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why is the rotary so inefficient??

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Old 11-20-02 | 07:25 PM
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why is the rotary so inefficient??

I don't mean to say I dislike the rotary, but why does it only make around 140 HP NA?? I mean for a motor that technically displaces 2.6 liters why doesn't it make a LOT more power, or at least get better mileage? I don't get it.
Old 11-20-02 | 07:30 PM
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You didn't mention torque but it doesn't have very much torque because torque is a measurement of force x distance from rotating axis. If you assume that the force is distributed equally across the rotor face with the maximum half the distance from the center there is a distance of aboot 2 - 3"... not very much
Old 11-20-02 | 07:39 PM
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Re: why is the rotary so inefficient??

Originally posted by wes2k3
I don't mean to say I dislike the rotary, but why does it only make around 140 HP NA?? I mean for a motor that technically displaces 2.6 liters why doesn't it make a LOT more power, or at least get better mileage? I don't get it.
How was the 84 you looked at on Sunday? How much horsepower did other 2.6 liter engines from 18 years ago make?

You are aware that the new rotary in the Rx-8 next year will produce approx 247hp? Is that comparable to other 2.6 liter piston engines today?

Brian
Old 11-20-02 | 07:41 PM
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2.6 liters? um try 1.3, this aint no p1st0n engine
Old 11-20-02 | 07:44 PM
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booyah! Rotaries rule, Pistons drool!
Old 11-20-02 | 07:45 PM
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Re: why is the rotary so inefficient??

Originally posted by wes2k3
I don't mean to say I dislike the rotary, but why does it only make around 140 HP NA?? I mean for a motor that technically displaces 2.6 liters why doesn't it make a LOT more power, or at least get better mileage? I don't get it.
the last generation factory 13Bs were rated at 163hp i belive and slight port jobs you can get them over 200hp and many 13Bs are able to put over 300hp with bigger ports ( not very street legal )

There is a video on the forum of a White NA FD .... do a search
Old 11-20-02 | 07:45 PM
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The combustion chamber shape=hella shitty.

The flame front has quite a ways (relatively) to travel.
Old 11-20-02 | 07:45 PM
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Its better to be Rotary than to be Pist-on!!!

Ahahaha

Rotaries are NOT inefficient.
Old 11-20-02 | 07:47 PM
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gotta remember the new rx-8 is n/a gotta love that.. lol
Old 11-20-02 | 07:51 PM
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They're thermally inefficient.
They can also spool turbos like a ************
Old 11-20-02 | 07:58 PM
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what's different about the RX-8 motor? I was thinking about the 2.3 liter ford in comparision to the wankel, in 84 it was making 100 HP and maybe 200 TQ, but with a turbo (T-bird turbo coupe or SVO mustang) it was 190 - 210 HP and 250 TQ. So i guess they were doing pretty well. Do the wankels spin up turbos well because of the high exhaust temps?
Old 11-20-02 | 08:01 PM
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Re: why is the rotary so inefficient??

Originally posted by wes2k3
I don't mean to say I dislike the rotary, but why does it only make around 140 HP NA?? I mean for a motor that technically displaces 2.6 liters why doesn't it make a LOT more power, or at least get better mileage? I don't get it.
Ohhh yeah ... totally forgot about the RX-8 ( that is because they are dragin on the release for so many freagn' years and changing the dates all the time )

Any ways ... 1.3 mashed out 280hp and they firmed up on 250hp for the production model.

So here is a production car with 215hp/L .... WTH are you talking about ???

And one more thing ..... the rotors spin at 1/3 the speed of the cranck shaft ( 9,000rpm = 3,000rpm )

Last edited by Project RX-7; 11-20-02 at 08:08 PM.
Old 11-20-02 | 08:11 PM
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Originally posted by wes2k3
Do the wankels spin up turbos well because of the high exhaust temps?
high exhaust temps arent good for a turbo, its the airflow over the exhaust turbine. If you could have freezing exhaust gas (i dont know how you would do that...) it would work the same, its all a matter of airflow
Old 11-20-02 | 08:19 PM
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The milkman touched on the real reason, the combustion chamber shape being long and narrow as well as the charge velocity and flame propagation all combine to produce a condition that does not allow the charge to burn completely before it's expelled out the exhaust port.
Old 11-20-02 | 08:22 PM
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Would the 3 spark engine ( 26B ) be more efficient than a 2 spark 13B ?

