The Three-Cylinder Has Become a Performance Engine

Paolo

New member

The Three-Cylinder Has Become a Performance Engine​

Perhaps there is a replacement for displacement.
BY LUCAS BELL
OCT 19, 2021
gr yaris g16e gts

The auto industry is in the middle of a monumental transition. As regulations demand that gasoline use become a thing of the past, automakers are signing on for an all-electric future. Of course, we aren’t quite there yet. But the industry needs to strike a balance between emissions compliance and the unending demand for ICE-powered machines. As a result, we’ve seen turbocharging, hybridization, and outright engine downsizing take hold. Perhaps the most extreme example of the latter is the sheer number of three-cylinder engines on sale today.

That said, not all of these three-pots are built solely with efficiency in mind. In fact, some of these inline-threes pack a lot more performance into their tiny packages than you might realize.

The Ford Fiesta ST earned a reputation as one of the greatest hot hatchbacks ever, but sadly left American shores in May 2019. Thankfully for our friends across the pond, Ford didn’t ax the baby ST in Europe, debuting a brand-new model that same year. The refreshed and improved sporty Fiesta received a new engine known as the Dragon. This 1.5-liter three-cylinder is an evolution of Ford’s smaller 1.0-liter EcoBoost, but don’t let its size disappoint you: It’s rated at 197 hp and 236 lb-ft of torque. For reference, that means the little EcoBoost is cranking out over 131 hp and 157 lb-ft of torque per liter of displacement. For comparison, the hottest version of BMW’s 3.2-liter S54 inline-six makes 103 hp per liter.

To make that sort of power, Ford’s 1.5-liter uses both port and direct fuel injection, variable camshaft timing, and an integrated exhaust manifold. However, as Ford’s powertrain manager for the Dragon engine, Gareth Maxwell, explains in an interview with Road & Track, the real secret to the 1.5-liter is its radial-axial turbocharger design. Compared with a traditional turbo, a radial-axial unit has significantly less inertia and therefore reacts much faster to throttle inputs with reduced lag. Working in tandem with that slick camshaft, the diminutive 1.5-liter is able to provide both low-end torque and top-end performance. While the Dragon was admittedly created with an extreme attention to fuel economy, Maxwell says this turbocharger design has legitimized the 1.5-liter as a performance product.

A three-cylinder engine is generally stronger than a four-pot of the same size. Maxwell notes that this is a result of fundamental components such as combustion chambers, pistons, and holding pins all being larger in a three-cylinder engine of equal displacement. This allows automakers to run higher internal pressures and develop more power while still ensuring reliability.

“I think there’s a bit of a perception historically that more is better,” Maxwell says. “And there is this perception that if you got more cylinders, you got better reliability. I think, from an engineer’s perspective, we challenge that completely. More isn’t always better, and from an engineer’s perspective, less is actually better. It is simpler and lighter, and it has less friction.”

Ford isn’t the only company to turn to a three-cylinder to power a hot hatch for this reason. The glorious Toyota GR Yaris is also powered by a three-pot, though the Yaris unit measures in at a slightly larger 1.6 liters. For the Japan-market GR Yaris, Toyota claims output figures of 268 hp and 273 lb-ft of torque, numbers you’d expect from a larger four-cylinder. With a rating of 166 hp per liter, the GR Yaris’s G16E-GTS engine has the most per-liter specific output of any Toyota road car ever made; even the Lexus LFA’s glorious 4.8-liter V-10 manages only 115 hp per liter. In fact, GM’s more modern 755-hp LT5 V-8 is good for only 122 hp per liter.

