Best cruise RPM
 

I'm thinking of putting a 13B rotary into a 1974 VW Beetle but what worries me a bit are the gear ratios. I've read that rotaries are rev happy but from what I've seen they normally only run at about 2500 RPM at 100km/h or 3000 RPM at 120km/h in the RX-7's.

Using a stock bug tranny would mean the engine would run at 3000 RPM @ 100km/h (62.5 MPH) and 3500 RPM @ 120km/h (75MPH) or ~500 RPM higher than normal.
What would long periods of 3500 RPM do to the longevity of the engine?

Thanks
Paul

talk to this guy
https://www.rx7club.com/showthread.p...&highlight=bug

You'll be fine. My 1990 n/a convertible turns 3500 rpms at 80 mph on the highway with no problems.

My 1st-gen turned about 3600ish in 5th at 60mph, before I ran out of 1st-gen gearboxes and had to put in an FC unit. (Nonstock rearend, 4.78 vs. stock 3.91)

Now it's only turning maybe 3100ish at 60mph, the '86-up trannies have way-tall 5th gear. It's not as happy on the highway, and the 5-4 shift (which is now more necessary) has a huge drop.

Anyway I'd drive all day long at 4500ish RPM and still knock back 27ish MPG give or take a couple.

Great! I'm worrying about nothing again. :)

Paul