just out of pure curiosity, how much power would a 4 rotor put out if your were to just slap together 2 S5 na engines together? ( i know there's more involved but just for simplicity sake) with the bare minimum to get it running....

 

Xtreme Rotaries - 4 Rotor Engines

Rx7, Rx8, Mazda Rotary Engines, O ring, Race Car Engine Parts

 

too much to make any realistic use of in a street car

 

well all they are showing are PP engines that are at 600+ they say. so if you were to use the stock ports and a crude intake and exhaust(bare with me) 400? More? Less?

 

So you want to build a quad rotor just to say u have one?

 

Easy.

Take the power output of a two rotor in whatever configuration and double it.

 

no, not really. it would be cool but rather do something easier on the wallet.


for real, im just curios.

 

The 787 had almost 800 in full trim tho

 

+1.

 

they quote 690 in the SAE paper, but that is WITH the intake restrictor they had to run in that class, when they rebuilt it in 2012 (1991 to 2012 without a rebuild!) they didn't put the restrictor back in, and they do claim more than 800hp

which is a LOT. if you divide by 2 to get 2 rotor its like 400hp NA

 

I'm not aware of any intake tract restrictions being forced back in Group-C days. AFAIK they were limited only by minimum weight and overall fuel amount. I'm not doubting the numbers, just looking at fastest all motor 13B reveals that they must produce over 400 HP at crank.

If you have any more specific information, please share

 

What he said; no restrictor in Group C. However they didn't necessarily run it at the full revs it was capable of, given the 24 hour race and the fuel consumption metric it was running on. And with the same engine in the IMSA GTP class in '92 in sprint races, they were claiming around 650 horsepower. You can throw around all you want about "claims" and such, but if it was 800hp it would have been qualifying a lot better than it was, even if the race reliability wasn't there. There's a bunch of quotes around about an engine making 700+hp in the pipeline for '93 before the plug got pulled on the program... I find the idea that there was secretly an extra couple hundred horsepower in the '91 configuration R26B that nobody knew about pretty doubtful.

As for making a non-peripheral-port 4-rotor, the big problem is that you're going to end up with only two rotors having decent sized intake ports. The middle two rotors are just going to be fed by the tiny primary ports and it would suck.

 

because you can't slap 2 13Bs together and keep it a side port intake engine.. the middle irons can't be ported enough to match end plates. and when going through all that why would you want to keep it that mild?

as for the other end. i'm not 100% set that a 2 rotor multiplied by 2 would equal the same 4 rotor equivalent. you have 4 rotors working in unison, there has to be some additional benefits in there, not to mention the peripherals not being multiplied by 2. ie less overlap waiting for the power stroke to carry the rotor into the next firing sequence, it should make the same power with less stress, but charging the engine is always going to have some limits. basically filling the chamber will be very difficult once you hit that incline, but it should be easier to get to that incline.

 

i see all your points, and i understand. but im not trying to build a engine here, just a discussion to indulge my curiosity.

also posted here in the fd section, looking for a build log, but nothing yet.

https://www.rx7club.com/3rd-generati...lease-1025720/

saw this video and was curios. how much power do you think this engine can make?

 

that particular combination sounds 180 degree phased(that or some chambers sound unhealthy), meaning you are firing 2 rotors at the same time. this setup would make torque easier than a 90 degree phased engine which is more suited to higher revs and higher peak power.

both can be equally as fast at the end of a stretch of road but each has their benefit and drawbacks.

most real 4 rotor engines you will see will be 90 degree phased, which takes more technical work to actually get it running and properly, taking advantage more of the rotaries long winded-ness.

no one really knows much about that particular engine because it probably never made it much further than that video.

 

i see just thought it would be cool to read up on it and to see if it got running well and what kind of power it made.