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Old 12th January 2008, 23:50   #181
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Originally Posted by rrnsss View Post
Sir, it is just plain mathematics that will prove that if the torque is reduced but the BHP remains the same (as swift ) then the power curve is smoothed out.
This is new for me.

Could you please explain the mathematics for us, sir?
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Old 12th January 2008, 23:59   #182
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For example if you take 110 hp Cedia and 110 hp Verna diesel , for the same Max BHP the torque in Cedia is lesser than that of the verna. Verna engine is more punchy but shorter range of rpm whereas cedia engine keeps producing power over a wider rpm range . Both have the same max power. But the range through which each keeps producing power is different.


Power = Work done / unit time

Work done = Force x distance moved

here in an engine distance moved is angular and not linear, so it is measured in radians (or degrees 360 degrees representing i rev ) . So to produce the same amount of power , if a petrol engine has lesser force per rev ( torque ) , then it can/ has to rev faster to achive the same max BHP. (as max work per unit time done by both engines are the same ).

If it has to rev faster and keep producing work , it has to have a smoother torque curve. i.e. even though it produces less torque, it will keep producing over a bigger range of rpm , as compared to a torquier engine with the same bhp.

Last edited by rrnsss : 13th January 2008 at 00:00.
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Old 13th January 2008, 00:10   #183
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Originally Posted by CrAzY dRiVeR View Post
This is new for me.

Could you please explain the mathematics for us, sir?

If I am unable to explain it properly , you can try reading this link. http://vettenet.org/torquehp.html

and this Horsepower Vs Torque

sir

Last edited by rrnsss : 13th January 2008 at 00:12. Reason: Added links to support
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Old 13th January 2008, 00:12   #184
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Originally Posted by rrnsss View Post
For example if you take 110 hp Cedia and 110 hp Verna diesel , for the same Max BHP the torque in Cedia is lesser than that of the verna.
That is due to the inherent nature of diesel & petrol engines. Comparing a diesel and a petrol is different ball-game altogether.
Quote:
Originally Posted by rrnsss View Post
If I am unable to explain it properly , you can try reading this link. http://vettenet.org/torquehp.html
and this Horsepower Vs Torque
sir
ok. Let me go through.

Last edited by CrAzY dRiVeR : 13th January 2008 at 00:17.
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Old 13th January 2008, 00:16   #185
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Originally Posted by CrAzY dRiVeR View Post
That is due to the inherent nature of diesel & petrol engines. Comparing a diesel and a petrol is different ball-game altogether.

No it is not, the mathematical equation does not care if the Torque produced at a given rpm comes from a diesel or petrol engine. The formula is the still the same.

The formula used to calculate the Max BHP for a petrol engine is not different from that of a diesel engine .

I used a petrol vs diesel to just highlight a point . I just used the two engines for convenience as they both produce 110 bhp and easier to compare


If there are 2 diesel engines one with a lesser max torque than the other but producing the same max Power, the less torquier engine HAS to have a wider band.

Not a different ball game.

Last edited by rrnsss : 13th January 2008 at 00:30.
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Old 13th January 2008, 00:37   #186
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Quote:
Originally Posted by rrnsss View Post
here in an engine distance moved is angular and not linear, so it is measured in radians (or degrees 360 degrees representing i rev ) . So to produce the same amount of power , if a petrol engine has lesser force per rev ( torque ) , then it can/ has to rev faster to achive the same max BHP. (as max work per unit time done by both engines are the same ).
That only implies that torque comes higher up in the power band for the petrol engines. It has to rev more.

From your example, Cedia produces maximum torque at 4250 rpm compared to Verna CRDi that has it at 1900 rpm.

Now, how does lower torque convert to lesser gearshifts?
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Old 13th January 2008, 00:45   #187
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Originally Posted by CrAzY dRiVeR View Post
That only implies that torque comes higher up in the power band for the petrol engines. It has to rev more.

From your example, Cedia produces maximum torque at 4250 rpm compared to Verna CRDi that has it at 1900 rpm.

Now, how does lower torque convert to lesser gearshifts?
Before I explain the gear shifts , do we have an agreement on a wider power band for the same max BHP for two engines , one with lesser max torque than the other, whether the two engines we compare are petrol or diesel or any other fuel?

Last edited by rrnsss : 13th January 2008 at 00:48.
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Old 13th January 2008, 00:47   #188
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Before I explain the gear shifts , do we have an agreement on a wider power band for the same max BHP?
No. Not yet. But i think we are going seriously OT.

As i said in the previous post. You have explained why petrol engines rev more to produce same torque, and not why less torque means wider power-band.
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Old 13th January 2008, 00:54   #189
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Originally Posted by CrAzY dRiVeR View Post
No. Not yet. But i think we are going seriously OT.

As i said in the previous post. You have explained why petrol engines rev more to produce same torque, and not why less torque means wider power-band.
Sir, I assume you have mistyped. Petrol engines do NOT rev more to produce the same torque, they actually produce less torque but they can / have to rev more if they have to produce the same max BHP.

