[k_kumar]

Have voted for NA. I'm not much convinced about long term reliability of turbo petrol mills. Also, I prefer linear and consistent power delivery. But it seems turbos will become mainstream until electric motors edge them out in not-so-distant future.

[anb]

Originally Posted by TwistOfFate!

If the comparison is strictly between a 1.0L Turbo and a 1.5L NA, I'd definitely opt in for a 1.5L NA as the Power & Torque figures would almost be identical.

Polo 1.0 TSI produces more torque than new Civic's 1.8 I-Vtec engine. 1.5 engine doesn't even come close. I would prefer 1.3 mjd over 2.0 NA Lancer diesel any day. Similar case with petrol engines also.

[nuew]

Small turbocharged engines v/s larger naturally aspirated ones. That’s something of a conundrum. I think it's more dependent on individual preferences and the prowess of the manufacturer. As CrAzY dRiVeR mentioned, most of the modern turbo-petrols are outperforming the naturally aspirated counterparts. Smaller turbos are not with their flaws. Many haven't nailed the NVH levels (like Tata). Most (if not all) have a weak bottom end, fuel efficiency is dependent on driving style etc. But they are a necessity due to various reasons like the emission norms, cost control, tax structure, scalability and all.

Like most, it's the Honda iVTech that comes to mind whenever a 1.5L NA is mentioned. As much as it’s a fun engine, it isn't without its flaws. It too has a weak bottom end and with the comparatively weaker torque. The turbos have better accessible power at lower RPMs. The Brezza's 1.5L petrol also has been found uninspiring to drive as per TeamBHP review. The specific output and the torque figures of most of these small turbo petrols are much higher than most of the naturally aspirated 1.5Ls.

The best of both worlds would be a 4 cylinder 1.2L Turbo that would have better NVH along with the tax benefits. But from the 1.0L Ecoboost to 1.0L TSI, I think 1.0L was chosen by most international manufacturers for the compact hatch segment in moving to the turbo era. As for the choice of 3 cylinders, I remember watching some engineering video explaining how 3 Cylinders are better suited for the turbocharging than 4. The smaller size, lower number or parts, lower weight, lesser frictional losses etc. could be the additional reasons. The non-turbo versions can be used to power smaller cars too. I hope the long term reliability doesn’t suffer much though.

As manufacturers are moving towards smaller turbocharged engines complying with emission norms and cost cuts, I think it's time to embrace them over the naturally aspirated ones. As the technology progresses, they are getting better and better with each iteration. Someday the tech on that "Tiny Friendly Giant" spawned by Koegnizegg is going to trickle down to the passenger cars and we may get over the naturally aspirated engines for good. ICE engines are likely to be on their way out in a decade or two anyway.

[shinuak]

I would choose neither, A "larger turbo charged" is what my heart will get hooked to. The likes of 1.4 Tjet from Abarth/Linea or 1.8 TSIs from Laura/Octavia or the 2.0 litre TSI from vRS etc.
With the new BS6 norms, that creed is slowly getting endangered, which is a painful fact for any enthusiast. Not that I am blind to the figures on paper for the new 1.0 TSIs, but somehow being an "engine" person, I cannot bring myself to terms with a rapid running on a 1 litre or a city running on similar

[fache89]

I always subscribed to the saying, "There is no replacement for displacement". However, when it comes to Turbo Petrols, I would choose the latter sacrificing the displacement.

That said, I have a question. Is there any impact on AC performance on 1.0 Turbo versus 1.5 NA? I have driven a friend's Turbo Petrol Venue and did not see any sloth on performance of AC. It would be nice if other BHPians share their experiences.

[fhdowntheline]

Originally Posted by shinuak

I would choose neither, A "larger turbo charged" is what my heart will get hooked to. The likes of 1.4 Tjet from Abarth/Linea or 1.8 TSIs from Laura/Octavia or the 2.0 litre TSI from vRS etc.

In the city, the 1.8 Tsi or 1.4 TJet dont hold much of an advantage. In fact, I'd say that in D-Mode, the 1.8 Tsi is not significantly faster than an NA equivalent like say a Corolla 1.8. There is a tendency of the DSG to upshift earlier and so the Octavia may find itself a bit bogged down if it has to navigate through traffic at say 40-70 kph. The linear response of the NA engine will help a lot here. Where the 1.8 Tsi will really open up is in the Sport/Manual mode, but then opportunities to do this are few and far between (in a safe driving manner).

