Mulsanne Straight

[vs346]

Yeah 1999 to Le Mans is like 1945 to Bordeaux.

Had a good mix of drama, craziness, and action.

I wonder when we will see such a fabulous grid again at LM. 6 factory efforts and a host of quality privateers. True endurance racing in my book!

[jross427]

the gt-one never raced against the C9, wasn't that car the Toyota 88-CV that raced in the 89' le mans

[Purist]

JAG, modern cars accelerate quicker on the circuit to a significant degree because they are geared for it. The long straight meant you geared the thing for top end, so you didn't blow the engine sky high. More efficient in all areas? Which cars produced more downforce? (Group C) Which cars had the better downforce to drag ratio? (Group C) That high downforce probably did contribute to the loading on the tires. I can acknowlegde that the brakes are likely better on the nweer car; however, with more downforce and in many cases less weight, the Group Cs may well have had similar brake effectiveness (stopping distances).

Like I said already though, it looks like a near certainty to me that the Group Cs had LESS frontal area AND MORE horsepower, which would indisputably give them the higher theoretical top speed over the LMPs.

[MikkoJalonen]

Yeah the GT-One didnt never raced against the C9 as them are totally for different years of racing history. I think I havent posted wrong years to my message but if I have then its my mistake and I am sorry for it.

If this wouldnt go all spam up I just say that Mulsannes straight is a great one!

[djb]

a point that noone has brought up is the difference in speeds of the prototype cars and the lesser classes and the dangers associated with a much faster car getting into a dicey situation with a slower car. I'm sure some of you know the numbers, what sort of speed differences were there in the past? I'm taking a guess that when there were the 1 litre cars going for the economy thing in the 50's and 60's, they must have topped out at 100, 110, maybe 120; and the fastest cars would have been 50, 60, 80 mph faster. So what years would the speed difference been the highest. If in the last years of no chicanes cars were regularly hitting 350 etc (again, annoraks help me out) there must have still been Gt cars like Porsche 911's etc "only" going 170, 180mph.

What I'm getting at, and not perhaps rightfully so without the info, is that this may have been a legitimate factor in the chicane decision, based on the various closing speed difference accidents from the past.

watcha think?

[TheNewBob]

djb - I could easily be wrong but I think GT's only came back in about '93 sorta time, before that it was all group C's on the LM grid - so the worry of running into something going slow might only apply if a car was slowing with a mechanical fault? I know nothing whatsoever about the speed differences between the front and back of the LM grids in the Group C days...

[Adam43]

The speed differential may play out differently now. Many of the GT1 cars are fast in a straight line. There will be a couple less braking areas for LMP1 cars to easily get by.

[Happy Snapper]

Originally Posted by TheNewBob

djb - I could easily be wrong but I think GT's only came back in about '93 sorta time, before that it was all group C's on the LM grid - so the worry of running into something going slow might only apply if a car was slowing with a mechanical fault? I know nothing whatsoever about the speed differences between the front and back of the LM grids in the Group C days...

The LMP1's were over 100KPH faster than the Morgan at the speed traps and were lapping it every 4 laps!

[gucom]

about the group C cars having the track to their own before '93, i believe that's right, although i dont know when they were banned from le mans...i know from the (derek bell?) vid of a 956 in '83 that the 911s were still racing in that year...

[JAG]

Many of the current GT1s lap quicker than the Group C2 cars, even some of the slower Group C1s, including the odd 962.

Even cars like the TWR V12 Jags were qualifying in the 3.36-3.45 range, thats mid to lower LMP1 times.

There was a massive differential in the quality of the teams in the Group C days, Le Mans teams today, with the odd exception, are very high quality.

Regarding the efficiency of the cars, considering the much more restrcitive regs, a modern LMP has a Group C beat in all areas, probably only the turbo Mercedes C11 and Nissan R90C, and 3.5l Peugeot 905 EVO and Toyota TS010 are quicker over a single lap.

[Splatz the Cow]

Originally Posted by Garrett

No, the Audi's were faster in a straight line than the McLaren's. From the trap speed records from the Le Mans annuals from 1995 to 2005, the McLarens toped out around 195/200mph. The Audi's all 7 years they have been there (99'-05') have toped out around 195mph to 212mph.

While this is technically true, it is just a statistic about top speed. It does not take in to account some very significant factors,

1. The McLaren was a road car and had very low downforce, even with its wings. So the car was a lot slower through the final corner before a straight than a prototype like the Audi.

2. To make up the downforce the wing angle had to be enough to keep lap times down and stabilise the car, leading to increased drag and lower top speed.

3. Tyres have improved significantly in the years of the Audis reign, and this increases grip in the corners meaning wing angle does not need to be so great to maintain the same corner speed and lap times, this resultant decrease in drag increases top speed. Had the McLarens been running in the last few years they would have benefited from the modern tyres.

Its hard to estimate the improvement of top speed with these very few changes but I would expect between 20 - 30 Km/h.

PS. you have PM.

[Purist]

JAG, I did some checking on poles and fastest laps at Le Mans.

