Back from my annual Nurburgring trip

[DivineE]

ORIGINAL: edh
I don't think power to weight is so important over 100mph - look at how Caterhams struggle at those speeds unless they have very powerful engines. I believe it's more about absolute power - and that drag rather than weight is your biggest factor.

I'd love to do some serious testing on this one day. I've always felt exactly the same as this but I can't see how it makes any real sense. Mathematically even though drag is the biggest issue at high speed you should still have the same power to drive your mass in a little light car than a heavy one with more power but the same power to weight ratio?

Maybe what we're feeling is torque as bigger heavier engines tend to have more than a car where weight is the most important factor.

We once raced a Pulsar GTi-R which had been dyno'd at 400hp against the 300zx that my friend dyno'd at 380hp at the Titanic 944 rolling road day and the Pulsar was easily as quick up to about 100mph and then just seemed to start running out of breath while the big 300z just kept going and going. It wasn't even a race by 120+ and the Nissan was about 500kg heavier.

 

[944s222]

Nice one thanks for info ......Andy

 

[edh]

Power / torque is the same thing really - power expresses the rate at which you are applying the torque. Diesels have high peak torque, but at low revs so don't always make much power, whereas a car with lower peak torque but delivered at much higher revs can make more power (most racing cars).

http://www.epi-eng.com/piston_engine_technology/power_and_torque.htm

Here's a quote from wikipedia on Drag

http://en.wikipedia.org/wiki/Drag_%28physics%29

"Note that the power needed to push an object through a fluid increases as the cube of the velocity. A car cruising on a highway at 50 mph (80 km/h) may require only 10 horsepower (7.5 kW) to overcome air drag, but that same car at 100 mph (160 km/h) requires 80 hp (60 kW)."

Did you see the Mclaren F1 vs Veyron on top gear? the F1 was quicker at low speeds (power/weight) but at higher speeds the veyron was accelerating much faster as it has ~ 400hp more. Gearing also plays a part, but I think the veyron is geared for a higher top speed as well.

QED

ORIGINAL: DivineE

ORIGINAL: edh
I don't think power to weight is so important over 100mph - look at how Caterhams struggle at those speeds unless they have very powerful engines. I believe it's more about absolute power - and that drag rather than weight is your biggest factor.

I'd love to do some serious testing on this one day. I've always felt exactly the same as this but I can't see how it makes any real sense. Mathematically even though drag is the biggest issue at high speed you should still have the same power to drive your mass in a little light car than a heavy one with more power but the same power to weight ratio?

Maybe what we're feeling is torque as bigger heavier engines tend to have more than a car where weight is the most important factor.

We once raced a Pulsar GTi-R which had been dyno'd at 400hp against the 300zx that my friend dyno'd at 380hp at the Titanic 944 rolling road day and the Pulsar was easily as quick up to about 100mph and then just seemed to start running out of breath while the big 300z just kept going and going. It wasn't even a race by 120+ and the Nissan was about 500kg heavier.

 

[Hilux]

I don't think power to weight is so important over 100mph - look at how Caterhams struggle at those speeds unless they have very powerful engines. I believe it's more about absolute power - and that drag rather than weight is your biggest factor.

I know what you mean. I had a Westfield which was phenominally fast (up to three figures) and then hit an aerodynamic brick wall.

On the other hand my Golf had a simple 90bhp engine and when lightened went off the clock easily (long legged final drive/5th gear) and soon, touch wood, will be on the road with 170 plus bhp/tonne

 

[zcacogp]

Interesting one, about acceleration above 100mph.

F=MA, but drag will mean that a certain F will need to be applied merely to maintain a given velocity. And, as velocity increases, the F needed to maintain that velocity goes up with the cube of the velocity. This will mean that the F available to provide acceleration will drop off rapidly with speed.

Remembering also the kinematics that says P=MAV (power = mass x acceleration x velocity), suggests that as velocity increases, for a given power the acceleration will drop off significantly due to the higher speed.

So, two factors working against you when you try to accelerate at high speed. Both power-related.

Which suggests that the amount of power you have at your disposal is a significantly bigger factor than weight when it comes to achieving big speeds.

(Note: this is all theoretical. And I never drive at more than 70mph anyway. [])


Oli.

 

[barks944]

P=MAV becomes P=M(A-Drag)V, and in our atmosphere drag increases exponentially with velocity. So not only do you need more power to maintain your acceleration at increasing speeds as P=MAV suggests you also need more and more power to overcome drag.

 

[zcacogp]

ORIGINAL: barks944

P=MAV becomes P=M(A-Drag)V, and in our atmosphere drag increases exponentially with velocity. So not only do you need more power to maintain your acceleration at increasing speeds as P=MAV suggests you also need more and more power to overcome drag.

... which is what I said. Only you said it much more clearly - thanks! []


Oli.

 

[barks944]

You did say that didn't you. Should read more carefully before I hit the reply button!

How are the caterhams geared? Do they have 4 close gears for rapid 0-100 and then one high 5th gear for cruising?

