Rotary engines

saftey

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Apr 29, 2002
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If rotary engines have amazing torque output efficentcy and price efficentcy why dont we see them in the car scene anymore?I havent seen one since a rx-7 and the rx-8 isnt even going to be a turbocharged model.Did ford have alot to do with this?Ford does own most of mazda.
 

JC

Diamond Member
Feb 1, 2000
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Rotaries have amazing horsepower efficiency, not torque efficiency. Their fuel mileage isn't the best, either.

JC
 

saftey

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Apr 29, 2002
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umm are you sure about the gas efficentcy?i mean theres one major througput of fuel instead of various injectors no inconsistancies to deal with.Horsepower efficentcy over torque?so this one massive trangluar object spinning creates less torque then a bunch of verticlly mounted cylinders.
 

apoppin

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Mar 9, 2000
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Mazda is the only car company that was able to deal with the practical problems of rotaries in passeger cars.

They are a bit had to control emissions on.

I am selling both of my 1976 Mazda Cosmos (13B rotary) on ebay next week . . . great cars . . . a 1.3 L engine will put out nearly 300HP without turbocharging . . . I have neither the time or energy to restore them as I had originally planned. :(

Gas mileage isn't really that bad for a "muscle" car. In the mid to high 20s as I remember..
 

apoppin

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Mar 9, 2000
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Originally posted by: b0mbrman
The last RX7 sold in the US had 255 hp and got 17/25 mpg


The reason the gas mileage is poor is because of all the extra emissions controls. Mine got better mileage because (the one set up for race) had no controls.
 

Bleep

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Oct 9, 1999
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In the beginning with the Mazda or Wankle rotory engine the big problem was with the rotor seals not lasting very long and very expensive to replace. In a raceing enviroment this means nothing because the race engine is not run for very long without a complete rebuild. The seal problem has not completly gone away and the rotory was doomed from the start because of this problem.
Bleep
 

ThisIsMatt

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Aug 4, 2000
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Originally posted by: Bleep
In the beginning with the Mazda or Wankle rotory engine the big problem was with the rotor seals not lasting very long and very expensive to replace. In a raceing enviroment this means nothing because the race engine is not run for very long without a complete rebuild. The seal problem has not completly gone away and the rotory was doomed from the start because of this problem.
Bleep
Word. You have no way to fully isolate the oiled side from the combustion side...
 

apoppin

Lifer
Mar 9, 2000
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The seal problem has not completly gone away and the rotory was doomed from the start because of this problem

Wrong. New seal material and better lubrication (the oil is metered into the gas) has allowed current rotary engines to last over 150K miles before rebuilding.

And rebuilding is such a piece of cake (compared with piston engines).
 

ThisIsMatt

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Originally posted by: apoppin
The seal problem has not completly gone away and the rotory was doomed from the start because of this problem

Wrong. New seal material and better lubrication (the oil is metered into the gas) has allowed current rotary engines to last over 150K miles before rebuilding.

And rebuilding is such a piece of cake (compared with piston engines).
And we all know how well (and clean burning) that is...
 

Bleep

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Oct 9, 1999
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OK guys I stand corrected. Just have not kept up on the tech. lately I guess I apologise.
Bleep:eek:
 

apoppin

Lifer
Mar 9, 2000
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And we all know how well (and clean burning) that is...

Mazda rotarys always had problems meeting emission standards (I know in 1976 they had to use a special thermal chamber along with 3 sets of points). The seals used to go out on the early RX-2 about every 30K miles. The Rx3s improved to about every 60K miles and my 1976 (Cosmo -RX-5) easily went over 100K miles. I learned to rebuild my own engine cause I wanted to - not out of necessity.

Rebuilding a rotary is SO easy. Two guys can lift the block out of the car and it simply disassembles into sections. The only thing that (usually) wears out IS the seals.

The newer ones are supposed to also hit around 200K miles but I can't say for sure.

For a tiny engine in an "inexpensive" well balanced car with a reputation as a Porsche-killer, Mazda's rotarys have come a long way. And they have solved their turbocharging problems.
 

ThisIsMatt

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Originally posted by: apoppin
And we all know how well (and clean burning) that is...

Mazda rotarys always had problems meeting emission standards (I know in 1976 they had to use a special thermal chamber along with 3 sets of points). The seals used to go out on the early RX-2 about every 30K miles. The Rx3s improved to about every 60K miles and my 1976 (Cosmo -RX-5) easily went over 100K miles. I learned to rebuild my own engine cause I wanted to - not out of necessity.

Rebuilding a rotary is SO easy. Two guys can lift the block out of the car and it simply disassembles into sections. The only thing that (usually) wears out IS the seals.

The newer ones are supposed to also hit around 200K miles but I can't say for sure.

For a tiny engine in an "inexpensive" well balanced car with a reputation as a Porsche-killer, Mazda's rotarys have come a long way. And they have solved their turbocharging problems.
That's the thing, they're not very consumer friendly. And they're not advantagous enough to be made for performance only cars...

 

MisterPresident

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Mar 6, 2002
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Can someone please describe how a rotary engine works? I feel dwarfed by the vast technological knowledge all of you posses.
 

apoppin

Lifer
Mar 9, 2000
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That's the thing, they're not very consumer friendly. And they're not advantagous enough to be made for performance only cars...

That may change with Mazda's reintroduction here. After all the rotary engine is only - what? - 30 years old in passenger cars. How many years have piston engines been around in cars?

We'll see . . . I still have hopes for them.