I’m sure that at least some of you will remember the early-90s Mazda MX-3, a pert little subcompact sports-coupe that was sleek-looking but suffered from tinny sheet metal, lack of adequate sound insulation, and an overly/cramped interior with a useless back seat for anyone larger than a toddler. It did, however, have a very interesting power plant-option…….. a tiny 1.8L transversely-mounted V6 driving the front wheels, different from the small longitudinal-mounted Lexus 2.5L V6 in the IS250, which was RWD/AWD. I sampled one or two MX-3s with the 1.8L V6, and found it lacking in low-end torque, but otherwise bringing big-car engine smoothness and refinement to the small inexpensive entry-level class, which usually had somewhat raucous in-line threes and fours. Back then, it seemed like only Toyota and Honda could produce a truly refined in-line four…Mazda certainly didn’t, but compensated for it with the small V6. It was rated at 129 HP at 6000 RPM and 157 ft-lbs of torque at 5000 RPM….wimpy figures by today’s standards (and why the low-RPM response was poor), although the advances in power plant engineering in the last 30 years would probably give much better power figures in that same block today.

I cannot help but imagine how nice an updated version of that small 1.8L V6 would be in today’s small sedans and crossovers. Like it did 30 years ago, it would bring big-engine smoothness and refinement to some of those small crossovers and sedans that clearly lack it.
I know that, in the mad rush by the auto industry to convert to electrics today, the chances of actually seeing a very small V6 again like that are probably close to zero, but it is an interesting thought.

 

Not a bad idea. But doubt the fuel economy would be good enough to make it worthwhile

 

Modern up-to-date engineering would also probably give it good MPG, especially with that small displacement.

 

I see no reason to want an engine like this over a modern turbo/supercharged 4 cyl.

 

IMHO, it can be summed up in one word….smoothness. Like the Lexus 2.5L V6, that little 1.8L V6 was not a powerhouse, but had smoothness and refinement. Some of today’s fours are very good, and produce a lot of power, especially with turbos, but you still know they are fours.

 

V6s are not inherently smooth either, if this was an I6 I might agree. There is nothing especially smooth about the powertrain in my Pacifica for instance. If they replaced it with a turbo 4, I bet it would improve the cars feel and performance.

I think you will find that modern turbo 4s are plenty smooth for the majority of people who buy them. I know plenty of people who drive cars with 4 cyls who thought they were 6s. Most people don't know or care.

 

I know you are probably a couple of decades younger than me, but did you get a chance to sample an early-90s MX-3 with that powerplant? The tinny body sheet metal and lack of insulation amplified road noise like a drum, but the engine itself was like a sewing machine….I could just imagine it in something from Buick, Cadillac, or Lincoln with otherwise effective sound insulation.

The only V6 engine I can ever remember running rough was the Buick 3.8L from the early 60s, and it ran rough back then mostly because the engineers did the simple/cheap thing and cut off the two back cylinders from the 5.0L V8, and left the 90-degree angle between the banks, which interfered with the pulse-firing cycle of 6 cylinders as opposed to 8. Most modern V6 powerplants all have a 60 degree bank angle to cancel out that disharmony, although VW did some recent V6s with a super-narrow 15-degree angle…..and some W-shaped adaptations.



And the ancient Buick 3.8L had so many improvements over the years that by the time it went out of production not very long ago, it had a reputation as one of the best powerplants on the market… you couldn’t tell it from a V8 in many ways. The late Pat Goss from Motorweek raved about it for years.

 

I think the 3.0 V6 or inline 6 is a sweet spot. Every one I've sample in a Toyota/Lexus was impressively smooth. Just not real efficient.

But if smoothness is the priority, Lexus's 2.5 V6 in the first ES250 was crazy smooth. Like you could not hear or feel the motor wind up even under hard throttle. I haven't come across a match since that early 2000's experience.

Audi's 2.0T also strikes a nice balance between smoothness, power, and efficiency. Early version were not reliable. But I think they have improved with recent units.

Another motor that received high accolades was VW's VR6. Never had a chance to test one out, but when placed in a Jetta, it seemed sublime.

 

Where space is available and smoothness is the goal, the answer is always straight-six, as that and the V12 are the only intrinsically-balanced engine designs that have been widely available. But since we're talking small cars and SUVs, and probably FWD-based at that, space would definitely be an issue.

So I would go with either the BMW N20 or VWAG EA888 turbo 4-cylinder. Both are smooth, powerful, and reliable, which is why they're used in everything.

As @Fizzboy7 mentioned, an updated version of the VR6 might also be a good fit. It retains much of the benefit of an I-6 in a much smaller package, due to it essentially being two inline threes packaged side-by-side under a single head, and sharing a common crankshaft. Reduce the displacement to 2.5L or so (most of the ones VW produced were 2.8-3.2L), perhaps add a small electric supercharger to help with low-end grunt, and you'd have a winner.

 

I had a Lexus IS250 with the 2.5L V6, and now have a BMW 2.0T and a Hyundai 2.0T. I would have no desire whatsoever to go back to the 2.5 V6 over my BMW 2.0T or the Hyundai 2.0T. The Lexus was not any more smooth or refined than what I have now.

YMMV.

 

I haven't driven that specific car but I have driven many many many other cars with V6s and I highly doubt that little Mazda engine is any smoother than the best V6s Ive driven. Its not that the V6 in the Pacifica isn't smooth, its just not impressively smooth. A V6 is just inherently not as well balanced as a straight six. I've got an Avalon rental right now while my car is in for brakes with the ubiquitous and excellent 3.5 V6 and its okay, nothing special.

I just see no reason to prefer an anemic NA 1.5L V6 to a modern turbo 4 cyl.

 

Basically this, a 6 is always smoother than a 4 pound for pound.

My X-type actually has a 2.0 engine option overseas that you would think is a 4 cyl but they just made the 6 even smaller, the other advantage is you have more power potential with 6 cyl since total intake valve area is greater than with a 4 cyl.

The most major drawback though is cost, 50% more parts and complexity vs a 4 cyl for the most part and potentially more pumping losses depending on choices made.

I would have vastly preferred to see advanced diesel engines so that 50-70mpg and great low end power feeling would be more commonplace. However VW ruined that and we have never really liked diesel here in the first place, I would gladly swap over ever non-flagship in my line to diesel if I could.

 

So, would you take a 170 hp 1.5L V6 over a 300 hp turbo 4?

 

I don't mean to bring EV's into this conversation, but one of the reasons I can't buy ICE anymore. I can't live with these tiny downsized turbocharged/hybridized engines. 3.0T or 3.5L NA and up, or I'm not interested. That 1.8 would put me to sleep. Disappointing times for ICE IMO

 

Where did you come up with 170hp vs 300hp?