Image of Bugatti Chiron Super Sport 300+

Bugatti Chiron Super Sport 300+ specs

Car type Coupe
Curb weight 1978 kg (4361 lbs)
Power / weight 820 ps (809 bhp) / t
Introduced 2020
Origin country France
Views 1.9k
Submitted by lafars
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HighGear  2m ago

Likely 1180 lb-ft, like the standard Chiron.


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HighGear  2m ago

Source: https://www.topgear.com/car-news/supercars/bugatti-chiron-super-sport-300-production-300mph-car

The power output is 1,578 hp (1,600 PS).
Price: 4.2 Million pounds (5.18 Million US dollars)
Top Speed: 304.77mph*
*https://www.topgear.com/car-news/bugatti-has-broken-300mph-barrier?fpn=1


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manone  2m ago

"Why can't it reach 490 kph with 1600 ps? What are those "engineering peeps" that are so convinced it can't? Have they studied the shape of the car?"

Ok, let's do few computations for Veyron SS. The formula relating power to CdA, speed v and air density rho is:

P = CdA * v^3 * rho/2.

Knowing V=431km/h=119.7 m/s, P=1200bhp=895kw and rho@15C=1.225 kg/m^3,
we get a CdA of 0.85.

Therefore, for the Veyron SS to reach 490km/h you need 1307kw=1753bhp for
overcoming the drag alone from 431kmh to 490kmh. Then you have to add:

Rolling friction term, which linear with speed, and dynamic rolling resistance term, quadratic with speed.

Back to the Chiron SS: the A factor of Cd*A is seemingly not less than the
Veyron SS's. How much they could have decreased the Cd from the Veyron SS to the Chiron SS, provided the extra front venting surfaces the latter has?

 

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lafars  2m ago

can you calculate if the SSC Tuatara can reach 300mph and with how much power left? Cd=0.279, power is 1750hp


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FastestLaps  2m ago

Veyron and Chiron have different shapes, it would be natural to assume that Chiron is more slippery than Veyron, as clearly the goal of Bugatti was to make a faster car. The Chiron SS is even more slippery still - Bugatti say 40%, that is probably misleading, but it has to be somewhat significant amount.

Now add to that fact that Chiron SS has 1622 PS and possibly less transmission losses than Veyron and you must conclude that 490 @ 1600+ PS seems possible and there is no need for John Hennessey conspiracy theories.

The rolling friction I am not very knowledgeable about, but I believe the difference is not too significant. The tyres are probably just as rock hard at 490 as they are at 430.


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SpeedKing  2m ago @FastestLaps

Where does it say that the Chiron 300+ has 40% improved aero over the current Chiron?


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FastestLaps  2m ago @SpeedKing

In video interview lafars posted below.

If you look at streamliners built for land speed records or top speed competition on salt flats, they are all elongated with long overhang fairing at the back. Streamlined motos in particular can be surprisingly fast with surprisingly little power. The long tail is significant change for Chiron SS.

Fun fact: did you know it is possible to reach 144+ kph with less than 2 horsepower? https://en.wikipedia.org/wiki/List_of_cycling_records#History_of_unpaced_records

Aero drag is everything.


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SpeedKing  2m ago @FastestLaps

No what the Bugatti engineer said was that there was a 40% decrease in size of the rear tear off area not that there's a 40% overall decrease in drag. A 40% decrease in drag would result in a drag coefficient of 0.21 which is a pipe dream.


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SpeedKing  2m ago @FastestLaps

Aero is one aspect. There's complexity to going over 300 mph without doing a Mark Webber.

"Most speculators have settled on around 1,800bhp being the predicted amount of power needed to push a car to 300mph, but power isn’t as big a problem as you would think – the real issue is cooling things down and the consequences of doing that.

The established method for cooling down the excessive heat an engine produces is by channelling the vast quantity of air that rushes past the vehicle as it moves over the hot parts to strip away the excess heat. It's a simple and elegant solution; the faster you travel the more you need to cool, and the faster you go the more air you are provided with. It’s perfect - except for the drag that’s produced.

As you channel that air through intakes and scoops, those gaps and holes reduce the aerodynamic efficiency of the car and cause drag. And the faster you are travelling, the more that drag slows you down and wastes more of the power produced by the engine.

