40 replies to this topic

[Ali_G]

Why do people say that CART has a higher top speed than a F1 car.

SOme say it is because a CART car has more bhp.

Yet a McLaren F1 road car only has 750 bhp and has a higher top speed than both.

AN F1 car has a better power to weight ratio than a CART car and so should be faster if they were to change the F1 car's gear ratio's.

Also an F1 car is slimer and so should cut the air better.
Anyway a CART car is aerodynamically less efficient.

ANy explanation anyone.

Niall

[Downforce]

The McRoadcar can only do that speed in a straight line.

Cart cars at one time would AVERAGE about 240+ for a lap in qualifying.

The reason that the CART cars are less aero efficient is basically a function of 2 things.....RULES and MONEY.

F-1 teams spend HUGE amounts of $$$ in the tunnel to get the smallest gain in efficiency. Also, F-1 rules allow for a considerably more favorable configuration of the wings.

In a straight line and in the VERY low downforce configuration, I would not be surprised to see the CART and F-1 cars BOTH exceed 250 MPH by a decent amount.

[Limey]

The McRoadcar is more aerodynamic. Exposed revolving wheels on formula 1 or CART cars are NOT aerodynamic. The Porsche 917 with 500 - 500 bhp would do 240 - 250 mph but an F1 car from the 70's with about the same power would be lucky to do 200.

[PDA]

Weight only influences acceleration. Top speed is determined by aerodynamic drag. If both CART and F1 cars were in typical road course wing configuration, top speeds would be similar. CART use very low downforce wings on superspeedways, so drag is much reduced, and they go much faster, so much so that CART now mandate a drag inducin element (the Handford devise) to slow the cars to about 250 mph.

[swoopp]

The only reason they say CART has a higher top speed is because they race on ovals like Michigan and California, where they reach about 240mph.

Around any road coures, F1 cars would be faster. Don't know about the oval...someone should do a shootout.

I rememder a few years back one of the magazines did a top speed test between Al Hoberts IMSA GTP Porsche and one of the NASCARs, guess who won... the NASCAR

[Halfwitt]

If the McRoadcar had 750 hp, then it would be quite a bit faster than has been reached. As far as I know, it has always had marginally MORE horsepower than the GT racecars, or event he BMW prototype racing in the ALMS series, but nowhere near the fantastic 750hp. 650 maybe for a good engine on a good day, but 750? not a chance.

[Ray Bell]

I doubt that there has very often been a F1 car with a top speed on a circuit as high as the same year's Le Mans cars. The aerodynamics again...

[Marco94]

Just for the record, the Mclaren F1 in road car version has 627 bhp. On the Ehra-Lessien the XP5 prototype, having driven some 70000 km, was able to reach 387.5 km/h. This is not the fastest car in the world. If I am not mistaken the DAUER Porsche 962 went to more then 400 km/h. Only it had some 800 bhp.

As far as Champcar and F1 is concerned. Mo Gugelmin holds the record for the fastest _average_ lapspeed. This speed is higher then the official recorded fastest topspeed in F1 by Coulthard. During the 1994 Indy 500, Penske used their specially build pushrod V8. The estimated topspeed for this 1000 bhp car-engine combination was over 400 km/h.

Marco.

[C F Eick]

As for the Dauer-Porsche 962 LM, I believe it had 730 bhp and reached 403 km/h during tests performed by the German TüV organization.

/C F Eick

[Halfwitt]

If I remeber correctly a team called something like WM400 went to Le Mans a few years ago with a very low downforce car with the sole aim of reaching 400km/h on the Mulsanne straight during qualifying. I believe they did it one cool evening, but the car was useless anywhere other than the straight.

[Yelnats]

No one can give a definative answer about the theoretical top speeds of these cars on race tracks but in the past the CART car has proven to be faster due to the low down-force setups run on superspeedways. Surely this speed test would not be run on the salt flats because both cars would be equiped with super-narrow tires and no wings so no one could predict the speeds in this configuration.

But if current cars are considered (If not should we include pre-war streamliners by Audi and Mercedes which exceeded 270 mph on public roads or the 1300 HP monsters of the 80's?) the F1 cars would likely win if setup within the current rules. This is because any low-downforce setups for CART must use the Handford device which restricts these cars to about 240 mph. There are no such restrictions in F1 and several years ago F1 cars with the narrow track configurations reached 236 mph in testing at Hochenhiem where they have to accelerate from a 120mph corner to reach this speed. On a superspeedway where cornering speeds are in the 230 mph zone, 250 mph should be attained.

