(why not a six cylinder 2.0litre?)
Firstly I thought you were talking about small cars?
Secondly a 6cyl engine is inherantly less torquey than a 4 or 8 cyl, particularly a straight 6, due to the spaces between intake pulses, and needs complex variable manifolds to compensate. Notable engines, Triumph 2000 straight six on a single carb, only 84 bhp and virtually zero torque, Lexus is200, early BMW 2.0 6cyl, Jag 2.0 V6 (actually a 2.1 though a world away from the 2.5 it is based on).
If augmented via vaiarble intake systems ets a 2.5 6cyl produces useful torque and power as well as refinement where as a 2.0 would generally be a dispointment on the flexibility front to anyone used to the inherantly flexible 4 cyl even though it would, or rather should be, more refined.
A 2.0 V8 might do though !
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I would say this wouldn't I - I'm getting boringly predictable. I appreciate all things are relative, but to my mind the Lexus IS250 you named yourself ticks all your boxes and IS a pretty titchy car?
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>>the Lexus IS250 you named yourself ticks all yourboxes and IS a pretty titchy car?
Really?, small and luxury to me means more like Clio Priviledge etc.
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A3, BMW 3, Lexus? Someone needs to get the tape measure out! I moved UP from an A2 to an A3 (which to get four doors needs to be a Sportback which is longer than the 3 door model).
If someone posted on here saying they were looking for a small car for city work, easy to park, with respectable running costs would the same posters really come up with a list of a Focus, Astra and Golf?
From reading threads on such an issue they don't. Fiesta, Colt, Swift are always mentioned.
The only true small car (Fiesta, Colt, Swift) which offers luxury options on a par with it's larger stablemates is the A class and even this may be too large for some.
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Mitsuoka Viewt - that strange Jag MkII meets Nissan Micra creation that only the Japanese could come up with... You'd have to be pretty brave to drive one in public though!
tinyurl.com/2xwon4
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my parents have the new MB A-class and my Auntie the older original one - the new one is far superior in every way - definately worth a look if you want a small luxury car. Wouldn't fancy doing DIY on it though...
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The A-Class isnt a bad option, even if it is expensive because someone who is used to paying say £50k for a proper luxury car, would see £25k as cheaper by some margin.
The Merc also does come with many big-car options to give the toy-tally of a luxury car.
From speaking to owners, I understand the longer wheelbase works best, hence why many have moved up to a B-Class.
Only real issue is its width as a small car. But as a downsizing option from larger cars, its certainly worth a look if you can rationalise the pricing to yourself.
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Straight sixes like the Triumph and real Jaguar had enough "virtually zero torque" to be able to pull away in top gear from idle revs, at least the straight sixes I remember.
If find cheddars analysis is 4/6 cylinder engines confusing.
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RT - I find your post more confusing than Cheddars...
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Sorry to be a wee bit controversial, but this whole debate seems to me to call into question the very definition of "luxury" motoring. I of course recognize that we all have our differing needs and preferences, but when it comes down to "brass tacks" surely the factors which best define a cars' level of luxury are those which cause it to be more comfortable when transporting people and their stuff ?
I would therefore contend that a small luxury car is to a great extent a misnomer in that by dint of sheer physics it is not as capable of transporting humans and their possessions in as comfortable and versatile a manner as a larger one.
My view is that a small car is at its best when it is a pragmatic and utilitarian transport solution, mainly aimed at cost and space saving. If you want luxury, why not have it with a bit of "elbow room" ?
For what its worth we run two types in our family. A biggish estate with all the toys as the main car, and a basic hatchback for short distance town/city/spare use.
What's the old saying ? ....."Horses for Courses".
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I'm also not sure about the analysis.
It may be better to find some comparable engines - i.e. similar technology, similar states of tune, similar design philosophy and vehicle usage class.
For example, Mercedes Benz tend to make engine families, where the engine layout of the 4, 5, and 6 cylinder engnes are the same.
So, as an example,
M102.962 2 litre 4 cylinder 122BHP - 61 BHP per litre
M103.980 3 litre 6 cylinder 177BHP - 59 BHP per litre
When expressed in specific terms, not a huge amount of difference! This doesn't seem to support Cheddar's assertion.
Number_Cruncher
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Two questions that this raises in my mind.
1) Why do you want a small car?
2) How do you define "small" - i.e. how small is small?
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M102.962 2 litre 4 cylinder 122BHP - 61 BHP per litre M103.980 3 litre 6 cylinder 177BHP - 59 BHP per litre When expressed in specific terms not a huge amount of difference! This doesn't seem to support Cheddar's assertion.
NC, it is a matter of torque at lower revs do you have the respective torque figures or ideally curves?
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>>NC, it is a matter of torque at lower revs
If the engine power is comparable at comparable revs, then the torque follows - you can't have one without the other.
Number_Cruncher
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>>NC it is a matter of torque at lower revs If the engine power is comparable at comparable revs then the torque follows - you can't have one without the other.
Agreed NC though between the two engines power may be comparable at high revs and not at low revs.
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>two engines power may be comparable at high revs and not at low revs.
With low tech engines, like the ones I'm quoting, it's extremely unlikely. Typically, wou would expect the low speed torque curve to be fairly flat (until gas dynamic effects and port choking take over at high speed, there isn't much going on), and if the torque curve is flat, the the power curve is similarly defined.
