Have you checked the website I quoted? They have measured many cars both on dyno and also timed them @ various speeds. Also they have measured the weight of the cars.. If you rely on factory specs you're just guessing as much because the weight of the car will always be different depending on equipment, amount of doors etc. Usually announced weight is with minimum equipment possible. But if you believe the car you bought will produce exactly the figure the factory claims go ahead. Not saying it's not possible as many cars do give pretty much the same power as claimed, but also some give less and some more

Have you checked the website I quoted? They have measured many cars both on dyno and also timed them @ various speeds. Also they have measured the weight of the cars.. If you rely on factory specs you're just guessing as much because the weight of the car will always be different depending on equipment, amount of doors etc. Usually announced weight is with minimum equipment possible. But if you believe the car you bought will produce exactly the figure the factory claims go ahead. Not saying it's not possible as many cars do give pretty much the same power as claimed, but also some give less and some more

I checked the website, but my spanish isn't up to much! They measured the car on a rolling road? Skoda measure the engine on a bench dyno. Which is more accurate? Factors which affect the rolling road include tyre slip, different tyre pressures, transmission losses (which have to be calculated and not measured), etc, etc.

I never said the cars come out of the factory spot on the power, but I find it hard to believe that they all come out with 10% more than the company benchmark - 1 or 2 bhp either way I could understand. The point you make about weight is an interesting one - is your car the same weight as the one Skoda benchmarked for the 0-62mph run? I have no idea how they reached that figure - did they have passengers, a full tank of fuel? I suspect they had good quality timing gear though

If you want to believe the car you bought produces more than the factory claims, then go ahead But without a bench dyno of the engine you will never get an accurate figure for it..... Me, I'm happy to believe mine is 130bhp ... why should I doubt it?

Chris

Of course power measurement from wheels is not 100% accurate, you can however draw conclusions from other facts also. Weight and timings serve as good guideline IMO.. From what I know car magazines usually have quite accurate devices for measuring speed.

Not sure what you mean by that remark about weight though, I have vw polo 2005 older model before facelift. Fabia weights almost 100kg more and factory quotes 14.4sec 0-62, the spanish magazine got over a second faster time. Audi a2 that weights nearly the same as my car got 12.5 sec time, 80-120 timings are also pretty much spot on with my experiences.. They also have figures for polo 1.4 tdi but they are overly optimistic (hair under 12sec 0-62).. I believe the figures got mixed as they are the same as in older article of 6n polo with the same engine but the car weights even less than the current one thanks to smaller chassis.

btw, I'm not gaining anything from this debate as my car is still slower than most cars when driven hard and the 0-62 in 12.5 sec is still not anywhere near fast even though it's faster than factory claims.. it's still reasonable performance and certainly feels faster than the promised output - also partially thanks to effective gearing.. I've also owned a lot faster cars, my last car was peugeot 406 turbo that got 190bhp and over 300nm torque with modified boost. Anyway I'm still impressed with this new little machine as it gives me plenty of performance for everyday driving. Just trying to give food for thought about claimed performance figures that's all..

Torque probably helps overcome weight to a degree - hence why they are good at towing, so the heavy weight of the TDI / vRS is somewhat overcome by the huge torque, and so explains why their 0-60 slightly exceeds what you'd get in an equivalent petrol powered car. For example the 100 bhp TDI is faster than the 100 bhp 16v Petrol model despite being slightly heavier.

Torque probably helps overcome weight to a degree - hence why they are good at towing, so the heavy weight of the TDI / vRS is somewhat overcome by the huge torque, and so explains why their 0-60 slightly exceeds what you'd get in an equivalent petrol powered car. For example the 100 bhp TDI is faster than the 100 bhp 16v Petrol model despite being slightly heavier.

Dude, factory quotes say that both those models you mentioned have the same performance. 11.5 seconds to hundred, 185kmph top speed. It doesn't make sense the diesel would be faster with the same power. The torque however is immensely different, for the sole fact that the diesel engine is pretty much heavier than the petrol engine.

A petrol NA car does not feel as fast as a TDi at all, but it can be as fast. Like I've said before, the Ibiza GT I was in was a 90bhp TDi model, but it felt bloody fast because of the torque it had, and tested it performed about 11.5 seconds to 100.

The torque has nothing to do with the power, and the torque is not what determines the acceleration times. If you tell a professional mechanic that he will laugh, because it's happened to me. In FACT, another thing I've been told is that increasing torque usually brings down horsepower. Why so I'm not clear on, but this is information from a professional.

The immense torque on diesels enable it to tow heavy loads. That initial 'pull' is there, which is not available in weakly torqued petrols.

