Alright finally back with another update.
Installing my torque arm turned into a bit more of a project than I thought it would... as most things do!
First, the failure analysis. My old torque arm was a 2-piece design with one end attaching to the rear axle and the other end bolted the transmission crossmember. The 2 pieces slid into eachother so the arm could shorten and lengthen as the suspension cycled. My torque arm broke right at this joint between the 2 parts of the torque arm when a collar broke off. This torque arm was old, so my guess is it was on it's last legs anyway, and the stress of autocrossing and high RPM shifting was the straw that broke its back. I'm just happy it happened on a closed course and not on the highway where I would have been stranded.
I ordered my new torque arm from UMI. They have 2 options, a longer one that attaches near the transmission and a shorter one that attaches to a dedicated crossmember you can weld in. I chose to go with the longer one that attaches to the transmission crossmember. The issue for me, however, was that my old crossmember used a bolted joint where my new torque arm uses a bushing. So, I started the search for a new crossmember!
There were only 2 options I came across that would accommodate my T56 transmission and a bushing mounted torque arm: One from BMR and the new Hooker LS-swap crossmember made by Holley. I ordered both to give them a try.
I tried the BMR crossmember first since it showed up first. Everything bolted up pretty well, but man does it hang low! It was by far the lowest thing hanging below the car, including the exhaust and subframe connectors. This might be ok for a car with stock springs, but for my car that's lowered 2+ inches I could just see this thing scraping on every driveway and speedbump:
The Hooker crossmember showed up a week later and I noticed right away that it would be far from a bolt on job. This crossmember is made for LS-swapped cars using Hooker's matching engine mounts that move the engine out of the stock position for better space under the hood. My car still has a small block, so the engine is in the stock location. It was clear this thing was going to require some "tweaking" to fit. The good news was that it sat WAY higher up in the chassis and if I could get it to fit the ground clearance would be awesome.
So, I had a decision to make. Keep the BMR crossmember which is an easy installation but hangs down low, or dive into modifying the Hooker one and have great ground clearance if I could get it to work. I chose the hard path!
There were 3 big modification I had to make to fit the Hooker crossmember in my car. The frame holes all lined up great, but I had to modify the mounting holes for the transmission bushing:
Next, the mounting bracket for the torque arm bushing sits really close to the transmission tunnel, so I had to trim back my heat shielding to make space:
Finally, that same bracket for the bushing was hitting against a threaded boss on the tailshaft of the transmission, so I had to trim that back a bit:
After all that, I was able to get it all bolted up in place and am really happy with it. Super sturdy piece and tons of ground clearance:
Torque arm bolted up and pinion angle set:
Big difference from the old piece!
While I was at it, I also ordered some lower control arms from UMI and their relocation brackets. I had been running some old, non-adjustable Hotchkis ones that came with the car. Without the relocation kit, they were at the incorrect angle with my car sitting at ride height (angling up towards the rear) so I was looking forward to making this upgrade to help with some forward bite. I ordered the control arms with UMI's roto-joints, which are Delrin bushings that provide a super tight feel (zero deflection) without the squeaking you'd just with a rod end. Super easy install compared to the transmission crossmember!
Finally, I got around the installing my racing seat as well. I had bought this seat before the UMI autocross in July but just ran out of time before I could get it installed. The seat is a Cobra Imola and it's FIA certified, which was important to me for safety reasons. I'm using brackets from a company called Planted combined with the side mount brackets from Cobra. The seat is sitting super high right now, so I'll need to do some tweaking in the future. It feels AWESOME though once you're out driving... huge upgrade in driving confidence!
That's all for tonight!