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Old 8th October 2015, 12:21   #196
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Default Re: Torque vs BHP?

For uphill-driving, where some stop-and-go may be involved (s.a. stopping at viewpoints / vistas, or slowing down for crazy downhill lorries or other stupid downhill traffic who won't slow down for you or give you way), which is more important ?
- Maximum Power, or
- Maximum Torque

Looks like, most Diesel vehicles are able to deliver very good torque at very low RPM, compared to Petrol vehicles. From what I recollect of my physics and bit of reading, I think "Torque" is what helps us get moving, so is it right to say, that in my context, I should be looking at higher Torque (for uphill driving) ?

Also, is the Max Torque mentioned, for the engine while it is mounted in the car, i.e. pulling 'Kerb weight' of the car, or in it's unmounted condition (somewhat like 'free running') ? That is, is 200Nm of max torque that a Ertiga Zdi engine produces is inspite of it's kerb weight of 1235Kgs, compared to 130Nm of max torque that a Ertiga Lxi engine produces is inspite of it's kerb weight of 1160Kgs ?
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Old 8th October 2015, 18:06   #197
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Default Re: Torque vs BHP?

Quote:
Originally Posted by bdutta View Post
For uphill-driving, where some stop-and-go may be involved (s.a. stopping at viewpoints / vistas, or slowing down for crazy downhill lorries or other stupid downhill traffic who won't slow down for you or give you way), which is more important ?
- Maximum Power, or
- Maximum Torque

Looks like, most Diesel vehicles are able to deliver very good torque at very low RPM, compared to Petrol vehicles. From what I recollect of my physics and bit of reading, I think "Torque" is what helps us get moving, so is it right to say, that in my context, I should be looking at higher Torque (for uphill driving) ?

Also, is the Max Torque mentioned, for the engine while it is mounted in the car, i.e. pulling 'Kerb weight' of the car, or in it's unmounted condition (somewhat like 'free running') ? That is, is 200Nm of max torque that a Ertiga Zdi engine produces is inspite of it's kerb weight of 1235Kgs, compared to 130Nm of max torque that a Ertiga Lxi engine produces is inspite of it's kerb weight of 1160Kgs ?
For hill driving it is the low end torque that matters more. Modern turbocharged diesels are designed and tuned for highways where maximum torque at higher RPM pays dividends, but have poorer low end torque. That is why you will see low HP (50-60) and low maximum torque DI diesels tackling hills and obstacles with ease at low speeds, where modern diesels huff and puff.

In most of the cases, the Torque and HP figures are on Dynamometer, that is they are for the engine only, without taking into account transmission losses.
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Old 29th August 2017, 09:06   #198
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Default How does a car's horsepower affect in real life situations?

Hi all,

We all know that higher BHP means better acceleration and top speed. But in my numerous highway drives I have observed that a 80 BHP Maruti Swift can run neck to neck with my 125 BHP Optra Magnum. So how much significant or negligible is each incremental BHP in real time?

As per my understanding, torque is the measure of an engine's internal power and what really matters is the output power i.e horsepower. So based on that we can put to rest torque comparisons and petrol vs diesel comparisons and only take BHP into consideration. Correct me if I am wrong.

Last edited by GTO : 29th August 2017 at 10:53. Reason: STRICTLY no mention of street racing on Team-BHP
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Old 29th August 2017, 09:21   #199
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Default Re: How does a car's horsepower affect in real life situations?

You might want to visit these threads:
http://www.team-bhp.com/forum/techni...ue-vs-bhp.html (Torque vs BHP?)
http://www.team-bhp.com/forum/techni...isleading.html (How BHP, Torque and power-to-weight ratios can be misleading)
http://www.team-bhp.com/forum/techni...top-speed.html (Understanding Power, Torque, Gearing and Top Speed)
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Old 29th August 2017, 09:38   #200
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Default Re: How does a car's horsepower affect in real life situations?

Quote:
Originally Posted by chevyman View Post
As per my understanding, torque is the measure of an engine's internal power and what really matters is the output power i.e horsepower. So based on that we can put to rest torque comparisons and petrol vs diesel comparisons and only take BHP into consideration. Correct me if I am wrong.
Chevyman,

Please go through this thread. You will find the answers here.
http://www.team-bhp.com/forum/techni...ue-vs-bhp.html (Torque vs BHP?)

PS : Oops. the above post wasn't there while posting.

Last edited by GTO : 29th August 2017 at 10:54. Reason: Quoted post edited
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Old 31st August 2017, 19:52   #201
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Default Re: How does a car's horsepower affect in real life situations?

Quote:
Originally Posted by chevyman View Post
Hi all,

We all know that higher BHP means better acceleration and top speed. But in my numerous highway drives I have observed that a 80 BHP Maruti Swift can run neck to neck with my 125 BHP Optra Magnum. So how much significant or negligible is each incremental BHP in real time?

As per my understanding, torque is the measure of an engine's internal power and what really matters is the output power i.e horsepower. So based on that we can put to rest torque comparisons and petrol vs diesel comparisons and only take BHP into consideration. Correct me if I am wrong.
The Swift is a much lighter car, hence you should compare BHP/Ton to get any meaning ful data.
Here is some background information :
. HP = Torque x RPM x K (where K is a constant that links them)
. Torque curve (torque at each RPM) can be designed for a massive peak to assist high speed or pretty flat for drivability.
. The HP cited is the maximum HP at nearly peak RPM, and depending on the torque curve the HP at lower RMP may be quite low.
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Old 1st September 2017, 00:09   #202
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Question Re: Diesel kind of Low End Torque in a Petrol Vehicle?

Quote:
Originally Posted by bdutta View Post
Looks like, most Diesel vehicles are able to deliver very good torque at very low RPM, compared to Petrol vehicles. From what I recollect of my physics and bit of reading, I think "Torque" is what helps us get moving, so is it right to say, that in my context, I should be looking at higher Torque (for uphill driving) ?
I miss my swift diesel for uphill driving, as am now stuck with an alto. I do NOT have much of an experience with any other petrol vehicles but our 15+ year old alto(800cc) is definitely under powered for uphill drives.

Are there any petrol vehicles(hatchbacks) delivering as near a low end torque as a diesel vehicle?
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Old 1st September 2017, 16:55   #203
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Default Re: Diesel kind of Low End Torque in a Petrol Vehicle?

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Originally Posted by JMaruru View Post
I miss my swift diesel for uphill driving, as am now stuck with an alto. I do NOT have much of an experience with any other petrol vehicles but our 15+ year old alto(800cc) is definitely under powered for uphill drives.

Are there any petrol vehicles(hatchbacks) delivering as near a low end torque as a diesel vehicle?
Not that I know of those made in India. I know that Jeep and G Wagen petrol 4x4 have oodles of low end torque, but these are specialized vehicles.

For a small petrol vehicle, the trick is to climb hills at high RPM - 2nd upto 40km/h and 3rd upto 60. You climb down in the same gears to maintain control of the vehicle

Last edited by Aroy : 1st September 2017 at 16:58.
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