Project RX-8 - To Improve Performance, Add Reliability - Tech

Lotus founder Colin Chapman famously said, "To add speed, add lightness." Well, Charles R. Hill of Black Halo Racing may not be quite as famous as Chapman (though in his other career as a rock musician, he has played in front of 15,000 fans), but his company's mantra could easily be, "To improve performance, add reliability." That's because BHR - a small but widely respected Mazda RX-8 specialist based in Phoenix - has focused its attention on fixing a number of the 8's most glaring shortcomings.

As we showed you with a baseline dyno graph last month, the Renesis in our 8 isn't performing to its full potential, with power dropping off after 7100 rpm when it should continue to build power all the way up to about 8100 rpm and then drop off gradually to the 9000-rpm redline. When I posted this graph on RX8club.com, the more experienced members immediately chimed in that this type of power drop off is typical of tired old ignition coils and spark plugs. One way to fix this is to swap in fresh OEM coils, plugs and wires every 20,000 miles, but a more durable and long-term solution is the product that really put Black Halo Racing on the map, its bulletproof BHR ignition system.

According to Charles at BHR, "Weak ignition coils are a source of frustration for a lot of RX-8 owners, since these lead to loss of power and catalytic converter function, in some cases even leading to destruction of the cat. If you add forced induction, nitrous or any kind of racing to the mix, having an ignition system that's reliable and with higher electrical output becomes even more important."

And that's exactly what BHR's ignition system kit is designed to provide, using stronger GM ignition coils (used in many racing applications and proven reliable in high-heat/high-stress environments), custom-built MSD ignition wires and a patent-pending plug-and-play wiring harness. Installation is a breeze (we removed the intake to ease access to the coils), and with a one-year warranty, you're covered in the unlikely event of a manufacturing defect. Better yet, BHR takes customer service so seriously that if you buy one of its ignition systems second-hand, for $20 they'll completely refresh the wiring harness, rebuild the ignition wires and check the coils for you.

After installing the BHR ignition system, we headed over to SG-Motorsport to dyno test the 8 on U2Ndyno.com's Dynapack, a machine that produces extremely reliable and repeatable numbers even when testing isn't done on the same day (as is the case with this test). As you can see, we've picked up some good horsepower and torque in that critical area between 6500 rpm and 8000 rpm (peak horsepower having improved by 5.1 whp and peak torque by 3 wtq), but we didn't see that third hump in the graph outperform the second hump the way a healthy Renesis graph normally looks, where power normally peaks 10 whp higher and 1000 rpm later.

Normally, a refreshed or upgrade ignition system cures weak high-rpm performance, but since we've installed the best available ignition upgrade and are still seeing poorer than expected power above 7000 rpm, it would appear our Renesis has some other issues that need to be addressed. We suspect a clogged catalytic converter may be the culprit, since RX-8s that see a lot of high-rpm abuse like ours tend to destroy the cat pretty quickly. Since we've got a very special motorsports cat on the shelf waiting to be mated to a Racing Beat resonated mid-pipe, we'll find out soon if this is the source of our Renesis' poor high-rpm output.