Of that 1,800hp estimate, almost 1,500hp of it will be used just to overcome the drag of the vehicle.

You’re now faced with solving one of the conundrums that has so far prevented engineers from building a car that can reach 300mph. How do you add more power to an engine which then needs to be further cooled, but cooling then slows down the car by increasing its drag".


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manone  2m ago @FastestLaps

"possibly less transmission losses than Veyron"

this i would say it is just the same.


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dr. cosimo  2m ago @SpeedKing

it's simple with vw group, you download a different map with higher boost and tell the public it hardly has an extra 100 hp and still manages to hit a new speed record.

post a video, limit production and have the idiots put down a deposit.

another aventador story

vw is a complete cluster fcuk disaster, when it comes to the cars history and heritage


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FastestLaps  2m ago @dr. cosimo

Messing around with ECU is not unique to one specific manufacturer. Oldest trick in the book.


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SpeedKing  2m ago @dr. cosimo

If VW wait till 2024 to replace the Aventador that would be fcuking stupid. Domenicali wants the V12 to continue but the Germans want V8 hybrid turbo's so no prizes for guessing who's gonna come out on top pfft idiots!


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dr. cosimo  2m ago @FastestLaps

there's a lot more that hasn't been disclosed yet, the ecu part is just tip of the iceberg

"There are other differences between the 300+ and the actual record-setting car, which was shown on the Bugatti tour complete with grime and bug splatter from the track. The road-legal Super Sport won't have the full roll cage that was fitted to the car Andy Wallace drove at Volkswagen Group's vast Ehra-Lessien test track in Germany, and it will also come with the passenger seat that was taken out in the speed-run Chiron to accommodate computer and timing equipment. It will also have a standard ride height—the 300-mph car sat lower—and Bugatti admits it will have a speed limiter, although the company hasn't said what that will be set to yet. It seems likely that the determining factor will be the maximum speed that the car's Michelin tires can digest for anything other than very short periods. Although not confirmed yet, we also presume the 300+ will have a working air brake, something that the record-setting car didn't use."


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manone  2m ago @dr. cosimo

"it's simple with vw group, you download a different map with higher boost and tell the public it hardly has an extra 100 hp and still manages to hit a new speed record."

my guess is that they have left some engine parameter free to self-adjust in order to break 300mph. Wallace said that they have made several tests up to 450km/h stable, so they probably got a pretty accurate figure about the power needed for 300mph, but in the video i saw it looks like the speedometer is going to threshold at about 470, but then reaches 490.


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BTICronox  1m ago @manone

You miscalculated by taking the Veyron SS's top speed, which included the other resistances, for your calculation of ONLY (!) the wind resistance. The Veyron SS has a cd of 0.35 and a front surface of 2.1m² according to this:
http://rc.opelgt.org/indexcw.php
That results in a combined cdA of 0.735

So if you take the front surface of this for the Chiron, you'll come up with following result:

cd = 2P /( v³ * rho * A)

cd = (2 * 1176470W)/(136.1(m/s)³ * 1.25(kg/m³) * 2.1m² )

cd = 0.355

The Chiron already has a cd of 0.35 according to Bugatti, so this is very probably a little lower, 0.33 or so. 490km/h is totally realistic for the 1600hp to achieve.


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manone  1m ago @BTICronox

having a data on cd and A of veyron, may help the estimates.
width x height of Chiron is 6.3% more than veyron, so assuming this implies
A(chiron)=A(veyron) x 1.063, we get CdA(chiron)=0.78 (@cd=0.35) or 0.736 (@cd=0.33).

The formula expressing the power necessary to overcome JUST the aerodynamic drag @490 kmh implies that Chiron needs 1.230kw (cd=0.35) or 1.160kw (cd=0.33). Bugatti Chiron supersport 300 claimed max power is 1.177kw. You say that's totally realistic?


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BTICronox  1m ago @manone

Again, I don't know what your problem is. Out of all driving resistances:

  • rolling resistance
  • acceleration resistance
  • inclination resistance
  • air resistance

Air resistance is the ONLY one of these forces which includes exponential speed. At these kinds of speed, air resistance basically makes 98% of the whole equation.

