[Kanwar7421]

Hello to all the fellow Team-BHPians. This is my first post on this forum and I'd like to start this journey with a question that has kept my brain cells busy since the last 3 days.
The question is "Have Automobile companies really found a replacement for displacement?"
Let me take an example of 2 of India's favorite 'real' SUVs - Toyota Fortuner and Ford Endeavour
1. Fortuner was launched in 2009 and it came with a 3.0L 4-cylinder turbocharged diesel engine producing 171PS of power and 360Nm of torque. Presently, the 2nd generation facelift comes with the 2.8L 4-cylinder turbocharged diesel engine producing 201PS of power and 500Nm of torque. The engine capacity was downsized by around 200cc whereas the power and torque outputs increased significantly.

2. Ford Endeavour 2nd generation which was launched in 2015 came with the massive 3.2L 5-cylinder turbo diesel engine producing 197PS and 470Nm of torque. But due to implementation of BS6 emission norms, Ford introduced the new 2.0L 4-cylinder turbo diesel which churned out 168PS and 420Nm of torque. The engine capacity was downsized by nearly a K12 series engine (1,200cc) yet the decrease in power and torque output was only around 30PS and 50Nm respectively.

I know that as time progresses, newer engine technologies are developed due to which the power and torque outputs are not drastic even after engine capacity downsizing BUT if a smaller displacement engine developed with tech produces better power than its larger capacity counterpart which was developed 4-5 years back. Then in what areas will the larger engine be better so as to prove the statement "There is no replacement for displacement"

And......in 2022, if I want to buy a true BOF SUV like the Thar or Scorpio-N, can their TGDI Petrol engines (if FE is not much of a concern) be the better choice or follow the universal option that an SUV has to have a diesel engine.

P.S -> I am also a fun of larger capacity engines and love their excellent low-end torque delivery and abundance of power reserves at all points BUT do we really big gas-guzzling engines when their smaller counterparts can do the job at a similar level?

[vishy76]

Whatever you have assumed above about Ford's 3.2 and 2.0 is purely on paper. The same applies for many other engines too. On paper, I can make a downsized engine a lot more powerful than its larger counterpart by putting a bigger turbo. But have you considered factors like tractability and reliability? A large turbo bolted to a smaller engine can in many cases lead to turbo lag. It will cause the power delivery to be peaky. Such engines are irritating to drive in traffic due to poor low end torque. I believe the 2.0 turbo by Ford suffers from the same issue, but it is reduced to an extent thanks to the closely spaced ratios of the 10-speed gearbox.

Secondly, I firmly believe this "downsizing trend will help fuel efficiency" tactic to be pure BS, especially when it comes to petrol engines. What I have noticed personally is that turbo petrols (even 1.0L displacement engines) are very sensitive to the way you drive them and their urban fuel economy isn't all that great. Simple reason again being they are off-boost in city traffic. On the highway, sure, you can get good fuel economy if you are in the turbo zone. However, NAs are a lot more predictable in terms of fuel economy and the despairity between urban fuel economy and that on the highways isn't much.

I am not saying downsized engines are bad. I have had the time of my life driving some very potent low displacement direct injection turbo petrols. It's just that some of the claims wrt fuel economy and on paper figures are over the top. Power figures on paper are just that. Power figures on paper. There's a lot more to an engine than this. There's a reason why a Bolero 2.5 DI will do a much better job in hilly regions than a 2.0 Turbo diesel, even though the diesel might make twice as much power and torque as the 2.5.

Downsizing also often means manufacturers end up integrating complex tech (direct injection, turbocharging etc) and developing relatively high stress engines. I don't think this is a good thing from a reliability POV.

I would conclude by saying downsizing is definitely here to stay. It's given rise to some very entertaining engines (1.0L TSI, 1.0 TGDI et all), but there are myths surrounding the same and not all marketing statements are to be believed.

[shankar.balan]

Don’t you think the Ford EcoBoost 1 litre engine clearly disproved this old saying about displacement?

It was so small in dimensions that it could sit within a 1 square foot pencil outline on paper..

[Rajeevraj]

The saying itself is probably still true but from a relevancy point probably not too much especially in the mass market space. Mainly because with the advances in tech, smaller displacement more powerful engines with turbos are becoming the norm now and they probably meet the needs of say 98% of the people out there. So there is no real need for manufacturers to keep building higher displacement engines.

