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[Webby the Bear]

good stuff lads. so Michelin PS 2 or 3 

[BazaJT]

Anyone offering odds on how many pages this "laid to rest" thread will run to before it actually is laid to rest?

[Webby the Bear]

Anyone offering odds on how many pages this "laid to rest" thread will run to before it actually is laid to rest?

Well, we have around 3 months 'til the next RWYB so that's ample time to get to over 100 pages imo 

[T.m.f]

Do we know what brand of petrol was also used 

[Nick W]

The thing to do is to match the tyres they had on the day of testing. . . So get searching for me 

Whatever next, ensuring that your hairstyle and attire match the original roadtester's?

[Diamond Black Geezer]

Do we know what brand of petrol was also used 

Fair point - Vauxhall, presumably, wouldn't have used higher octane, as it didn't exist (or did it?)

[Diamond Black Geezer]

The thing to do is to match the tyres they had on the day of testing. . . So get searching for me 

Whatever next, ensuring that your hairstyle and attire match the original roadtester's?

I assume Mr The Bear was completely nude for the test, possibly even had a 'trim' beforehand for extra weight-saving. 

[Diamond Black Geezer]

If we look here... just a direct comparison for the saloon and estate omegas, show a half-second difference in 0-60 times, for a 38kg weight penalty. Just shows what a 'few' stone can do if you're really trying to squeeze the tenths of a second out... and also how an empty tank, nowt in the boot and a skinny driver can falsely give a better result.

That's why I always only ever have about 5 litres in my fuel tank, anyway! 

[Marks DTM Calib]

Although the estate also has an aero penalty as a well as a weight one (weight is key at launch but, as speed increases aero quickly takes over)

[Diamond Black Geezer]

Indeed  if I remember my aero lectures, as speed doubles air resistance increases 4-fold, which surprises a lot of people.

However, any appreciable aero resistance only really starts to kick in around 50mph plus, so hopefully any aero penalty is only a relatively smaller amount, as on a 0-60 test you are just 'scraping the bottom' of the 'aero penalty zone'.

If, for instance, there's 5 kg of air pushing on a car doing 30 mph, that's (I think!) turned into 60kg at 90mph. So Mark's right, aero plays a big part.

Just in case Webby Schumacher is wondering about starting up a 'what's my top speed' thread... we got taught that - contrary to popular belief -  something like a 4 ton block in the boot of a car will affect the top speed by about 1mph, that's it. It will take a lonnng time to get there, of course, but the real gains in improving a car's top speed is to be found in the aero side. Bugatti Supersport is a perfect example. All that fancy malarky with closed-off rear window, NACA ducts etc isn't poncy styling, it's vital to get the top speed up by a mere 10mph/or whatever is it, over standard Veyron. 

[Marks DTM Calib]

Key issue with the estate is the turbulent air at the rear which increases the drag, given the shape I suspect drag will kick in quite a bit below 50mph 

[Diamond Black Geezer]

Hear what you're saying, you're right, of course; but there's turbulent air coming off the back of any moving vehicle. Best figures I can find is Omega saloons at 0.29Cd, the estate 0.32Cd, (though something tells me those figures aren't quite right  )

So roughly there's 10% difference between the saloon and estate versions in Cd, with the effective air pressure/force acting on the front quadrupling with every doubling in speed. Or, if there's that theoretical 5kgs at 30mph, which would be 5.5kg on the estate, that's 66 kg at 90mph, or 4kg at 60mph. Or an effective, theoretical 3kg extra 'weight'/force at 50mph.

Not disagreeing with you, because, of course air resistance is acting on moving objects all the time, otherwise the famous demonstration of dropping a hammer and a feather on the moon wouldn't have gone the way physics professors said/knew it would. Definitely, weight affects acceleration at lower speeds, aero at higher. I'm just going by my old Aero Engineer / Lecturer's feelings at what speed air resistance starts to become 'substantial' but of course one person's idea of 'substantial' vs another's can vary massively, it's opinion. Like I say, can't say you're wrong, as it's a grey area, there is no black and white line where air resistance doesn't affect things. (well, being stationary, I suppose, haha!)

Don't know if the saloons and estates had different diffs to counteract things, but the top speed difference is only between 2 and 4% between saloons and estate, too. 

[Webby the Bear]

The thing to do is to match the tyres they had on the day of testing. . . So get searching for me 

Whatever next, ensuring that your hairstyle and attire match the original roadtester's?

lol while that is amusing, I don't think matching tyres is being particularly pedantic /anal........ after all, they are the things that connect us to the road and are important.....plus I've only ever driven on budget ditchfinders.......fancy a decent set 

[Webby the Bear]

....and high octane fuel wasn't used in original testing as you rightly estimated DBG 

[Webby the Bear]

PPS, just a reminder that for testing purposes originally....it matters not whether you have a full tank, half a tank whatever.....as long as it has 200kg over kerb weight.

example...

if you race on half a tank of fuel (roughly 25kg) then you only have to find another 175kg. your body weight will be one factor.... then whatever you can chuck in to make the weight up