SW20 Half Cut Trailer Build

We saw a couple at the Toyota Nationals on the weekend.
 
 
 

Don't forget to include a generator and battery bank to keep the 2GR going ;)

I've continued working on the trailer last weekend and this weekend. I've made some good progress so far. 
 
First step was putting the suspension in the car. It sat wayyyy too high, the guard is 5 inches above the tyre.I fixed this in later photos by cutting the springs. 
 

 
Temp wheels on until I can find some
 


The first step was bracing the chassis so that when i cut the tunnel and firewall out, it wouldn't get floppy.
 

 
Tacked the braces on and got cutting!
 

 
Sabre saw made life very easy. I still have some more trimming to do, but I wanted to get the majority of the material out of the way. 
 

 

 


I did a fair bit of reading on draw bar design, and after talking to the trailer shop I decided on a hybrid single beam. The Beam will have some very short diagonal braces as a backup and additional strengthening. I opted for a 75x50x5mm piece of steel 
 


The benefit of the single beam is that my turning radius in small spaces is increased greatly. When measuring the drawbar length up, I copied my 6x4 box trailers for length as it is easy to reverse and tow. The trailers tub will not hit my car at any point during turning.
 

 
Craig and the trailer shop had both informed me not to weld directly onto the top and bottom of the drawbar, as the bar would fatigue over time. I used some 4mm angle to mount the bar on the sides. As a backup, I will add two bolts that go through the intersecting points of the front cross beam and the subframe. 
 

 
And yes, I did weld directly to the subframe. Since it doesn't' have an engine, I should never have to remove the subframe
 
Tomorrow I will add  the hitch and do some more welding on the drawbar and chassis before taking it for a quick test in the yard with the subaru. 
 
 

Things progressed quickly for a while, but I had some very important exams so the trailer got put on the back burner. 

Updates on what has happened:

Cutting progressed and I ran into an issue. The suspension mounts are part of the chassis that I was cutting out. I came up with an idea to brace this area and also make the drawbar stronger. 


 
I made up a hybrid draw bar, consisting of a small A frame onto the beam. This setup allows me a lot of turning room. Hard to see in this photo, but I used some thick angle to brace the original suspension mounting points back to the chassis, then welded the rear section of the A frame to the angle. 

I did a quick mock up behind my car:

The trailer sits nicely and pretty level too. I am going to get a custom made tow bar to suit the trailer. Drawbar weight is about 20kg's which is where I want it to be at this stage. This will change when I add tools and wheels in etc.

Finally, I cut out the front bracing as it was no longer necessary with my new supports. Even with no supports the chassis is extremely stiff. i was really surprised! 

Its sitting in my driveway at the moment waiting for me to have some time. As I am going to do some sheet metal work. I bought a tig welder to do the more intricate stuff. 


 
More updates soon! (I hope)
 

I sold the halfcut to a gentleman who had been in a nose to tail.
Since then I bought an Easytrailer 830TA which only weighs 65kg complete and can carry all my equipment to the track :)

me too, but it would have weighed over 200kg unlaiden... my new trailer setup including 4 wheels and tools weighs about that.