shop... I called around locally... 6 point cage seems to come in around $1800 on average. Added bonuses like a-pillar gussets are $200ish... I want 6 point, a and b pillar gussets as well as a diaganol bar above head. I believe this would add decent rigidity to the chassis. This will add $500 to the base price. I havent negotiated with the guy yet so i think I can get this setup for $2000...
Anyone with more experience on increasing chassis rigidity with roll cage care to chime in?
Ah, I see. I was going suggest that perhaps you build a hatch skeleton out of balsa wood and then glass a shell of that. This is kind of how model airplanes wings are made. It works extremely well and is very light. It will be as rigid as it needs to be.
That cage price is spot on. A local race shop will charge about the same for an equal cage.
When it comes to rigidity, the differences between the cages have the slightest effect on what flexes(so minor, it probably wouldn't even matter). If you have a full 6 point with single diagonals where they are required, you will be more than good to go. The most effective additional braces you could have will be seen in the picture I posted, the lower diagonal from the rear strut tower to the bottom of the main hoop. The door bars as an X work very well too.
I wanted to add an idea to consider. You are very focused on weight savings so, it would be a good idea to go with Chromalloy if your budget allows. It is significantly lighter and a bit stronger than mild steel, even when it's not normalized after welding.
Last edited by 90nissanS13; Dec 15, 2015 at 12:29 PM.
Very interesting... although its not an obvious place I would add tubing, seeing it makes perfect sense why it would stiffen up the chassis. Thank you very much. So you are saying opt out of a and b pillar gusseting? Although I dont want to cut corners, my budget is not very high (as you can tell by the ghetto hatch making ) and id like cut unnecessary costs. Any advice is appreciated.
I have considered 4041 chromoly, its what we built the frame for out SAE Baja car out of... need to speak to the shop owner about his pricing with this option.
Thanks for the advice. I might be down in Florida with my R6 race bike doing a track day at Jennings... any chance you're in that area?
Originally Posted by 90nissanS13
Ah, I see. I was going suggest that perhaps you build a hatch skeleton out of balsa wood and then glass a shell of that. This is kind of how model airplanes wings are made. It works extremely well and is very light. It will be as rigid as it needs to be.
That cage price is spot on. A local race shop will charge about the same for an equal cage.
When it comes to rigidity, the differences between the cages have the slightest effect on what flexes(so minor, it probably wouldn't even matter). If you have a full 6 point with single diagonals where they are required, you will be more than good to go. The most effective additional braces you could have will be seen in the picture I posted, the lower diagonal from the rear strut tower to the bottom of the main hoop. The door bars as an X work very well too.
I wanted to add an idea to consider. You are very focused on weight savings so, it would be a good idea to go with Chromalloy if your budget allows. It is significantly lighter and a bit stronger than mild steel, even when it's not normalized after welding.
I'm digging the hatch Rev. B lol. I'm excited to see how it progresses. It's not ghetto, it's called innovating with a bit of improvisation.
LOL I totally meant to write chromoly. Chromalloy is a locally related company to where I work. Ahaha, I feel dumb. I'm not familiar with 4041. 4130 is the common alloy for a roll-cage. Engineering student I assume, I think everyone should be required to be involved in the SAE programs.
I'm closer to PBIR and Sebring. Jennings is cool, it seems like a big bike track.
I wouldn't opt out of gussets. They only help to reinforce a welded joint. When you say gusset, I'm imagining a 2 inch section. An "A" pillar gusset can sometimes be from the roof to baseplate like a GT3 spec car. A "B" pillar gusset can be a little 2 inch section or a 12inch section from the main-hoop to halo-hoop(provides head protection as well). I'm a fan of the "large" gussets, that's what I'll be doing on mine as I move towards the front axle.
A cage like this is usually bare minimum for SCCA and NASA spec road racing. The rulebook specifies tube thickness, diameter, material and baseplate details. Anyother braces you add(whether they are logical or not) are usually allowed. You could probably ditch the diagonal over your head, that won't really do much for rigidity or "safety". A roll-over should be on the main-hoop, Halo and a-pillar.
A cage like this is usually bare minimum for SCCA and NASA spec road racing. The rulebook specifies tube thickness, diameter, material and baseplate details. Anyother braces you add(whether they are logical or not) are usually allowed. You could probably ditch the diagonal over your head, that won't really do much for rigidity or "safety". A roll-over should be on the main-hoop, Halo and a-pillar.
Really? The diagonal in the main hoop is what keeps it from collapsing on your head.
Yeah, the mainhoop and halohoop are in two seperate planes which are perpendicular from eachother. The mainhoop(behind the driver) includes the seatbelt bar and the diagonal brace. Those aren't considered "over your head". The halohoop(over your head)can be in two configurations but doesn't require any additions braces. This stuff can get messy and confusing, many rulebooks dont even get too in depth with details so it takea a lot of research to gather the right info. The nutshell is, start with a bare min requirement and add from there.
On the other hand, that overhead diagonal isnt a bad idea but isnt required. This car probably flip 20 times down a montain and you can see its all supported on the main hoop, halo and a pillar.
Yeah, the mainhoop and halohoop are in two seperate planes which are perpendicular from eachother. The mainhoop(behind the driver) includes the seatbelt bar and the diagonal brace. Those aren't considered "over your head". The halohoop(over your head)can be in two configurations but doesn't require any additions braces. This stuff can get messy and confusing, many rulebooks dont even get too in depth with details so it takea a lot of research to gather the right info. The nutshell is, start with a bare min requirement and add from there.
On the other hand, that overhead diagonal isnt a bad idea but isnt required. This car probably flip 20 times down a montain and you can see its all supported on the main hoop, halo and a pillar.
That guy looked like he's had better days lol... here's today's progress
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Right on man, hopefully non of us get to experience what he did!
The hatch is coming along great. Is this without the OEM hatch underneath of the fiberglass panel? Would you show an interior shot?
Negative, that is just the fiberglass panel.. in the third picture you can see the oem hatch sitting on the floor. Ill get you a shot of the interior tomorrow, right now its just the inverse of the top, its only 2 layers of cloth and 3 layers of resin thick.... going to do the ribbing tomorrow. Only part that needs ribbing is the big part right after the window, if you push down on it its super flimsy! Once the ribbing is in itll be solid. The other one i made had ribbing and it wasnt going anywhere... heres a picture of the one thats in the trash.
It reminds me of a big waffle. What are you using to create the ribbing? It almost looks like a foam filled sub-layer. You could always make a thin wood rib but, mock it out of cardboard prior to fabricated the wood. The wood can graph on to the fiberglass very easy.
I'll be doing something similar with my 240sx when I get to the body.
I hope you are using a proper respiratory-filter when you are sanding! Those little glass-fibers are no good in your lungs.
BTW, it this your daily driver? I don't suppose you need one so much based on where you live. I NEED a car where I live.
Looks like you got your hands full! Ill be doing a cage soon, was planning on dropping car off after new year but I just messed up the fiberglass rear hatch I was working on so I gotta start over from scratch :/.
) and id like cut unnecessary costs. Any advice is appreciated.
