Project 4 from Agent4573 - Category - Offroad Fabrication

[agent4573]

I picked up a sandrail frame for a project and am going to be building it up over the next few months/years. I figured I would start this thread now and use it as a complete build thread as I make progress. This is what I'm starting with:





The front beam and complete rear end are going away. I picked up a set of A-arms for the front, and 5x5 trailing arms for the back that I need to modify to fit the micro-stub 930 cv's that I want to run. I also picked up a complete 1995 300zx motor for the back of it. Came with all sensors, wiring and ECU, so it should be relatively easy to get it to run. It will need an exhaust fabricated up though, because the headers point the wrong way right now.

The next part of the project was going to be building up a frame jig out of 2x2 steel tube. Just so happens the guy I bought the A-arm from has one made for his rail and he is letting me borrow it. Its a pretty nice 4x10 foot table, all 2x2 inch square tube with leveling feet and castors built in. Will save me at least a couple hundred on tubing and a bunch of time not worrying about making a straight table. I should be able to start cutting and welding in the new frame next week.

EDIT* Also, if anyone needs one, I have a pretty stock 1600 dual port that I'll be selling with the entire IRS and trans in the pic. Let me know and we can make a deal.

[agent4573]

Decided the other frame wasn't even worth trying to save. Designed one myself that should just fit inside my trailer. Started the mock-up in 1/2 inch electrical conduit so I can get an idea of what it looks like without spending real money on tubing yet. 100' of tubing is 17 bucks. The bender cost me the most and was almost 25 bucks in it self, but still worth it. I should be able to finish up the mock-up tonight and go pickup some real tube tomorrow and start cutting and bending.

[youngnstudly]

I like the design of the first frame, but since you're set on getting rid of any traces of VW, starting from scratch will probably be easier since you can put your parts where you want them. Design the frame around the stuff you want to run, so to speak. It's nice you didn't have to build your own jig either. With any horsepower at all, rear engined rails are a lot of fun to drive (and even scarier if one of your "nut job" buddies is behind the wheel!).

Are you actually planning to make this street legal when finished, or just use it as a toy?

[agent4573]

California won't let you reigster buggies for the street, so it'll be just a toy. If I can ever move out of this state, I'll try to get it registered for street use. I wanted to save the old frame, but once i measured out where stuff had to go, it would be a complete hack job to stretch it from a 2 seater in to a 4 seater. I feel safer with solid bars everywhere and not cut and spliced bars running around everywhere.

[youngnstudly]

I had a buddy that was set on building a street legal rail, only to find that California didn't allow that. It was VW powered so he was able to build a legal Manx using his existing components and a VW chassis (lucky for him!). You're absolutely right about being safer with less splices! Can't put a price on your life or health, so it's better to be safe than sorry.

[CGCINC]

Can't wait to see more progress pics!
I have wanted to build a custom buggy for awhile since I have an ATV state park two miles from my shop. They always have "sand" drags up there and some really cool buggies come through

[agent4573]

Well, I tried to start the build a tuesday and it didn't go well. Got to the metal supply shop and they changed the price of steel on me. Over the phone they quoted $27 for a 20' length, got there and it was $40 for an 18' length. They said the guy on the phone quoted me the standard 1018 price and not DOM pricing, so the steel is going to be quite a bit more than I thought. I also mocked everything up assuming I could get 20' sticks of steel, because almost all the long pieces I need come in at just under 10' in length. Now that I can only get 18' pieces, I'm going to have to buy almost twice the amount of tube I was planning on, because I'm only getting a single 10' length instead of 2 out of each piece. There is another place that will sell me a 24' length, but the price is $75, so in my opinion its worth it to buy the 18' and have all that extra tube laying around. Also, they only had 2 18' pieces in stock, so I bought both of them and they said they would order more for me and have it in by yesterday.

I also made my first bends in one of my covetted 10 foot sections, and screwed it up. The bends came out really nice and were exactly the angles I needed, so I was happy at first, but then I held it up to the mock up piece and found that my two bends were about 6 inches too close. After about an hour of trying to figure out what I did wrong it hit me. I scribed the tube where I wanted the bend to start, then loaded the tube in the bender backwards, basically putting the bend on the wrong side of the scribe. Steep learning curve, but I should have it figured it soon. I have enough lengths of tube left to get 2 or 3 pieces in place and tacked together, so hopefully I'll do that tonight/tomorrow. If I can get out of work earlier enough to go buy pick up some more tube I'll be able to get much further along this Sunday.

[youngnstudly]

Bummer! I hate it when things seem to work against you all at once on a fresh project! It's like a sign from above (or below?) not to get started. I try to keep the same sizes of tubing around so that screw ups on one project are useful on another project, and it sounds like you are the same way.

The metal supply shops around here are unbelievably high on prices, and cut charges are always $8 to $12 (per cut) for chop saw or band saw cuts, and $5 (per cut) for torch cuts. Their idea of giving you a discount price on multiple cuts is knocking off a few bucks on the second and third cuts!

I don't ever remember getting 18' long pieces of tubing from anywhere, maybe that's just for DOM in your area? Or maybe they figured out that they could charge you twice as much by removing 2' immediately upon delivery (kidding of course!)? Better ask if they offer a discount on bulk 2' sections that are out in the yard though...just to be sure!