Toytota’s decision to use a three-cylinder didn’t come down to fuel efficiency. The GR Yaris is a genuine homologation special, and its powertrain was a tried-and-true motorsport takeaway. In fact, Toyota had to file a petition with the FIA to be allowed to run a three-cylinder in the World Rally Championship at all. The team fought for the three-cylinder because of its simple, compact design and its ability to make big power thanks to a lack of exhaust-gas interference. Like the Ford 1.5-liter, the G16E-GTS employs both port and direct fuel injection, but the race engines get some more serious kit, like a ball-bearing turbo and oil sprayers for the pistons. Even in road spec, Toyota says there is no 1.6-liter turbo motor more compact or lighter than the G16E-GTS.
toyota gr yaris chamonix white

Three-cylinders aren’t just for hatchbacks anymore. In fact, the little engines have even found their way into the bays of seven-figure machines. The all-new Koenigsegg Gemera is a four-seat hybrid hypercar with over 1700 hp at its disposal. Unlike other exotic hybrids with V-8s and V-12s, the Gemera’s gasoline engine has only three cylinders. Known as the Tiny Friendly Giant (TFG), this twin-turbocharged 2.0-liter engine is an absolute marvel of engineering. The TFG features Koenigsegg’s Freevalve technology, which allows the car’s ECU to independently control the intake and exhaust valves, without a camshaft, based on load parameters of the engine. With the ability to adjust timing on the fly based on those parameters, this system allows the car to adjust for driving conditions and actively increase efficiency. The engine can even run the Miller cycle, allowing for high power output and fuel efficiency at the same time. The Texas-based artificial-intelligence company SparkCognition is helping the automaker develop AI engine-management software to work with Freevalve.

three pots

Koenigsegg says all of this tech allows the TFG to be 15 to 20 percent more efficient than a typical 2.0-liter four-cylinder engine. Impressive stuff, especially when you realize that the TFG makes 600 hp and 443 lb-ft of torque. No other engine in production rivals the TFG, with a rating of 300 hp per liter, in terms of specific output. Even if you were to take the sequential-turbo system off the TFG, Koenigsegg believes around 280 hp would still be possible.

It isn’t hard to say, therefore, that the TFG is one of the most extreme engines we’ve ever seen, regardless of cylinder count. As allowance for fuel continues to be scaled back each year, this sort of hardware could help prolong the life of the enthusiast ICE-vehicle market. While Ford is committed to a fully electric future, Maxwell did note that he believes combining three-cylinder engines with hybrid systems is the next logical choice for automakers seeking to retain ICE powertrains. If this early crop of hot triples is anything to go by, there could still be some exciting gasoline-powered offerings to come.


 
Last edited:

Duke

New member
I'm firmly in the 'who cares how many cylinders/what displacement an engine has?' camp.

For cooking transport I literally don't care if it even has an engine at all, the ultimate expression of which is of course BEV.

For something like a GR it could have a single 2.5cc engine as long as it is

a) effective i.e. provides the required shove
b) willing i.e. not strained and eager to rev
and, ideally
c) characterful to some degree i.e. makes a decent, or at least not offensive, noise

The best engines have a good mix of all three - Busso V6, BMW S14, various Ferrari V8s and V12s - but let's be honest, most performance engines today don't score highly on c)

So on that basis I'm as happy or happier with a 3-pot than I would be with a 4-cylinder with otherwise equal properties.
 

JonW

New member
I agree with you Duke, interesting article Paolo. For me its about power, its delivery and character.

3 cylinders is also good for servicing and rebuilds as less parts to replace and for size of the engine, ie weight and access.
 

Paolo

New member
I've had 6 cylinder(2 cars) , 4 cylinder (mostly 3 cars) and now 3 cylinder (1 car).

The 3 cylinder has been the most charasmatic and fun engine I've ever felt behind the wheel. It kinda feels old school turbo but without the lag.

You'd honestly think it was 4 cylinder if you didn't know the specs.

Well done Toyota and shimoyama. 👍
 

JonW

New member
Modern electronics and boosting has been amazing for ICEs. Its not only got the fuel use down, but also upped the power and made it usable.

About 10 years back I bought one of the ill fated Polo Gtis, it was a 1.4 4 cyl and had a supercharger and a turbo. Supercharger for low revs where the little engine wasnt putting out enough exhaust to spin the turbo enough for boost and a turbo to take over at higher revs once the gasses were building, where it decoupled the supercharger to reduce its drag on the engine to make peak power. A clever system but complicated of course but I was keen to try it as Id read about in David Vizards Mini A series tuning book in the 80s when growing up and wanting a fast mini (I never did get one lol).

