(engine) 1.3 = 2.6
09-19-06, 07:24 PM
#1
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(engine) 1.3 = 2.6
Alright i just need a quick explantion as to why the rotary engine is more equivilent to a 2.6 litre. I cant remember. lol
Theres a kid trying to say its more like a 4.1 one litre, and i need to tell him why its not. Thanks.
Theres a kid trying to say its more like a 4.1 one litre, and i need to tell him why its not. Thanks.
09-19-06, 07:36 PM
#2
Originally Posted by RX(ZONE)
Alright i just need a quick explantion as to why the rotary engine is more equivilent to a 2.6 litre. I cant remember. lol
Theres a kid trying to say its more like a 4.1 one litre, and i need to tell him why its not. Thanks.
Theres a kid trying to say its more like a 4.1 one litre, and i need to tell him why its not. Thanks.
Instead of worrying about rated displacement, the correct means to compare them is "capacity". Capacity is the rating of the engines ability to pump air through them. For piston engines, Capacity = Total Displacment/2. For a rotary Capacity = Total Displacment.
09-19-06, 08:10 PM
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Blake provided a good response. The only reason Mazda used the 1.3 figure was to reduce taxation which was based on 'capacity'.
The argument whether 1.3, 2.6, or 3.9 is the correct capacity has been around for the last thirty years without conclusion.
For most race regulations a figure of 2.6 is used in determining the division.
The argument whether 1.3, 2.6, or 3.9 is the correct capacity has been around for the last thirty years without conclusion.
For most race regulations a figure of 2.6 is used in determining the division.
09-19-06, 08:24 PM
#7
Originally Posted by PaulFitzwarryne
Blake provided a good response. The only reason Mazda used the 1.3 figure was to reduce taxation which was based on 'capacity'.
The argument whether 1.3, 2.6, or 3.9 is the correct capacity has been around for the last thirty years without conclusion.
For most race regulations a figure of 2.6 is used in determining the division.
The argument whether 1.3, 2.6, or 3.9 is the correct capacity has been around for the last thirty years without conclusion.
For most race regulations a figure of 2.6 is used in determining the division.
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09-19-06, 08:39 PM
#9
Do not try to compare rotary engines to pistons. Rotarys are not held back by a valvetrain. Why would a 1.3 liter engine be compared to a 2.6......or even a 4.1? I never did understand why someone would compensate displacement for a different design. Let me guess.....Someone doesn't understand rotaries and they want to make up excuses for their car getting smacked around my a 80 CI engine!
09-19-06, 08:58 PM
#11
Originally Posted by XLR8
Do not try to compare rotary engines to pistons. Rotarys are not held back by a valvetrain. Why would a 1.3 liter engine be compared to a 2.6......or even a 4.1? I never did understand why someone would compensate displacement for a different design. Let me guess.....Someone doesn't understand rotaries and they want to make up excuses for their car getting smacked around my a 80 CI engine!
09-19-06, 09:11 PM
#13
A 13B IS A 1.3L!! I hate this ****. it only displaces 1.3L per revolution so it's a 1.3. If you have a 2L 2 stroke you don't call it a 4L just cause it displaces it's full displacement in one revolution. A 2L 4 stroke is a 2L engine a 2L 2 stroke is a 2L then a ******* rotary is a 1.3L cause that's all it fawking displaces...
09-19-06, 09:35 PM
#14
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I call the rotary a 4-cycle 2-stroke engine. It has the 4 distinct cycles of the Otto Cycle and it displaces it's full capacity in one revolution. It's a good way to confuse the piston guys. 
09-19-06, 10:33 PM
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Blake; while I think you put forward a sound technical argument, I am happy to let the disagreement continue. When I use my car for Government trips, the rate of reimbursement is based on engine 'capacity'. My 12AT is officially rated as 2.2l so I receive the 2,000-4,000cc per km allowance. This is 44% higher than for a small Japanese sedan such as the Mazda 2, and what I would receive if the Government rated my engine as 1.1l.
I think you will find most European countries use 2.2 or 2.6 as the RX-7 capacity for road taxation purposes.
I think you will find most European countries use 2.2 or 2.6 as the RX-7 capacity for road taxation purposes.