Without the Handford device I belive these cars would be evenly matched because the much smaller frontal area of the F1 car and superior acceleration would compensate for the 10% HP disadvantage the currently have.

[Sudsbouy]

One big difference between CART and F1 configurations that has not been mentioned in this thread yet are the tires. If I recall correctly, CART's are larger and would present a higher drag coefficient than the groovy F1 donuts.

Thank you.

[SlowDrivr]

Top speed is dependent on HP and drag. Champ cars have more HP. If an F1 car and Champ car were set up with similar levels of drag, the Champ car would have a higher top speed. The F1 car would out accelerate the Champ car, but eventually the Champ car would catch up and pass the F1 car.

On most road/street coarses I would think an F1 car would be faster- lighter, better acceleration (power/weight ratio), slightly better brakes. OTOH, the Champ cars do still have real tires....maybe F1 would be better on faster courses, the Champ cars better on slow ones?

On an oval or superspeedway I'm not sure who would be faster. Probably whichever driver gets the least dizzy.

[DangerMouse]

SlowDrivr, how wide and tall are each respective cars? if we removed the wings completely the F1 car would probably be faster, they are narrower and run narrower tyres, IMHO this would give them a huge advantage even if they're 50 BHP down (which they are not.) Frontal area matters!

[Ali_G]

Slowdrivr : But you are not taking into account that Gear Ratios can be altered to turn power from acceleration to top speed. An F1 car has a higher power to weight ratio than a CART car.

Therefore if both were set up to have equal aerodynamics and equal acceleration (by altering gear ratios) the F1 car would have a higher top speed due to its higher power to weight ratio.

Niall

[DangerMouse]

Ali_G, given equalish power aerodynamics determine top speed not weight, weight just determines how long it takes to get there.

[Ali_G]

I know every one says tat to me. But think about it this way.

Gear Ratios can be lenghtened or shortened.

Say if a car weighed 600 kg. Its gear ratios would be set to a certain lenght to optimise acceleration and top speed.

Yet just say you were allowed to take out 100 kg of ballast. Now you might set the gear ratios up differently. If you do not change the gear ratios you will have better acceleration. But you might want more top speed so you will use a longer set up.

Therefore the 500 kg car and the 600 kg car will both have the same acceleration but the 500 kg car will have a hgiher top speed.

Niall

[mhferrari]

The reason CART cars reach higher speeds is because of the wing. A F1 wing, would never be put as nearly as flat as a CART car, since the CART car races on ovals and F1 races always on road courses. As for power to weight, I know F1 is 800+ bhp to 1323 pounds but only know CART's horsepower 900 bhp.

[andy_bee]

It would have been intersting though if the infield at Indy wasn't quite so slow and twisty so that the F1 cars could go quicker.

BTW- XP5 later broke the record at a VW testrack I believe about 18mths ago with Andy Wallace at the wheel

[Top Fuel F1]

Re: Regarding several Posts back: "CART races ovals and F1 races road courses".

I always knew these cars of Indy origin raced a few road courses, because I attended one years ago and once in a while I see them on T.V. Also NASCAR races one or more road races, but I still consider them oval race cars. Likewise, I was still considering CART to be oval race cars. However, I recently updated myself on CART's schedule:

CART Races: Varied venues, 160-500 miles, 9 oval races, 11 road courses; 15 in the U.S., 2 in Canada, 1 each in Austrailia, Brazil and Japan.

So CART is doing a lot more road racing than some of us non-CART followers had been recently aware of. So we can see that CART's wings ,gear ratios, etc. are going to be changing to a great degree from venue to venue. Other than setting up a super long drag race to see who's (F1/CART) faster, we need to determine what is meant by faster. The super long drag race would determine acceleration and top speed. On the other hand, would Fastest most clearly be determined by a F1 car and a CART car qualifing on the same race course? Seeing that both run road races I would think we would use that type of track. Seeing that neither of these two methods are going to happen any time soon we may have to resort to comparing data. I don't have the info; but perhaps one or more of these (outside the U.S.) CART venues are road race venues. If so, that could possibly be a track that is also a F1 venue. Interested parties could then compare CART and F1 qualification data for that venue, if achieved under similar climatic conditions. Since F1 is desiged exclusively for road races the criteria for Fastest should be what gets around their venues the fastest. I would think the same applies to a CART car. However,in that CART has both road race and oval to deal with their design may have to start out with a compromise to cover both situations. Therefore I believe Fastest has to be considered under the same circumstances. I believe if just plain Fastest was the objective both F1 and CART would design either a drag racer or a Super Car.

Best Regards;

[colejk]

I think you have to be more specific.

Faster is a very relative word to use in this situation.

