25 replies to this topic

[jpf]

At 600kg with about 800 hp, a modern F1 car has about .75 kg/hp. At 900kg with 600 hp, an LMP has 1.5 kg/hp. However, considering the superior aero efficiency of the LMP with its covered wheels etc. and the better grip with the use of slick tires and wider track, how do you guys think things average out between the two of them?

At high speed circuits, would the LMPs with their high trap speeds and efficient aero make up for the big power/weight difference? Or would they be left behind coming out of chicanes and low speed corners?

At slow circuits where the power deficit is less important, would the grip from big slicks and wide track outweigh the more sluggish handling from the extra weight?

Frankly I don't know where to begin in answering these questions. Not to mention that LMPs are set up for endurance not sprint so there are other compromises made there with tire compounds etc. I guess maybe we can get an idea this November when the ALMS becomes the Asia Pacific Le Mans Series and races at Sepang.

Any ideas?

[nzkarit]

The F1 would acceralrate fast than the lemans. Because of the better power to weight ratio.

I would expect the F1s to have a higher top speed becasue more hp.

The lemans with the higher downforce would be able to carry more speed in the corners.

You can do the same type of comparsion between Superbikes and 500cc GP bikes. I can't remeber the details but different bikes because of their specs were faster at different things.

[PDA]

Check the lap times for circuits on which they both race e.g. Silverstone.

[Janzen]

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The lemans with the higher downforce would be able to carry more speed in the corners

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But they would also have to overcome the weight penalty in the cornering, especially braking, 300 kg is a lot!

So in acc. and speed the pwr/weight is everything, braking F1 wins, and in the corners, I am guessing pretty equal.

Just my opinion.

[PDA]

Silverstone pole, 2000 ELMS, 1.37.030
Silverstone pole, 2000, F1, 1.25.703

So F1 cars are 10% or so faster than LMP cars.

[Halfwitt]

Do the LMP cars have that much higher downforce compared to F1 cars? They run no front wing, and only single element rear wings (as far as I know).

[BRG]

Le Mans is traditionally a low down force set-up because of the Mulsanne straight - even with the chicanes, it is still a high-speed circuit. Pre-chicanes, speeds of 220-230mph were commonplace at Le Mans.

Another factor is sportscars are not restricted to 13 inch wheels like F1, so they can run much bigger brakes, which counteracts the extra weight.

[Eau Red]

Originally posted by Halfwitt
Do the LMP cars have that much higher downforce compared to F1 cars? They run no front wing, and only single element rear wings (as far as I know).

True, but remember that the LMP rules allow them to get a lot of downforce from the underbody of the car... especially the old Group C cars.

From <http://www.mulsannes...er.com/data.htm>:

1999 Ferrari 360 Modena
Downforce: 400 lbs. @ 180 mph

1999 Nissan R391 LMP
Low downforce configuration: 3000 lbs. @ 200 mph, with 1200 lbs. of drag
High downforce configuration: Downforce: 4750 lbs. @ 200 mph, with 1357 lbs. of drag

Mid 80s Group C prototype
Downforce: 4000 lbs. @ 180 mph, with 930 lbs. of drag
5218 lbs. @ 225 mph, with 1213 lbs. of drag

Jaguar XJR-8LM
Downforce: 1800 lbs. @ 180 mph, with 720 lbs. of drag
4000 lbs. @ 240 mph, with 1600 lbs. of drag

1991 Mercedes-Benz C291 3.5-liter "Group C" car
Downforce: 5000 lbs. @ 180 mph, with 1000 lbs. of drag

1998 Formula One Car
Monza Trim Downforce: 2500 lbs. @ 200 mph, with 909 lbs. of drag

Monaco Trim Downforce: 3000 lbs. @ 165 mph

[jpf]

You're right, Le Mans isn't a very high downforce track, but PDA's post says it all. Set up for Silverstone, the LMPs are more than 10 seconds slower. Hey, Toyota's F1 car would be competitive with them...

Just kidding, I'm expecting good things. Anyway I think a critical point is the tires. LMPs are set up for endurance racing so who knows what the chassis are capable of if running sprint tires. However, that's just speculation and not in the spirit of the comparison. I guess now we know that the increased aero efficiency of a fully faired body and slicks doesn't make up for the porky weight and lower power.

[Yelnats]

Unless the LeMans car was running on a track like a high speed oval (200 mph+) the vastly superior acceleration of the F1 car will render the top-speed advantage meaningless. The F1 car would be running at above 180 mph on any significant straights while the Le Mans car would be struggleing to reach 150 mph. A thirty MPH advantage that is unlikely to be regained anywhere on a modern track with it's lack of long straights.