[reignofchaos]

Once you get used to a DI turbo petrol, there's no way one can go back to NA. They just feel anemic.

There's a very valid reason manufacturers are moving towards turbo petrols - emission requirements. To comply with the latest emission norms, the only option is downsizing and making the engines more efficient. As a side effect of making the engines more efficient, we petrol heads get more power as efficiency and power go hand in hand.

I for one am really happy that these horsepower wars are permeating down even to the budget segment. Better engines, faster and safer cars for all I say.

[the.shivaraj]

I have two different cars i.e VW Vento 1.6TDI and 2006 Baleno, I would go with Baleno any day as NA offers linear power delivery, and since 1.5 NA engines are simple enough so there won't any issues regarding turbo failure. Forced induction engines run relatively under pressure and the engine components will be under stress, in addition to that one has to idle the engine before turning off. I religiously follow this in my Vento, so I will be the last person to get out of the car. Moreover it has relatively poor power delivery pre-1800 RPM but post that it surges ahead great push. It might uncomfortable in the city but I truly enjoy it on highways. Having said that, NA engines are becoming a thing of past so better to enjoy them now.

[zaheermk]

In my opinion, it depends more on where the vehicle will be driven the most.

If the vehicle owner is situated near relatively traffic free highways, I would say, an eager to rev NA vehicle would be enjoyable, but if he stays inside the city, I say a TC vehicle, which will eagerly show more performance from the word go.

If it is a free road, then an NA vehicle would be entertaining, by taking it to higher rpms easily, but if there is traffic, when the rpm drops frequently due to braking, then to maintain average speed, it becomes difficult, in which case, a TC vehicle can much more easily go to higher vehicle speeds (since it does not have to rev that high to reach higher vehicle speeds). In other words, thru gear acceleration might be comparable in both NA and TC vehicles, but in-gear acceleration is relatively better in TC vehicles.

NA engines are rev happy, but then it also need to rev to a higher rpm to produce the same power/torque, whereas TC engines start developing higher power/torque from lower rpm onwards (please refer the engine specs given below), which is why in-gear acceleration tends to be better in TC vehicles.

This was experienced on different long drives on our Logan (1.4 NA Petrol) and on my Verna (1.5 TC Diesel). The Logan whenever the speed dropped due to some traffic or speed breaker, I found it stressful (due to the low acceleration) to bring the vehicle again back to cruising speeds, but with the Verna, when similar happens, it is a delight (mainly due to the low end, which is enhanced by the VGT) to bring it back to highway speeds.

I realize the above two examples are on the extreme ends of the power/torque-to-weight spectrum. Logan 1.4 Petrol has one of the lowest power/torque-to-weight ratio and Verna 1.5 Diesel has one of the highest power/torque-to-weight ratios, so the effect what I felt is far more pronounced than in a regular TC Petrol. So, for better understanding, I have given below, the specs of the above two vehicles and a TC Petrol, Polo 1.2 (GT) for our easy comparison.



I have also compared the same 1.0 litre engine which does its duty as NA in Celerio and in TC mode in the Baleno (RS), and also the 1.2 litre NA engine in the Baleno, which is the regular variant of that model.



Similar comparison is made of the 1.2 litre NA engine in Tiago and also its TC avatar in the Nexon. From the two 1.0 litre and 1.2 litre engine specs, it becomes evident how the turbo changes the character of an engine. I have also mentioned the Logan 1.6 NA spec, to understand to how far a relatively higher displacement engine fares.



I also understand there are many of us here who like the relaxed cruising nature of the NA engine more than the relatively aggressive character of the TC engine. And though I use a TC vehicle as my daily ride, I like to drive an NA vehicle for a relaxed weekend outing.

However, it needs to be understood that the TC iteration is a later revision of the NA engine. In the sense, as technology improves and/or to meet upcoming exhaust emission requirements, an NA engine might be required to be turbocharged (and intercooled). Just like how all two wheelers have become fuel injected, from the previously carburetted version, moving from BS4 to BS6. Or like how all Diesel engines had to convert from indirect injection to direct injection (plus turbocharging and intercooling) moving from BS3 to BS4 and from BS4 to BS6, all Diesel engines required a DPF (Diesel Particulate Filter) too.

