It comes as no surprise to anyone when the 86 chassis is talked down for being so slow, it really is; and the aftermarket community has stepped up to help fix it. For the project FR-S, a Sprintex 210 twin screw supercharger helped improve the oomph of the car, but the supercharger unit itself was maxed out. Running the Stage 2 water intercooled kit, E85, and the smallest pulley available, our FR-S put down a total of 283.41 horsepower and 219.96 torque at the rear wheels, which really gave our car the boost (sorry) it needed to be a bit more fun on the road course. Barely keeping up with the others on track wasn’t enough, however. We wanted to be faster, so when the opportunity came up to swap to a larger supercharger, we jumped at the chance.
Installation for the larger supercharger was pretty straight forward, and the 335 unit easily bolted in place of the 210. While the original 210 Sprintex unit offered 1L of additional displacement, the new 335 unit was 1.5L. The Sprintex S5-335 offers more power, torque, and headroom for us to grow, since we can now use a larger pulley (than the smaller 210 unit) and still make more power–great! After a quick reflash of the ECU with Ecutek, we pulled the car out for initial shakedown and hopefully noticeable power gains. On an empty stretch of road, we dropped down to Second gear and proceeded with a nice wide open throttle run. Whoa! We were immediately pushed into the seat, and soon grabbing Third gear…which provided an immediate let down. With the speedometer reading roughly the same, the RPM of the car began to skyrocket–uh oh, the clutch can’t hold the power! So much for this “upgrade,” right?
Continued testing proved that First and Second gear seemed to do okay (most likely the wheelspin), but Third and Fourth provided only burning clutch at any hint of boost. Hmm, with 50k on the clock and a large majority of that with boost, we knew it was only time until the factory clutch gave out. Luckily our friends at McLeod just released a new “tuner series” line of clutches, which would prove to be a perfect fit for the FR-S.
Let’s Make A Phone Call, Shall We?
A quick call up to McLeod had me chatting with Joe Macasero, Import Specialist, and Krista Baldwin, Media and Customer Relations, to discuss with me the new options they had and help determine the best clutch for my application. With four new variants, they had something for stock cars all the way up to bolt-on and boosted, race abused cars.
Starting out with the Street Tuner clutch (P/N 760661), McLeod offers this as an upgrade to the OEM clutch. This is a full organic clutch, with a sealed back disc and pressure plate that will feel similar to the stock pedal feel. Users of this clutch have either very basic mods, or none at all! A great option for those seeking a replacement for their factory clutch that is just worn out. From there, the Street Power clutch (P/N 761661) is next for the lineup. Considered “Stage 2,” this clutch features a clutch disc that is a mix of both ceramic and organic, which is a new friction material for the industry. You can expect the easy grab of an organic clutch, with the heat holding of ceramic–and users of this clutch covers stock vehicles to full bolt-on.
Moving on up lands us at the Street Elite clutch (P/N 762661), which can be considered “Stage 3.” This clutch offers a higher clamp load, stiffer plate, and organic clutch disk. If you’re running full bolt-ons and lower boost levels, this is what you’re looking for. Lastly, is the Street Supreme (P/N 763661), or “Stage 4” clutch. This heavy duty, dual sprung carbon disc is made for big power, whether you’ve got a supercharger, turbo, or crazy N/A. Designed to see track time, high RPM launches, and lots of power; this is the perfect clutch for our project FR-S.
The clutch seems like the whole thing, but it’s only half of the puzzle. McLeod recently released a lightweight aluminum flywheel (P/N 581005), and it’s a perfect match to the new clutch lineup for import cars. McLeod told us that they removed as much weight as possible from the edges of the flywheel since that would have a more profound effect than removing weight closer to the crank.
Since McLeod was able to take as much weight off the flywheel from the outside edges, as that would have more significance than rotational weight removed closer to the crank.
When less weight is placed on the drivetrain, more power makes it to the wheels. Power isn’t just the only benefit of a lighter weight flywheel either. On the track approaching a corner, you can get off the gas later, make it easier to heel-toe downshift, and allow you to get back onto the gas faster and quicker. Weight savings in a lightweight flywheel is some of the best bang for your buck you can get when it comes to weight savings on a road course car.
While you don’t need the lightweight flywheel, it offers a huge performance benefit. It seems ridiculous to be pulling the transmission to swap the clutch and NOT upgrade flywheels while we’re at it. Krista and Joe assured us that the Street Supreme clutch and lightweight aluminum flywheel make an awesome combo, and informed us it will really shine in the supercharged FR-S.
Upon receiving the clutch, care and quality were noted. Although it has been a while since we’ve held a stock 86 clutch in our hands, the clutch and lightweight flywheel seemed quite a bit lighter than we remember the stock stuff being. After throwing everything on a scale, I was right–the McLeod clutch and lightweight flywheel were significantly lighter. Check it out! The entire stock clutch assembly weighed in at 13lbs 8oz, and the flywheel was 20lbs 12oz. Checking the scales for the McLeod clutch and lightweight aluminum flywheel gave 11lbs 4oz and 9lbs 4oz respectively. The weight reduction seen here will help free up additional power, improve gear changes, and make heel-toe a little easier on the track.