A huge power advantage simplifies everything!

[MattPete]

If you look up the pole times last year, when they visited the same circuits, ALMS/ELMS cars had pole times nearly identical to F3000/Indy Lights (Portland, Laguna Seca, Nurburgring, and Silverstone).

Here are some times, along with an analysis of CART vs F1:

				 Laguna	Portland   Silverstone  Nurburgring

F1				 -		  -		85.703	 77.529

CART			 67.722	 57.738	   -		  -

f3000/lights	 75.891	 65.275	  97.683	90.403

ALMS			 75.408	 64.4		97		87.9

These are all 2000 times, except for Silverstone F3000. The times were really out of whack, so I assumed it rained last year during qualifying. The only time I could find from 1999 was 9th place. I subtracted one second to estimate pole position.

The first thing you might notice, is that despite being very different forms of race cars, ALMS cars produce pole times that are very similar to F3000/Lights.

So, let's compare F1 vs. CART, using ALMS as baseline. We'll start with simple subtraction first:

				 Laguna	Portland   Silverstone  Nurburgring	Average

F1									  11.297		10.371	  10.834

CART			  7.686	 6.662								  7.174  

f3000/lights	 -0.483	-0.875	   -0.683		-2.503

ALMS			  0		 0			  0		   0

So, at first glance, it looks like F1 cars are around 3.5 seconds faster than CART cars [note: this is a rehash of a CART vs. F1 post I made back in 3/2001]. But at second glance, based on the ALMS times, the F1 circuits are longer, which might distort the results a bit. So, normalizing to ALMS we get:

				 Laguna	Portland   Silverstone  Nurburgring

F1										  88%	 88%

CART			  90%		90%		  

f3000/lights	 101%	   101%		   101%	 103%

ALMS			 100%	   100%		   100%	 100%

Either way you look at it, it suggests that CART and F1 machines weren't that different in 2000. It would bet that, except for Monaco, the fastest CART car would have no problem qualifying for an F1 race and would probably end up mid-pack.

Looking at ALMS/ELMS cars (open-top, not the closed top GTP), it looks like they're quite a bit slower than F1 or CART machines and closely match the speeds of F3000/Indy Lights. Interestingly, in the last years of IMSA, the IMSA GTP cars (Eagle Toyota and the Cosworth Jaguar?) had poles faster than the CART cars. I don't know how the modern ALMS cars would compare to those beasts.

-Matt

[jpf]

Thanks MattPete! In addition to your LMP-F1 insights, that has to be the most coherent comparo between CART and F1 I've seen (and not for lack of discussion on the BBs all over). Very interesting.

[Yelnats]

I find it very difficult to believe that a CART car with about a 20% disadvantage in power to weight ratio would qualify anywhere near a F1 car. Don't forget that a F1 car with a 50 HP disadvantage runs at the back of the pack. In effect a CART car has the accelerative power of a F1 car with a 150 hp disadvantage, an impossible handicap on any modern road course with the short straights involved.

[MattPete]

Originally posted by Yelnats
I find it very difficult to believe that a CART car with about a 20% disadvantage in power to weight ratio would qualify anywhere near a F1 car.

I don't. CART cars not only have ground effects, which F1 cars do not have (unless you count that dinky little diffuser), but they also have big, manly, sticky slicks. Those grooved tires are hard as rocks.

Don't forget that a F1 car with a 50 HP disadvantage runs at the back of the pack.

It aint all horsepower, it's also the chasis and talent. In the case of Minardi, there is a distinct lack of talent in the form of Tarso Marques. In the case of Benneton/Renault, their whole chasis/engine combination is a complete bag of worms this year (I won't comment on Button's talent).

In effect a CART car has the accelerative power of a F1 car with a 150 hp disadvantage, an impossible handicap on any modern road course with the short straights involved.

In effect, an F1 car has the handling of a CART car with groovy tires and no ground effects [I'll ignore the CART weight penalty for the moment], an impossible handicap on any modern road course with all of the tight corners and such ;-).

You also have to remember, that last year, without the tire war, Bridgestone made their tires with an especially hard compound. Firestone, on the other hand, despite being the only tire manufacturer, still has some problems with marbling in CART.


I think the empirical results speak for themselves. What you make of the results is a different matter. As long as the configurations aren't changed, we might have a chance to see CART and F1 cars run on the same track next year at Montreal (obviously not on the same race weekend).

[jpf]

Unfortunately, MattPete, I've heard that there will be some small modifications to the Montreal circuit that will make a true direct comparison impossible. Still, it will give a good idea. In the meantime, I think using ALMS as a common standard is great thinking.

