>> I *was* going to buy a Mazda RX8. Almost the same price. [Obviously both
>> are second-hand.] It has a 3.0 L Wankel engine, agressive styling,
>> bucket seats, the whole lot.
>>
>> ...but then I took it for a test drive. Man, it JUST DOESN'T MOVE!
> 
> You could have tried pressing the gas pedal, you know?

I tried that. Nothing seems to happen. The car just feels heavy and slow.

> The thing about
> wankel is that it constantly rotates in just one direction

I'm pretty sure normal engines rotate in only one direction too. ;-) 
Perhaps you ment there's no reciprocol motion?

>> Well maybe it just *looked* 30 years old then. It was really, really
>> rusty. (But then, it was a Land Rover.) For example, there was a hole
>> under the accelerator pedal where you can watch the road go past below.
> 
> Well yes, Land rover has incredibly traditional look and all, also it
> one of the toughest (if not The toughest) cars ever done - they just
> keep running.

IME, the Land Rover can go places where other "off road" vehicles can't, 
which is impressive. But IT IS NOT RELIABLE. They break down constantly. 
(The again, I've only ever seen ancient ones...)

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> I tried that. Nothing seems to happen. The car just feels heavy and slow.

Apparently 0-60 is 6.2 or 7.0 seconds depending on which engine it has, that 
doesn't sound too slow to me.

As Eero said, you are probably used to a normal petrol engine where the 
maximum torque is usually at quite low rpms and then fairly constant.  With 
the RX8 the torque builds up until it hits a maximum at quite high rpm, so 
if you are trying to drive around at 1000 or 2000 rpm it *is* going to feel 
slow.

> IME, the Land Rover can go places where other "off road" vehicles can't, 
> which is impressive. But IT IS NOT RELIABLE. They break down constantly.

They are probably really simple to fix though, compared to newer cars.

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>> I tried that. Nothing seems to happen. The car just feels heavy and slow.
> 
> Apparently 0-60 is 6.2 or 7.0 seconds depending on which engine it has, 
> that doesn't sound too slow to me.

The infamous Acinonyx jubatus manages > 3.0 seconds, and it's MADE OF 
MEAT! ;-)

...on a more related note, the car I actually bought manages 8.9 
seconds. (But only according to the spec sheet, obviously.)

> As Eero said, you are probably used to a normal petrol engine where the 
> maximum torque is usually at quite low rpms and then fairly constant.  
> With the RX8 the torque builds up until it hits a maximum at quite high 
> rpm, so if you are trying to drive around at 1000 or 2000 rpm it *is* 
> going to feel slow.

So what you're saying is, it won't drive away from the curb quickly?

>> IME, the Land Rover can go places where other "off road" vehicles 
>> can't, which is impressive. But IT IS NOT RELIABLE. They break down 
>> constantly.
> 
> They are probably really simple to fix though

Um...

> compared to newer cars.

Oh, right. Sure.

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> So what you're saying is, it won't drive away from the curb quickly?

No, because if you're trying to do a fast start you can just give it more 
rpms before engaging the clutch.  What I'm saying is that to get the most 
performance from the car you need to keep the rpms very high, this means 
only changing up a gear when you get near the redline, and probably changing 
down 2 or even 3 gears if you decide you suddenly want to overtake someone 
(where normally you might only change down 1 gear).

It has what is known as a very narrow power band, and outside of that band 
it sucks.  A more "driveable" engine will have a more equal spread of power 
across all rpms, and thus might seem more powerful when driving around town, 
even if in a race it would be slower.

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Stephen wrote:
> 
> I don’t know how long a test normally takes. 

In Finland they temp to be theoretical test + handling test + 30min in a
live traffic.

-Aero

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scott wrote:
>> So what you're saying is, it won't drive away from the curb quickly?
> 
> No, because if you're trying to do a fast start you can just give it
> more rpms before engaging the clutch.  What I'm saying is that to get
> the most performance from the car you need to keep the rpms very high,
> this means only changing up a gear when you get near the redline, and
> probably changing down 2 or even 3 gears if you decide you suddenly want
> to overtake someone (where normally you might only change down 1 gear).

Or you can have a turbocharged engine and you don't need to change down ;).

> It has what is known as a very narrow power band, and outside of that
> band it sucks.  A more "driveable" engine will have a more equal spread
> of power across all rpms, and thus might seem more powerful when driving
> around town, even if in a race it would be slower.

Yep.

http://www.dragtimes.com/images_dyno/8792-2004-Mazda-RX-8-Dyno.jpg

Note that the measuring starts at 3krpm and hits the maximum 125 ft-lbs
(according to Google ~170Nm) at 6krpm and continues to 9krpm. As a
comparison, my 1.9TiD tops 320Nm somewhere around 1700rpm, hax max hp
(150) at 4krpm and hits a limiter at somewhere around 5krpm - so it's
stopping the pull where RX-8 is just beginning. Totally different
engines to drive and the RX-8 beats my 9-3 easily from the line, if the
driver just knows how to drive it (rev it high).

-Aero

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Eero Ahonen wrote:
> temp

Tend. A brainfart.

> -Aero

-Aero

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Eero Ahonen wrote:
> Stephen wrote:
>> I don’t know how long a test normally takes. 
> 
> In Finland they temp to be theoretical test + handling test + 30min in a
> live traffic.
> 
> -Aero

I’m talking about 30 years ago, there was no theoretical test in the UK 
then. Only a driving in light traffic then set manoeuvres and a short 
test of the Highway Code.

 > Tend. A brainfart.

I say old chap! Are you sure that’s English? :-P


-- 

Best Regards,
	Stephen

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> In Finland they temp to be theoretical test + handling test + 30min in a
> live traffic.

The handling test sounds cool :-)

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> http://www.dragtimes.com/images_dyno/8792-2004-Mazda-RX-8-Dyno.jpg

Very interesting, I tried to look but couldn't find one.

> Note that the measuring starts at 3krpm and hits the maximum 125 ft-lbs
> (according to Google ~170Nm) at 6krpm and continues to 9krpm. As a
> comparison, my 1.9TiD tops 320Nm somewhere around 1700rpm, hax max hp
> (150) at 4krpm and hits a limiter at somewhere around 5krpm - so it's
> stopping the pull where RX-8 is just beginning.

Mine's similar: (the grey line, not the blue one!)

http://www.superchips.co.uk/curves/BMW20D177bhp.pdf

The main point is that at around 3500 rpm our diesel cars have 3x the torque 
available as the RX8, and at 2000 rpm it's probably 5x or higher.  That is a 
huge amount of "feeling" for when you try to accelerate at low RPMs, the RX8 
is going to feel *really* slow in these situations.  Of course in the RX8 
you can change down 2 or 3 gears to get similar levels of acceleration, I 
guess it depends how often you feel like using a lot of power :-D

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