 

[zcacogp]

I *think* they are simply a stack of low gears. Caterhams aren't intended to be speed machines; they are about acceleration and handling. I'd expect the engine is revving at a good couple of tho' RPM at 70mph.


Oli.

 

[Hilux]

I dont do sums/physics very well...............[&:]

In Catering vans and Westy`s you need at least 250bhp to head towards 150mph despite their lightness.

The `busa BEC`s are really rapid though.

 

[edh]

I'm really looking forward to a pax lap in a mate's Westfield GT sometime - he sprints it with a 400hp John Eales v8 []

Last year I had some laps at a greasy Oulton Park in November, on cold slicks [] - I don't think he made much use of full throttle...

 

[Hilux]

I had a John Eales V8 in my G27 (hoop stays/brace not yet fitted - taken just before I rolled it) A mental car - sorely missed.

 

[333pg333]

Great trip and pics. Much jealousy from Down Under. [&:]

Any video?

 

[sulzeruk]

A group of us had been going to the Ring for a few years. It has certainly got a lot busier, no thanks to Mr Clarkson unfortuantely. We found it was just far too busy now especially on Touristenfahrten days, best time was at 8am when the track opened or at 6pm when it was closing. Any time in between, just much queueing and lots of track closures. Have seen 3 fatal accidents there, 2 bikes and 1 car. Not very pleasant at all. It is an amazing place, sunshine on 1 bit of track and peeing down at the other side. It is also rather chingy for a lap too. Your car will also drink the juice as well. One of the guys with a Diablo filled the tank 3 times (100 litre) in 1 day, we worked out the average at 2.5 MPG!
With regards to most vehicles with proper German plates, Mk 3 Golf VR6s and E36 BMWs, don't try to keep up with them. We got completley done over by 2 very nice looking women in a Mk1 Golf with crazy camber on the back wheels. It looked like a bog stock Mk1 driver in brown but left my Turbo on outright power away from the barriers. Last I saw of it! Also, a mate in a 996 911 C4S got trouced by a guy with his kids in the back of a 328 BMW who certainly knew how to handle a car. What laughes we had at him!!!! Will have to dig out some pictures.
Alasdair

 

[edh]

ORIGINAL: sulzeruk

A group of us had been going to the Ring for a few years. It has certainly got a lot busier, no thanks to Mr Clarkson unfortuantely. We found it was just far too busy now especially on Touristenfahrten days, best time was at 8am when the track opened or at 6pm when it was closing. Any time in between, just much queueing and lots of track closures. Have seen 3 fatal accidents there, 2 bikes and 1 car. Not very pleasant at all. It is an amazing place, sunshine on 1 bit of track and peeing down at the other side. It is also rather chingy for a lap too. Your car will also drink the juice as well. One of the guys with a Diablo filled the tank 3 times (100 litre) in 1 day, we worked out the average at 2.5 MPG!

This year was much quieter than last year - over the whole weekend there was never a queue to get on the circuit, and relatively few closures. I believe last weekend was busier - so maybe avoid UK bank holiday weekends? the new circuit owners are trying to have it open much more often. It seems to be open most weekday evenings, and sometimes afternoons. Weekend openings are 8-7.30. I agree that early & late are the best time for clear laps, but I only had 1 lap over the whole weekend where there was too much traffic. I just backed off for a mile or so to give myself some room & to let the queue sort itself out, then it was OK

As far as costs go, I think it's comparable to UK track time - €250 for 15 laps ~200 miles, which is a lot of laps of a UK track! Fuel consumption is similar - the Honda was doing just over 4½ litres per lap, so roughly 13mpg, which is probably 2x what I'd get from a 944 turbo.

There are some idiots certainly - and Clarkson's 10min lap is a target for them. I gave one lad a pax lap - he was a Honda enthusiast and for some reason got very excited about my car. as we set off, I had to tell him not to film it on his iphone and that no, I didn't want to time my lap... [8|] Coming down out of wehrseifen towards breidscheid he pointed out a mate in a 535d up ahead. I passed him coming out of Bergwerk, but had to slow right down for yellows at the Karussel, at which point he decided to overtake me at the scene of the incident! I followed him through hohe acht, wipperman etc.. as he tried his best to stay ahead/crash /take me off as well. There was no way I was going to get close to him to try & get past, & he certainly wasn't lifting to let me through. The only thing to do is back off & let him go, followed by a few choice words...[]

No video I'm afraid Patrick - they are officially banned, but I'm thinking about getting hold of one of those little mini DV camcorders off ebay - the vids are surprisingly good.

 

[wayner007]

Thanks EDH for all advice learning more about the ring everyday and agree the 10min thing is pretty well known but for me now I just want to have a go around not set the timing screens alight but just to have go and say i've done it. Go like a loon and the law of averages will get you one day, or you'll get your lights punched out when your back if you make it.
Slightly off on a tangent but tried following a UK go kart champ around the track and did well for around half a lap until I span it at full speed when I ran out of talent and he just carried on and lapped me a little later for the second or third time.