Mazda RX8 Horsepower Controversy

Mazda RX8 Horsepower Controversy

Because its start, the Mazda RX8 has been the matter of close scrutiny by enthusiasts. The superior level of notice is not only due to the car’s admirable driving dynamics but, in portion to the early stories of beneath-than-expected overall performance. To be much more certain: wheel horsepower calculated on a number of chassis dynamometer runs resulted in values perfectly under the anticipated 17%~20% drivetrain parasitic losses. And quarter mile operates of any place concerning .5 and 1.5 seconds off of individuals developed by magazines on allegedly pre-manufacturing automobiles.

In connection with the RX8’s horsepower rating: the unique marketing substance from Mazda North America (MNAO) advertised the 6 speed guide transmission RX8 at 247hp @ 8,500rpm. Assuming parasitic drivetrain loses amongst 17%-20% -common for modern-day rear wheel drive motor vehicles, a stock RX8 ought to evaluate concerning 205~197 horsepower at the rear wheels (rwhp) -based on elevation, barometric force, temperature and correction components utilized. As a substitute, a stock RX8 chassis dyno run demonstrates success ranging any where from mid-large ~160 to ~185rwhp. These kinds of readings would symbolize parasitic drivetrain loses in extra of 25%. To say that, it is unacceptable to knowledge this kind of a higher degree of reduction by means of the drivetrain of a “sporting activities car or truck” with a carbon fiber drive shaft -among other matters- is an understatement.

To further more consolidate doubts about the true energy output of the new Renesis, a number of entrepreneurs have been unable to reproduce mid-minimal 14 next quarter mile passes -as found revealed by properly recognised U.S. car magazines. Very low entice speeds ended up an additional hint to the apparent absence of energy output.

Shortly right after, quite a few debates on on the internet enthusiast community forums and discussion boards turned into heated arguments as to what was producing this kind of bad “straight line efficiency.” Numerous previous Miata entrepreneurs remembered a earlier “snafu” in Mazda’s historical past, when the maker admittedly overstated the horsepower figures of their redesigned Mazda Miata.

After a couple months, MNAO arrived forward and spelled out that they had misrepresented the Renesis’ electricity output. The revised determine was now 238hp @ 8,500rpm nonetheless, according to MNAO, this revision did not change the beforehand realized monitor performance results.

Speculations about the factors behind the unexpected deficiency of electricity output have been quite a few. However, there are at the moment two colleges of considered:

  • The very first 1 supports the idea that the RX-8’s engine management device (Ecu), in conjunction with the many “nanny” products -this sort of as Ab muscles & TCS- do not let to obtain precise readings from a chassis dynamometer. To simplify, when the car or truck is run on a chassis dyno, only the pushed wheels are turning. The RX-8’s European would detect an abnormal driving problem and retard timing and apply other security actions to protect possibly the “driver” or the “engine” -or both equally- from problems (browse: skidding scenario, or a vehicle likely out of the road.)
  • The second one thinks that MNAO was forced to re-engineer the software that runs the motor management even ahead of the initially batch of RX-8’s attained U.S. shores, because of to forthcoming Federal emissions polices. I have study of one particular in distinct, which involves catalytic converter lifespan of ~100,000 miles. The enemy quantity 1 of catalytic converters on any car or truck is warmth (and warmth is the quantity 1 attribute of rotary engine’s exhaust gases.)

MNAO offered two selections to those people who experienced pre-ordered an RX-8, or experienced procured no late than September 2003:

  • They would acquire again the car, no thoughts requested.
  • They would offer you Free Scheduled Maintenance for the lifetime of the guarantee, moreover a 500 greenback “present card” to individuals who opted to keep the motor vehicle.

I was amongst individuals who opted to hold their RX-8. Right after all, the driving practical experience had not modified given that check driving the auto prior to obtaining it. Due to the fact August 2003 I have clocked well in excess of 20,000 miles -as of 1/18/2005- and I have but a single ounce of regret about my conclusion. If you would like to go through more about owners’ opinions, visit this thread @

There have been a variety of European “updates” produced all through the past 2 many years. To the finest of my awareness, all early samples of ’04 RX-8s, came from port with degree “J” of engine management program. Due to the fact then, we have escalated all the way as a result of the alphabet to “M” -which was unveiled on a TSB campaign by Mazda North The usa (MSP04) in buy to have ALL motor vehicles taken in for Support @ Authorized Sellers flashed to “M” calibration.