Is There a Real Alternative to the Epitroch RX8 Sohn Adapter Kit?
The Epitroch is Gone. Here is the True Successor for Your RX8.
Why Twin Sticks Technologies has finally closed the "Mounting Gap" for Series 1 owners.
For years, the answer to "How do I install a Sohn adapter?" was simple: Buy the Epitroch kit.
It wasn't just about the adapter itself. It was about the completeness. You opened the box, and everything was there: the tanks, the lines, the hardware, and—most importantly—that beautiful laser-cut mounting plate that made the installation look factory.
But with Epitroch kits becoming "unobtainium," the community has been left in a lurch. Owners are currently piecing together DIY solutions, zip-tying generic tanks to the firewall, or scouring eBay for knockoffs that warp.
I found myself asking the question: "Is there a true alternative that doesn't require a trip to the hardware store?"
Until recently, the answer was "Not really." But that has changed with the Twin Sticks Technologies (TST) kit. Here is why I believe this is the new gold standard for Series 1 owners.
1. Solving the "Oilcanning" Problem
The biggest failure point of DIY brackets and cheap knockoffs is flex. When a metal plate is too thin or poorly designed, it suffers from "oilcanning"—that popping/flexing movement that happens under stress or heat cycling.
The Twin Sticks kit features a laser-cut mounting plate that specifically addresses this.
Speed Holes: They aren't just for looks. The design includes dimpled speed holes that significantly increase the stiffness of the plate without adding weight.
Result: A rigid mounting platform that doesn't flex as you drive.
2. Vibration is the Enemy of Plastic
A major issue with mounting plastic reservoirs (like oil and washer fluid tanks) directly to a metal bracket is vibration. The RX8 engine bay sees high-frequency vibration, which can eventually crack the mounting tabs on plastic tanks.
The TST Fix: This kit includes nylon bushings for the mounting points.
Why it matters: This isolates the tanks from the chassis vibration, acting as a damper. It’s a small detail that adds years to the longevity of the kit.
3. The "One-Box" Solution (No Hardware Store Runs)
The "Epitroch Gap" was never about the adapter; it was about the hassle of sourcing hoses and bolts. The TST kit restores that "one-box" convenience.
What’s included: It comes with the oil tank, the oil-resistant lines, the fittings, and the specific hardware needed for the install.
The Washer Fluid: Just like the Epitroch setup, this kit requires removing the bulky factory washer bottle. However, TST supplies a replacement washer fluid bottle (identical in size to the Epitroch version) so you don't lose functionality.
4. The "Bring Your Own Adapter" Flexibility
This is where TST actually improves on the old market standard.
A lot of you already have a Rotary Aviation adapter sitting on a shelf because you couldn't figure out how to mount the tanks cleanly.
The Option: TST allows you to buy just the mounting kit (tanks, brackets, lines) if you already have the metal adapter.
The Full Kit: If you are starting from scratch, they can supply the adapter as well.
5. Installation: Zero Drilling
One of the scariest things for an owner is taking a drill to their chassis.
Bolt-on: The TST kit utilizes existing factory bolt holes.
Reversible: Because no drilling is required, the installation is 100% reversible if you ever want to return the car to stock.
OUR Verdict
For a long time, we've had to tell customers to "figure it out" when it came to mounting Sohn adapter reservoirs. That era is over.
The Twin Sticks Technologies kit doesn't just copy the old standard; with its reinforced plate design and vibration dampening, it arguably engineers the solution better.
Availability Note: TST keeps these in stock in small batches to ensure quality control. If they sell out, the lead time is generally kept under 2 weeks—a massive improvement over the months of silence we see elsewhere in the market.