Out with the old and in with the Exedy
Owning a manual transmission holds many important benefits over an automatic one. For instance, you never have to worry about your car accelerating out of control, you never have to worry about having a dead battery and it also cuts down on distracted driving since it’s hard to text or talk on the phone with that 3rd pedal.
Exedy Clutch and BHR Flywheel ready to be installed.
There is one downside to the manual and that happens to be the clutch. If you’re not familiar with a manual transmission, the clutch is the device that connects your engine to the rest of your drive train through a high friction surface. This, sadly, makes this a wear item although it is designed to last for a very long time. The nice thing is that if you are rough with your transmission the clutch tends to take the brunt of the punishment. Since it’s replaceable it’s possible to save your whole transmission from a costly mistake.
So, on the agenda this weekend was replacing my worn out OEM clutch that has 106,000 miles on it. I have a bit of pride in the fact that this clutch has lasted this long considering this is my first manual car as well as having numerous track, autocross, and drag racing events on it. Since the flywheel would be easily accessible during this job it made sense to swap out the OEM flywheel as well. The parts being installed are the BHR 9 lbs. flywheel and the Exedy Mazdaspeed clutch. Before getting into the install I’d like to talk a bit about the choosing of these products because the whole aspect of clutch choice is a seriously flawed one.
One of the biggest mistakes we have seen people make with clutch choice is thinking more is better. By that, I mean that people think that since they drive their RX8 or any other car hard that they have to purchase a Stage 1 million clutch with gobs of torque holding capacity and a super exotic disc face. These customers soon realize their clutch went from an analog to a digital device, in terms of driving feel and control. Stock clutches have a wide range of engagement (called the “friction zone”) allowing you to more easily control the slipping of the clutch for a smooth take off. Racing clutches like mentioned above are literally on/off switches. You might have lightning fast engagement but you’ll never take your girlfriend for a ride again. To avoid this mistake, here are some basics to clutch choice.
Exedy Mazdaspeed Stage 1 clutch
The two important parts of choosing a clutch would be the pressure plate clamping force and the disc materials. You need a clutch that can handle the power you are putting through the transmission, otherwise it will slip and wear quickly. Since clutch changes don’t happen often you’ll want to choose a clutch for future modifications if you know you’re headed for big power gains. Second, you need to look at the disc. This includes what kind of material it’s made from, whether it is sprung or unsprung and whether it’s a 4 or 6 puck clutch face or a full face. All of these decisions have their place. In my case my RX8 is running mostly stock power levels with the possibility of going turbo or supercharged between now and the next clutch change. It is also my daily driver so I will be doing 90% of my driving on the street in traffic. For this I chose the Exedy Mazdaspeed unit. The Exedy Stage 1 is a full face, sprung, organic disc but the Mazdaspeed version has a bit more clamping force than the standard Stage 1 Exedy. There is much more to clutch choice than these simple areas mentioned above so if anyone has questions about purchasing their clutch through Black Halo Racing please contact us for proper guidance.
Now, regarding the flywheel. The flywheel’s purpose in life is to serve as the connection point to the engine. The flywheel also has an outer ring gear that is attached to the starter motor. You crank the starter, it turns the flywheel which rotates the engine and so on. Flywheels tend to be very heavy. In some vehicles they exceed 30 pounds. While that doesn’t seem like a lot of weight, the energy required to turn this hunk of metal is substantial when it’s spinning 6,000 RPMS or more compared to a lighter version. The stock RX8 flywheel is almost 17 lbs. and would be replaced by the 9 lbs. Black Halo Racing flywheel. This weight reduction means quicker acceleration due to more energy being transferred to the driveline instead of wasted turning the flywheel. The BHR flywheel requires (as do other lightweight flywheels for the RX-8) a counterweight for balance purposes so the total weight reduction is 3.8 lbs. Still, that’s an easy horsepower gain for a part replacement. It also helps the throttle response of the car which I’ll discuss in the “review” aspect.
