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Old 9th May 2011, 17:47   #181
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Default Re: Torque vs BHP?

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Originally Posted by teknophobia View Post
That's not the case, sorry. Nothing much else to say except that either a) you have no idea what you're talking about or b) you're deliberately trolling.

It may be (a) - my experience, as I have already written, is on a WagonR from the driving school. And as you pointed out, that may not be an ideal vehicle to form an opinion on.

Why would it be trolling? Do you think I have been rude to anybody?
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Old 9th May 2011, 18:11   #182
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Default Re: Torque vs BHP?

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Originally Posted by mayankk View Post
Shouldnt the bold bits be flipped?

Well on a Figo, if the speedo is showing less than 5 (half of the 10 mark) and you release the breaks fully - the car stalls even if there is no incline. The rpm falls below idling. On an incline engine stalls if you release the clutch fully and the rpm falls below 800-900. All of these are with AC on (moderate). Without AC on the numbers may go down a little.

All of these observed over the last week, as I wrote many times, I'm a new driver so I'm keeping tabs on these things.


On the WagonRs that I trained on there was usually no tachometer, but one car did, and I saw that car wouldn't stall even on incline at low speeds, even if I released the clutch too soon (within 5kmph) - it would jerk a little but always kept moving.


Now my apologies to our friend techno, and I'm not trolling or making this up - this is personal experience.

I used my M800 very few times, but next time I'm back in NCR I'll check that one too and let you guys no.
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Old 9th May 2011, 18:52   #183
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Default Re: Torque vs BHP?

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Originally Posted by vina View Post
... that may not be an ideal vehicle to form an opinion on....
Yes, Vina.

Well, the part that petrols revv much higher is definitely true.

Regarding low end torque, try driving an N/A diesel engine and comment on its low end torque. A turbocharged diesel, and an NA diesel's low end driveability differs a lot. In an N/A diesel, on plain stretch, you not only can move the vehicle without any throttle input, but sometimes, the idle rpm is sufficient to propell 2-3 gears tru ~ 30km/hr.

Well, you really cannot generalize that diesel's have poor low end torque by drving only the Figo (Correct me if I'm wrong).
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Old 9th May 2011, 18:54   #184
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Default Re: Torque vs BHP?

Vina, I usually get my Wagon R to start moving without pressing the accelerator.

A funny incident that happened long back: http://www.team-bhp.com/forum/techni...st-solved.html (Wagon R:Acc Lost: Solved)

But I think this movement is more due to the MPFI. If the car was carb driven it would not have been possible.

About diesel stalling or feeling it has more static friction. The tires would also play a big role. Since you mention the wagon r was w/o a tacho. It would have been an Lxi or Lx variant. The tires on that are quite thin. Hence lesser rolling resistance as well.

Compare the sizes of the figo tires and the wagon .
Also the tire pressure is important. Under inflated tires would need more force to coax them into moving.
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Old 9th May 2011, 20:28   #185
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Default Re: Torque vs BHP?

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Originally Posted by vina View Post
If you try the same thing in a diesel car, engine will stall - you have to keep slipping the clutch until the rpm at wheels reaches a respectable number.

My point is this - if you happen to be driving in the turbolag regime (less than 1750 for a Tata, less than 2000 for a Maruti, less than 1200 for Figo/Ford) in a diesel - you are going to regret not having a petrol. This can happen very easily in stop and go traffic on an incline.
In Vista QJD even if you do not touch the gas pedal, you can comfortably keep running with your foot off the clutch also in all the gears successively.
Which means, in First gear you can completely give rest to all your feet on a vacant stretch, engine running ~800 RPM. This feat I could never achieve in my earlier cars viz. M-800, padmini

Quote:
Originally Posted by teknophobia View Post
That's not the case, sorry. Nothing much else to say except that either a) you have no idea what you're talking about or b) you're deliberately trolling.
a) you have no idea what you're talking about- +1 absolutely
Quote:
Originally Posted by mayankk View Post
Shouldnt the bold bits be flipped?
It says it well.

Cheers
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Old 9th May 2011, 20:40   #186
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Default Re: Torque vs BHP?

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Originally Posted by bblost View Post
Vina, I usually get my Wagon R to start moving without pressing the accelerator.