1985: Pole-3:14.80
1989: Pole-3:15.04
1990: Pole-3:27.02

1985: Fastest Lap-3:25.1
1989: Fastest Lap-3:21.27
1990: Fastest Lap-3:40.93

Djb, there aren't any of the really small cars around, so we're not going to see Ford GT40 MkIVs at 230-mph whipping past Lotus Elites doing 130-mph. The 911 GT3 RSRs can hit 160-mph on the start/finish straight at Road America, so they may be doing 165-170 at LM already. I could see them topping out at 190-195 perhaps. If the touring cars going along the Dottinger Hohe are any indication, the GT1s could see 225-mph at the end of an uninterrupted Mulsanne. I honestly don't see the prototypes getting much beyond 240-mph. That would give a split of around 50-mph between GT2 and LMP1. As it is, the gap is already around 40-mph.

[JAG]

The 1990 time, with the chicanes, is interesting.

These days cars regularly lap under 3.40 for much of the race.

The pole winning Nissan ran 3.27 with a qualifying engine, while other turbo cars with race spec engines ran 3.35-45 times.

What could an R8 run if it had 850bhp for a qualifying run, >3.25?

[djb]

Originally Posted by Happy Snapper

The LMP1's were over 100KPH faster than the Morgan at the speed traps and were lapping it every 4 laps!

yes I remember those two, I have a good shot at the entrance to the Porsche curves of the older Morgan driver checking in his mirror as the ADT Audi is coming blasting up behind him. The Morgan chap was well over and aware of what was coming. It makes me think of the years past, of being in the rain and in the middle of the night and having really big closing speeds between cars, must have been bloody scarey! (and hence my wondering about this factor being a part of the chicane decision)

if I remember, I'll stick up the Morgan/Audi shot.

cheers

[djb]

here's a low rez jpg of it,

http://www.beaulieuphoto.com/MorganAudi.jpg

this topic touches on a bunch of issues, but it really does make me think of the drivers from the past who drove cars that were insanely dangerous no matter how nostalgic we can feel about them, and on circuits with little runoff areas and hugely underdeveloped safety issues such as ambulances, proper marshalling, pit-in pit-out lanes, unprotected crowds etc etc etc.

[rcarr]

Just for the record-

I found the top speeds for Le Mans in recent years

2003 - Dome Judd @ 331km/h

2000 - Johansson-Mathews Reynard-Judd 2KQ @ 329 km/h

1999 - Toyota GT-One (Brundle, Collard, Sospiri) @ 351 km/h

1988 - W.M.P. 88 @ 405 km/h

1989 - Sauber Mercedes C9 @ 400 km/h

The cars now are aerodynamically limited by drag, for example, they are open top. Group C cars were designed with slippery bodies with low drag.
They are also limited by downforce too, the old group c cars had massive double element or at least triple plane rear wings creating fenominal ammounts of downforce.

Now the stepped floor and the fixed shape of diffuser, they are completely different from the group c cars which really didnt have any restrictions on diffuser size or floors.

[Kempi]

I beg to differ: While Group C had less aero restrictions, the aerodynamics principles weren't as well understood as they are now so I'd be brave enough to say that a modern car is much more aerodynamic efficient, which is the most important part: creating downforce while not creating too much drag.

The Toyota GT-1 might be another story.

[Randy]

In the Group-C and IMSA days aerodynamic performance was a long way behind where it is now. lift/drag was the ultimate goal and many of the cars were designed with LeMans' long straight in mind from the outset. This gave great top speeds at LeMans and very good looking lift/drag ratios on paper. Compared to modern prototypes few concessions were given to pitch sensitivity and aero centre of pressure versus CofG etc etc and as a result the performance of the cars was compromised. I know this first hand from my Nissan which exerts phenomenal downforce but only over a VERY small working envelope. This makes it a tricky beast to set up and drive, quite at odd with a modern LMP. From my experience over many Group-C cars aero balance and drivability are far more important than outright downforce. So, to summarise, numbers can be misleading.

[Nordic]

Just for comparision the pre Grp C cars, Grp 6 for the younger ones amongst us, where Porsche 936's battled with Renault Alpines. These too where open topped and had very basic, compared to today, areo packages.

78 Alpine 367 Kph
79 Porsche 353 Kph
81 Porsche 356 Kph

For 82 the first year of Grp C the top speeds hardly changed, the fastest being 355 Kph.
However the following year 20 Kph was found and the fastest speeds where in the 370 kph region. they contined to climb with a few blips until the chicanes where put in and the required package changed.

Not sure what it proves or disproves, but they you go!

[Splendid Cat]

Post deleted. Can't be bothered today

[djb]

Randy, appreciate the first hand comments. Arm chair enthusiasts as we all are, it adds another dimension to hear real experiences and opinions based on that. It must have been a hell of a thrill to get on that circuit the first time. Going there for the 2004 race (my first full race experience there) still holds great memories. Doing scouting walks before the race to plan out angles, focal lengths to use and estimating travelling times from here to there, I was struck by images in my head of photos from the past from a given corner (or thereabouts with the changes) so I can sort of imagine driving the place in a serious car. Very impressive.

cheers