By the way, what is the weight requirement for CART?

[MattPete]

Originally posted by jpf


By the way, what is the weight requirement for CART?

It must be pretty high -- take a look at Paul Tracy ;)

This is off the top of my head, so it wouldn't suprise me if I have something wrong:

				   kg	 lbs

F1 (w/driver)	  600   1323

CART (w/o driver)  703   1550

CART w/ driver	 771   1700

[Ali_G]

For god sake.

Comparing CART cars and F1 cars are ridiculous.

F1 cars would blow them away.

For a start with the new pop off valves introduced last week a CART car now probabley has less power than an f1 car.

Secondly, the Venturi Tunnels on a CART car are ridiculously limited and are no where near as big as they could be.

A Cart car runs with only 2 elements in the rear wing. Give little downforce.


ont he other hand a F1 car runs with a Splitter Diffuser Undertray config. its likley that this produces as much downforce as the CART's venturi's as it isn't so limited.

The ultimate things though is Weight. With such a weight advantage an F1 car can corner faster, accelerate, decelerate and basically do anything faster.

An f1 car also gives off less drag. Have any of you seen the wings they use of Speedways. They give off more drag than any F1 car.

Get out of it.

Niall

[jpf]

Ali-G: Did you read through MattPete's analysis? The numbers don't lie - it looks like CART are indeed slower than F1, but they are not blown away as it's only by a few percent.

Now I like F1 much better than CART, the technology and the drivers are both head and shoulders above. That's factor 1. But, regulations play a part here, and that's factor 2. It seems to me from this admittedly rough analysis, that regulations bring F1 to a level closer to CART than factor 1 alone would imply. It seems to me that you're ignoring factor 2 and basing your post only on factor 1, and on your preferences and preconceptions.

Don't take it as an insult to F1 cars, teams, or drivers, just think of it as one more reason to be pissed at the FIA!

[Ali_G]

Muppet: your wrong about one thing.

40% of an F1 cars downforce comes from the undertray.

When the air goes under the nose its split into 2 sections under the car. This hence reates a bernoulli effect which hence creates downforce. The diffuser then decelerates the already acelerated air to gain even more downforce.

Niall

[Yelnats]

MattPete, Your comparison is interesting and worthwhile but as it involves extrapolations of data based on single races held on different tracks at different times, margins of error must be applied if engineering and statistical principals are adhered to. If a margin of error of 2.5 % is used for each of your figures, the answer could swing over a range of about 8% and the results would be too inaccurate to draw any solid conclusions.

Experience should tell us that the massive power to weight advantage enjoyed by the F1 car over an Indy car has never been overcome in any other class of road racing. We have all seen mixed classes where the lap speeds inevidably divided along P/W ratios. Considering the similarities of chassis design beween F1 and CART, ie both are open wheeled cars with wings and underchassis downforce of some type, I see no reason to assume they would break this P/W ratio rule.

[MattPete]

Originally posted by Yelnats
MattPete, Your comparison is interesting and worthwhile but as it involves extrapolations of data based on single races held on different tracks at different times, margins of error must be applied if engineering and statistical principals are adhered to.

I'm a statistician, and with that data set, I wouldn't even bother trying to establish confidence intervals. After all, where would you start? There's so little data that establishing confidence intervals would be meaningless.

If a margin of error of 2.5 % is used for each of your figures, the answer could swing over a range of about 8% and the results would be too inaccurate to draw any solid conclusions.

2.5% is larger than the gap between 1st and 26th place in Portland qualifying. Sure, we could use 8%, but where's the justification? And without a reasonable method of calculating confidence intervals, the use of confidence intervals would be far more misleading than not. So, do you wanna risk commiting a Type-I error (fale alarm/false positive) or a Type-2 error (miss/false negative)? It's up to you.

In this case, I think it's best to use the ol' eyeball statistics. What's really remarkable is depite their differences, the qualifying ratio between F3000/Lights and ALMS/ELMS is remarkably consistent. Likewise, so are the qualifying ratios between CART:ALMS and F1:ALMS. Keep in mind that the chasis difference between ALMS/F1 and ALMS/CART is far larger than the difference between CART/F1.

So all we can go by is these ratios and their surprising consistancy. I'd be willing to say that these figures are in the ballpark. Of course, how big is that ballpark (which was kinda your point in the first place)? Like I said, I don't know, but my eyeball says it's small enough to not even bother.