Having said that, even with the turbo petrols for example, displacement still plays a major role. For example the VAG group has the 1.0,1.5,1.8 and even 2.0 TSIs. I am sure given a choicewe would all prefer a 2.0 TSI

[ajayc123]

With transtion towards hybrid and electric, the relevance will continue to reduce.

[Turbohead]

The saying still holds true when you compare engines with the same technology be it turbocharged, hybrid, fuel injected etc.

However the technologies between manufacturers vary quite a lot that it isn't a definitive way to compare two engines.

They say that the 1.0 and 1.5 TSI from VW isn't comparable since the 1.5 TSI was obtained from the erstwhile 1.4 TSI while the 1.0 and 2.0 were built from scratch. Thus comparing products doled out by a manufacturer isn't exactly easy. That along with the various ECU tunes a given displacement engine is given complicates the equation quite a lot.

Practically, it's no longer a measure to compare two engines while theoretically it's still true.

[sunikkat]

I think it’s subject to what you are comparing against - if it is low displacement turbo with a high displacement NA engine, the former will perform better. But if it’s lower displacement turbo with a higher displacement turbo, most likely latter will be better.
We cannot compare a higher displacement turbo engines from yesteryear’s with lower displacement turbo of current gen (as in case with Fortuner in OP) as technology has advanced.

[Shreyans_Jain]

This saying is applicable and will always be applicable as long as internal combustion engines remain in use. Two engines of similar outputs, one larger than the other, the larger one will always be more tractable and less strained. Which means better drivability, better reliability and more consistent fuel economy under varied conditions.

[shancz]

Welcome to TBHP

Good question, the answer to which lies in the real world like others have aptly pointed out.

Originally Posted by Kanwar7421

- "Have Automobile companies really found a replacement for displacement?"

- Then in what areas will the larger engine be better so as to prove the statement "There is no replacement for displacement"

- if I want to buy a true BOF SUV like the Thar or Scorpio-N, can their TGDI Petrol engines (if FE is not much of a concern) be the better choice or follow the universal option that an SUV has to have a diesel engine.

- BUT do we really big gas-guzzling engines when their smaller counterparts can do the job at a similar level?

Talking only about petrol engines as my experience with diesels is negligible.

- No. What they've found is a way to show higher numbers for power, torque and FE all at the same time but with the ubiquitous "conditions apply".

- Vishy76 has already pointed out the golden words, adding on to them is the capacity to handle load. Smaller engines will need way more throttle input/downshifting to maintain the same speed as compared to a larger engine.

- Although it's universal in the Indian context and I agree with having diesels to haul heavy load but massive 2-4 tonne SUVs overseas have been running on petrol for decades like the LandCruiser/Suburban etc.

- IMO gas guzzling isn't exactly right in the Indian context. The mainstream cars are just adequately engined for their purpose. While the smaller turbo petrols promise the moon in FE and power but both can't be had simultaneously. Try flooring any 1.0 turbo and see how the FE drops.

That being said what the turbo petrols will do is if you're cruising on the expressway at 100kmph(where allowed) a 1.0 turbo will let you do that at a lower rpm(lower throttle input) while having a good reserve of power for a quick overtake without downshifting if needed.
In my experience I have found the turbo petrols to be smoother than their NA counterparts especially at higher rpms.
While we can debate as much but smaller turbo petrols are the way forward in ICE mass market cars and I recommend having them with an automatic gearbox which will alleviate much of the turbo lag which will otherwise be apparent in manual.

Originally Posted by vishy76

- I firmly believe this "downsizing trend will help fuel efficiency" tactic to be pure BS, especially when it comes to petrol engines. What I have noticed personally is that turbo petrols (even 1.0L displacement engines) are very sensitive to the way you drive them and their urban fuel economy isn't all that great.

- There's a reason why a Bolero 2.5 DI will do a much better job in hilly regions than a 2.0 Turbo diesel, even though the diesel might make twice as much power and torque as the 2.5.

- not all marketing statements are to be believed.

- Agree that's just to attract more customers with unbelievable and practically unattainable FE.
Forget turbo petrols the difference in displacement is very palpable even when driving the K10B vs the K12B in the wagonR. Certain sections which need the K10B to be in first gear to avoid knocking are dismissed in second with the K12B. Especially in city driving I have found the K12B and the Kappa 1.2 to deliver better FE than the K10B with the AC on and 3-4 passengers. Not to forget the larger engines are so much easier and fun to drive.

