[morphique]

I was just wondering how is the low end torque on Fiesta Classic 1.6?
Is it comparable to that of Santro when driving in bumper to bumper traffic?

[mallumowgli]

I dont think it is fair to compare the torque of bigger engines with those of much smaller engines. DCEite started the post comparing the torque availability (or torque curve to be precise) in the current hatches with those of a decade back, having similar or very close engine capacity. The performance of a 1-1.3L engines cannot be compared to the performance of 1.6L or above engines

[morphique]

^^ No offence but I would have agreed to that if I was comparing top speed or in-gear acceleration. I understand that Santro and Fiesta Classic are from different segments and there is a huge difference but what if I am looking for a (non-automatic) car, irrespective of engine capacity, within a specified budget, say 7 lakhs, and my only criteria is that it should be breeze to drive in bumper to bumper traffic?

I did not see a point in opening a new thread just for this question and found this thread had already an ongoing discussion on low end torque of small cars. As per the thread, Santro seemed to be the winner until now, so I wanted to know how is a Fiesta Classic on that aspect, although I am aware that we cannot consider Fiesta Classic in "small car" category!

[anandjha]

My take on it.

Has anyone observed the torque of the car while it is reversing? It packs power and the pull in the first gear compares nowhere to the pull of the reverse gear.

As someone had mentioned earlier, the factor for low torque is short gear ratio which in turn is to enhance the FE.

[Utopian]

The reverse gear is comparatively taller than the 1st to increase the max speed and hence reduced pulling power aka torque.
The factor for low torque IMO, is taller gearing and peaky torque characteristics of modern engines which boast of more power from smaller displacements.

[yogeshnagpal]

A friend and me took a TD of Toyota Liva petrol. He drives a Wagon R and I drive a Zen. However, both of us felt that the car lacks low end power delivery. It felt very sluggish in the 1st gear and wasn't pulling as easily as a Wagon R or a Zen. I can relate this in the 0-25 band where my zen pulls upto 25 quite fast.

Anyone having TD'ed the Liva faced similar sort of experience ?

[Aroy]

Originally Posted by arvi86

Of late, I found the Alto K10 to be extremely peppy, nimble and fun to drive. Not even the Civics and Corollas can hold a candle to the Alto K10s and Santros.

You have hit the nail on the head. Alto K10 is the car for city travel, especially when you are the sole occupant. But even here the low end torque is not enough for it to support AC at low speeds, hence a bit of gear changing. But due to its high revving engine you can easily drive at 4K rpm without batting an eyelid, and that reduces gear changing a lot.

[Doylthippo]

I understood that there should be different ways to handle this low-end torque. I drive 1.2 i-vtec in the form of Amaze.
For example: When ever i slot the car in gear 1, i take the engine beyond 1.5k RPM and then i try to slot to gear 2, then i have not met this low end toque and the engine feels more peppy and eager to move ahead quickly.
If i try to move to gear 2 with less RPM of gear 1, then comes this low end torque issue and the car behaves as if the engine is dead and it is very frustrating.

[Aroy]

Low end torque is nice to have when you are pottering around, but for highway driving it is the high RPM of the engine which makes for effortless driving. We were taught to drive a car at RPM where the torque was substantial. Driving in a low torque band is not only frustrating but also consumes lot more fuel. That is the reason for aiming to be above 2500 RPM in high revving modern engines. I have noticed that driving my Alto K10 (and previously Esteem MPFI and the old Baleno) in the 2500-4000 band gives the maximum FE in city driving. For highways it is 5th gear at around 2500 RPM.

[Divya Sharan]

Older cars had 2 valves per cylinder and newer ones are 4 valved per cylinder!
That alone takes away the low end grunt.

Then, cars today especially in the <10L segment have engines tuned for efficiency (geared to achieve good KMPL figures) while mimicking satisfactory performance traits.

Just my 2 pointers.

[abhishek46]

Originally Posted by Divya Sharan

Older cars had 2 valves per cylinder and newer ones are 4 valved per cylinder!
That alone takes away the low end grunt.

Could you pls kindly elaborate how 4 valves per cylinder results in less grunt in low rpm?

I find the low end grunt of my polo 1.2MPI to be decent, inspite of 4 valves per cylinder.

[ashis89]

Originally Posted by Aroy

Low end torque is nice to have when you are pottering around, but for highway driving it is the high RPM of the engine which makes for effortless driving. We were taught to drive a car at RPM where the torque was substantial. Driving in a low torque band is not only frustrating but also consumes lot more fuel. That is the reason for aiming to be above 2500 RPM in high revving modern engines. I have noticed that driving my Alto K10 (and previously Esteem MPFI and the old Baleno) in the 2500-4000 band gives the maximum FE in city driving. For highways it is 5th gear at around 2500 RPM.

+1.
Even I discovered that my WagonR 1.0 FE has increased progressively after I started revving it higher. Now my ideal shift point is between 3-3.5k RPM. The power starts tapering slightly and the sound is not pleasant too.

[Divya Sharan]

Originally Posted by abhishek46

Could you pls kindly elaborate how 4 valves per cylinder results in less grunt in low rpm?

I find the low end grunt of my polo 1.2MPI to be decent, inspite of 4 valves per cylinder.

A 4 stroke engine requires at least 2 valves, one for inlet charge (air + fuel) and another for outlet/exhaust (combustion gases).
Adding more valves per cylinder (3,4,5 as per the engine design) increases valve area and improves the flow of inlet and exhaust gases. Now, more charge/gases are entering and exiting per valve stroke, as opposed to less charge per valve with higher frequency.

Effectively, the engine starts breathing better and it starts revving to higher RPMs. The engine is now able to make more power from higher RPMs than before without running the risk of valves bouncing or loss of compression.
In layman terms, the engine starts making more power, but at higher revs.

The BHP/Nm curve rises to higher RPMs when compared to its 2 valve per cylinder counterparts.
So, we feel the 'reduced' effect in lower revs.

I'm sure if your car had a 2 valve per cylinder version, if would have had a much better low end grunt, even if it had a few horses less than what it has right now.

[lapis_lazuli]

I am tempted to put here, all the (Very Old/Old/Evo) Punto 1.2 petrols, a very under rated car, with its 1172 cc SOHC 8V engine, probably leads the class now. (Or, the obsolete Vista Safire 1.2.)

I am talking of NA mills only, so Revotron/EcoBoost doesn't apply.

All the torque (~100Nm) develops at 2000-2500 rpm, and it is almost diesel like. It will roll up ramps in first gear with no throttle and no/mild throttle in second gear, too, depending on the ramp slope!

I drive it daily, and never ever have I had a knee pain due to excessive gear shifts. It pulls all the way from 20 in 4th gear, for example! Second gear speed breaker test? All the time, any day!

[antz.bin]

It has more to do with the stroke length and less to do with the no. of valves per cylinder.

Higher no. of valves help the engine breathe better at higher revs, boosting peak power outputs but low end remains practically unchanged either way.

As I give the following stroke length data, you will surely find a pattern given that all these engines are naturally aspirated.

Polo 1.2 MPI : 86.9mm
Tiago Petrol : 85.8mm
Suzuki K14 : 82mm
Suzuki K10 : 79.5mm
Spark 1.0 : 77.4
Grand i10 Petrol : 75.6mm
Suzuki K12: 72mm
Honda Jazz : 71.58mm