Experiences of 3 cylinder automatics?

[raybarrow]

Hi Folks,

When my unexpected inheritance arrives I am looking to buy a small automatic. Currently have a 1.25 Fiesta, which is nice, comfortable drive. Not fast but then I don't need fast at my age.

Torn between three cylinder Fiesta auto and a 1.4 Polo auto. Something about three cylinders just doesn't sit right in my head. The noise wouldn't sound right or am I just a stick in the mud.

With Lockdown trying these things is not an 'easy' option. Maybe Boris will release us next week.

I was looking to see if any has experience of a three cylinder (manufacturers seem to be forcing us down that route) auto or even manual. Most of my motoring would be local with the occasional long distance journey, daughter in Aberystwyth, son in Norwich, holidays. We live in the middle in Birmingham.

Any comments appreciated,
Ray.

[swill453]

If you're looking at buying new, the only options for the Polo are 1 litre 3 cylinder or the GTI, a 2.0 litre 4 cylinder.

The previous generation, up to 2017, had the 1.4 litre 4 cylinder BlueGT. I have the auto (DSG) of this, I like it.

Edit: I'm assuming petrol not diesel.

Scott.

[Stonge]

Had a 3 cylinder Focus on lease. Manual, drove well. Engines explode frequently though, bit of a drawback.

https://www.facebook.com/groups/FordEcoboostNightmare/

Now have a 3 cylinder Toyota. Drives well. Manual. Engines don't explode frequently, allegedly. We'll see.

[tjh290633]

I have a Suzuki SX4 S-Cross with a 1.3 litre Boostjet engine, 3 cylinders, and I can honestly say that I haven't noticed the difference from my previous 1.6 litre unblown motor. If anything, it is faster, but a lot more economical. I got 39.66mpg over 37k miles with the previous SX4, and I am averaging 45.5mpg over the 3,700 miles with the S-Cross. Doing less mileage due to Covid, and ambling along country lanes helps, but it has not been below 43mpg on a tank-full to tank-full basis. 48.3 mpg has been the best.

TJH

[GrahamPlatt]

The other half has a Peugot 3008 3 cyl petrol. I think it's the 1.2 litre. Whatever it is it is excellent. Seriously can't tell without knowing that it's 3 cylinders, and it is a very nice ride.

[redsturgeon]

I have a BMW hybrid with a 1.5l 136 bhp 3 cylinder engine. It does sound a bit strange when I put my foot down but it doesn't worry me. Along with the 88hp electric motor it has plenty of oomph.

John

[swill453]

My dad got a Peugeot 107 (or 108) a few years ago, 1 litre or 1.2. The first time I went out with him in it I said "Is this a 3 cylinder?" (Only because I'd heard of it, not because I could tell). "No, of course not" he said.

He phoned me up a week later to tell me sheepishly that it was 3 cylinder because he'd looked it up.

Scott.

[staffordian]

I've had two 3 cylinder engines and found them both to be fine. First was a 2004 SEAT Ibiza and the second a 2015 Nissan Note. But neither was an automatic, so can't comment on that aspect.

Neither were powerful but both were more than adequate and I had no trouble with either.

Personally, I rather like the sound of a three cylinder engine, they seem to have a sort of sporty rasp about them, but having said that, I'm by no means sure I could tell one from a four cylinder if I didn't know what it was...

[wilbobob]

I have had a 1litre 3cylinder Honda Civic Automatic. Quickest car I've ever had. Raspy when accelerating hard but smooth and quiet otherwise. 40mpg average over three years.

[jackdaww]

.
absolutely suggest a petrol automatic - sane and civilised .

im no expert but i think a 3 cyl may actually be smoother than a 4 cyl .

[DrFfybes]

Most 'non-car' people won't notice the difference.

Mum had a friend who was in his 90s and was an engineer and into cars etc. I collected him in my sister's Ford 3 cyl engine and as soon as I started it he said "this sounds rough, is it only firing on 3?"

However they drive fine.

Paul

[Lootman]

If you didn't know, in my opinion, it's unlikely you would ever notice out how many cylinders the engine had.

Most 'non-car' people won't notice the difference.

I am not sure it can be measured but the difference often described with having more cylinders is "smoothness". At one point I went from a 4 cylinder vehicle to a 8 cylinder vehicle and I definitely noticed the difference. The only problem with 6 or 8 cylinders is that you might not notice a misfire, which you certainly do with a 4 cylinder.

I have never driven a 12 cylinder car but the adjective I usually hear about them is "silky".

Now that I drive fewer miles and make fewer road trips, even without the lockdown, I no longer care about fuel economy. Living in an urban environment as I do, I usually have other options than to drive, and so when I do drive I want a more luxurious ride with aircon, leather this and electric that. That all takes power but if it guzzles petrol then I don't care, as the miles driven is low and I want to travel in style.

And I am only interested in automatic gearboxes these days, which again are more common in larger and more powerful vehicles.

So as you can imagine I would not touch a 3 cylinder car.

[richlist]

My wife has had x4 .....3 cylinder Fords, two 100hp & two 125hp.
All great little cars.
She currently has a Puma 3 cylinder and loves it.
Wouldn't hesitate getting another.

[Mike4]

Most 'non-car' people won't notice the difference.

Mum had a friend who was in his 90s and was an engineer and into cars etc. I collected him in my sister's Ford 3 cyl engine and as soon as I started it he said "this sounds rough, is it only firing on 3?"

However they drive fine.

Paul

Thinking about it carefully but without going so far as drawing diagrams, I don't think it is possible for a three cylinder four stroke engine to run 'smoothly' like a four, six, eight or twelve. By 'smoothly' I mean an equal gap or time space between each firing stroke.