I've mentioned this before, but I would *seriously* recommend you look up a series of articles by SS Tresilian (former chief designer [engines] at Rolls-Royce) about comparative engine design. They are also presented in edited form in the book, Gasoline Engine Analysis by J Fenton.
Number_Cruncher
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I don't know the full engine code for these, but as far as I can tell, they are comparable, they certainly were put into the same car. There's definitely no variable manifold trickery going on!
M102.xxx 2 litre 4 cylinder 116BHP - 58 BHP per litre 127 lbf ft - 63.5 lbf ft per litre
M103.yyy 3 litre 6 cylinder 178BHP - 59 BHP per litre 188 lbf ft - 62.7 lbf ft per litre
Still not a great deal in it.
Do you have a reference for the poor performance of inline sixes?
Number_Cruncher
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Do you have a reference for the poor performance of inline sixes?
Yes somewhere though I have not found it yet.
Do you have the rpm at which max torque is produced for these two?
From memory the issue is that a 4 stroke inline 6cyl fires every 120deg, with regard to valve timing, specifically duration, this means that one inlet valve is still open though closing while another is opening, likewise on the exhaust side, this upsets gas flow/speeds, pressures (rather vacuum on the inlet side) and scavenging. This is aplicable to a single carb or FI system with a single throttle body, twin carbs largely negate this issue because they are effectively run as 2 x 3 cyls. 6 into 2 into 1 exhaust manifolds / systems also help.
More to follow if I can find it.
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>>run as 2 x 3 cyls...
This issue of inter-valve overlap will happen with any single manifold, single throttle body engine without 360/180 spacings, it's not a purely 6 cylinder thing. It's just extremely unusual to find engines with more than six cylinders of any layout that use a single path manifold. It's also extremely unusual to find a modern six cylinder engine with a purely single manifold - manifolds which switch between 6 and 2 x 3 layouts are now almost normal - our 1995 E300D even has this!
Looking at 1950, and 1960's inline sixes with small single carburettors and peashooter inlet and exhaust manifolds, and it's no mystery that they were a bit asthmatic!
Number_Cruncher
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>>Do you have the rpm at which max torque is produced for these two?
No, I don't have that info - but, I would fall off my chair if there were any significant difference between the two.
Number_Cruncher
Edited by Number_Cruncher on 07/12/2007 at 20:24
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but I would fall off my chair >>
Giving this some further thought and trawling my memory as Google is not helping the following seems to make some sense:
On an inline 6 as one cylinder is 120 deg into the induction stroke the next cylinder in the firing order is commencing its induction stroke thus creating additional vacuum in the inlet manifold for the final 60 deg of each cylinder's induction strokes.
This effect is negated if the next cyl in the firing order is on a different inlet manifold.
Likewise as one cylinder is 120 deg into the exhaust stroke the next cylinder in the firing order is commencing its exhaust stroke thus creating additional pressure in the exhaust manifold for the final 60 deg of each cylinder's exhaust strokes.
This effect is negated if the next cyl in the firing order is on a different exhaust manifold.
However on a 4cyl engine one cylinder has completed its induction stroke and is at BDC before the next to fire commences its induction stroke, likewise one cylinder has completed its exhaust stroke and is at TDC before the next to fire commences its exhaust stroke.
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I'd have thought the C class Sports Coupe fits the bill. It's a decent [C Class] size inside, but shorter than its namesake, and wing-mirrors pop in to keep it narrow enough for parking/garage etc. Rear seats [two separate] lie flat to create a large boot for two people. Engines and spec are multiple for 3.2 [6 cylcinder, faster than most could cope with] down to the 1.8 classed as a 160. Sports suspension and 17" tyres spoil a soft ride, but its horses for courses so go for the 16" if you prefer, as on the SE.
I think BMW missed a trick in not making its MINI Clubman a better thought through car, since a small estate ticks lots of boxes for lots of people. What happened to a Polo estate, which did the job in the 80s?
The marketing boys that insist on each suceeding model being larger than it s predecessor do make life complex.
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Just reviving this thread as I sat in a Nissan Note today.
It seems to tick almost all the boxes. It is small but not too small on the outside and with a great deal of pasenger space in the inside making use of the sliding rear seats. I don't need a large boot, so the boot was small and the rear legroom huge. It is well fitted out with bluetooth on the radio and lots of useful toys as well as lots of storage. I would say that the only things missing in terms of kit are heated seats and satnav. As it has cloth seats, the heaters are not vital and I can get TomTom for about £200.
The engine is a decent 1.6 and comes with a Nissan (not Renault) autobox. Pity its not a nice 2.5 V6, but you can't have everything.
Am I missing anything apart from fuel bills?
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Has the SVE not got a built in Sat nav probably a lot dearer than a Tom Tom mind you.
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Now that Lancia are on their way back into RHD markets, how about an Ypsilon or Musa?
(Based on Fiat Punto and Idea) www.lancia.com/cgi-bin/lancia.dll/LANCIA_COM/home....#
Spiritual successor to the Vanden Plas Princess, Renault 5 Baccara and the like...
Or import a LHD one and be the first in your road!!
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Pug 206 Roland Garros. Loaded with gear.
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