For this job I recruited the services of Charles Hill due to his vast experience with RX8 clutch installations as well as rumors he’s a better mechanic when on his back! Charles offered to graciously help me with tackling this installation due to the various headaches of dealing with the power plant frame and transmission. He also is familiar with important details such as replacing the pilot seal and bearing as well as the release bearing. We gathered at Jeff Abram’s house early Saturday morning to abuse his air tools and got to work. The installation consisted of removing the cross braces, mid-pipe and starter to get at the important stuff. Next to come off was the transmission wiring harness, clutch slave cylinder and then the power plant frame. We then disconnected the driveshaft, removed the transmission bell housing bolts and dropped the transmission.
Clutch and Flywheel installed on the motor.
With the transmission out of the way we began removing the stock clutch and flywheel. Despite the wear to the OEM clutch, both looked in good shape with no signs of heat damage. The pressure plate and disc came right off. The infamous flywheel nut didn’t last under a few seconds of impact gun hitting and came right off. The flywheel was next preceded by a few hammer hits to get it loose. Meanwhile, we removed the old crappy release bearing and installed the much heavier BHR version. The new flywheel was bolted into place followed by the clutch. The pressure plate took a few hammer hits to seat onto the dowel pins but everything went in without a problem. We then reinstalled the transmission and all remaining parts to wrap up the installation. Charles’s experience with this installation made the process issue free.
First thing was to check the clutch pedal engagement. This is another area of the installation often overlooked by many. This is a critical step to ensure proper engagement of the clutch and prevent grinding gears. Since this was a new clutch, the engagement point would obviously be much closer to the floor. At first adjustment I twitched my leg and the clutch engaged. I asked Charles to give me a bit of free play but he suggested not much more than what I had. After the pedal adjustment I ran though the gears to ensure everything engaged properly. It was then time for the road test.
Shortly afterwards, Charles reminded me “You’re going to have to relearn to drive this car with all this new stuff.” I thought, yeah I know…I’ve got this. I had nothing more than a tingle in my left leg with the car in reverse when the car bucked and died.
Ok, so I don’t got this.
I quickly got the groove of the new clutch and flywheel and managed to limp the car into 1st gear like it was my first day driving a manual all over again. Initial feel around the block by Jeff’s house was tough gear engagement but this was due to the disc material needing to compress as well as the marcel needing to seat. Within 1 to 2 miles of street driving the shifting smoothed right out and the car was back to normal.
OEM clutch with not much life left.
Initial impressions of this package are really good! While I wish I could have gotten my hands on a lightweight pressure plate for additional weight reduction, the flywheel provided noticeable improvements in acceleration and in throttle response. I noticed in higher gears like 5th and 6th that there was much less effort needed to overcome the initial forces on the car and accelerate. The power gain isn’t substantial but the butt dyno approves. The new clutch as well as the lightweight flywheel do require that I engage the throttle before the clutch pedal is released. Previously I had a good grove with doing both at the same time but the clutch will disengage before I can even roll into the throttle to compensate.
Overall I give this two thumbs up! There is a performance increase from the flywheel and I now have a fresh clutch in the car that will handle any future FI upgrades to the car. If you have to do a clutch change I’d suggest springing for the BHR flywheel in the process as it’s a nice addition to any manual RX8. I want to say thank you to Black Halo Racing for providing me with these awesome parts.
Anyone who has watched Tom Cruise in “Days of Thunder” knows that tires win a race.
I bought my first set of Invo’s at about 70,000 miles literally on the same day that I set out on a cross-country road trip back to NorthWest Indiana where I grew up. The weather leaving Phoenix was terrible. Near flagstaff the rain started coming down in buckets and I recall that being some of the most nerve racking driving yet. Driving in the pitch black night at 75mph with the rain coming down hard sapped the life out of me. Still, the Nitto’s performed very nicely and prevented me from hydroplaning in situations where other tires might not have faired so well. I wasn’t able to easily see puddles in the road but when I hit them the Invo’s deep rain channels took care of me.