The Polo felt like a 2L Golf Gti to drive to be honest, i expect the light weight helped but it was actually quite quick, not fast fast, but sporty. Of course history tells us now that it was a highly strung engine that had the wrong piston rings in it and the smaller dry clutch DSG box wasnt up to the job. But, when it wasnt puking out oil or slipping its clutches it was actually a really good thing to steer and was a fun engine, even if the rest of the car was built worse than an 80s skoda. Id have loved to stick one of those engines in a Mk1 Golf GTI etc.

Ive had a bunch of different engines over the years. Some have been super dull to be honest, mostly the 4 cyl petrol engines in cars that were bot designed to be sporty, but even diesels like the BM3 3.0 litre 6 had character (well, while it wasnt eating its own turbo vanes). Others like TVRs 6 cyl were like having a mad friend who you only see on lairy nights out lol. I had a K series in a Lotus and it was dull (even in uprated sports 135 trim) but the same engine in R300 spec with roller barrel throttles in a Caterham was a revelation if for me a little too linear.

Im a 2 stroke bike fan as thats what i grew up on. The big 6s and lazy V8s and other huge cc engines have all been ok, but the slow revving isnt really my thing Ive found. I prefer small engines with turbos as they give me the feeling i first felt as I mastered motorised transport and that makes me smile. :)
 

Duke

New member
Yeah, I had a 1.0 Ecoboost Focus hire car a while back, the 100ps version, and considering it is the equivalent of a 1.6 na from yesteryear, the new engine is better in every single way, sometimes remarkably so. Much more low-down torque, eager enough to rev, and even made a better noise. So much more pleasant to drive than a wheezy old lump.

People, you know the type, pop up at this point and say "oh but they're much more complicated and will therefore implode after 50k miles" but the evidence really doesn't bear this out. Cars have never been as reliable, and these kind of engines have been around long enough for them to demonstrate that they are not grenades. Unlike the VW 1.4 twin charged, that is :ROFLMAO:
 

docadiddle

New member
3 cylinder lumps have certainly come a long way from the Subaru Justy I had for a while in the 90s. What a dog of an engine. But brilliant low speed fun in deep snow. Seemed impossible to get stuck.
 

Lanman

New member
I've had 6 cylinder(2 cars) , 4 cylinder (mostly 3 cars) and now 3 cylinder (1 car).

The 3 cylinder has been the most charasmatic and fun engine I've ever felt behind the wheel. It kinda feels old school turbo but without the lag.

You'd honestly think it was 4 cylinder if you didn't know the specs.

Well done Toyota and shimoyama. 👍
As an Aussie I have had everything from V8 down to single cylinder outboards! Driven a few V 12 Fezzas but brought up on V6 Lancias . Recommend a very comprehensive book ‘ Lancia with De Virgilio at the Centre’ by Geof Goldberg with a superb description of De Virgilio’s development of the V6 engine and all the issues relating to engine balance and couples etc .
The only time I notice the GR 3 is when the stupid stop start kicks in , at which time the
Start up is not as smooth as a four or six , possibly the Rocking couple . Maybe why Kiwi Greg found ‘ breaks’ in the rear engine mount? Always try to turn it off but at first stop remember! When revinf it is indeed a mighty little power unit that impresses everyone who has driven it .
 

odl21

New member
agreed. its a shame the start stop has you taking pity on the engine ever time it struggles to get the engine going again. still glad to have it though. remember it doesn't come on in sport mode though. so i end up actively turning it on when i feel i want it (school run when traffic bad).
 

eqcons

New member
agreed. its a shame the start stop has you taking pity on the engine ever time it struggles to get the engine going again. still glad to have it though. remember it doesn't come on in sport mode though. so i end up actively turning it on when i feel i want it (school run when traffic bad).
I like the stop start, so I'm usually in track mode so it stays on. Are you saying that in Sport mode, a press of the button turns it on?
 

odl21

New member
I like the stop start, so I'm usually in track mode so it stays on. Are you saying that in Sport mode, a press of the button turns it on?
no, if i need start stop, i don't need sport mode! so i press the normal button. its just i always start off in sport, imt, lane assist off, expert mode.
 
Top