A funny incident that happened long back: http://www.team-bhp.com/forum/techni...st-solved.html (Wagon R:Acc Lost: Solved)

But I think this movement is more due to the MPFI. If the car was carb driven it would not have been possible.

About diesel stalling or feeling it has more static friction. The tires would also play a big role. Since you mention the wagon r was w/o a tacho. It would have been an Lxi or Lx variant. The tires on that are quite thin. Hence lesser rolling resistance as well.

Compare the sizes of the figo tires and the wagon .
Also the tire pressure is important. Under inflated tires would need more force to coax them into moving.

That's what I'm saying. And it was the case with those cars (they had multiple WagonRs) even on a moderate incline !

My Figo moves without pressing the accelerator, but that is on a flat surface, on a similar incline, when I release the clutch a little (and it starts slipping) I have to press the pedal, or the rpm falls and it stalls.


In addition to the other reasons you are mentioning it might be that the engine is almost brand new (or may be not) and still undergoing the run in process.
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Old 9th May 2011, 21:44   #187
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Default Re: Torque vs BHP?

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Originally Posted by dhanushs View Post
Yes, Vina.

Well, the part that petrols revv much higher is definitely true.

Regarding low end torque, try driving an N/A diesel engine and comment on its low end torque. A turbocharged diesel, and an NA diesel's low end driveability differs a lot. In an N/A diesel, on plain stretch, you not only can move the vehicle without any throttle input, but sometimes, the idle rpm is sufficient to propell 2-3 gears tru ~ 30km/hr.
Agree.
The turbo spooling up will take time, so NA diesel, no turbo, will show the grunt of a diesel.

Quote:
Originally Posted by sanagg1 View Post


a) you have no idea what you're talking about- +1 absolutely

Cheers
Wasnt necessary, yaar.
like he said, he just got on the road.

Quote:
Originally Posted by vina View Post
My Figo moves without pressing the accelerator, but that is on a flat surface, on a similar incline, when I release the clutch a little (and it starts slipping) I have to press the pedal, or the rpm falls and it stalls.
Ideally, for a consumer segment diesel, the driving dynamics should not be hard.
do you face a problem when doing inclines?
I drove a TDCi fiesta once, but there was hardly any problem, except for the "pull" difference in the petrol.....

and with such tight tolerances in manufacturing processes nowadays, run in has become a partial myth(partial).

add:even petrols will stall if you remove your foot slow off the clutch.
try it.you'll sometimes see it drop to as low as 3-400 rpm.

Last edited by mayankk : 9th May 2011 at 21:46.
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Old 9th May 2011, 23:30   #188
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Default Re: Torque vs BHP?

Quote:
Originally Posted by vina View Post
It may be (a) - my experience, as I have already written, is on a WagonR from the driving school. And as you pointed out, that may not be an ideal vehicle to form an opinion on.

Why would it be trolling? Do you think I have been rude to anybody?

Trolling is not just being rude to someone, but also refers to making baseless comments to deliberately provoke heated arguments The reason why I mentioned that is because the whole petrol v. diesel thing has been beaten to death several times and I don't want to get drawn into an argument and I also hate repeating myself over and over.

I'm not trying to insult you when I say there seems to be something seriously wrong with your driving style. Even my ancient Indica Turbo requires a deliberate effort to stall it out and the Figo has the best low end response among the diesel hatches.
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Old 10th May 2011, 00:09   #189
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Default Re: Torque vs BHP?

@Vina - If you know anyone owning a Palio 1.9D (unfortunately they don't make it anymore), take it out for a spin and try this:
Slot it into 3rd and start from a standstill. You would be surprised how easily the car begins to roll!! Now that is brute power of a diesel engine for a mid-sized car. I have never tried the Cruze, but people tell me its very similar. I am quite sure you will see diesel in a new point of view from then on.
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Old 10th May 2011, 11:39   #190
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Default Re: Torque vs BHP?

Everybody please take this in the right spirit.
But please stop lugging* and damaging your engines.

* Lugging, when an internal combustion engine is run at overly low RPMs for the load being applied to it, potentially damaging the engine in the process.
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Old 10th May 2011, 20:32   #191
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Default Re: Torque vs BHP?

