3 cylinder cars

[PandaBear]

I guess NVH is one reason, and just marginally better mpg is another. It won't be much cheaper to make unless you have economy of scale (i.e. same piston and rod as your 4-6-8 cyl), and today's customers are willing to pay a bit more for 4 cyl in the US market.

I think the only way they would be worth it is if they are turbo 3, and it package better than a turbo 4 with similar displacement.

 

[fdcg27]

Nothing wrong with an inline triple. Physically smaller engine allowing better packaging, easier service access and a smaller block with fewer holes and pistons to fill them along with only three crank throws and cam(s) to serve but three cylinders bringing lower manufacturing costs as well as reduced weight.
We've had rental turbo triples and they were okay in actual use if not lunar rockets.
For a small vehicle intended to be low priced, nothing wrong with a turbo triple.
We'll see how these things hold up over time, but I'm guessing that with their modest power outputs they should be just fine.

 

[barryh]

Did you feel they vibrated any more than a 4 cylinder?

I've driven a few 3 cylinder cars. The Stellantis 1.2 in a Peugeot I thought was an excellent engine and smooth both on the move and at idle. A Volkswagen 1.0 3 cylinder was fine on the move but at idle it was very obviously not as smooth as a 4 and that's something I couldn't live with.

 

[BHopkins]

Geo metro was available with a 3 cylinder in the early 90’s. There not anything new really.

I remember those. A guy I used to work with way back then, drove one. He loved it, primarily because of the fuel economy.

 

[fdcg27]

I remember those. A guy I used to work with way back then, drove one. He loved it, primarily because of the fuel economy.

I worked with a couple of guys years ago with long commutes who drove Metros for that purpose.
The thought of being driving one of these and being involved in an accident seemed cringe-worthy, but the same could be said of a Mirage today.

 

[Exhaustgases]

3 cylinder does not need balance shafts like the 4's do, that is a manufacturing cost savings.
The time to start worrying is when they start using 1 and 2 cylinder engines. That would be like a dream to some of us that always wanted go carts to drive on the freeways. And with an almost smart car size every 2 lane road would then be like a 4 lane road. That should be the future no more big cars.

 

[E365]

I had a 2015 Focus 1.0 EcoBoost. Loved it. 6-speed Getrag manual. Best “tank” was 54 MPG - a 2.0 Focus could never. Routinely sat at about 45 MPG at 70 MPH. It was also the lightest Focus, so it handled really well too.

 

[meep]

I would not be opposed to one. It would have to have forced induction, preferably a small turbo which could spool quickly. Built properly, which they can be, it would be a hoot.

Cut the ford 2.7 ecoboost in half and you’ve got a great start.

 

[Pew]

Plus they tend to since more like diesels, so no 4cyl raspy.

 

[hank2]

I put a lot of miles on a Subaru J-10 3 cyl. I believe the body was called the "Justy" in the US and had a small 4 cyl. in it.

I believe the US market Subaru Justy was also a 3 cylinder. At least the early ones. Also, the first CVT in the US on the non-manual models. A small bore 3 cylinder was all the belts could handle and that took some time to happen. I think they bought into Van Doorne's patents.

 

[Bailes1992]

I've driven a few 3 cylinder cars. The Stellantis 1.2 in a Peugeot I thought was an excellent engine and smooth both on the move and at idle. A Volkswagen 1.0 3 cylinder was fine on the move but at idle it was very obviously not as smooth as a 4 and that's something I couldn't live with.

Those 1.2 Puretech engines are absolute junk, up there with the 1.0 Ecoboost, or Ecoboom as they are now called in Ford circles.

My Aunties Vauxhall Corsa with the 1.2 Puretech engine is just coming out of warranty and I've told her to get shot of the thing before she suffers with wetbelt failure like the rest of them.

 

[andrew_j]

The 3cylinder Escape I rented on Puerto Rico seemed decent for its purpose. The 26 MPG in essentially island driving “not great, not terrible”.

 

[Snagglefoot]

Nothing wrong with an inline triple. Physically smaller engine allowing better packaging, easier service access and a smaller block with fewer holes and pistons to fill them along with only three crank throws and cam(s) to serve but three cylinders bringing lower manufacturing costs as well as reduced weight.
We've had rental turbo triples and they were okay in actual use if not lunar rockets.
For a small vehicle intended to be low priced, nothing wrong with a turbo triple.
We'll see how these things hold up over time, but I'm guessing that with their modest power outputs they should be just fine.

Actually the power output on some of them is not modest in a HP per cubic inch basis. It’s almost 2 HP per cubic inch.

A 1.2 liter engine is 73 cubic inches. The 2024 Trax makes 137 HP or 1.9 HP per cubic inch. A Ford 302 would have to make 574 HP with the same ratio.
The turbo 3’s are high performance engines.

 

[repairman54]

My Ski Doo snowmobiles are 1.2L 3 cyl. NA Rotax motors. 135 hp and normally operate from 4k to 8k rpm. with their belt drive CVT drivetrain. 10k miles on my '09 and zero issues with the engine. IMO pretty tough for an off-road vehicle.

 

[sohccammer427]

I once owned a 3 cylinder GEO Metro. 1,000 cc I believe. For what it was , it was one of the most reliable, cost effective, and easiest to maintain I've owned. Fuel economy was excellent. If environmental impact was an issue, it was probably more earth friendly that an EV could ever be.

Just to add, my Metro was one of those 3 door hatchback types. It was a manual with a 5 speed.
Believe it or not it was pretty nimble. I was just like this, only red in color. Memories of my younger days.

The engine was a Suzuki, in line 3, 1 liter. Probably around 50 hp.

 

[IndyIan]

I had a 2015 Focus 1.0 EcoBoost. Loved it. 6-speed Getrag manual. Best “tank” was 54 MPG - a 2.0 Focus could never. Routinely sat at about 45 MPG at 70 MPH. It was also the lightest Focus, so it handled really well too.

It's too bad those engines don't seem to last long... How long did you have yours for?

 

[Rmay635703]

Better MPG due to a reduction in rotational mass via one less piston to move. I despise them. I had one in Las Vegas as a rental. The driving experience was best described as gutless and unrefined.

3 cylinder cars are more thermodynamically efficient and harmonically more efficient.

The reason is simple, less contact area for heat loss per liter.

Harmonically a 3 banger breathes easier because it has constructive harmonics on both exhaust and intake which also improves efficiency.

All in all odd cylinder engines are more efficient than even, too bad we have so few of them.

 

[4WD]

I was requesting the little Ford AWD’s at Enterprise Canada - always a treat when I’d get a Titanium with the bad to the bone 4 banger !
All jokes aside - a more pleasant driveline …

 

[fdcg27]

Actually the power output on some of them is not modest in a HP per cubic inch basis. It’s almost 2 HP per cubic inch.

A 1.2 liter engine is 73 cubic inches. The 2024 Trax makes 137 HP or 1.9 HP per cubic inch. A Ford 302 would have to make 574 HP with the same ratio.
The turbo 3’s are high performance engines.

OTOH, that's not much more than 100 bhp/liter and there are many production vehicles that have that kind of specific output.
A factor to consider is that the Trax you cite will not be called upon to produce anything close to its rated output for 90% of the time it's running, but then this is true of almost all street vehicle engines.

 

[tiger862]

I did an engine in a Metro and it was easy. I reached in and removed engine without a hoist and installed new one the same way. Easiest 100 dollar bet I won. Wonder why I am now disabled years later.