It’s important to note here, that although lighter weight components don’t add power, they take less away compared to heavier components. For example, while chatting with McLeod, they recently swapped clutches on a newer Mustang and picked up 22 horsepower. Unfortunately we won’t have a direct comparison with just the clutch change alone since the supercharger was swapped too, but we tallied up a total of 13lbs 12oz weight reduction–which is really going to help considering the twin screw supercharger we’ve got bolted on is adding more rotational mass to the engine.
The FR-S is a very mod friendly chassis, and we opted to install this in our garage. Joe and Krista claimed that their new clutch kits “are designed to be a straight forward install, made for the weekend warrior. This is a very DIY friendly install, with no shimming or extra things required for installation” and I was going to put that to the test. Luckily the transmission for the FR-S is pretty easy to get to, and after a few hours wrenching I finally had it off.
The dirty factory clutch was soon visible, and I began unbolting it all to make the swap. Everything was removed pretty easily, but I was quickly reminded about the weight when I removed the factory flywheel while laying on my back. Sure 20 pounds isn’t that much weight, but after handling the McLeod lightweight flywheel, the stock one felt like a lead brick.
Once everything was pulled off, we compared the factory clutch along with McLeod. The differences were immediately identified, as the factory clutch is full faced and clearly not designed for the power figures the engine was now putting out. It’s a shame the new clutch is hidden inside the transmission, but we’ll be reminded of its performance not bright appearance once we hit the track.
Of course while I was in the trans, I upgraded to the Versus Engineering clutch fork and pivot too. The Versus Engineering clutch fork is a billet aluminum piece that replaces the factory stamped steel fork which is used across multiple Subaru models (278 variants actually) and has proven to be a failure point when used with stiffer clutches. When the factory fork fails, you’re dead in the water and pulling the transmission is the only way to swap it. The billet chromoly clutch fork offers less fork deflection, which can improve clutch feel and ensure that the new McLeod clutch disengages since it has a heavier pressure plate than the stock clutch.
Driving, Break-In, And Power
Now that everything is bolted back up, it was time to take the car around the block. Initial thoughts while pressing the clutch was that it was heavier, but provided much more feedback. One of our biggest complaints about the factory clutch was that modulation was difficult, and it was darn near impossible to tell what the clutch was doing. This made driving inconsistent and clunky–not something you expect out of an OEM clutch.
During the few weeks we spent breaking in the clutch, we became more accustomed to how it feels and how to best drive it smoothly. We found that while leaving from a stop, slightly higher RPM slip was preferred, or we suffered clutch chatter at take off. Once rolling, additional upshifts and downshifts were very smooth.
During our break-in process, we experienced no concerning sounds or issues that required any attention. Of course the most difficult task during break-in was to not go wide-open throttle, even though our right foot was begging us to. McLeod specified that 500 to 600 miles was usually the appropriate amount of actuations for the clutch, which is around 1,200-1,500. We made sure to take the long way to work, and if we found ourselves on the freeway we would make frequent and unnecessary upshifts and downshifts to really rack up the number of times we engaged the clutch and flywheel.
Once we were certain the clutch was broken in, we strapped the FR-S to our in-house dynojet chassis dyno for some final numbers. With three pulls back to back, we put down a max of 304.98 hp and 254.71 lb-ft. Not too shabby, and the new Sprintex 335 provides a healthy dose of power over the smaller unit we had before, which should help propel us from corner to corner faster than before.
After being invited to Willow Springs by Carbon Revolution, we grabbed some basic tools, 20 gallons of E85, and our helmet. Lucky for us, we had just passed the 600 mile mark, and our wide open throttle wishes were coming true.
Upon arriving at the track, we were eager to unload the car and hit the road course–this was it!
Run groups were very small, with only six or so of us out at any one time; with the majority of the field being GT350 Mustangs. Even supercharged, our FR-S was certainly down on power, but significantly lighter too, meaning we might just have a chance to hang.
Pulling onto the track on the main straightaway, we mashed the gas and rocketed toward the first corner, dancing on the pedals in an effort to smoothly heel-toe.
Whoa! Was the first thought, as the McLeod clutch provided a very smooth disengagement while we downshifted from Third to Second, while at the same time a quick blip of the throttle brought our RPM up and allowed an extremely smooth gear change, which brings up another solid point of complaint. The gas pedal. The FR-S, BRZ, and 86 use a drive-by-wire setup which can sometimes be frustrating to use; too quick of an input and the car seems to just dismiss the request, while too long and you find yourself over-revving.
This time was different, though, and a quick ankle roll to blip the gas brought the engine RPM up to just the perfect spot and allowed for seamless gear changes without disrupting the balance of the car while entering the corners at Streets Of Willow. Reduced weight from the aluminum flywheel enabling quick pedal work was only part of the equation; how did the clutch feel? Modulation is important on the track when you’re trying not to upset the balance of the car. If you have trouble finding that “sweet spot” on engagement, you risk botching a gear change or negative balance shift costing you precious time or a potential off-track excursion. Luckily we had no trouble figuring out what was going on under the left pedal, and when the loud pedal pushed to the floor we experienced no slip as we were propelled corner to corner.
During our session we experienced consistent pedal feel, easy modulation of the clutch, and excellent power holding when we needed it. Even when pushed lap after lap, the McLeod Street Supreme clutch and lightweight aluminum flywheel proved how capable a clutch can be, while still remaining driver friendly–when you have to drive it back home.