[Watis]

Most 'non-car' people won't notice the difference.

Mum had a friend who was in his 90s and was an engineer and into cars etc. I collected him in my sister's Ford 3 cyl engine and as soon as I started it he said "this sounds rough, is it only firing on 3?"

However they drive fine.

Paul

Thinking about it carefully but without going so far as drawing diagrams, I don't think it is possible for a three cylinder four stroke engine to run 'smoothly' like a four, six, eight or twelve. By 'smoothly' I mean an equal gap or time space between each firing stroke.

I may be wrong, but I thought that the fabled smoothness of a straight six engine was due to the crankshaft big ends being offset 120 degrees from each other, which could be replicated in a three cylinder engine, surely?

Watis

[GrahamPlatt]

https://en.wikipedia.org/wiki/Straight-three_engine

PS, we’ve been down to southern Spain (& back) in the Peugeot. Really, you wouldn’t know it’s a 3-pot, and with 130bhp it’s by no means sluggish. Comfortable cruising at 130kph through France.

[Lootman]

Most 'non-car' people won't notice the difference.

Mum had a friend who was in his 90s and was an engineer and into cars etc. I collected him in my sister's Ford 3 cyl engine and as soon as I started it he said "this sounds rough, is it only firing on 3?"l

Thinking about it carefully but without going so far as drawing diagrams, I don't think it is possible for a three cylinder four stroke engine to run 'smoothly' like a four, six, eight or twelve. By 'smoothly' I mean an equal gap or time space between each firing stroke.

I may be wrong, but I thought that the fabled smoothness of a straight six engine was due to the crankshaft big ends being offset 120 degrees from each other, which could be replicated in a three cylinder engine, surely?

By that argument a 12 cylinder engine would be no more smooth than a 3 cylinder engine.

And a 16 cylinder engine would be no more smooth than a 4 cylinder engine.

I think one can accept that a 3-cylinder engine might be adequate for some purposes without believing that more cylinders are a waste. And if you want a decent displacement then to achieve that with a small number of cylinders would require a very long stroke, or a very wide bore, or both. There is a theory about the stroke to bore ratio but I forgot it long ago.

[Mike4]

Most 'non-car' people won't notice the difference.

Mum had a friend who was in his 90s and was an engineer and into cars etc. I collected him in my sister's Ford 3 cyl engine and as soon as I started it he said "this sounds rough, is it only firing on 3?"

However they drive fine.

Paul

Thinking about it carefully but without going so far as drawing diagrams, I don't think it is possible for a three cylinder four stroke engine to run 'smoothly' like a four, six, eight or twelve. By 'smoothly' I mean an equal gap or time space between each firing stroke.

I may be wrong, but I thought that the fabled smoothness of a straight six engine was due to the crankshaft big ends being offset 120 degrees from each other, which could be replicated in a three cylinder engine, surely?

Watis

I think not (but still not sure!), because in a six pot engine there are always two cylinders at the same angle on the crankshaft, one on the compression (firing) stroke and the other on the exhaust stroke. On a three pot, you don't have enough cylinders in a row to do that.

Edit to add, looking at the Wiki page linked above, it IS possible!

[Breelander]

Torn between three cylinder Fiesta auto and a 1.4 Polo auto. Something about three cylinders just doesn't sit right in my head. The noise wouldn't sound right or am I just a stick in the mud...

I have owned and driven a three cylinder Polo from new, albeit a manual rather than automatic. Some 10 years and 89,000 miles later it's still going strong and reliable, all the engine has ever needed was routine servicing.

Yes, three cylinders sounds different. The first thing I noticed was that engine note is more akin to that of a diesel, but in all other aspects it behaves and responds like any other petrol engine.

Oh... and servicing is a little cheaper - there's only three of everything to replace, like spark plugs

[Urbandreamer]

I think not (but still not sure!), because in a six pot engine there are always two cylinders at the same angle on the crankshaft, one on the compression (firing) stroke and the other on the exhaust stroke. On a three pot, you don't have enough cylinders in a row to do that.

Is smoothness the issue? I think that morgan 3 wheelers are known to use 2 cylinders as are 2CV's.

A 2 cylinder under the Otto fires once a revolution, a four cylinder twice. Two strokes* twice that. A three cylinder, well it's fractional, As is a six or five or ... more. Then there is the configuration. A V configuration throws when things fire. Some love that. Others, not so much. Then again a V configuration takes less space. Do you really want a bonnet that you have to stick into the oncoming traffic before you can see it's there, when joining a main road? How about the concept of smaller lighter engine's? It's far easier to achieve with less cylinders. Or what of transverse mounted engines? A 12 cylinder would be a very wide car.

Possibly someone can tell me of a car with more than four cylinders in a transverse mounting.

Ps, yes I had a 3 cylinder car about 30 years ago. I have not driven one since because of what I buy. However, horses for courses. While I don't entirely agree with Lootman on this issue, he does have a point that; IF you are going the IC route AND you are wanting to drive fast, AND you want it to be quiet inside, then you need more than 3 cylinders, OR a lot of sound insulation and absorbsion. I never noticed the fact that it was a 3 cylinder as I could only compare it to the likes of a mini, ford escort or a capri. Non of them were known for refinment. I wouldn't refuse to buy a 3 cylinder now, were I looking to buy a petrol car. In fact I would look upon such with a poitive light.

*Can we claim that modern engines follow the Otto cyle? It's not that difficult to switch between 2 stroke and 4 stroke with good engine managment and a turbo. Almost all cars now have both.