View Full Version : Why is the RX8 always compared to cars 2x the engine size?
champi0n 09-16-2007, 11:24 AM I'm not sure i understand why everyone puts a 1300cc engine in the same class as a 3500cc engine? I don't get the comparison.
They dont put 150lb fighters in with 300lb fighters in the UFC.
ken-x8 09-16-2007, 11:41 AM Because the rotary engine is twice as good as a piston engine.
Ken
Our engine fires every stroke.... unlike a piston which is every other stroke.
So our engine acts more like a 2.6 liter from a power and breathing standpoint.
Rootski 09-16-2007, 11:45 AM Because if you didn't, all the comparos would be against the Chevy Aveo.
CTrx8 09-16-2007, 11:58 AM They dont put 150lb fighters in with 300lb fighters in the UFC.
they used to :)
robrecht 09-16-2007, 12:07 PM Because if you didn't, all the comparos would be against the Chevy Aveo.Is the Chevy Aveo faster? :lol2:
NgoRX8 09-16-2007, 12:07 PM Well, considering everyone compares this car to others in the same price range. it is compared to those of much larger engines in "size." I'd say the rx-8 was put in comparison with them from the beginning, wouldn't you? if not, then tell me what cars you were considering before you decided on the 8. engine size doesn't matter. it could be thought of as 1.3, 2.6, or even 3.9.
tajabaho1 09-16-2007, 12:46 PM i was looking for a 5.4 v8 corvette
Rems31 09-16-2007, 02:07 PM cuz it's in the same price range and hp as those with "2x the engine size"
lucifuge 09-16-2007, 05:12 PM Well, considering everyone compares this car to others in the same price range. it is compared to those of much larger engines in "size." I'd say the rx-8 was put in comparison with them from the beginning, wouldn't you? if not, then tell me what cars you were considering before you decided on the 8. engine size doesn't matter. it could be thought of as 1.3, 2.6, or even 3.9.
No, as Kane correctly said, it is effectively a 2.6L engine. 1.3L only makes sense when compared to other rotary engines(ie 12A =1.2L or 10A = 1.0L). But when you want to compare to traditional piston engine cars you need to understand it as a 2.6L engine, not 1.3L nor 3.9L. Rotary engine has one power stroke per cycle per revolution. Normal piston has one power stroke per cycle per every 2nd revolution....hence the doubling required to equate fuel usage to piston engine cars.
Revolver 09-16-2007, 06:26 PM Forget about engine size - think power and (lack of, lol) torque. It is usually compared to cars of similar price, performance and configuration (i.e. mid-priced coupe-shaped respectably quick sports cars). The fact that it has such unique characteristics just makes such comparisons more interesting. :)
saturn 09-17-2007, 11:22 AM It is usually compared to cars of similar price, performance and configuration (i.e. mid-priced coupe-shaped respectably quick sports cars). The fact that it has such unique characteristics just makes such comparisons more interesting. :)
This is exactly right. For anyone who is actually planning on buying a car and not just magazine race, price is pretty much the starting point -- not engine size.
rotopsycho 09-17-2007, 04:20 PM i was looking for a 5.4 v8 corvette
heh good luck finding that (5.4=332=ford 5.7=350=chevy) there hasnt been an engine smaller than a 350 since 76
Razz1 09-19-2007, 12:03 PM When the under dog wins races, you have to compare it to the big boys.
pf100 09-19-2007, 01:06 PM I'm not sure i understand why everyone puts a 1300cc engine in the same class as a 3500cc engine? I don't get the comparison.
For the same reason why they allowed the 4 stroke bikes to have twice the displacement as the 2 strokes when they started allowing them in MotoGP, because otherwise it would have been unfair.
I like the rotary, and if more people besides Mazda developed it, I am sure it would be even better than it is now.
It still has terrible fuel mileage.
I could ask, why does a car with double or even triple the displacement get better mileage?
tajabaho1 09-19-2007, 01:32 PM heh good luck finding that (5.4=332=ford 5.7=350=chevy) there hasnt been an engine smaller than a 350 since 76
I have a buncha those, 69s 70s blah blah, 7k for 1....
Ploppity Drown 09-19-2007, 05:35 PM When I read this in a comparison between the RX-8, 350Z, and 330i on Automobilemag.com (http://www.automobilemag.com/reviews/coupes/0304_mazda_rx8/interior.html) I was initially confused in light of the discussion in this thread about doubling the Renesis' displacement to compare it to a four-stroke engine:
...the twin-rotor Mazda 13B displaces just 1308 cubic centimeters and produces only two power pulses per engine revolution versus the reference cars' three.
But I think I've made sense of it now. The gearing between the E-Shaft and the rotor results in 1 power pulse per revolution. With two rotors connected to the shaft, that's two power pulses per revolution.
http://upload.wikimedia.org/wikipedia/commons/f/fc/Wankel_Cycle_anim_en.gif
With a 6 cylinder piston engine, though, you get 3 power pulses per revolution of the crankshaft, since it takes 720 degrees for each piston to complete the four stroke cycle--only half of the pistons fire per 360 degrees. Which means that power is produced by the full displacement only after two revolutions.
So depending on your perspective, the displacement of the Renesis is either 100% underrated, or that of the piston engine is 100% overrated.
And this means that the twin-rotor engine delivers power like a 4-cylinder.
Jedi54 09-19-2007, 05:57 PM because people are idiots.
Uncivilizedracer 09-19-2007, 06:05 PM I say give me the MAzdaspeed version and run another comparison... see what they have to say then
because people are idiots.
http://www.mazdausa.com/MusaWeb/keyCompetitors.action?vehicleCode=RX8&modelYear=2007
Including Mazda?:lol2:
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