I think Top Speed is more appropriate. And yes, WEIGHT has nothing to do with top speed. Weight and torque is very important in acceleration, but top speed is soley determined by horespower and drag. As speed increases drag increases by a factor of 4, I believe. That's why that extra 25 hp might only get you 3-5 mph top speed. You'll feel improved acceleration but at the top end it won't change that much.

They design F1 cars to be quick around the track, just like top fuel dragsters are quick in a 1/4 mile.

There are road cars made with less hp than a F1 car that have more top end soley because they are more aerodynamic. F1 cars are just not aerodynamic. (relative to other cars.)

So CART cars, are slightly more aerodynamic, and have more HP. Easy equation.

[Top Fuel F1]

colejk:

The originator of this Thread claimed the CART cars are less aerodynamically efficient than F1. I think he is saying the F1 cars are narrower. You say that CART cars are more aerodynamic. Are you assuming that being Turbo Charged, eliminating the need for the large F1 air intake, is making the CART car more aerodynamic than F1 cars?

[desmo]

Aero efficiency can be expressed in terms of a Lift/Drag ratio. F1 cars are around 3:1. I don't know about CART cars. It is hugely affected by the downforce set-up employed to match the needs of the track and conditions. The low-downforce set-ups are more efficient in terms of Lift/Drag ratio. I'd think that the undercar aeros in the CART car might be more efficient because of the difference in the regs, but that is just a guess.

[PDA]

According to gascoyne (and if ANYBODY knows, he does), an F1 car in Monaco, high downforce rig, has a coefficient of drag of 1.0 or more. In Hockenheim rig, it is about 0.7. This was in F1 Racing magazine in one of Gascoyne's columns on the technicalities of F1. Very good articles IMO.

[Timm]

Juan Pablo Montoya

(Brace Yourself Michael!)

[david_martin]

I think there needs to be some distinction made between CART cars when the run on superspeedways and when they run on road circuits - they are really very different. All of my comments relate to superspeedways only.

One thing nobody has mentioned thusfar is this discussion is the floor of CART cars versus the floor of the current F1 cars. CART cars do not have flat floors (you might consider them semi-ground effect) and there is no "plank" rule limiting ride hight as there is in F1. Although they cannot touch the ground, there are no curbs to worry about, so they run lower than F1 cars. In superspeedway configuration I suspect that CART cars are actually aerodynamically cleaner that F1 cars in Hockenheim or Monza setup. CART cars generate basically all of their downforce from the floor - the front wings are absolutely tiny (and generally not perpendicular to the plane of the car) and the back wings are almost flat. Compare this to F1 cars which commonly sport "winglets" and flaps on the rear deck to generate the low drag downforce they can't get from the floor and rear diffuser because of the F1 rules. In practice the front and rear wings on CART cars are really only used to fine tune the centre of aerodynamic pressure for handling purposes. The requirements for brake cooling are neglible on superspeedways too - they use very small "emergency" style carbon disk brakes designed only to stop for pit stops and accidents. Couple these things to a almost flat rear deck (the turbo engine helps here) and I would bet their Cd is lower, desipte wider track and larger front tyres.

These aerodynamic differences, added to more hp probably gives CART cars a top speed advantage over F1 cars - despite their weight penalty. If it were a drag race, the F1 car would almost be certain to win - the weight and the gearing of CART cars gives them pretty aweful acceleration. Although they can run six ratios under the rules, many only run five on the fastest ovals. Additionally, many CART drivers actually run the top two ratios in the gearbox only a few 100 rpm apart to get the engine rpm where they want them in some of the tighter speedway corners or during overtaking or in traffic. So quite often they run on what is basically a four speed gearbox with two nearly identical top gears. Amazing top speeds, but pitiful acceleration.

[Ali_G]

Yes but think about this Dave. Couldn't an F1 car just lenghten its gear ratios so to give a higher top speed. As an F1 car is light te acceleration wouldn't be so bad even though there would be a slight reduction. Hence Top Speed would be increased. So an F1 car would have a similar top speed (even faster depending on how lenghtened the gear ratios would be) and better acceleration.

Also about Aerodynamics.
I find it hard to see a CART car having good aerodynamics. Yes they have two venturi tunnels. But no flaps down the sides so they are inefficient. Also the rear wing is only allowed to have one element. Usuallly this wing is huge and is very inefficient. Also on superspeedways CART cars use the Handford 3 device. This rear wing is pathetic and limits top speed.

Also about the width of the cars. An F1 car is slimmer than a CART car and so should cut the air better.

Also the high front nose cuts the air better than the low slung nose.