I have a diesel pick up in my homeland, which is extremely slow because of it's weak weak power. However it has alot of torque, hence we can load upto 2 tons onto it and go pretty much the same way we could without a load. HOWEVER, overtaking with it is never easy, because of the lack of power. It's the POWER that makes it easy to overtake, and with that little oomph of torque, makes it feel like it's doing a great job of it (I'm not saying it doesn't, but you get my drift).

Tonight I'm going to see what 1/4mile figures I can get with Jasmine

What is the average 1/4 mile time for a standard vRS?

Is that really true? Isn't torque just a turning force' date=' whereas the power of the engine determines how much the car will move? Otherwise wouldn't lorries be able to accelerate ridiculously fast?

Rob.[/quote']

Like said above, torque has nothing to do with the power of the car. It's like you say, how much the car will move at different engine speeds. If this was the case with torque determining acceleration, the Fabia vRS should be doing STi times of 4.6 seconds since it has that much of torque. However it doesn't, because it is only 130bhp.

A 2.0 is 115bhp standard, it is lighter, and it has half the torque of a vRS (170Nm is good torque for a small NA 2.0 btw), and it performs like the Fabia vRS (though it won't pull on 5th gear from 50 like a vRS would because of the longer gearing).

So you see, torque has nothing to do with power, and it isn't what determines the acceleration times.

Torque = Rotary Force.

The effect of more rotary force (via some complex sums) makes the mass of the accelerated body have less of an effect. Basically it means that power to weight ratio is only a useable guide where the torque of the engine is the same; ie it is not a fair benchmark for performance unless the engine used is the same.

Look at the R500 Caterham - 500bhp per tonne but no faster than some cars pulling 3/5 this figure.

torque has nothing to do with the power of the car.

Torque has everything to do with the power of the car.

Your BHP is calculated through the amount of effort your car can produce (torque) to turn the flywheel.

BHP is a measurement of power, which is directly produced from the effort your engine can give, which is measured in torque.

Horsepower = torque * revs/minute * 1/5252

This is also the reason why a higher-revving engine will have a high horsepower output, as the revs are used as a multiplier

High torque * high revs = lotsapower

And the higher range of RPM that you can use max torque in each gear is what makes one car accellerate faster than another.

Torque has everything to do with the power of the car.

Your BHP is calculated through the amount of effort your car can produce (torque) to turn the flywheel.

BHP is a measurement of power' date=' which is directly produced from the effort your engine can give, which is measured in torque.

[/font'] Horsepower = torque * revs/minute * 1/5252

Fine. Double check that with a professional mechanic who knows his stuff, and ask him if torque plays a big role with acceleration figures. Because as far as I know, it's minimal. If there is no power, torque won't matter. Like trucks. They maybe heavy, but they have huge amounts of torque and they don't fly.

Also, explain why a 2 litre has half the torque but performs the same as a standard Fabia vRS. Also explain why an Octavia vRS has much less torque than the Fabia vRS and is weak in performance compared to the Octavia vRS, or even a Pug 206RC.

Fine. Double check that with a professional mechanic who knows his stuff, and ask him if torque plays a big role with acceleration figures.

Torque comes into it because torque is proportional to power.

I get what you're saying though - just because something has a high peak-torque figure doesn't mean it will necessarily be fast, as the torque alone is not what causes a car to be fast.

The other important thing to consider when quoting figures is that these tend to be peaks...it's the "area under the graph" which is more telling...

Rob.

Fine. Double check that with a professional mechanic who knows his stuff, and ask him if torque plays a big role with acceleration figures. Because as far as I know, it's minimal. If there is no power, torque won't matter. Like trucks. They maybe heavy, but they have huge amounts of torque and they don't fly.

Because they have a very narrow rev band to use the torque they have, and the gearing is made for pulling power and not speed. Combined with the weight of the Truck.

Here is a link from my deep dark vaults that helped me understand the concept of torque in a motoring sense:

http://www.houseofthud.com/cartech/torqueversushorsepower.htm

and to quote a section on it regarding torque and BHP:

One interesting side note. It's possible for an engine or motor to make torque at 0 rpms.

A steam train engine' date=' for instance has a direct drive from pistons to wheels so when it needs to get moving it can actually generate some ungodly number like 10000 ft-lbs of torque at 0 rpms and thus by our formula HP = 1000 ft-lbs * 0 / 5252 = 0 hp. Cute eh?

