When the RX-8 was initially introduced in 2003, it came with a small 1.2kw starter motor known as the ‘N3H1’ which generally achieved a crank speed of around 220 to 250rpm. The N3H1 soon proved insufficient however, forcing Mazda put out a service bulletin that allowed RX-8 owners to have their starter motor swapped out for an uprated 2kw model, the N3H1-A.
Spinning the engine over at between 260 and 280rpm consistently, the N3H1-A worked and was much more reliable than its predecessor. More than that, it not only did what was needed but also had a little room left over to allow for short falls in engine compression. These starter motors we have found to be very durable with most lasting 10’s of thousands of miles without needing to be replaced. They are easily identifiable in comparison to the N3H1 starter motors by their longer body.
In around 2006, Mazda quietly began started fitting the N3Z1, an uprated 2kw starter motor. Not much was changed from the N3H1-A, just a few internal components. These more powerful starter motors are capable of cranking the engine over as fast as 290rpm, leaving a large margin again, to allow for any shortfalls in engine compression. Oddly we have found this model to be a little less durable than its predecessor, the N3H1-A, though much more readily available and a popular upgrade for older cars because of the performance gains and lower price.
The last and latest starter motor was introduced with the release of the Series 2 RX-8: the N3R3 is again a 2kw starter motor based on the earlier N3Z1 and N3H1-A, but contains an additional tooth on the pinion gear. This starter motor offers the fastest cranking speed of all by far. You will often see a starting RPM of around 290, going right through to 330rpm in some cases at the top end. This means that the N3R3 starter motor is capable of starting engines in some cases, which are well past their serviceable life.
All of the RX-8 starter motors (above), fitted by Mazda, were manufactured by Mitsubishi.
Related Problems: In some instances, old or worn starter motors can be the root cause of starting issues and particularly Hot-start Problems when the engine is warm. Learn more about the RX-8, its unique engine and common faults in the Expert Help section of the Rotary Revs Garage.