Rotary (Wankel)


American Rotary Engine /Auto PSRU’s

We’re combining these two very separate companies under one heading because they join to offer a Mazda 13B rotary engine conversion package. American Rotary builds the Wankel engines while Auto PSRU’s makes the propeller gearbox. Their long-standing offering is a 200-hp firewall-forward fitment for the RV-7.

We’ve already introduced Auto PSRU’s in this guide under our Inline and V Four-Stroke heading; American Rotary Engine is the aviation sidebar to Atkins Rotary, a hot-rod shop up to their necks in modifying and supporting Mazda Wankels for auto racers.

While American jokes that customers all want a “500-hp engine that weighs 30 pounds,” they offer up to 200-hp, naturally aspirated and turbo-normalized packages, and will support Reno racers. An aviation-specific development of theirs is a spring-loaded pop-off valve set to 4 pounds to avoid overboosting after descents or on go-arounds.

Naturally aspirated Mazda 13B in an RV-6. (Image: Atkins Rotary)
ModelDrive TypeHorsepowerWeightPrice
American Rotary Engine
2 rotor 13Bgeared180 hp @ 6000 rpm320 lb wet w/ alternator, starter, ECU, EFI and EI$20,000
Auto PSRU’s
Mazda 13Bgeared180 hp @ 7600 rpm (centrifugal clutch) 2.778:1 ratio385 lb installed, typical, complete$34,100 FF, est. call
Mazda 13B turbo-normalizedgeared200 hp @ 7600 rpm (centrifugal clutch) 2.778:1 ratio410 lb installed, typical, complete$42,700 FF, est. call


  1. Yes, rotary (Wankel) engines are allowed and several rotary powered racers have been proposed or taken to partial completion. None, however, has actually competed to date.


Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.