Still, for meeting the present BS6 norms, there is no requirement that Petrol engines need to be turbocharged. So, the present turbo petrol engines are more of a showcasing by those manufacturers who have developed this technology. But there could be a day in future, if stricter norms come into force, that all Petrol engines would have to be turbocharged and be fitted with a GPF (Gasoline Particulate Filter) also.

There is also a benefit of efficiency when the engine is turbocharged (and intercooled) - the engine’s specific fuel consumption/thermal efficiency improves. Meaning for developing a given power/torque, the TC engine consumes lesser fuel than an NA engine. It might not get translated onto the road always, since efficiency depends on driver demand also. In my case, I tend to drive an NA vehicle relaxingly whereas I push my TC vehicle most of the time (which is due to my mindset). But yes, if you drive both vehicles similarly, at the same rpm, then the TC vehicle will be more fuel efficient, plus at the same time, remaining more driveable.

I feel the old adage “there is no replacement for displacement” is only half-true these days. But yes, one more situation, where I would recommend a large displacement NA, is if the vehicle is to be used on inclines often. In that case, I feel a larger displacement NA would be of more use, since, in a practical world, there would be turbo lag, and due to that lag, it could be slightly uncomfortable to pull the vehicle off from rest on a gradient, specially if loaded with people/luggage. But here too, with the arrival of variable geometry/vane + electrically actuated turbos, overcoming this difficulty with regular turbos is also gradually being realized.

With best regards.

[CrAzY dRiVeR]

1.0 TSi showing 1.5 NA how to roll.

"More fun, more enthusiastic, better bottom-end, better top-end" as per Sirish.

https://www.youtube.com/watch?v=6X4IofqOFYM

[amitayu]

There is no replacement for displacement.
A NA aspirates engine is more reassuring any day.
Coupled with the fact that most turbo petrols are 3 cylibder derivatives of bigger cousins, i would prefer the bigger provided I can afford it

[Artyom]

Entirely depends upon your driving style.Someone who is not looking for that turbobkick and prefers a relaxed driving style will go for a NA engine and vice versa.Moreover NA engines are less complex so logically are easy to maintain as against the Turbo ones.

[shancz]

Originally Posted by Fury

From an enthusiasts point of view, which one do you think is better? The good old 1.5 naturally aspirated motors or the new gen 1.0 litre turbos? I, personally, am hoping Honda's plan of bringing in a forced induction, small capacity motor to replace the 1.5 IVTEC never materializes!

1.5NA hands down.
1.0TC is just too small to match the 1.5NA(assuming the 1.5 iVTEC as reference) in real world.
I don't think having anything lower than 1.2 turbo makes sense for any car, anything lower is better off with a larger NA.
Also from an enthusiast's perspective and IMHO if we're talking about challenging a 1.5NA it should be a 1.4TC.

I hope the same for Honda's plans as well

Originally Posted by arindambasu13

The power just keeps flowing in a linear and predictable fashion (sorry - I am not a fan of sudden turbo spike which I find to be unmanageable in daily bumper to bumper driving and traffic scenarios).

I have been very pleasantly surprised at the low-end throttle response of this engine. Unlike my earlier Swift K12 which did not have great low end response, the 1.5 iVTEC's throttle response is way better, starting to respond right from around 1200-1300 RPM and extending up to a dizzying 7100 RPM!

Exactly, that's why we love good NA petrols, their behavior is so natural
How much you press the gas is how high the revs climb and how fast you go. All directly proportional to the effort being applied and we have the entire rev-range to play with the engine.

The turbo boost, when it comes in, doesn't seem natural.
I was caught unawares by the boost too but that was a swift diesel(manual). haven't driven a manual turbo petrol but will drive the XUV 300 soon. The turbo automatics I drove the gearbox was well tuned to the engine and felt good to drive, so didn't feel any sudden surges or lags.

But coming to turbo petrols, these are the future but best enjoyed with a well mated automatic. And of course at least a 1.2

Mods : the examples mentioned might be repeated as I had also used them in an earlier thread but here they are very specific to the quoted post so using it again.

[Venkatesh]

Drag Race 1.0-litre Turbo and 1.5-litre NA

2020 Honda City
Skoda Rapid 1.0 TSI

https://youtu.be/ilkyGAbaXS0

[Kosfactor]

^ a result that proves that a turbo engine does not need to spin to ungodly speeds to make a car go fast.