No small torque.

[Ixion]

Bike A: a ROAD bike with 100hp and 50 ft lbs (just pretend numbers for eg)

Bike B: 160 hp and 50 ft lbs

I'm taking the bike A every time.

I know where bike B develops that power and at what speed and know I won't be using it long. It turns to a whole mess of red and blue.

Torque is much better.

On that basis, you want a side valve.

[Big Dave]

On that basis, you want a side valve.

I don't want to go to 1935 to get it!

[Ixion]

Side valve bikes is still being made. Trade in the Triumph.

[madandy]

If you re-read it you'll see I didn't miss it at all. I just pointed out that it wasn't a racebike, and the reason for me doing so, was that when we start talking perfomance figures we'll inevitably edge towards racing as well.



Pardon the technobabble - ignore the following unless you appreciate such things, please.

Define k as the constant that makes the following equation

P = T*R/k

specify the relationship between power, P, torque, T, and angular frequency, R - for a given set of units. Then the following is true:

dP/dR = T/k

Choose your units so k = 1 and torque is indeed the derivative of power with regards to engine speed.

Would you not agree?


And the diesel golf vs. the petrol golf is irrelevant... VWs are crap!

Used a Dyno? They measure torque. I don't understand that stuff you wrote above...I just think you're trying to be too clever now.

Reading back a page or so you techno guys started this whole thing! us luddites were simply enjoying some solid torque about a preferred riding style and engine type. We know what power is all about

PS: quatify the VW's are crap statement....it makes less sense to dismiss the fact that a diesel beat a petrol in a fair fight just because they are VW's than anything us dumb cunts have stated.

[jrandom]

Bike A: a ROAD bike with 100hp and 50 ft lbs

Or you could pick a GSX1400 - 100hp and 88 ft lbs.

[Big Dave]

and a big fat arse. :-P I like skinny bikes. With Torque.

[Mikkel]

Used a Dyno? They measure torque. I don't understand that stuff you wrote above...I just think you're trying to be too clever now.

As I wrote, that was technobabble about a specific point - no attempts to be clever at all.

I haven't studied dynos much - just read this page right now (pretty interesting IMHO). And I can see what you mean that the dyno measures the torque. However, you need to measure the engine speed as well - and thus the power is given.

However, it is important to note that the purpose of a dyno is not to quantify the torque - it is to quantify the power output. I think that alone is a valid argument!

PS: quatify the VW's are crap statement....it makes less sense to dismiss the fact that a diesel beat a petrol in a fair fight just because they are VW's than anything us dumb cunts have stated.

Nah, I was stating my personal opinion there. I couldn't care less if a diesel or a petrol golf was faster... since I'd never own one.
But you say the fight was fair - in order to refute that claim I would have to know quite a bit more about how the test was made. A scooter will beat a ferrari in an urban environment - it doesn't make the scooter faster than a ferrari though. And yes, I am aware that these two cars are very much more similar than that - but if the test favoured the strengths of one over the other by only a tiny margin then that would make a difference. Personally I would expect that the diesel would be better in most situations, but slightly slower on a track - but I'd have to see the power curves before I'd put money either way.

[madandy]

As I wrote, that was technobabble about a specific point - no attempts to be clever at all.

I haven't studied dynos much - just read this page right now (pretty interesting IMHO). And I can see what you mean that the dyno measures the torque. However, you need to measure the engine speed as well - and thus the power is given.

However, it is important to note that the purpose of a dyno is not to quantify the torque - it is to quantify the power output. I think that alone is a valid argument!

The race engine builders and all the 'tuners' I know use dynos to tune their engines...They don not focus on the peak HP figure. They tune to create the best possible torque curve. Their cylinder heads breathe well, which leads to good hp but they focus on strong torque as peaky engines tend to suck on race circuits and on gravel. And they win.
The people that focus on peak HP on a dyno are commonly known withinh the performance engine building industry as 'Dyno Queens'

Look I'm not saying the numbers are wrong but theory seldom works in the real world where people have to be taken into account.

[madandy]

As for the Golfs. The accelleration testing was conducted at Oran park race track. And on a Drag strip, against proper timing equipment.
Interestingly the FSI has 83kw/tonne v's 76kw/tonne for the TDI.
All the previous discussion has been about straightline accelleration. Take some bends into account and it becomes so variable doesn't it. The heavier nose of the diesel would, I expect handicap the TDI around bends, eventually overheating the front tyres and handing victory to the slightly better handling FSI - then suspension tuning & all that comes into it. 0-140km/h took 18.7sec in the FSI and 15.9 in the TDI.