Experience should tell us that the massive power to weight advantage enjoyed by the F1 car over an Indy car has never been overcome in any other class of road racing. We have all seen mixed classes where the lap speeds inevidably divided along P/W ratios. Considering the similarities of chassis design beween F1 and CART, ie both are open wheeled cars with wings and underchassis downforce of some type, I see no reason to assume they would break this P/W ratio rule.

At the same time, look at what huge effect tires has on performance. Look the huge effect of a tire war on lap times. Now, imagine that the 2000 F1 machines used big gummy tires, like CART. I'm sure that in that instance the F1 machines would be able to take advantage of their lower weight (for cornering and braking) and the higher power-to-weight ratio (for acceleration) to leave the CART cars in the dust. So instead of talking about a 2% difference, we might be talking about a 7% difference between CART and F1.

P.S. you might be able to do something with bootstrapping and the distribution of qualifying times (and the distributon of the ratios beteen series) for the various event, but the thought of doing that makes my head hurt.

[Yelnats]

MattPete. I'm glad to see we are much closer in our viewpoints now than when you made the following statement. [;->

Originally posted by MattPete


I think the empirical results speak for themselves. What you make of the results is a different matter. As long as the configurations aren't changed, we might have a chance to see CART and F1 cars run on the same track next year at Montreal (obviously not on the same race weekend).

From this satement I got the impression that you put great confidence in you calculations. I was therfore surprised to read in your rebutal an error about the F1/CART races in Montreal, (CART is running a different track therel) which if repeated in your calculations, would have rendered them just as invalid. My point being if you were in error in you Montreal assumption how can you be so confident of the data you have derived from your comparison examples. Who knows what the weather or racetrack configuration was in use in those days?

[MattPete]

Originally posted by Yelnats
MattPete. I'm glad to see we are much closer in our viewpoints now than when you made the following statement. [;->


[snip]

From this satement I got the impression that you put great confidence in you calculations. I was therfore surprised to read in your rebutal an error about the F1/CART races in Montreal, (CART is running a different track therel) which if repeated in your calculations, would have rendered them just as invalid. My point being if you were in error in you Montreal assumption how can you be so confident of the data you have derived from your comparison examples. Who knows what the weather or racetrack configuration was in use in those days?

Actually, I think you misunderstand what adding confidence intervals (or intervals of uncertainty) does to my little analysis. By adding confidence intervals you increase the uncertainty. For example, if we were to use 2.5% as our confidence intervals, we would have to accept the Null hypothesis. That is, we would have to conclude that there is no significant difference between the 2000 CART and F1 cars. I don't think that's what you wanted.

On the other hand, I'm very confident in stating that in 2000, CART cars were suprisingly close to the performance of F1 machines ;).

[Yelnats]

MattPete. Only a statistician (or a politician) could draw a conclusion that by reducing the confidence in your data your comparison becomes more valid.;)

Any way I've never heard a CART driver say he though a F1 car handled more sluggishly than a CART car even after the grooves were installed. As a matter of record they comment how nimble and manuverable the F1 car and how much superior the braking is. Even after the dreaded grooved tires the loading of an F1 tire is similar to a CART car due to it's 30% greater weight so the grooved tire is not a insurmountable obstacle to state of the art handeling. This is demonstratted by the way that the 2001 F1 cars are in the process of obliterating the lap records set by slick shod F1 cars of earlier days.

For the CART car to overcome a 20% PW ratio disadvantage it would require such visibly superior handleing that it would be obvious to both viewer and driver. This has not proved to be the case and a extrapolations from uncertain data will do little to convince me of otherwise.

[Schummy]

I think in CART/F1 relative lap speeds we have to forget all that "macho" thing about how wonderful are F1 cars, how great is its braking, how fast is in cornering, etc. I'd follow MattPete's idea searching more third party comparisons in other tracks/series. If F1 is a lot faster than CART, fine. If CART is very close to F1, fine, no hypersensibility here ;)

In 70's in the high days of SportCars, they were faster than F1 in certain circuits (very high speed ones) and the world was not over for that. It is not a "fault" of F1 if any series is close or even faster than it. After all, old CanAm cars had the potential to be a lot faster. It is just the regulation. If next year you put a 600 kg min weight and a bigger engine in CART, they would faster than F1, and it didn't prove CART is "better" than F1.

I think it would be fairly easy for a manufacturer to make a car faster than a F1 in a regular F1 track, just eliminate restrictions as currently regulated.

Appart for what series we like more, or what series is more "advanced", why not to take this issue as a neutral one? Just as a "scientific" observation.

[DOHC]

Interesting thread.

Just to throw in another comparison, F1 cars in the wet are usually a trifle faster than F3000 cars are in the dry. At the same track and the same year. But I have neglected the technical development happening overnight between Saturday and Sunday.