Additionally, i calculated air density with this site:
https://www.timeanddate.de/wetter/@2932872/rueckblick?month=9&year=2019
And the result was 1.205

That results in a needed cd of 0.347 at 1600hp for 490km/h even with YOUR estimation of surface area. So yes, i say that's TOTALLY realistic, knowing that the base Chiron already has 0.35 and this car is 25cm longer and has massively smaller tear-off edges.


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manone  1m ago @BTICronox

problems? absolutely none. But it is hard to follow you if you constantly change your estimates each message.

"Additionally, i calculated air density with this site:
https://www.timeanddate.de/wetter/@2932872/rueckblick?month=9&year=2019 And the result was 1.205"

1.205 is not what you used in your previous computation:
"cd = (2 * 1176470W)/(136.1(m/s)³ * 1.25(kg/m³) * 2.1m² )"
that was 1.25, so i just used that. Do you know the exact temperature the air had when bugatti conducted the test?

" Out of all driving resistances: rolling resistance,... Air resistance is the ONLY one of these forces which includes exponential speed."

none of them "include exponential speed", i guess you mean polynomial non linear. Certainly, tyre rolling resistance is non linear, especially close to their rated max speed.

"At these kinds of speed, air resistance basically makes 98% of the whole equation."
In your previous message you claimed "You miscalculated by taking the Veyron SS's top speed, which included the other resistances, for your calculation of ONLY (!) the wind resistance".

LOL, so which one of the two?

The truth is that it is extremely complicated to model rolling resistances, and most of them can only be estimated experimentally and your 98% claim for air drag is totally unsubstantiated, just like your chiron's cd.


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SpeedKing  1m ago @manone

Using formulas to calculate all the various resistances/aerodynamics factors will not be 100% accurate. I still believe it had more than 1600 hp to do 304 mph but unless we were privy to dyno figures we'll never know for certain.


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manone  1m ago @SpeedKing

yes. often you can expose blatantly false german bs tests/claims by using some physics formulas. Here, though the crucial variable is cd of the cars, which cannot properly assessed except by experiments. This is why i tried to estimate the one of Veyron SS with data from their max speed run. Extrapolating chiron's cd from veyron's cd is not very sensible, but i do not expect those values to be hugely different. Another approach is to plug in bugatti's stated cd values and see what you get, but as germans are not exactly well known for stating the truth, this may lead to fake results. Since using veyron's
estimated cd in Chiron's formula leads to substantially higher power necessary to reach 304mph than 1600hp, i tend to think chiron too was likely overpowered (100-150hp? just my guess), but no clear proof of this i have.


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dr. cosimo  1m ago @manone

vw did a lot of cheating in the past, so who would suspect a 1600 hp has even more hp to reach those speeds ?

99% of the people can't get their hands on one, so why bother and question their integrity ? after all, it's a bugatti and it's the fastest car on the planet, but not everyone knows it's another brand owned by german vw cu_nts with fake spec numbers and different aerodynamics


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BTICronox  1m ago @manone

Just type in the ****ing date and time for ****s sake and you'll have the air density...

"none of them "include exponential speed"
air resistance force: F = cdA * rho/2 * v^2
rolling resistance: F = croll * m * g * cos(alpha)
croll being the rolling resistance coefficient and m being the mass of the car. And yes, rolling resistance is nearly linear (mass "increases" when having downforce, the Chiron SS however nearly has none with all spoilers hidden).

"LOL, so which one of the two?"
Very first comment.

"P = CdA * v^3 * rho/2.

Knowing V=431km/h=119.7 m/s, P=1200bhp=895kw and rho@15C=1.225 kg/m^3,
we get a CdA of 0.85.

Therefore, for the Veyron SS to reach 490km/h you need 1307kw=1753bhp for
overcoming the drag alone from 431kmh to 490kmh. Then you have to add:

Rolling friction term, which linear with speed, and dynamic rolling resistance term, quadratic with speed."

And the last one:
"most of them can only be estimated experimentally and your 98% claim for air drag is totally unsubstantiated"

Taking the other equations from the driving resistance forces, you'll come up with well over 8000N for air resistance and ~200N for rolling resistance, the nearly inexistent (according to Andy Wallace in Shmees video) downforce adding to the weight being ignored. So yes, that makes 97.5% for air resistance ;)


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SpeedKing  1m ago @BTICronox

Denser air = greater resistance but more horsepower. The additional factor that hasn't been mentioned is transmission and gear ratios. The 300+ must have different gear ratios coz the standard Chiron in 7th gear equates to 41.6 mph @1000 rpm and the 300+ produces max power at 7000 rpm which would = 291 mph.

