Charles R. Hill

Now that I have had a few weeks with the BHR Flywheel and BHR/Spec Clutch combo I can tell you a few things; 1) The further reduction in weight offered by the BHR/Spec Lightweight Clutch Kit is apparent.  How much more h.p. is available at the rear wheels?  We will know in a couple weeks after my car hits the dyno (I am guessing about 5-6 h.p.).  For certain, revving from idle to 9,000 RPMs is noticeably quicker and I can feel a bit more power to the wheels as the RPMs climb higher, especially from 4,000 RPMs on up.  2) The Stage 2+ (Kevlar/carbon hybrid) isn’t the easiest to drive.  The disc engages differently as it heats up.  Carbon gets a little “grabbier” as it gets hot so the engagement can chatter a bit when trying to drive the car smoothly.  Hammering the clutch is not an issue but for a daily-driven RX-8, I would strongly advise a Stage 1 for N/A to mildly-boosted engines and the Stage 2 for seriously-boosted engines.  The Stage 2+ should probably be reserved for drag/drift cars.  As regards the Mazda RX-8; clutch “stages” higher/more aggressive then the Stage 1, Stage 2, and Stage 2+ are going to be overkill and tougher to drive smoothly on the street.

For those not wanting to go with the super-light BHR Flywheel/BHR Clutch combo, the Exedy Stage 1 is a nice clutch and so are the ACT HDMM or HDSS units.

It should also be noted that clutch kits don’t generally have EVERYTHING needed for a comprehensive swap but Black Halo Racing includes everything in every kit we ship.

Well, Gang, we finally had a chance to install more BHR parts on my own car! (We company-owners rarely have the opportunity to use our own parts as we would rather provide them to our customers, first, and team members second).

Tonight, the BHR crew installed a BHR Flywheel and BHR Stage 2+ Clutch to replace the Fidanza flywheel and Exedy/OEM clutch I had been using.

The BHR Flywheel is the same unit offered by Fidanza and Spec, except BHR has Spec lathe off .75 lbs. for a total weight of 9.0 lbs.

Although the vast majority of the BHR Clutches we have sold are the Stage 1 (organic disc) version, we installed a Stage 2+ (Kevlar/carbon disc) on my car. Not that I needed such a clutch due to my engine, just that we already have a Stage 2 (Kevlar) version on a pretty wicked ported and ceramic-sealed Renesis I recently built and I drove it after the engine installation.

Suffice it to say that all the BHR/Spec clutches have pedal pressures lighter than stock, are 3.8 lbs. lighter than other standard diaphragm-type clutches, and the Stage 1 and Stage 2 clutches engage silky smooth.

Although a 300-500 mile break-in is strongly advised, I did manage to notice a slight acceleration improvement during a bit of driving and revving the engine from idle to 9,000 RPMs takes a mere blip of the gas pedal and it happens pretty quick.

By using the BHR Flywheel/BHR Clutch combo, we are removing nearly 8 pounds of mass from an OEM weight of 31 pounds. Pretty dramatic reduction which requires the driver to re-learn their clutch/gas pedal finesse. Nothing too difficult but it can be surprising for those who don’t know what to expect.

As the clutch breaks-in I will let all of you know how it goes.

At last year’s Socal Dyno Meet I put down 213 RWHP (without nitrous) and I am rather curious to see what the result will be in taking off another 4.5 (or so) pounds from my rotating mass.

Maybe I will get close to 220 this time? BTW, my engine has 110K miles on the bearings, irons, and housings, with over 60K on my rebuild (which was my first ever and I do a FAR better job of it these days than I did back then). I would be surprised if my compression values were anything more than 7.6-7.7 on this engine right now. By comparison, that ported/ceramic-sealed rebuild I recently did measured in the high-8s/low-9s for compression values just the other day. The difference in the two engines places mine at about 4-5% less torque output right now than it would have with similar compression values.

Well, I finally have a chance to post something so here it is;

I have a VERY busy couple of weeks coming up and the most notable work I will be doing involves building what will probably be one of the more “epic” street Renesis engines we have seen in a while in the RX8 community.  Some of you may recall that I rebuilt my own engine a couple years ago and I had a good friend (”Rotarygod” from the RX8Club website) do a little mild porting work on it for me.  That effort resulted in a little more midrange torque when the secondary/shutter valves open up.

The engine I am next building has a somewhat similar porting approach to it (performed by Rick’s Rotary in San Francisco, CA) except this build will also be sporting a set of NRS Ceramic apex seals (SpeedSource prepped the rotors for the seals), I will be custom gapping the side seals for F/I use, and the engine’s internal clearances are so good that I am calling it a “semi-blueprint” build.  I am actually jealous of the guy who is getting this engine.  Hopefully, his core return will be in equally good shape.  We will be shooting video of the build process and I am sure the video will be posted on BHR’s own website, on YouTube, and the RX8Club website, as well.