If an F1 car was set up for a superspeedway it would beat a CART car. The only reason why they say a CART car has a higher top speed is as they run on higher speed circuits like Fontana. So they will have a high top speed. But the fastest F1 runs on is Monza. Tere is no way that with similar set up an F1 car would be beaten for top speed at any circuit.

Niall

[slipstream]

I would not say that a Champ car has awful acceleration. A champ car was tested in Car & Driver a couple of years ago and it did a 1/4 mile in 9.4 seconds at 167 mph, I would not call that slow. I would bet a champ car could out accelerate a F-1 car to about 100 mph because of its better traction, but After 100 mph the better power/weight ratio of the F-1 car would make a big diffence.

[david_martin]

Well, underbody venturis, even without side skirts, are better that a wooden plank!! CART cars in superspeedway configuration produce a lot of downforce (about 1800lbs and 200 mph is the figure I read was mentioned by Malcolm Oastler, who designed most of Reynards CART chassis), and they do nearly it entirely under the car. The rest of the aero package can basically be designed with low drag it mind. Are CART cars as aerodynamically sophisticated as an F1 car? No. Do they produce more downforce than an F1 car in minimum downforce setup? No. Can they have less drag than F1 cars in minimum downforce setup? Yes and I believe they do.

Continuing with the aerodynamic theme the high nose has nothing to do with "cutting the air more cleanly". The idea of raising the nose is simply to improve airflow around the splitter and into the diffuser to produce more downforce. In fact the concensus is that the low nose is aerodynamically cleaner - I once read where Patrick Head and Adrian Newey estimated that the low nose produced about 10% lower drag than their high nose design on the mid nineties Williams shape. But the loss of active ride height control and the accompanying reduction in the aerodynamic efficiency of the floor and diffuser meant that it was a better compromise to raise the nose and restore the underbody downforce with the now common modern splitter design and live with the increased drag it and the higher nose produced.

And that is, I guess, the nub of my argument. F1 aerodynamics are fundamentally about downforce at the lowest drag penalty, where the CART superspeedway aerodynamics is primarily about low drag, period. Downforce is not really an issue. Certainly, the Handford flap has slowed things down a bit for the CART cars - it is essentially a drag inducing device. Even in their lowest downforce configurations, F1 cars are designed to produce downforce surplus to superspeedway requirements and take a drag penalty as a result because they have to do it with the upper surface of the car body - the rules make the floor off limits. The modern F1 car shape is simply not designed with that type of setup in mind and is not going to be as good at it as the genuine article. CART superspeedway aero packages do not have the Hockenheim complex or the Monza Lesmos to contend with and all the corners have 11+ degrees of banking angle. Hence, I still doubt a modern F1 car could go as fast, even with taller gearing: too little torque and too much drag even in their lowest downforce configuration.

[Powersteer]

An F1 car is quicker but not faster than CART car. Only some F1 engines do over 800 bhp's where CART engines do more than 850 - 900bhp, thats 50-100 horse more and the drag difference is not enough against those horses.CART teams are now trying to hit the 17G RPM so expect more speed.


About drag, it seems that CART has a much less fussier rear aerofoil package, less drag to F1's. Just remember, the high nose in F1 does not improve drag(i've explained before). CART do not have barge boards,less naughtier diffusers and the air intake above the drivers head is non excistent.They have aerodynamic wheels as well, banned in F1. Important and true to tradition CART races too tend to be more high speed so i wont believe an F1 car has less drag.

[Top Fuel F1]

On the other hand CART has larger tires (dia. and width) causing more drag than F1 tires. However, I don't know if that's only true for ovals and not for road races.

[Powersteer]

Top Fuel, look at the width of an F1 cars front wheel and look at the CART's front wheel, i see the CART's are much narrower

[Marco94]

In 1987, Stefan Johanson has driven a McLaren-TAG MP4/3 on the Phoenix 1 mile oval. Marlboro was filming some promotional work. He had to do some silly things like putting has car in a spin. Appearantly he had great difficulty, since he spend al his life trying not to spin a car.

After the work was done, Stefan and the mechanics wanted to have some fun and drive some quick laps around the oval. In the very few laps he did, the McLaren was very comfortably cruising near the lap record. Of course all of that was during the 1200+ BHP days, but in those days the F1 definitely was quicker.

Marco.

[colejk]

Originally posted by Top Fuel F1
colejk:

The originator of this Thread claimed the CART cars are less aerodynamically efficient than F1. I think he is saying the F1 cars are narrower. You say that CART cars are more aerodynamic. Are you assuming that being Turbo Charged, eliminating the need for the large F1 air intake, is making the CART car more aerodynamic than F1 cars?