No, I had used petrol just to highlight a point. The same arguement is true when comparing two diesel engines or diesel and kerosine, kerosine and peanut oil engine. The fuel does not matter.

As I said before the mathematical formula does not care about the engine for which it is calculating the power.



Yes we are getting off topic, so this will be my last post on this. If I you do not believe that engine A having lesser max torque that Engine B but producing same max bhp as engine B has to have a wider torque curve, then I cannot take the arguement any further as you do not agree on the fundamental science.

Anyway , Wider band engine as compared to a narrower torque band engine with the same Max BHP means lesser gear shifts because you can acclerate and decelrate and acclerate back through a wider rpm range in the same gear as compared to the narrower band engine

Last edited by rrnsss : 13th January 2008 at 01:05.
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Old 13th January 2008, 01:27   #190
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Quote:
Originally Posted by rrnsss View Post
Sir, I assume you have mistyped. Petrol engines do NOT rev more to produce the same torque, they actually produce less torque but they can / have to rev more if they have to produce the same max BHP.

No, I had used petrol just to highlight a point. The same arguement is true when comparing two diesel engines or diesel and kerosine, kerosine and peanut oil engine. The fuel does not matter.

As I said before the mathematical formula does not care about the engine for which it is calculating the power.



Yes we are getting off topic, so this will be my last post on this. If I you do not believe that engine A having lesser max torque that Engine B but producing same max bhp as engine B has to have a wider torque curve, then I cannot take the arguement any further as you do not agree on the fundamental science.

Anyway , Wider band engine as compared to a narrower torque band engine with the same Max BHP means lesser gear shifts because you can acclerate and decelrate and acclerate back through a wider rpm range in the same gear as compared to the narrower band engine
The last few arguments have been very tempting to decide not to comment on. I would probably agree to your argument about a wider torque-band, provided the maximum power/torque rpms are the same in both cases. In this case we do not have adequate information.

On top of it, the presence of a wider torque band does not necessarily say that a car will be easy to drive, that depends on how much torque the engine is producing at any given rpm anyway.

Moreover how fast a car will be does not necessarily gets guided by the flat-ness of the torque band, but the area under the torque curve.

Bring into it the factor of how the driver is using the rpms in terms of which gear he is using. The area under the curve between the boundaries of the gearshift rpms (for each individual gear) is what matters most.

So although it might appear that a flatter torque curve is better, a peaky torque curve isn't to be regarded as bad when in the right hands. Its more like a case of autofocus camera vs SLR's, average users would probably do better with the former.

Now as far as suitability in the Palio package is concerned, lets understand that no other car in that bracket generates the kind of passion this one does. So it is quite logical to expect the followers to be dissapointed with a smaller number, even if, it might appear to be made in a general interest. Which too, I would like to beleive is not the case, the decision seems to have been made purely from a business case perspective, wherein the Tata branded car (X1) might get the 19kgm torque engine to keep its upper hand over the similar engined palio , in turn the GP and Linea will get the 90bhp state of tune.

The numbers in the spec sheets do matter, but merely serve as an academic exercise for thumb rule expectation settings. To know the truth, you might have to bring in too many factors to be discussed on this forum.

Last edited by 1100D : 13th January 2008 at 01:32.
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Old 13th January 2008, 01:49   #191
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I am also very passionate about the Palio 1.3 MJD even though I might not own it. I really hope that it will be a huge hit and help fiat get a larger market share. It is too good a package .

I did not understand about the palio until I sat in one and closed the door.


Yes it is an acedemic exercise. I was just argueing about the fact that when you have two engines producing the same max bhp , the one with the lower max torque will have a wider band. I guess it went way off topic.
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Old 14th January 2008, 13:20   #192
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Good news may be that Palio 1.3 will be much cheaper than SWIFT.
Fiat wants to play the price game on Indian roads-India Business-Business-The Times of India
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Old 14th January 2008, 20:25   #193
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Originally Posted by manish_symc View Post
Good news may be that Palio 1.3 will be much cheaper than SWIFT.
Fiat wants to play the price game on Indian roads-India Business-Business-The Times of India
I had mentioned this here:

http://www.team-bhp.com/forum/684618-post23.html

Had posted about localised content as well.
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Old 14th January 2008, 22:21   #194
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Is it a matter of concern that incase of Palio 1.3 diesel more engine noise will be audible inside the car.
I am asking this because I myself had noticed that in New Palio 1.1, engine noise enters into the cabin.
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Old 14th January 2008, 23:24   #195
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Quote:
Originally Posted by rrnsss View Post
Sir, I assume you have mistyped. Petrol engines do NOT rev more to produce the same torque, they actually produce less torque but they can / have to rev more if they have to produce the same max BHP.
.
.
.
Anyway , Wider band engine as compared to a narrower torque band engine with the same Max BHP means lesser gear shifts because you can acclerate and decelrate and acclerate back through a wider rpm range in the same gear as compared to the narrower band engine
I think that the slope of the power curve w.r.t rpm also matters. You cannot drwa a straight conclusion that for same peak power, the engine with lower torue will have a smoother torque curve.
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