SCCAForums.com

 Rotary Engines (Wankel): These units will be classified on the

basis of a piston displacement equivalent to 1.8 liters plus the

volume determined by the difference between the maximum and

minimum capacity of the working chamber, times the number of

rotors.   

So if you have an 1146cc 12A equivalent displacement becomes?

What would it be if you had a turbo 12A?

 

Thanks

 

 

 

Rounding up you would have 1.2 + 1.8 = 3.0  for the NA version.  ADD another 1.4 for the turbo...4.4.  (Note:  I rounded up to make it easier, you can use the exact number).

Rotary adjustment (like FI) was used as an adder since we felt that using a multiplier made it more difficult to equalize between a 2 rotor NA and a 3 rotor FI, it always ended up being too generous (or too painful) one way or the other. 

 -Andy M.

So that means the minimum weight for a NA 12A is 2200lbs and for a NA13B is 2400lbs in a non 12A car.  But if you add a turbo minimum weight goes to 2900lbs which means you need to add at least 500lbs!  A 1st gen Rx-7 base weighs 2300Lbs ish.

Quess there is no point in adding a turbo

 

I think you used a multiplier for FI, it is an adder as well in SM.  Personally, I think the NA weights are a little harsh, but you can make quite a bit of power even out of an NA rotary (though maybe not the best torque). 

1.2 NA ..2200lbs

1.3 NA .. (1.3 + 1.8) * 200 + 1600 = 2220

1.3 Turbo ... (1.3 + 1.8 + 1.4) * 200 + 1600 = 2500

2.0 NA...(2.0 + 1.8) * 200 + 1600 = 2360

2.0 Turbo (2.0 + 1.8 + 1.4) * 200 = 2640

 -Andy

Thanks for the clarification and fixing my bad math.

For the power these machines put out... thats a very generous weight restriction.

Heh... this heaviest possible RX7(2640) is still 100 lbs less than the lighest corvette possible (2740)
 

---

Michael "MrPickles" Feldpusch
#144 SM2
Broomfield, CO
rmsolo.org
lefthandracing.com

Michael, I know what you are trying to say, but you are also wrong on the Corvette.  You are assuming that the min displacement for a Vette is with a 5.7l.   Let's say you used a 3.8l with twin turbos...which would be 3.8 + 1.4 = 5.2  ==> 2640lbs.   If you want to make the argument that the rotary factors are not valid, I'd suggest you come up with an alternative and use some data to back yourself up.

 -Andy

Who says you can't make the C5/C6 motor smaller? It would be easy to make a 316 cube (5.18L) LS motor. 4.8L truck crank, 6.250" rods and a shelf 1.314" CH piston. The Daytona Prototypes run a 305 cube LS1 motor and make over 500hp with it on 11:1 compression and a max of 7100rpm so you could be very competitive with the fast RX-7's in terms of weight and power.

2636lbs would be the same as a 20B with a Turbo on it.

Then again I don't know anything about LS motors I just work on them all day ;-)

Bret

PS You also might want to look at ASP results vs. SM2 results at National Races, a C5 with a good driver is at the same level or better than the fastest SM2 cars.

---

Bret
Camaro SS FS