Metalurgically, that 5.0L V10 is impressive (for an internal combustion engine). It edged out the 7.0L LS7 in the engine of the year competition. Though the only reason, imo, that it won was because pushrods are considered "old tech." The OHC engine was invented in the early 1900's btw. The metalurgical tech involved in the Z06's engine is equally, if not more impressive than BMW's effort however. And a couple of the Ecotec engines share some of this tech. But this is a more relevant way to discuss engine merits than simply hp/L .

I don't know for sure, but I bet that 5.0L V10 is one heavy engine, with alot of weight up top. That's why I like modern pushrod engines, they're relatively lightweight, high power, full of low end torque, and packaged tighter than DOHC engines. They even have variable intake timing in some. The LS7 and the V10 are pretty comparable engines, all things considered. The V10 just has to rev a little higher (1500rpm?) to get the same hp output. The LS7 makes so much torque, it doesn't have to (but it does rev fairly high for a factory pushrod). When you factor in piston size. The forces placed on the LS7's components, would be quite a bit higher than on the V10's.

I'm not saying hp/L shouldn't be used to compare engines. Just that it's one small factor in determining engine superiority. Take the Mitsubishi 4G63 as an example. Without it's turbo it wouldn't make much power at all by today's standards (even with a naturally aspirated head/cam/piston setup). But the power you can get out of one using stock components is absolutely impressive. That tells me this engine should be considered one of the best currently in a production car. There are many variables to consider.

Damn, I didn't mean to type so much...

 

Comparing a rotary to a piston engine will never be a direct correllation so we have to get as close as we can. The closest comparison would be to consider the rotary a 2.6 liter 4 cylinder. When you set up a standalone ecu, that's what you tell it and that's what works. This does lower the hp/l down to 91.5 but that's still good compard to many others. That leaves the Renesis with 3 engines above it with higher efficiencies. Turbocharged engines should always be higher. That's the turbo making it look good. Basically it shows that while the rotary isn't the best of the bunch in all regards, it is average in some and above in others. It's definitely not as bad as many people claim it is.