Quote:
Originally Posted by vina View Post
this is for Figo (source: http://www.autocarindia.com/roadtest/ford-figo):

1st3.58/7.00, 3.58/7.792nd
1.93/12.99, 1.93/14.45 3rd
1.28/19.58, 1.28/21.79 4th
0.95/26.39, 0.95/29.365th
0.76/32.99, 0.76/36.70Final drive ratio
4.25:1, 3.82:1
If you see, the overall difference between the two gear ratios in about 20%, while the difference in torques is 40%. This means diesel will still retain 20% more torque on the wheels - though at stall speeds there will be almost no torque in diesel whereas petrol will still have some.

By the way, other cars have even less difference than the above for example Maruti swift (data taken from IndiaMART: Page not found
Vina Very interesting gearing for two vehicles with similar power. The petrol vehicle has quite tall gearing for its engine power and rpm (may be for better mileage) and the diesel looks under-geared for its power and rpm( I am not sure why may be to counter the turbo lag).
This is my experience and opinion others need not agree, and no I am not Trolling.
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Old 10th May 2011, 21:57   #192
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Default Re: Torque vs BHP?

Hi,
Does the petrol and diesel Figo have similar top speeds? In the same gear? And what is the corresponding rpm?

Regards
Sutripta
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Old 11th May 2011, 00:58   #193
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Default Re: Torque vs BHP?

Quote:
Originally Posted by Sutripta View Post
Hi,
Does the petrol and diesel Figo have similar top speeds? In the same gear? And what is the corresponding rpm?

Regards
Sutripta
From the gearing it looks like the petrol will have a higher top speed which can be achieved in forth gear as fifth is too tall and diesel will most likely have a lower top speed than petrol achieved in fifth gear. Can somebody please confirm my predictions as I have a thing for top speeds
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Old 22nd October 2011, 19:28   #194
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Default Torque and Horse Power

There have been a lot of discussion on torque and power, low end torque, high end torque and peak horse power of our vehicles. I feel that this is an appropriate time to have a separate thread to discuss these issues from a technical point of view.

I can think of the following point. Please feel free to add to the discussion

. Torque curves of various engines
. Tuning and engine (or ECU remapping) and how it modifies the torque curve
. Low end torque (or lack of it) in some engines

The net is full of information (and misinformation). Let those of us who are technically knowledgeable find references to increase the knowledge base of the forum members.

HP and Torque. Analyzing power curves. - Team Integra Forums - Team Integra
This article has an interesting paragraph, which partially explains why peaked torque give bad drivability
"The car making the "most horsepower" actually is making the least power over it's powerband, even less than stock. In a driving competition the 160whp GS-R will have trouble keeping up with the stock GS-R whenever it can't stay in it's narrow powerband.

Peak power numbers mean little in how much total power the engine is making but for some reason seem to offer the most bragging rights. I have wondered why dynos don't display the average horsepower or area under the curve when it's something that could easily be calculated. I'm guessing because then nobody could trick customers into making them happy with big peak numbers but weak powerbands."

or
"Size Matters
Engine torque is primarily determined by the percentage of cylinder fill (volumetric efficiency) and displacement. The greater the cylinder fill, the greater the torque will be. To increase power, it is important to improve the engine's ability to breathe. Peak torque is reached when the engine runs out of air or loses its ability to breathe better. And that is the point of maximum cylinder fill. An engine will continue to make more horsepower even when torque is falling as long as rpm increases faster than torque falls. If maximum torque is the point of maximum cylinder fill, then maximum horsepower is the point where torque begins falling off faster than rpm increases.
[COLOR=#000000]
Read more: Horsepower Vs. Torque - Hot Bike Baggers Magazine"
[/COLOR]

Some more
Corvette Action Center | Tech Center | Horsepower vs. Torque
Volumetric Efficiency (and the REAL factor: MASS AIRFLOW), by EPI Inc.
Sport Compact Car Magazine: Technobabble: August 2001
Mazda Miata Performance Handbook - Norman Garrett - Google Books

I will keep on adding material as and when time permits

Note from Team-Bhp Support - Kindly search the forum before creating a new thread.

Last edited by Amartya : 22nd October 2011 at 22:05. Reason: Please make an effort to search existing threads before creating a new one.
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Old 10th October 2012, 00:38   #195
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Default An interesting article on Torque and Horse power

The confusing terms unveiled(Torque and horse power) - please see the below link,

http://www.4x4abc.com/jeep101/torque.html

Thanks
Prabhu

Last edited by Prabhu : 10th October 2012 at 00:40.
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