Another reson why rotaries are not on par with the piston engines is because piston engines have been around for more than 100 years and thousands of companies and hundreds of car manifacturers spent trillions of dollars in research on it.

Where the rotary was only here for 1/2 the time the pistonsengines have and all the big companies gave up on it because they already had a powerplant to work with. In reeality MAzda was the only car company to stick and research the rotary engine .... and they have been in a not so favorable finacial situation.

Think where the rotary engine would be if it had the same time and research put into it.

Last edited by Project RX-7; 11-20-02 at 08:34 PM.
Old 11-20-02 | 08:25 PM
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its not so much that its a "2.6" litre, but that every stroke is a power stroke. now, i see how you'd compare the litreage to one another, but just because it takes 2 strokes to create a power stroke from a piston doesn't mean that a rotary is "technically 2.6 litres" (unless i'm missing something). but yes, they are becoming more efficient in power and gas, more power less gas, gotta love that. but it also can only produce so-much-power with whatever ports it comes with. the engine is still evolving, and is yet to be perfectly efficient in its design.
Old 11-20-02 | 09:00 PM
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2.6 liter is not very accurate either... if you are going that displacement argument route then you need to double the CC of a piston engine as well, since one whole stroke is not used or making power, but still traveled.

So your Ford 2.3 that you are comparing really was a 4.6 if you rate the 13B at 2.6 liters.

Wow 100 hp for 4.6 liters doesn't seem very much... heck 200 hp doesn't seem very much from a 4.6 liter motor
Old 11-20-02 | 09:20 PM
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I'd rather push my Mazda than drive a Ford
(although, Ford is part owner of Mazda, but u know what I mean)

I reckon it all comes down to Research & Development. Imagine if the same time & money was spent on developing the rotary engine???
Old 11-20-02 | 09:24 PM
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A rotary engine displaces only...well, in my case, 1.1 litres wich is about 100hp stock. Now compare this to say a honda civic with 1.8 liters of the same year, and maybe displaces pffff 65hp? LOL
Old 11-20-02 | 09:28 PM
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oops
Old 11-20-02 | 09:30 PM
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Originally posted by wes2k3
what's different about the RX-8 motor? I was thinking about the 2.3 liter ford in comparision to the wankel, in 84 it was making 100 HP and maybe 200 TQ, but with a turbo (T-bird turbo coupe or SVO mustang) it was 190 - 210 HP and 250 TQ. So i guess they were doing pretty well. Do the wankels spin up turbos well because of the high exhaust temps?
what the **** are you talking about? Which 2.3 liter four stroke gasoline engine makes 100hp and 200ft/lb torque N/A?!?!?

And what does this have to do with rotaries?
Old 11-20-02 | 09:30 PM
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Originally posted by 0pistn
I'd rather push my Mazda than drive a Ford
(although, Ford is part owner of Mazda, but u know what I mean)

I reckon it all comes down to Research & Development. Imagine if the same time & money was spent on developing the rotary engine???
One of the resons why there are not as many people pushing their Fords is because Ford has a stake in Mazda.

In the 70s Ford bough into Mazda because they needed sonome one to build better FWD small engine cars.

Let anyone look at FWD small engine Fords from that time !!!

Ford Festiva ( Mazda 121 )
Ford Aspire ( Mazda 121 )
Ford Escort ( Mazda Protege / 323 )
Ford Probe ( Mazda MX-6 )
Ford Ranger ( Mazda B-Series till early 90s )
Ford Laser ( Mazda Protege )
Ford Telsar ( Mazda 626 )
Ford TX-3 ( Mazda 323 GT/GTX )
Ford convertible thinge ( Using old school Mazda GT/GTX parts )

Last edited by Project RX-7; 11-20-02 at 09:40 PM.
Old 11-20-02 | 09:33 PM
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why in the world doesn't any one reffer to 2-stroke engines as doubble their size ??
Old 11-20-02 | 09:34 PM
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In the 70s? I thought that Ford bought into Mazda in the early 90s....
hmmm, can anyone confirm a year?
Old 11-20-02 | 09:38 PM
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Originally posted by Node
In the 70s? I thought that Ford bought into Mazda in the early 90s....
hmmm, can anyone confirm a year?
OMG !!! .... early 90s ?!?!?!? .... you crazy ?
What about all the cars i mentioned above .... you don't Ford just said, hey, lets copy the MX-6 Turbo and the 323 Turbo and call them Fords.

Last edited by Project RX-7; 11-20-02 at 09:47 PM.


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