[vivek_pinkoo]

Originally Posted by turbo_lover

thanks for the info merve and shuvc


starting from the
suzuki's(all),accent ,santro,optra,NHC,OHC,Lancer ,corolla ,octy list is long...

palios , indicas ,corsas have hydraulic power steering ...

Sorry for the comment in between but let me correct u, Baleno and Esteem having HPS not EPS. Please note it down.

Kripaya afwayen na failayen.

[turbo_lover]

yah my bad ..
the baleno and the esteem have hydraulic assistance ..
thanks for pointing that out ..

[santosh.s]

Coming back to the main topic of the thread....the torque

Going by the saying "a picture is better than thousand words", here are a few interesting ones-

A torque curve can easily be scaled to the torque-per-tonne (since it is more relevant
in judging car performance), by dividing it with the kerb weight + the payload (which is
the drivers weight, at its minimum!). It will look something like this, very similar to the original curve-

http://us.f3.yahoofs.com/users/43493...JHUSDB17CcRdut

Then if you factor in the whole motion (and corresponding torque) scaling right from
the crank-shaft to tyres, it can be converted to torque per tonne "on the road" versus
"actual" car speed. Of course, the curve will be different for each gear and surely
will show much more about acceleration AND driveability of the car, comparable to
tonns of expert reviews. It should look something like this -

http://us.f3.yahoofs.com/users/43493...uHUSDBFEdUOgO2

It sounds like a bit too much of data crunching to come up with such curves for
various car specs.... agreed, but... well, it may not be so for curious & enthusiastic
BHPians out there!??

[santosh.s]

sorry for broken links.... I moved them to another site, here are the new links-

http://putfile.com/pic.php?pic=10/28200064254.gif&s=x10

http://putfile.com/pic.php?pic=10/28200070522.gif&s=x10

[raja_ys]

whts the diff between bhp and tourqe to a car and also max rpm and min rpm, how are these terms co related in a car's pick up or fe?

[Abhay]

plz search this forum for the bhp/torque question...there have been threads discussing it

min rpm is your idle rpm (when the cars sits in neutral and you are not pressing the accelerator)...max is the max rpm your engine can rev up to till your rpm limiter

pick up/Fe relation ? higher the rpm more fuel you burn and more power you produce.

[rzoster]

Originally Posted by Abhay

pick up/Fe relation ? higher the rpm more fuel you burn and more power you produce.

Is it the RPM that decides the FE? I feel its the product of torque and RPm (i.e., engine power) that decides how much fuel is consumed. Finally, energy has to be conserved, and hence any energy generated by burning fuel has to be passed on to the wheels.

[rzoster]

Originally Posted by raja_ys

i have heard that keeping a slight higher pressure than recommended increases mileage, if this is true does the power or tourque get affected by higher tyre pressure?

Neither get affected. What happens is that as the tyre pressure increases, the tyre contact area decreases, and so the friction decreases. This means that the car doesn't waste as much energy in countering the frictional forces, thus saving power. Of course, lower frictional force
means that the road grip will suffer.

[rejika]

Originally Posted by turbo_lover

thanks for the info merve and shuvc


starting from the
suzuki's(all),accent ,santro,optra,NHC,OHC,Lancer ,corolla ,octy list is long...

palios , indicas ,corsas have hydraulic power steering ...

Hi , I think the only c segment car that has EPS is NHC. In the above list except for suzuki's small cars and NHC , all other models come with HPS.

[santosh.s]

Originally Posted by rzoster

Is it the RPM that decides the FE? I feel its the product of torque and RPm (i.e., engine power) that decides how much fuel is consumed. Finally, energy has to be conserved, and hence any energy generated by burning fuel has to be passed on to the wheels.

I agree with you. A car moving uphill at a given rpm/speed will consume much more gas as compared to the same rpm and speed over a plain road. However, its a thumb-rule that for similar loading, efficiency generally drops towards high side of rpm range

my few cents below for more information...
some part of energy generated is lost in various ways as discussed earlier in the thread, so lesser the loss better will be the efficiency. Just wanted to add to the list of "losses"- heat from engine directly transferred to the environment (through cooling, exhaust etc) should also be included since its not useful.

Apart from that the efficiency of an engine also depends on how much fuel itself is wasted, if it is not burnt completely its simply thrown away. This can happen if carburator (MPFI now a days) doesn't do its job properly, resulting in wastage and sever hit on FE. Max energy that can be extracted from any fuel (upon complete combustion) is represented by its octane value, higher the octane more it is.

[santosh.s]

Originally Posted by Abhay

santosh, torque curves etc are generally there in the car manuals...so if you can grab hold of one from a friend etc....you can have a look (atleast there is a torque curve in my Indica manual so safe to assume others will have it)

I saw the manual of my neighbour's "josh machine".... though its 1.3L (flair, not 1.6L), it seems the manual is common to both since it includes information on both engines. But, unfortunately I coudn't find the curve I was searching for. Leaving that aside I didn't even see gear and axel ratio's either

Also browsed through websites of leading car manufacturers.... found torque curves only for baleno and wagonR. MUL proudly advertises them for being flat. My primary concern was to compare ikon-1.6, baleno, petra, lancer and lately fiesta.... and a few other under powered cars to see the nature/extent of difference !

all said and done, I have already booked baleno.... subject to a chance of cancellation (very remote, though)

[sbasak]

I wrote a discussion between power/torque/RPM on Mouthshut in petrol vs diesel engine topic.

The link is

http://www.mouthshut.com/review/Petr...r-85834-1.html

It may help you to understand the relationships.

[duncan]

Originally Posted by santosh.s

sorry for broken links.... I moved them to another site, here are the new links-

http://putfile.com/pic.php?pic=10/28200064254.gif&s=x10

http://putfile.com/pic.php?pic=10/28200070522.gif&s=x10

santosh buddy thats some nice data put in a very neat manner. . .

[santosh.s]

Originally Posted by duncan

santosh buddy thats some nice data put in a very neat manner. . .

thanks for the appreciation.... I posted those curves because I thought that would be an easy way to explain the idea of torqe/power/rpm and gearing. I came across many web-pages with in depth description of the concept, some even had numeric tables and illustrations, but found hardly any article complemented with such curves...

By the way, I did see some interesting specifications like "kmph/1000-rpm" which is nothing but the net effect of the whole drive chain and the wheel size. Saw it in latest issue of autocar india magazine (referred to as ACI here, I guess) which is the first ever auto magazie I have ever bought! just to get the fiesta update. But the problem is that it is given for a few bikes, tata-safari & an another SUV + some BMW/porsche cars.... these vehicles are either too low or too high profile for now (for me of course ) I don't know if kmph/rpm is directly taken from manufacturer's specs or compiled by mag. analysts from other specs?? anyway, I am now hopeful of getting those specs for other cars too, upon searching old issues (which is a tedious job!)

I think peak-torque, peak-power & kerb weight (which are standard in any spec sheet) coupled with the above one can give you pretty good idea of the performance in normal rpm range. torque curve should be, to a good approximation, a straight line between peak torque and power point. But, unfortunately its the response in low/high rpm band that differentiates baleno's and vtec's from other engines of similar size! It is analogous to music systems, where mid range response can be taken for granted, but you need those expensive speakers and amps to get really good distortion free bass & trebel...

[santosh.s]

I saw an another specification in autocar, which I do not understand. If I remember correctly it is called "specific power" and is expressed in "BHP/litre".... can somebody explain what it is