[CGCINC]

Are you located anywhere near northern Arkansas? I use a supplier their that delivers 3 hours to me for free and the prices are Half the price that a local supplier wants.

Also, when you mark your metal to bend, it might help to draw an arrow pointing the direction or side of the mark you want the bend!?!

[agent4573]

Are you located anywhere near northern Arkansas? I use a supplier their that delivers 3 hours to me for free and the prices are Half the price that a local supplier wants.

Also, when you mark your metal to bend, it might help to draw an arrow pointing the direction or side of the mark you want the bend!?!

Southern California. Everything is more expensive here. Got two pieces made last night that were exactly what I wanted then had a brain fart and messed up a third piece. Its annoying, but I haven't really wasted any metal yet. All these screw ups can still be used as other bars in the project. I was planning on buy a few pieces a week every time i got paid, but these mess ups are pushing my purchases forward and I'm spending money faster than I would have liked. I should get the last 4 pieces bent up tonight (nice and slow like, no mistakes this time) and get the tubes notched and tacked together after work tomorrow. I'll try to have pictures by sunday night.

[Odyknuck]

Decided the other frame wasn't even worth trying to save. Designed one myself that should just fit inside my trailer. Started the mock-up in 1/2 inch electrical conduit so I can get an idea of what it looks like without spending real money on tubing yet. 100' of tubing is 17 bucks. The bender cost me the most and was almost 25 bucks in it self, but still worth it. I should be able to finish up the mock-up tonight and go pickup some real tube tomorrow and start cutting and bending.

The Parallelagram cage design will collapse on the first rollover. I would recommend flipping the "B" and "C" pillers to angle towards the "A" piller so your cage is in compression.

[CGCINC]

The Parallelagram cage design will collapse on the first rollover. I would recommend flipping the "B" and "C" pillers to angle towards the "A" piller so your cage is in compression.

How do you know this stuff because I want to learn it??!? Did you go to school or read books or just trial and error and learn along the way!?!?

[agent4573]

The Parallelagram cage design will collapse on the first rollover. I would recommend flipping the "B" and "C" pillers to angle towards the "A" piller so your cage is in compression.

The rear mid-crossbar has been moved back around 6 inches so the rear cage arms now come down at an angle like you suggest. Also, what isn't shown is that there will be an engine section added on to the rear so it will also have arms coming backwards at ~45 degrees off the top of the roll cage to tie it in as well. The "B" pillar can't be flipped because you won't be able to get in or out of the back seat, but the "C" and "D" pillars if you will will have the correct angles to suppost the cage properly.

EDIT* The "B" pillar has also been brought closer to the verticle for better support as well.

[Odyknuck]

Ok, Good to here as i do not want to see anyone hurt. Can you at least make the "B" piller vertical? Are you going to "X" brace the "B" and/or "D" pillers?

[Odyknuck]

How do you know this stuff because I want to learn it??!? Did you go to school or read books or just trial and error and learn along the way!?!?

Not to hijack the OPs thread however I have been in the off road arena for over 25 years, racing, trail riding and building Buggys. Your bound to pick up a few tips and tricks along the way lol.

[agent4573]

Planning on "x"ing in the top of the roof, and depending on radiator mounting location, will either box the C or D pillars. Also going to put a Y in the windshield tied into the front suspension points. Not going to x the "b" pillar, but I am going to gusset the a,b and c pillars with 3/16 plate, prolly just a simple triangle gusset with ~3 inch legs. If I take the b pillar vertical, it only leaves me with like 14 inches across the mid-rail to get into and out of the back seat. I know its a small car, but thats a little too tight. Leaving it at an angle gives me about 18 inches for both front and rear seats.

[agent4573]

Had to work saturday so I didn't get much done then, but I got quite a bit accomplished today. Laid out the bottom layer and tacked it together. Made 6 uprights to hold the midrail and got them all notched up. Tomorrow I should be able to bend the midrails and get them tacked in pretty quickly.

[agent4573]

Got the mid-rails tacked into place tonight.

[MuttonHawg]

Do you have an estimate of what you'll end up with for a wheelbase or final total weight? And what kind of oomph does that 300ZX motor put out?

Are you designing and building the suspension parts yourself also? Or do you buy those? For me, I'd probably trust myself with designing the roll cage, but for some reason suspension and steering geometry design freak me out a little

[agent4573]

Wheelbase will be right around 118 inches depending on how close to my design I can actually build it. Front track width is 76 inches, rear is 68, but overall width is the same due to different tire sizes front to rear. I would make the front narrower, but I got a deal on the a-arms below and thats as skinny as I can possibly make the front. I would make the rear wider to compensate, but that's as wide as I can go in the rear and still fit in my toy-hauler, so its going to be a completely square car. Stock 300zx puts out 222hp, and low 200 torque, but the internals can handle ~500 hp if I ever decide to turbo it. I'm hoping to come in around 2000 pounds. The rear arms aren't a great design, but they'll work for my light car, bought those too. The front spindles design in the steering geometry, camber, caster, etc so all I really have to do it mount the front arms and place the steering box correctly and I should be really close. I used a couple free suspension programs and found my inner arm mounts points that give me ~1 degree of camber change over the 18 inch travel range. I can live with that.