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Hello, Im starting to build my E30 and need help with the rollcage
Does anyone know where i can get any Bmw E30 Roll Cage Drawings?
Im getting ready to do mine and wanted to see if i could get some drawings so i could take ideas for mine!!!
Pics would be cool too!!!
Thanks
here’s the BTR design. If you do a search for “cage design”, you’ll find quite a bit of information. I’ve got a pdf of build pictures and more drawings if you still need more. But you should find more than you need here.
http://spece30.com/component/option,com_kunena/Itemid,86/func,view/id,6255/catid,12/
I’m trying to get my cage underway as well. I know the rules are different for spec-e30 cages and I had a couple questions.
So there are bars in the diagram that show two bars going forward to the engine bay. Do they connect to the strut towers like this? Or is this not allowed in spece30?
Also I think this is a better look/design for the door x’s. The two V’s, Ok? benefits?
Also how is the rear handled. Do you tie in the floor pan above the diff? What does this do? Illegal? Good?
Also what about the bar coming down from the main hoop and attaching to the area below the rear seat by the subframe bolts? Benefits? Necessary?
What material are the clamshell gussets made out of? Just sheet metal? Thanks guys.
I don’t care for the door bars, but otherwise a nice cage. Though it would not be legal in a Spec E30.
The pictures provided show illegal reinforcement points. Click on Spec e30 rules and read them. The rules are specific and easy to understand.
RP
Luis - Where are you located? It never hurts to take a look at some local cars for ideas.
Pink - Just about every illegal attachment method/point is in that cage. :laugh: Read the CCR Section 15.6.
Just a quick review:
Other than that, the photos look good. 
PS - Personal preference, but I like door bars that extend out into the gutted door almost to the outer skin. That gives a few more inches of room between you and the hitter. I like the factory-911-cage look of those cross bars, but I am skeptical that they provide as much protection as nascar bars.
lots of good points already made above
I like the dual V doorbar design and it can be pyramided (is that a word?) outward into the doors if you’re gutting them. The one in the white car pictures looks too low though. I also like the idea of a bar going vertically from the forward floor plate up to the bar at the top of the A-pillar as well, but that makes egress somewhat harder. Try to create nodes where multiple bars join at one point and triangulate as much as possible for stiffness.
There are a number of good cage threads on bimmerforums.com also. Look for “teh jaffscage” and also the various track build threads in the build subforum of the track forum.
cheers,
bruce
Those photos are from a couple different cages. I kind of figured the areas that were in question were not spec legal, but I only read the rules on this site so far. I suppose I should read the CCR rules if I want it to pass for spec! I’m not positive which direction to go.
It’s just a track car right now. I might run lemons or chumpcar depending on the team. If I chose to run a different series later I wanted it to tech for spec or maybe gts2. There looks to be more freedom in gts2 or is spece30 where it’s at?
Read either the Spec E30 or SCCA Improved Touring rules concerning cages. Both are clear. Next, get a cage builder with experience…they know much more than any of us and you just need to tell them your preferences…such as door bars and rear down tube location. Let them do their thing any you will be safe. Chuck
Here’s another option. It’s pretty much what Bruce mentioned. The point where the bars come together is within a few inches of the exterior door skin. The gussets are small triangular sections of 1x4 rectangular tube. It was a pain to get all the angles just right, but I’m really happy with how it came out.
Matt
That’s a nice alternative. Personally I want to learn how to build and fabricate. First couple go arounds aren’t going to be perfect, but that’s how you learn. It’s funny how whenever you talk about roll cages, everyone just says have a professional do it…how about building engines? Everything else? No one jumps the gun on other topics to go to the pros. To be considered safe it has to pass inspection. If it doesn’t pass it doesn’t pass. If it passes, it’s safe!
Pink wrote:
[quote]If it doesn’t pass it doesn’t pass. If it passes, it’s safe![/quote]The downside is that it could pass with a weld that looks ok from the outside, but that has bad penetration. Everybody has their own comfort level for risk, but personally, there’s enough of an art to it that it’s not worth taking the risk for a load bearing, safety component.
laz wrote:
[quote]Pink wrote:
Lack of penetration is a weld is only a bit worse than poorly fitting joints. Once welded in there’s no way for an inspector can tell how good the joint was. Having the right tools and experience is a large part of what makes for a safe cage.
Pink wrote:
the reason that this section is in the CCR is because an inspector cannot effectively check the welds
[quote]15.6.15 Welds
All welding must be of the highest quality with full penetration and shall conform to the
American Welding Society D1.1, 1994 Edition, Structural Welding Code, Chapter 10,
Tubular Structures and Standards for the material used. Arc welding should be used
whenever possible. It is strongly recommended that the welder inspect all welds using
Magnaflux™, x-ray, or other effective methods. All tubes must be welded 360-degrees
around the circumference of the tube.[/quote]
Pink wrote:
That’s silly. How much time do you think that tech is going to spend inspecting your cage when there’s a 15 cars behind you all trying to get their annual tech in a hurry before morning practice? Tech probably has a dozen things he checks because his experience indicates that those are the high probability issues that folks neglect.
Your car being safe is your responsibility, not his.
That being said, I entirely support your DIY desire. But maybe a cage isn’t the right place for it unless you are already really good at that sort of thing.
When I needed to build the bottom end of my motor last year. I mean the first time, not the 2nd or the 3rd, I went to a local performance shop and told them that I wanted to assist their engine builder do it because I wanted to learn. They told me that would cost me more because there’d be a fee to put up with me. If you knew me, that’d make sense.
So I built the bottom end under the (not very watchful) eye of their engine builder.
My point is that there are ways to take on DIY projects that you might not be ready for. When you’re highly motivated, there’s always a way.
Pink wrote:
I built our cage along with a professional who happens to be my brother. He builds plenty of cages for LandCruisers, but this was his first E30. After spending what feels like 1000 hours in the shop working on this, I’d recommend paying someone to do your cage. Even if you do have access to the tube, a chop saw, welder, angle grinders, tube bender, angle gauges, clamps, etc, etc, it’s still worth a couple grand to not have to deal with the huge frustration. Granted, the first time is always the most difficult, but after seeing Jim’s cage, $1800 seems really cheap. I have a new respect for the amount of time, knowledge and skill that goes into a good cage.
Also, if an engine fails when tested you probably won’t be injured or killed.
Matt
As a ME, I built my first cage. I had welded 20 or so years earlier, so I practiced with the actual tubing, cutting a joint apart and beating it flat with a large hammer/anvil to make sure the weld was structurally sound. Then I welded the cage. After I sold the car, it was tested 4+ times without failure.
There are three things first time builders must contend with: First, being able to bend DOM tubing…generally can’t do it at home. Second, fit up must be very good. Third, recognizing the heat line outside the weld and insuring it is equal on both pieces welded together. That is an indication of weld penetration. Good luck, Chuck