Electric motors also can do this. That's why diesel train engines drive use electric motors to turn the wheels, and a big nearly constant rpm engine to power the generator that powers the motors. [/quote']

If a Steam Train engine has 0bhp how does it move if it can't accellerate?

If a Steam Train engine has 0bhp how does it move if it can't accellerate?

But if the engine is not turning over, how is it moving?

Rob.

it has a direct drive from pistons to wheels?

A bit of a cheat as an example, as there's no rotary output the formulae doesn't work.

To be honest I don't quite get that bit so well, I'm not an engine person. But it's clear that without torque accelleration would be slow. Without a high BHP torque alone will not produce quick accelleration.

From what I understand, a Petrol engine with the torque of a vRS would be much faster as it can use the Torque to accellerate through much more of the higher rev range (and a larger range it is). a vRS with the torque of the Petrol would be much slower as it only has a smaller rev range in which it would produce that torque and therefore be able to use it.

Mil,

Several VRS have recorded 137 bhp without modification.

May I ask the 2.0 torque figure, I think it's around 70 lb/ft less than the vrs?

John

N.B Let's not have a diesel/ petrol battle!

Second thoughts, let's

John

Dieselhead

Very interesting stuff Mort

Thanks for that...so then the vRS Fabia, because of the immense torque and low bhp figure, FEELS extremely fast, but it isn't and therefore fall in the 'torque to the ground' category?

This also explains why the vRS Fabia can pull pretty decently on 5th gear from 50mph.

This also explains why Formula 1 cars are so bloody fast considering the extremely high rev range and low torque figure.

Hmmm...

Hmmmm....interesting

Thanks for that.

One question about the formula though...do this calculation for me based on this torque figure of 125lb ft with a rev range of 6200rpm, and tell me the result.

125x6200/5252 = 148bhp @ 6200(rounded up)

Blindly calculating now with no idea what this is for.

Mil' date='

Several VRS have recorded 137 bhp without modification.

May I ask the 2.0 torque figure, I think it's around 70 lb/ft less than the vrs?

John

N.B Let's not have a diesel/ petrol battle!

Second thoughts, let's

John

Dieselhead[/quote']

John,

The 2.0 has 125lb ft (170Nm) and 115 bhp standard.

However, it can do a 0-60 run in 8.5 seconds, and run from 50 - 70 in 5.5 seconds on 3rd gear and can do 137mph tops, probably because it is light. Also, 125 lb ft, as I've said many times, is a very good torque figure for a petrol N/A 2.0. A Mini Cooper with the same power has only 110 lb ft of torque.

However, based on this whole torque tutorial I've just been given, I can understand why the vRS Fabia will pull from 50 - 70 on 5th gear with decent times. With a 2.0 on 5th, I can pull in 9 seconds, the vRS will do better than that. Then again, gearing plays a role here as the vRS has 6 gears, six short gears.

125x6200/5252 = 148bhp @ 6200(rounded up)

Blindly calculating now with no idea what this is for.

That's the figure I should be getting for my car, but I'm not.

There's where I'm a bit lost.

However, it can do a 0-60 run in 8.5 seconds, and run from 50 - 70 in 5.5 seconds on 3rd gear and can do 137mph tops, probably because it is light.

Light and Fabia in the same sentence?

so then the vRS Fabia, because of the immense torque and low bhp figure, FEELS extremely fast, but it isn't and therefore fall in the 'torque to the ground' category?

Regardless of how fast it is or not, dont you agree that a car that feels fast is more fun than a car that has the same performance but doesnt feel as fast? I think it keeps in spirit with the nature of the car - i'd be disappointed if it didnt at least feel fast

And if you want to feel fast, try driving an old banger like what I've got 70 mph feels fast in that thing

But whether you like to believe it or not, the feeling of speed isnt neccesarily a false one in the Fabia - it aint a slow car thats for sure

I never said it was slow or thought it was slow. I know it's fast, especially for a bloody diesel.

And yes...MY Fabia...1190 versus 1315?

Is there a site with the engine specs on the 2.0l Fabia anywhere?

Ah, but there is a big doubt about the accuracy of VAG's weight figures... this has been done to death, but the top and bottom is its fairly unlikely that it really weighs that much, its probably closer to 1250...

For example, on the Seat site it has the TDI Cupra down as being LIGHTER than the 1.8T, and that cant be true can it...

And 1200 kg whichever way you package it up certainly isn't light

Is there a site with the engine specs on the 2.0l Fabia anywhere?

On Skoda UK it has the peak figures:

Peak power: 115bhp @ 5400rpm

Peak torque: 125lbft @ 2400rpm

So doing any calculation at 6200rpm won't necessarily work...

Rob.