what would have more top speed??

[Blem]

Surely all it comes down to with any vehicle.
Drop it as low as it can go for the surface it will run on.
Front maybe 10-20mm lower to help suck the butt down.
Tape up all that you can while keeping intake airflow.
Use a decent front splitter even with add ons.
Add kw's & boom.
Hold on.
Corners are not an option...

[Express]

This top speed business isn’t as easy as some may think.

It was discussed in an earlier thread.

You can read about some of the inherent problems here.

http://www.fordforums.com.au/showthr...hn+bowe&page=7

[LyleXR8]

Best aero is to completely cover the grill right up and all the headlight and panel gaps so nothing is catching the wind, a deep spoiler or skirt to stop air going under the car to stop it acting like a wing eg flat bottom of a car, and the top of the cabin is pretty damn close to a wing shape making lift

[asagaai]

Originally Posted by malazn mafia

FG2 GT at 253 kph was like driving on rails, could hold straight and even take sweeping curves at that speed. Amazing what 20 more kph can do.

I can relate to this.

I have done 255 kph going round a sweeping tight-ish bend up a hill in an AMG C63 with sports power and suspension pack and felt solid.

Then did 270 plus up pushing into limiter in same vehicle on straight-and that extra speed felt a whole world of difference to me. Did not help that I was in the passenger seat for that second run, instead of being the driver which I was at 255kph....

So I can only imagine an extra 30kph on top of 270 in a sedan-need to have soft hands and be very calm inside and focused.

Interestingly I am working for a client who drove a Lamborgini Huracan at some 315 kph with his girlfriend beside him-and he said it felt fine -no issues with steering or floatiness or drift etc. And he is not some Ayron Senna- he had a black series C63 and lost it big time on a track day....

Difference between Lamborgini and Ford I suppose.

[Express]

If you check out some of the high speed competition runs they have in the US you'll find many high powered cars can't achieve high speeds because they become too unstable.

It's the cars with good aero engineering that do well.

I read on the Mercedes Forums about the runs like they have in Nevada on 90 miles of deserted unrestricted highway a couple of times a year and many cars fail to hit high numbers.

http://silverstateclassic.com/event_description.aspx



Something like a mid level aero car along the lines of a C63 with the limiter switched off can make it to just over the 300km/h mark and still feel as though it's holding onto the road. I've also read of some instances where tuned C63's with aftermarket rear diffusers hit 319km/h.

The undercarriage of a stock C63



The same undercarriage after being fitted with an aftermarket exhaust






The Physics of Diffusers: How to Make a Car Really Suck

http://www.caranddriver.com/features...y-suck-feature


If you want a car that is capable of travelling at high speed you need a lot more than just horsepower.

[blackf6]

362km/HR BA ute.
https://m.youtube.com/watch?feature=...&v=eq4MQx00PJo

[Express]

Originally Posted by blackf6

362km/HR BA ute.
https://m.youtube.com/watch?feature=...&v=eq4MQx00PJo

You can see what that Ute looks like from the outside at the 20 minute mark of this video.

https://youtu.be/RITTucYNGCA

[383hq]

mark webbers experience shows the fine line between car and plane :-)

https://youtu.be/ZXZaAuyuYmQ


I personally like how the porsche gt series direct air through the front, pushing the front down as it exits through the bonnet, + ground effects, + canards on the modifieds.....

A lot of science in the trade off between drag, and lift (downwards). Mark'ill tell ya even the experts can get it wrong, dman maths - wheel slip, equivalent area, Cd, tyre size, gearing, frictional losses....

[Bent8]

HSV GTS (auto) 5th gear redline - 292 kph

FPV GT-F (auto) 5th gear redline - 296 kph

Picking up 6th will drop the revs to around 4900rpm in both cars.

They also have similar power/weight ratios (around 215kW/tonne) so it really does come down to aero....

[b0son]

What impact, if any, would overboost have on top speed?

[xtremerus]

Originally Posted by b0son

What impact, if any, would overboost have on top speed?

None. As the overboost is only for a short duration for passing type acceleration.
Top speed runs would not be in overboost.

[Brian_H]

Originally Posted by xtremerus

None. As the overboost is only for a short duration for passing type acceleration.
Top speed runs would not be in overboost.

I'm not entirely sure that's correct xtremerus. I'm certainly not an expert but logic says different, to me at least. I'm thinking of it like this: overboost is available for at least 10 secs in any gear except 1st, OK? - then, if humidity and heat are acceptable to the motor (so we'd choose a cold day for the run) then whenever asked the overboost is there for the taking, for 10 secs. So, just for the moment, lets say we've deactivated the 250km/h speed limiter. We take the car up to 'close' to top speed without activating overboost to say 220 - 240 or so, making sure not to use overboost. Once there just boot it for 10 secs and overboost will fly you past whatever would normally be available without the overboost. This 'booting it' would only require 10 secs to get you to top speed. Hope I'm saying this right - the main point is to get 'up there' in speed and rely on 5th gear overboost to fly you past the normal top speed that would be available without overboost. I think it would be doable but that's just me thinking realistically about it. Can anyone see anything wrong with this?

[xtremerus]

I see the logic and sounds good.
But I doubt Ford would have it set to have overboost available at all rev ranges. Especially
Vmax run.
Maybe someone can confirm.
Dyno runs would know.

[blackf6]

Go and floor your car, and see just how much aerodynamics plays a part. You will need the pedal mashed to the floor.