Last month, we tackled engine heat and oil temperature with the installation of a couple of big-ass Earl's oil coolers and some titanium exhaust wrap from DEI. This meant the next thing on our heat control to-do list was to address the direct and radiant heat in our engine bay. With our big single-turbo setup being in such tight proximity to the intake side of the motor, all the air cooled by the intercooler was in jeopardy of being heated back up again. No bueno.
To combat this, we decided to go in a similar direction as Project RX-8, by installing a Turbosource Inconel heatshield. Turbosource can fabricate custom heatshields for exhaust manifolds, turbine housings, downpipes, and pretty much any other component you're willing to ship the company, and it also pre-fabs a number of its more popular items, including the shield we've used on the Xcessive Manufacturing lower intake manifold. But we also took advantage of its custom shield service by sending Turbosource the Full-Race exhaust manifold—so the biggest source of radiant heat was under control.
These high-tech heatshields are constructed of 600-series Inconel. For you metallurgy geeks out there, Inconel is a synthetic alloy that possesses excellent strength and oxidation resistance at extreme temperatures, say like those made by every rotary engine that's ever been run in anger. When exposed to high temperatures, Inconel forms a thick stable shielding oxide layer that further protects it from degradation from heat exposure, making it the material of choice in high temperature applications such as heatshielding and exhaust components. Plus, Turbosource heatshields feature a clamshell design that includes fiberglass insulation in between the Inconel layers for extra heat protection. This design provides a thin air gap between the exhaust component and shield to allow for expansion and contraction of the part.
With these Star Wars–grade heatshields in place, we're pretty confident underhood heat will no longer be an issue, so we've moved on to more conventional concerns, like installing a clutch capable of holding that extra spinning triangle horsepower and torque. Plus, the old and worn-out OE motor mounts needed to be addressed, especially with the extra stress the big single turbo is going to put on them.
For the mounts, we once again turned to Xcessive Manufacturing. The company's full-floating motor mount design provides significant improvement over the usual puck-style mounts by eliminating the straight-through bolt used in the puck mounts. By eliminating this, Xcessive's mounts significantly reduce noise, vibration, and harshness (NVH), and the urethane bushings used are available in 80A (Orange) and 65A (Yellow) durometers, depending on your needs. The 80A bushings are significantly firmer, so you'll have to live with more NVH than the stock mounts. The 65A bushings are closer to stock, so if comfort is still on your list, then these are the way to go.
For our application, we chose the 80A bushings. Why? Because it's a race car. For a dedicated track car, it's easy enough to live with the increased NVH when the trade-offs are increased shifter precision and decreased strain on driveline components. In other words, energy is not wasted by the engine rocking back and forth when you stomp on the go pedal or while banging through the gears. Other than a slight modification to the driver-side motor mount required by our JDM RHD chassis, these mounts are a direct bolt-on affair.
Speaking of banging through the gears, we got in touch with Advanced Clutch Technologies (ACT) and Daniel Starksen for some guidance on a clutch and flywheel setup. We wanted to keep weight to a minimum but still have adequate torque capacity. Daniel recommended ACT's HD pressure plate and six-puck sprung race clutch disc. According to Daniel, the HD pressure plate provides a 42 percent increase in clamping load over stock and is also rated to hold 510 lb-ft of torque, a very ambitious number for our 1.3L powerplant. But it's good to know there is a large safety margin. Since we are still running a stock transmission, it was recommended that we use the sprung disc versus the rigid-mounted disc to help prolong our gearbox's life.
Clutch pedal feel and engagement are also factors to consider when choosing a clutch. I personally hate the dead spot in some clutches where there is a lot of pedal travel before the clutch is engaged. Due to the aggressive nature of the friction material used on the six-puck setup we chose, pedal engagement will be like a light switch: on or off. This is exactly what we are looking for, given our focus on attacking time with this project, but I can foresee some embarrassing stalls at the paddock. It'll be well worth it once we get accustomed to it and when we're out on the track.
Throttle response was another priority, so we completed the clutch system with ACT's Prolite flywheel. Weighing in at a scant 13.5 pounds with the counterweight, rotating mass has been significantly decreased, aiding engine response and making for some quick and sexy-sounding heel and toe downshifts.
We also took the added precaution of balancing the entire rotating assembly with the clutch and flywheel to ensure rotary happiness during the extended high-rpm use it would be seeing. The clutch system came in at a combined 30.5 pounds (17.0 pounds for clutch/pressure plate and 13.5 pounds for flywheel and counterweight), allowing us to reduce rotating mass by an impressive 9.2 pounds (stock clutch, pressure plate, and flywheel combo tips the scales at 39.7 pounds).
With this round of modifications complete, we are closer to getting the motor fired up, and it's rather exciting to see a light at the end of the tunnel. Stay tuned as we follow the yellow brick road by giving the car much needed spark as we tackle the ignition system and give the old FD a new brain in the form of an Adaptronic standalone ECU from the Land of Oz.