Since its launch, the Mazda RX8 has been the subject of close scrutiny from enthusiasts. The high level of attention is not only due to the car’s admirable driving dynamics, but also, in part, to early reports of underperformance. To be more specific: Wheel power measured over several chassis dyno runs resulted in values ​​well below the expected powertrain parasitic losses of 17% to 20%. And quarter-mile runs that are 0.5 to 1.5 seconds shorter than those produced by magazines on purportedly pre-production vehicles.

Regarding the RX8’s horsepower rating: Original Mazda North America (MNAO) marketing material advertised the RX8’s 6-speed manual transmission as 247 hp at 8,500 rpm. Assuming the parasitic drivetrain loses 17% to 20%, common in modern rear-wheel drive vehicles, a stock RX8 should have between 205 and 197 rear-wheel horsepower (rwhp), depending on lift , barometric pressure, temperature, and applied correction factors. Instead, a standard RX8 chassis dyno run shows results ranging from mid-high ~160 to ~185 rwhp. Such readings would represent parasitic powertrain losses of more than 25%. To say that it is unacceptable to experience such a high level of loss through a “sports car” drivetrain with a carbon fiber driveshaft – among other things – is an understatement.

To further cement doubts about the actual power output of the new Renesis, several owners were unable to reproduce low-medium 14-second quarter-mile passes, as seen published by well-known US automobile magazines. of snare were another indication of the apparent lack of power output.

Shortly thereafter, various debates on online enthusiast forums and discussion boards turned into heated arguments as to what was causing such poor “straight line performance”. Many former Miata owners recalled an earlier “mess” in Mazda’s history, when the automaker admitted that it overstated the horsepower numbers of its redesigned Mazda Miata.

After a few months, MNAO came forward and explained that they had misrepresented the power output of the Renesis. The revised figure was now 238 hp at 8,500 rpm; however, according to MNAO, this revision did not change the previously obtained runway performance results.

Speculation about the reasons behind the sudden lack of power was rife. However, there are currently two schools of thought:

• The former supports the idea that the RX-8’s engine management unit (ECU), along with the many “nanny” devices – such as ABS and TCS – do not allow accurate readings to be obtained from a chassis dyno. For simplicity, when the car is running on a chassis dynamometer, only the drive wheels turn. The RX-8’s ECU would detect an abnormal driving situation and retard timing and apply other safety measures to preserve “driver” or “engine” -or both- from harm (read: skidding situation, or a car that pulls out of the road.)
• The second believes that MNAO was forced to redesign the software that runs engine management even before the first batch of RX-8s reached US shores, due to upcoming federal emissions regulations. I’ve read of one in particular, which requires a catalytic converter life of ~100,000 miles. The number one enemy of catalytic converters in any vehicle is heat (and heat is the number one attribute of rotary engine exhaust).

MNAO offered two options to those who had pre-ordered an RX-8 or purchased it no later than September 2003:

• They would buy the vehicle again, no questions asked.
• They would offer FREE scheduled maintenance for the life of the warranty, plus a $500 “gift card” for those who chose to keep the car.

I was among those who chose to keep their RX-8. After all, the driving experience hadn’t changed since the vehicle’s test drive prior to purchase. Since August 2003 I have driven over 20,000 miles (as of 1/18/2005) and have not one ounce of regret for my decision. If you want to read more about the owners’ opinions, visit this thread @ RX8Club.com

There have been a number of ECU “updates” released over the last 2 years. As far as I know, all early ’04 RX-8 samples came from the port with level “J” engine management software. Since then, we have scaled the entire alphabet up to “M”, which was launched in a TSB campaign by Mazda North America (MSP04) for ALL vehicles brought in for service @ Authorized Dealers to display the “M” calibration. .