09-19-06, 11:55 PM
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My stand on the issue. Piston engines (4 stroke) displace the total volume every rotation, but only use 1/2 of it to produce power.
2 stroke engines use the full volume to produce power, but are not as volumetricly efficeint.
Rotaries have the volumetric efficeincy of a 4 stroke, and the power from every revolution like a 2 stroke.
Rotaries win.
BTW, a 12A would be rated as 2.3L, not 2.2L. 1146cc X 2 = 2292cc = 2.3L
2 stroke engines use the full volume to produce power, but are not as volumetricly efficeint.
Rotaries have the volumetric efficeincy of a 4 stroke, and the power from every revolution like a 2 stroke.
Rotaries win.
BTW, a 12A would be rated as 2.3L, not 2.2L. 1146cc X 2 = 2292cc = 2.3L
09-20-06, 08:06 AM
#18
Originally Posted by RX(ZONE)
Alright i just need a quick explantion as to why the rotary engine is more equivilent to a 2.6 litre. I cant remember. lol
Theres a kid trying to say its more like a 4.1 one litre, and i need to tell him why its not. Thanks.
Theres a kid trying to say its more like a 4.1 one litre, and i need to tell him why its not. Thanks.
Originally Posted by Evil Aviator
I think I can explain displacement in simple terms so that you guys can stop beating this dead horse. Do you understand the difference between a piston and a cylinder? Well, displacement is based on the cylinder, not on the piston.
For example, a 4-Stroke V8 may be rated at 5.0L based on the displacement of the swept volume of all its cylinders, no matter how many times the pistons produce a combustion cycle per crankshaft revolution. Now make that same engine into a 2-Stroke, and it is still rated at 5.0L, regardless of the fact that the pistons now have twice the combustion cycles as before.
OK, if you are with me so far, now look at the Wankel engine in the same manner. Its displacement is based on the swept volume of the rotor housing (cylinder), and it doesn't matter how many times the rotor (piston) produces a combustion cycle. The fact that the rotor has 3 faces has absolutely no bearing on the displacement of the rotor housing. In a similar manner, if there were such thing as a piston engine with one cylinder and three pistons that alternately traveled into the cylinder, its displacement would be based on the swept volume of that one cylinder, not on the 3 pistons.
Does this make sense now?
For example, a 4-Stroke V8 may be rated at 5.0L based on the displacement of the swept volume of all its cylinders, no matter how many times the pistons produce a combustion cycle per crankshaft revolution. Now make that same engine into a 2-Stroke, and it is still rated at 5.0L, regardless of the fact that the pistons now have twice the combustion cycles as before.
OK, if you are with me so far, now look at the Wankel engine in the same manner. Its displacement is based on the swept volume of the rotor housing (cylinder), and it doesn't matter how many times the rotor (piston) produces a combustion cycle. The fact that the rotor has 3 faces has absolutely no bearing on the displacement of the rotor housing. In a similar manner, if there were such thing as a piston engine with one cylinder and three pistons that alternately traveled into the cylinder, its displacement would be based on the swept volume of that one cylinder, not on the 3 pistons.
Does this make sense now?
https://www.rx7club.com/showthread.p...t=displacement
09-20-06, 11:28 AM
#19
Yes, Evil Aviator's post means that the DISPLACEMENT of the engine is 1.3L
But I like the explanation relating to CAPACITY as a way of explaining why a 1.3L rotary can perform in class with 2.6L vehicles.
So the question "What's the rotary's displacement in comparison to a piston engine" is answered with "1.3L"
but the question "Why is the rotary engine capable of producing the power of a piston engine of double it's displacement?" is answered with "Because it's capacity is equal (since in rotaries displacement=capacity but in pistons displacement * 0.5 = capacity), so output would be in the same ballpark"
Jon
But I like the explanation relating to CAPACITY as a way of explaining why a 1.3L rotary can perform in class with 2.6L vehicles.
So the question "What's the rotary's displacement in comparison to a piston engine" is answered with "1.3L"
but the question "Why is the rotary engine capable of producing the power of a piston engine of double it's displacement?" is answered with "Because it's capacity is equal (since in rotaries displacement=capacity but in pistons displacement * 0.5 = capacity), so output would be in the same ballpark"
Jon
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