I've had a lot of cars, some good some very good and some crap. I'll let you know what I think of the MK4 GTi when mine arrives in a few weeks

[Mikkel]

The race engine builders and all the 'tuners' I know use dynos to tune their engines...They don not focus on the peak HP figure. They tune to create the best possible torque curve. Their cylinder heads breathe well, which leads to good hp but they focus on strong torque as peaky engines tend to suck on race circuits and on gravel. And they win.
The people that focus on peak HP on a dyno are commonly known withinh the performance engine building industry as 'Dyno Queens'

Look I'm not saying the numbers are wrong but theory seldom works in the real world where people have to be taken into account.

I don't dispute that optimising your torque will give you a better engine for racing. But you're optimising it to provide the optimal power delivery - and by that I don't mean the highest peak power but instead a nice and predictable power-band that matches your gearing, setup, riding style, etc.

I already stated in an earlier post that peak-power doesn't make for a nice ride if the peak is too narrow. On the other hand - loosing power by tuning your engine to have a power-band wider than what is optimal for your gear box is equally wasteful (for racing - it's nice for the road I'm sure).

I'm not arguing for numbers or anything like that. I'm not trying to drag this down into technobabble. All I am saying is that arguments like 'torque is what makes the bike go fast', 'torque is all that matters', 'torque is what puts a grin on your face', etc ad nauseum are turning things on their head and, to me, appears as an obstacle preventing people from understanding how stuff actually works. It's reverse causality so to speak - no different than saying gravity exists because things fall down.

[Mikkel]

As for the Golfs. The accelleration testing was conducted at Oran park race track. And on a Drag strip, against proper timing equipment.
Interestingly the FSI has 83kw/tonne v's 76kw/tonne for the TDI.
All the previous discussion has been about straightline accelleration. Take some bends into account and it becomes so variable doesn't it. The heavier nose of the diesel would, I expect handicap the TDI around bends, eventually overheating the front tyres and handing victory to the slightly better handling FSI - then suspension tuning & all that comes into it. 0-140km/h took 18.7sec in the FSI and 15.9 in the TDI.

Interesting. I'm wondering what the top speed of these cars are. How about the 100-180 km/h segment and such?

Most family cars, being designed with fuel efficiency as a prime concern, will have a gearing that favours cruising (i.e. too tall). As such the diesel would have an advantage as it, most likely, develops more torque earlier.

I've had a lot of cars, some good some very good and some crap. I'll let you know what I think of the MK4 GTi when mine arrives in a few weeks

Aw mate, I feel so sorry for ya! Hopefully they've sorted out the suspension since the late 80s - otherwise you'll be stuck with something that goes around corners like an overladen shopping trolley

I reckon the GTi should be interesting enough - they have supposedly sorted it out and returned to some of the virtues they forgot about with the Mk3s. My main beef with VW is that I find them too expensive compared to what you get - I'd go BMW or Audi if I was thinking about buying a german car and couldn't afford a Porshe They are however german quality and are not likely to disappoint.

[Crasherfromwayback]

Bullshit - otherwise you'd see turbo-diesel engines dominate the racing scene... Not only are they more torquey - they are more fuel efficient as well.

Balls and skills are what wins motorsport races - if those two are about equal between competitors, such as is the case for international professional, then the vehicle becomes important.

Not bullshit. I stated torque wins races. It does. Fact.

As I wrote, that was technobabble about a specific point - no attempts to be clever at all.

I haven't studied dynos much - just read this page right now (pretty interesting IMHO). And I can see what you mean that the dyno measures the torque. However, you need to measure the engine speed as well - and thus the power is given.

However, it is important to note that the purpose of a dyno is not to quantify the torque - it is to quantify the power output. I think that alone is a valid argument!

Any race tuner worth his bladder weight is looking for torque, not peak HP.

We have one of the best dynos in the Southern Hemisphere, and we never chase peak HP numbers.

Nah, I was stating my personal opinion there. I couldn't care less if a diesel or a petrol golf was faster... since I'd never own one.
But you say the fight was fair - in order to refute that claim I would have to know quite a bit more about how the test was made. A scooter will beat a ferrari in an urban environment - it doesn't make the scooter faster than a ferrari though. And yes, I am aware that these two cars are very much more similar than that - but if the test favoured the strengths of one over the other by only a tiny margin then that would make a difference. Personally I would expect that the diesel would be better in most situations, but slightly slower on a track - but I'd have to see the power curves before I'd put money either way.

I don't dispute that optimising your torque will give you a better engine for racing.

Yes you did. And you're wrong. Full of shit in fact. All talk. No torque.

[Big Dave]

keep it polite you wankers.

[Mikkel]

Not bullshit. I stated torque wins races. It does. Fact

Yes you did. And you're wrong. Full of shit in fact. All talk. No torque.

I'm so glad we had this debate. You have given me so much to think about.

[Big Dave]

It's a BD thread - SPAAAAARTAAA