Here is a cheaper and quicker way of testing and demonstrating this concept.

Get an AIXRO Kart engine and mount it on the back of the RX8 differential.
Remove the stock rear cover.  Use a second pinion gear and run the AIXRO
only at cruising speed with a one way clutch to disconnect it at lower
speeds.

Assume a 30 inch diameter tire and that gives a 94.248" circumference. That is 7.85 feet in
circumference. At 95 feet per second or 65 MPH that is 12 revs per second or
720 RPM. Multiplying by the 4.77:1 rear axle ratio yields 3434 AIXRO engine RPM.

So you will need a 2.17 planetary gear reduction given 7452 RPM max HP for the AXIRO engine.
That is also 114 revs per mile... per hour or 96 MPH at 11,000 AIXRO max RPM.

Paul Lamar


Did you build a prototype to test your concept ?

Guido Bartolomei


Not yet. My guess is the MPG running on the AIXRO alone will
be .73/.52 X 25 will be about 35 MPG. Converting the AIXRO to an oil
cooled rotor and EFI and the RX8 MPG could jump to 38.8 MPG.

Going the full turbo compound route on the AIXRO and getting
the BSFC down to .4 or below the RX8 MPG would jump to
.73/.4 X 25 or 46 MPG at a steady 65 MPH.

The cost of testing this is not beyond the means of an individual.

Paul Lamar