Despite several track and SCCA events I still managed to get 30,000 miles out of a set of these tires. The main reason is they are bi-directional meaning you can rotate them on all 4 wheels. Most summer season tires are uni-directional so they can only be rotated on one side of the vehicle. I wasn’t really disciplined about doing rotations so I’m expecting to get much better mileage on my new set since I do them about every other oil change now.
With the talk about the impending doom of the RX8’s production there’s been a pickup of discussion about what the next generation rotary car will look like and what we hope Mazda has learned about the RX8. Sure there have been a mountain of reviews of this car with people who have lots or no rotary experience at all so hopefully I can offer you all a glimpse of my own perception. If you’re reading this site chances are you already own an RX8. However, maybe this will cause you to look at your car a bit differently.
The RX8 isn’t a piston powered car. Now, this might seem as a Captain Obvious moment but you would be surprised at how many people really don’t understand this. The aspects which make a rotary engine great also are disadvantages. The motor doesn’t produce a lot of low end torque or horsepower and requires being in higher RPM’s to perform. Yet, the biggest complaint is the “lack of power” whether it be torque or horsepower. This is because the vast majority of car buying public love being slammed into their seat by the violent piston powered action. Of course this only lasts a few seconds yet we seem to spend tens of thousands for these few moments.
Simply put, the RX8 is a driver’s car. This is applied from every angle from care and keep to performance and enjoyment. Drivers prefer to be involved with their car and the RX8 has plenty of room for that. As soon as the shortcomings of the vehicle were discovered the aftermarket industry moved quickly to fill the gaps. Small things like checking your oil, following the warm up and shut down procedure and having to beat on the car are some of the things that require a driver. People who neglected the car between oil changes found out in a couple years they had problems. The cars that survive the longest are often the hardest driven but the best cared for.
There are a few things that Mazda designed into this car which need to be corrected for the next generation. Black Halo Racing was one of the first companies to discover that low Oil Metered Pump injections were causing motor failures. This was no doubt a result of the EPA standards imposed on the car. The jury is still out on whether premixing has saved motors or not but clearly finding a way to lubricate/cool seals with as little oil as possible is a big change that is needed.
I arrived at the track early to secure a good paddock spot. The whole paddock organization changed the previous day so the spot that Jeff had picked out was no longer available. We ended up snagging a corner spot behind the main tower area which ended up being only about half full by the busiest part of the day. We were able to be left alone to park where we wanted and spread out a bit. Will, one of the other RX8 drivers that was with us, parked himself under the giant tree we set our tent up by and was greeted by the bird population by being crapped on. Nothing like a bird taking a dump on your shirt to say hello!
The power output was as well. While I don’t believe I’m able to release WHP figures let’s just say they were very big. The exhaust system had been moved to the engine bay and came right off the headers themselves. The entertaining part was every run the exhaust gas had such high velocity that it was blowing the hanging insulation out of the UMS shop roof! I didn’t have an opportunity to follow World Racing’s performance on Saturday but what I did see of the car looked like they were having a lot of challenges.
Things for myself and Jeff began fairly slowly. Once Jeff was finished with the autocross setup for the Porsche Club he went back home to get his race wheels and other supplies. Meanwhile, myself and the other AZMC people got our cars through tech and registration and proceeded to get everything ready for our first sessions. 
The issues I had were tire issues and also confidence. My Nitto Invo’s are at the end of their life so the tires were getting hot pretty quickly and then getting sloppy. I had set my pressures incorrectly for my first session and ended up with having about 6psi more air than I needed. As such my contact patch was reduced and I was getting a fair amount of oversteer. I got loose between turn 4 and 5 which freaked me out and I was a nervous wreck the rest of the rest of the session. This was also my first DE3 event which allowed open passing on the drag strip but passing anywhere in the infield with a point by. Dealing with traffic in the infield added complexity and prevented me from concentrating on my driving. Plus the cars were MUCH faster than me. Almost all the cars had me by at least 100whp or were much lighter. Many of them were also running race rubber or much sticker tires and no doubt had a lot more driving experience.
