SpideyFan6010

Ok how do you get the Equivalent of a rotary in piston liters? Don't you just multiply by 2 right? I hear the 1.3L rotary is equivalent to a 2.6L piston is this true and what would be the others for a 20B and the R26B. 4.0L and 5.2?

Rx7_Nut13B

iTrader: (1)

There no replacement to displacement dont you know that !!!


LOL just kidding

Kobura

FIA-regulations use a 1.5x multiplier when comparing rotary engines to piston engines, which means, 1.308cc * 1.5 = 1962
That's why FDs drive in SP3T-class in 24 hours endurance race on the Nürburgring, which is also used for piston engines reaching a displacement of 2.0l using a turbo.

fd93texas

iTrader: (2)

Dang people from the other side of the world in here. Nice

SpideyFan6010

so a 1.3L=1.9 the
2.0L=3.0L
2.6L=3.9L
is this correct?

Kobura

Yea. But they're pedants, so only 1 cc over 2.000cc and you're in the next upper class.

SingleTurboRx7

So for people in America, how would NASCAR rank it?

No_love_for_pistons

iTrader: (4)

A good explanation for rotary displacement can be found here

rotarygod

iTrader: (1)

2.6l

Rx7_Nut13B

iTrader: (1)

^^^^^ he has spoken ^^^^^^

SpideyFan6010

With that being said a 20B=4.0 and the R26B=5.2?

Kobura

Yes.
I think FIA considers the different progress in technology, because only one car manufacturer is working on the rotary engine. So that's why they only use 1.5x instead of 2.0x

SpideyFan6010

Thanks for clearing that up guys. I just always wanted to know so I can see if a 5.2L ever hit 750+ on N/A power like the R26B did.

rotarygod

iTrader: (1)

Lots of 5.2 liter piston engines have hit 750+ hp n/a. In fact many smaller ones have too. Even street built engines. (street legal being an entirely different matter) The sad truth that many rotary owners can't accept is that we don't make more than 100 hp/L as some good piston engines do. The rotary isn't that efficient. It does make good power compared to it's physical size though which is where the advantage is. Even the Renesis only makes about 90hp/L whereas a stock '86 n/a is only 56hp/L. That's downright pathetic by anyone's standards! Consequently an S2000 is around 110 hp/L. Sorry to break it to some people. Everyone with a 13B has a 2.6 liter engine so bragging to others about a 1.3 is worthless as that's not entirely accurate but solely Mazda's fault. It's fun to say but completely wrong!

However there is some fun to be had when we compare power of a peripheral port engine to displacement. The R26B being a good example. 5.2L of displacement and 750 hp. That's 144hp/L!!! Woohoo! Then again a 3.5L IRL piston engine also hit the same amount of hp which is well over 200hp/L so again the rotary is not on top.

Kobura

Well, the R26B is claimed to get a maximum output of 930 hp (690 kW), but was tuned lower spec for reliability.
But these are determined by higher revs. To compare the efficiency of engines you should take torque/liter.
The R26B gets 607 Nm out of it's "5.2l" so it's around 116.7 Nm/l.
Porsche's really great flat-6 of the 997 GT3 RS gets 405 Nm out of 3.6l -> 112.5 Nm/l
But this is a street-legal car in germany.
Well i found the specs of the Jaguar XJR12:
7l engine with 785 Nm resulting in 112.1 Nm/l

The rotary engine is not that bad in my opinion, it's just not as evolved as the piston engine to take on those high revs the piston's are using in the F1.

rotarygod

iTrader: (1)

If you can rev it faster (and live) and get it to breathe there, any engine will make more power.

Kobura

Yes, that's why i think torque / liter is a better way to compare engine types than power / liter. N/A compared to N/A and FI compared to FI though.

Rx7_Nut13B

iTrader: (1)

A NA Full Bridgeport 13B will make a easy 300hp while the P-Ported engines can do even more.