- This was bullseye

- True and especially when someone is promising a magic bullet it has to be probed further as it's going to be an expensive purchase.

[dhanushs]

With all hardware and add-on's similar, YES, there is still no replacement for displacement.

Electronics can try but, not completely compensate for real hardware!

[Gypsian]

The saying " There is no replacement to displacement" is a debatable line. Considering the street cars scenario the classic examples such as Fiat Punto Abarth, Polo GT TSI, Polo GTI TSI, other European counterparts and most recent Hyundai i 20N line, they have all gone the petrol turbo charging route with small displacement engines. Forced induction is the new norm albeit superchargers are at a nascent stage in India.
Majorly these engine specifications depend upon the manufacturer with manufacturers like Toyota still counting on naturally aspirated engines in some of their models such as Camery and Honda too with most of their models. Germans and now Koreans are subscribers of forced induction and it is still not tue case with the Japanese manufacturers present in India.
With Germans too when it comes to their large flagship cars or to their sports versions such as AMG for Mercedes Benz, M series cars for BMW and S ans RS versions of the Audi and not to mention the Italian beasts such as Lamborghini and Ferrari still count on displacement and will not change anytime soon. Lotus being an exception have equipped their sports cars with smaller displacement higher output engines.

[Kosfactor]

Welcome to TBHP Kanwar.

Overall it is a Yes!

However all downsized engines have not been able to match up to their larger legacy engines when it comes to customer expectations, as was the case with Ford Endeavour.

Engines and power trains designed for our traffic conditions will deliver good FE while not compromising on performance. Nothing to lose when it's done right.

A plus point of keeping displacement ~2L (4 Cyl) is that you get to keep the NVH low while good engine management and gearing will deliver fuel efficiency, performance etc.

Do we have lumpy and clattery small diesels ? Yes. Noisy small petrol engines? Yes. Engines need to be looked at from a fit for purpose perspective, if it works , size does not matter.

[Jeroen]

It has always been an ambiguous statement at best. It suggest more Volume is better. Better for what? Power, torque, fuel efficiency, reliability, noise, emissions, size, weight, maintenance? All these factors influence one another. All of those factors are relevant for car engine design. Any engine is always a comprise of many different aspects.

The simple truth was that it was never true. Has been one of the myths of the car scene for many decades. It stems from the bootleg days in the USA. Those good old boys did not have any sophisticated means to enhance the performance of their old bangers. When you need to outrun the cops delivering your moonshine, the only option is to shove a bigger engine in the same car. They were actually very good at doing so. Perhaps a bit crude, but very effective, especially on those big American cars. Very American, bigger is better, no matter what, not much finesse in those days.

This eventually became what is currently NASCAR. They still do without turbocharger cranking out some 600BHP.


Jeroen

[cool_dube]

Originally Posted by Kanwar7421

Have Automobile companies really found a replacement for displacement?

The principle of "no replacement for displacement" holds as good as Newton's laws of motion! The trend of downsizing is here to stay for various reasons - cost, emissions, fuel efficiency, etc. but the fact remains that you cannot get the same levels of performance from a smaller engine as that from a bigger engine by just adding turbos (yes, there are bi-turbo engines too), "official specifications" be damned. It is akin to putting a mule on steroids and expecting it to perform like a stallion I have experienced this first hand, having owned the Endeavour 2.0 and now driving the Fortuner 2.8 - leaving all the BHP/NM figures aside, the biggest testament is the supremely relaxed feel of the bigger engine across a much wider RPM range as opposed to a stressed, narrower one for the smaller mill. As vishy76 pointed out, the 10-speed gearbox on the Endeavour did a commendable job of masking the significant turbo-lag that the 2.0 lit engine was plagued with - one drive in manual mode and it was crystal clear.

Originally Posted by vishy76

A large turbo bolted to a smaller engine can in many cases lead to turbo lag

Absolutely. Turbo-lag in the Endeavour 2.0 was massive! Even the smaller 1.2 lit / 1.5 lit diesel engines of today's mid-size SUVs are plagued with the same symptom - while figures on paper look impressive, they are almost dead till ~2000 rpm, post which there is a mad surge of power as the turbo spools. Might be good for that instantaneous thrill but not enjoyable in the long run, and most importantly, a pain to drive in city traffic as well as off-road conditions.

[SmartCat]

When it comes to low end torque, there is no replacement for displacement.

Wait, cancel that. I forgot about hybrids.