My confidence in the car was low because of the tire issues I was having. The car didn’t feel as planted as it has previously and places where I felt I should have had grip I didn’t. I had an opportunity to follow Will around in his RX8 to see if I was using the proper line and with a couple of exceptions I was running the same line he was. He, however, was much more aggressive with his RX8 and it was obvious in the times clocked. Will was clocked around a 1.20.00 while I was about 6 seconds slower. During the time attack I was able to crack off a 1.24.20 so I picked up about 3 seconds somewhere in there.
So, that’s a wrap for this year’s NASA Nighttime Event and the Modified Time Attack Shootout! We had some Mazda owners come out that had never been on the track before and it was great to see them using their cars as they were intended. While the summer is approaching and the heat with it, it will give me an opportunity to get a better set of tires and prep for the fall season.
With the Ultimate Socal Dyno Day behind the BHR team we are able to now turn our attention back to our personal pursuits. With myself that is the upcoming Night Time Event put on by NASA (National Automotive Sports Association). The AZ region of NASA has one big blowout event every year and it takes place at Firebird on their main track. The event not only has the normal DE, race group and Time Attack events but they also do autocross, drift and the Modified Magazine Time Attack Shootout! The Modified competition brings probably the most attention since it’s 10 of some of the hottest time attack cars in the country with big names.
overadozen autocross events so I was well prepared and the experience was great. There was a lapse in events for about 10 months due to various things coming up in my life so track driving took a back seat. Last February I was able to do two back to back events on Firebird Main in DE2. This year I’ll be driving my first DE3 event at the night time event. While the change might not be a big deal per say, I will finally not have to share the track with DE1 guys who are still learning their car, the track and how to handle themselves. The biggest deal is DE3 will finally allow me to compete in the UMS Time Attack! Doing TA is the ultimate goal of mine as I want to get into a competitive racing event but not deal with the hassle and danger of wheel to wheel racing.
Jeff Abrams will also be driving his turbocharged RX8 in NASA Time Trial for the first time!
Well, the Ultimate Socal Dyno Day comes to an end. After 2 full days of dyno action and other fun I can honestly say that going back to work tomorrow will be a relief from my weekend! There was so much that happened this weekend that I could not honestly recap all of it but I’ll do my best.
Saturday had some seriously awesome turbo and supercharger cars. I had the opportunity to check out some of the installations that were done and many of them were very nice and clean. I wasn’t very involved with much of the dyno process on Saturday due to tending to the web broadcast and also working on a customer car doing a Samco Radiator Hose installation. The install went well and I was really impressed with the quality of the kit. It’s something I’ll be looking into for my own RX8.
The plan was to hit the town after Saturday’s event but all of us on the BHR team were really worn out. We didn’t get out of the shop till almost 9pm. We ended up heading back to the hotel and chowing down on some cheap Chinese cuisine.
Between dyno runs there was a lot going on. A few people were jumping onto the dyno rollers and hashing out a good old fashioned log rolling contest to see who would get thrown off first. It was pretty tempting to hit the dyno brake but I resisted since someone face planting into the diamond plate would have been ugly. There were a few people hanging out in the waiting room playing Playstation 3 and a few even decided to have some fun on the street in front of the shop. There was something for everyone that’s for sure! At some point the beer and Jager got busted out and I even got talked into taking a shot (or was it two?) of Sailor Jerry from Erick and Ray.
There were quite a few other fun things that happened but you’ll have to talk to some people who were there to get the details. We finished up the day with Jeff Abrams running his GT3076 turbocharged RX8 on the dyno as well as Charles Hill showing that the RX8 can indeed go all the way to 10,000 RPMS! Soon afterwards celebratory shots of Jager were passed around and everyone toasted to an awesome weekend and an event we won’t forget.
As the sun starts to rise here in Long Beach the second day of the Ultimate Socal Dyno day begins! Overall the trip has been fantastic fraught with only very minor issues and some serious traffic in the last 70 miles of the trip. Our journey began in Phoenix as it always does and we chose to deviate from the typical route to California buy heading through Julian for some awesome twisty roads and some of Mom’s famous baked pies!