Why Does the RX-8's Fuel Economy Suck So Bad?

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Scott in SoCal - 10 May 2008 16:15 GMT

Don't get me wrong, I have always loved the looks of the RX-8. The
main reason I never got one is because it's so under-powered and
lacking in torque. However, in these days of skyrocketing gas prices I
*might* be able to get past that problem if only there were an upside
such as excellent fuel economy. However, the RX-8 doesn't have that,
either! 16 city/22 highway? WTF?? A Corvette with a 6.2L engine gets
better fuel economy than that (16/26) and has twice the horsepower and
3 times the torque!!!

What is it about the w.nker engine that makes it so inefficient? And
why does Mazda still sell it?

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Brent P - 10 May 2008 17:39 GMT

> What is it about the w.nker engine that makes it so inefficient? And
> why does Mazda still sell it?

Wankels always sucked gas. The advantage of a wankel is light weight and
fewer moving parts.

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Nate Nagel - 10 May 2008 18:11 GMT

> Don't get me wrong, I have always loved the looks of the RX-8. The
> main reason I never got one is because it's so under-powered and
[quoted text clipped - 7 lines]
> What is it about the w.nker engine that makes it so inefficient? And
> why does Mazda still sell it?

light weight and small size.

nate

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Matthew T. Russotto - 11 May 2008 02:12 GMT

>Don't get me wrong, I have always loved the looks of the RX-8. The
>main reason I never got one is because it's so under-powered and
>lacking in torque.

[...]

>What is it about the w.nker engine that makes it so inefficient? And
>why does Mazda still sell it?

Buying an Wankel for fuel efficiency is like buying a Corvette for the
ground clearance; you're missing the point entirely. They're small
and light for the amount of power they produce.

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C. E. White - 12 May 2008 14:08 GMT

> Don't get me wrong, I have always loved the looks of the RX-8. The
> main reason I never got one is because it's so under-powered and
[quoted text clipped - 9 lines]
>
> What is it about the w.nker engine that makes it so inefficient?

The way the Wankel creates the combustion chamber and changes the
shape of the combustion chamber to compress the charge results in a
moving combustion chamber (the whole chamber moves, not just the
bottom) with an odd shape. The charge is forced into a relatively odd
shape with lots of thin areas next to realtively cool metal. This
results is a relatively slow, somewhat inefficient burn rate. This is
not ideal for fuel efficiency. A lot of still expanding gas escapes
out the exhaust port instead of moving the rotors along.

> And
> why does Mazda still sell it?

Becasue people buy it.

Ed

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