Anyway the smoke and mirrors show goes on and VW Bugatti have given us bullshit hp figures.


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Cocobe  1m ago @SpeedKing

lighter or denser air doesn't affect turbo engines much at all compared to the sheer resistance of driving through it, or else F1 cars in Mexico wouldn't be traveling at 360kph despite being in their highest downforce Monaco spec set up.


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SpeedKing  1m ago @Cocobe

Denser air is colder air and it makes a noticeable difference to my turbo's power and acceleration so i disagree.


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manone  1m ago @BTICronox

"Just type in the ****ing date and time for ****s sake and you'll have the air density..."

i have already asked you: do you know the day and time they conducted the test?

"rolling resistance: F = croll * m * g * cos(alpha)
croll being the rolling resistance coefficient and m being the mass of the car. And yes, rolling resistance is nearly linear"

absolute bùllshìt: one model for rolling coefficient of air filled tyres is quadratic with speed. Experimental rolling resistance coefficient measuments show a behaviour in function of speed which is almost asymptotical (certainly much more than quadratic) close tyre's max speed rating. You do not know what you are taling about.
The model you use might be reasonable for trains on rails and does not keep in account of tyre hysteresis.

"Taking the other equations from the driving resistance forces, you'll come up with well over 8000N for air resistance and ~200N for rolling resistance, the .... So yes, that makes 97.5% for air resistance ;)"

nonsense, since you are using a wrong formula for rolling resistance.
Look, if you wish (highly doubt) to enlighten yourself just a bit, compute
the power necessary to overcome the air drag @431kmh for veyron SS assuming cdA=0.735 (implied by Bugatti claims of cd and A of the car). That
is 772kw vs the 895kw effectively needed for the car to reach that speed (here i am being optimistical and giving Bugatti the benefit of the doubt regarding car's max power=1200hp). That is a 16% increase mate, not 2%, accounting for non-aerodynamic resistences.


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dr. cosimo  1m ago @Cocobe

"lighter or denser air doesn't affect turbo engines much at all"

402vbtr2mc7i.png?550x800m


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Cocobe  1m ago @SpeedKing

Warm air has the effect of poor fuel air ignition timing rather sheer less pressure. Not all turbo engines are the same.

And no, it’s cold air that is denser, but not neccesarily the other way around.

At higher altitudes, air is cold, but also less dense. Turbo engines don’t lose power from premature ignition, and the car can cut through the air faster too


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Cocobe  1m ago @dr. cosimo

what an idiot


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SpeedKing  1m ago @Cocobe

WTF when i said cold air is more dense i was referring to normal populated areas which are close to sea level rather than somewhere like the Death Road in Bolivia where Clarkson and co were. Heat soak is the culprit when it's hot and one is driving fast and any tuner will tell you that so naturally the electronics will retard timing to prevent knock or detonation which in turn results in a power loss regardless whether it has forced induction or not....


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SpeedKing  1m ago @Cocobe

Re F1 at Mexico yes they're very fast down the straight because the turbos are spinning so much faster to produce the same power as they do at other tracks but it comes at a price ie. excessive heat and cooling problems due to thinner air so the potential for engines/turbos failing is much higher. In a production car especially a modified one it would be so easy to burn a hole in a piston due to detonation from excessive heat. Fortunately the electronics retard the timing and lower the boost levels to avoid that scenario and of course this results in slower acceleration.


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BTICronox  3d ago @dr. cosimo

@dr. cosimo: Dude, those cars aren't 80s Audi S1s... when the Chirons ECU notices that there isn't enough air, it just closes the wastegates a bit more and it's all fine. For ****s sake, the Chiron has full torque at 2000rpm already... that's massive reserves.


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lafars  3m ago

very informative video regarding this car:
https://www.youtube.com/watch?v=DFlUYWfwOUg


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FastestLaps  3m ago

You know what is the saddest part - we still don't have proper data for the original Chiron :D

Bugatti are basically pulling a Christian von Koenigsegg.


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lafars  3m ago

maybe i should've added Super Sport 300+ to the model name, but then again @fastestlaps can reupload with proper changes