If you are talking about coefficient of drag C/D Indy cars have to be more aerodynamic. Be careful not to confuse aerodynamic efficiency and aerodynamic. CART cars still have venturis, enabling them to make do with wings to generate downforce. Thus less protusions, smoother airflow.
As for downforce, we're not talking about that here. Yes F1 cars have a smaller frontal profile, but it isn't that much different. The higher nose in f1 is due to lack of ground effects, or else they would use the extra area the nose provides.

Someone please confirm to Ali that weight has very little to do with top speed. Drag and horsepower (also gearing). very simple. And gearing is based on being able to reach max revs to take advantage of the horsepower overcoming the drag.

And please remember to differentiate between fastest and highest top speed. Fastest is a relative term.

[MacFan]

Originally posted by colejk
Someone please confirm to Ali that weight has very little to do with top speed.

Has been done, on several occasions, with little obvious effect.

[Ross Stonefeld]

I'm starting to think an Indycar would be faster based just on tires.

I base this on that a Formula 3 car is three seconds slower per lap at Putnam park than an Atlantic car, even though the F3 has more HP and more aero.

Ross Stonefeld
Aztec International

[Ray Bell]

So there's a difference in the tyres?
What about torque characteristics? Atlantics might be losing out because they are too peaky?

[Damop]

Ali tries hard. A for effort, F for technical knowledge. Weight has no impact on top speed, given sufficient distance to accelerate. I think a ChampCar will have a lower Cd - the large intake above the driver's head must create significant drag on an F1 car. At any rate, both would have very high top speeds, but when discussing efficiency, neither is an ideal shape due to open wheels.

[Ross Stonefeld]

Atlantic car has a wider wheelbase and some BIG rubber

Ross Stonefeld
Aztec International

[Top Fuel F1]

Re: Your 19-09-2000 Post

Powersteer:

You have very keen eye sight! Either that or you watch a lot of CART races. Anyway I was taking Road & Track magazine's (very recent issue) word on these tire sizes. I went to the rules for both FIA F1 and CART and boiled out:

**********************F1***/**CART******************
____________________________________________________________
1.Max Front Wheel Width= 13.98 in.,/ 12.50 in.
2.Min Front Wheel Width= 12.01 in.,/ 11.00 in.
3.Max Front Wheel Dia. = 25.98 in.,/ 26.00 in.
4.Min Front Wheel Dia. = 25.98 in.,/ 25.00 in.
5.Max Rear Wheel Width= 14.96 in.,/ 16.75 in.
6.Min Rear Wheel Width= 14.37 in.,/ 15.25 in.
7.Max Rear Wheel Dia= 25.98 in.,/ Ovals 27.5, Road 28.2 in.
8.Min Rear Wheel Dia= 25.98 in.,/ Ovals 26.5, Road 27.2 in.


The trouble with looking at these numbers is that you don't know at which end of the tolerances the teams would actually try to run at from a practical point of view. So yes, the CART front tires could look a lot narrower if for example the F1 car was running a Max. and the CART car was running at Min. The converse would make them about equal. An aero person would have to tell whether any of this makes any difference.

Best Regards; [p][Edited by Top Fuel F1 on 10-13-2000]

[Yelnats]

The drag of a F1 or CART car is determined by it's frontal area plus the parasitic drag around smaller elements such as wheels, wings and suspension elements. Parasitic drag around small structures such as suspension elements and between tire and body tend to cause far more drag than their measured ares would reveal.

Because of the rule changes in 98, the parasitic drag elements between the wheels and body of and F1 car were significantly reduced when the tires were moved closer to the chassis. This had a disportionatly greater effect on the drag that a simple frontal area calculation reveals. Tests after this change saw cars running at 236 mph at Hochenhiem in last year's (1997) configuration. And these speeds were achieved on a straight of about one half mile (excluding braking zones) entered at less than 140 mph. The small differences in HP (830 F1 vs 930 CART) are easilly swallowed up when the cube law of drag generated by additional parasitic drag and frontal area is considered. Of course F1 setups have given away about 10 mph of this speed (now about 225 mph) to higher down-force by cranking on more wing. A few mph peak speeds on the straight means little when compared with the gains to be made on the 50% of the lap time spent on corners and braking.

If we include the Handford Device in our comparison, the F1 car will undoubtably hit a higher top speeds as setup within the current rules. Deviations from the current F1/CART rules (such as removing the Handford Device) open this game up to anything including narrower tires and no wings so will prove little about the potential of these cars as they stand. (ready to race).