Original setup datas from Prost GP Team in 2001

I put online some interesting datas from PROST GP Team on 2001 Barcelona race, about setup, driver comments, aero simulation...

http://www.gurneyfla...tap04datas.html

There are bits of telemetry datas too that I don't understand completely, I'll show you these drawings here tomorrow, there must be some experts in this forum who could explain them.

Very interesting, keep it coming!

Few things I think I can understand (my french is rusty) :
- According the crib sheet, there was 76.7 kg of ballast in the rear monocoque. I thought most of the ballast would be at the front. From another bit I think it says the front weight distribution is 44.2% with a weight of around 655.1 kg.
- The rear left tyre temp is higher than the others, as you would expect at Barcelona.
- Is that front camber is -2.5 deg and rear camber -0.5 deg (seems about right I guess).
- After prac 7 (?) it seems they added more rear bar and found better grip. But later dropped the rear bar again when they removed weight and appeared to raise the front ride heigh. I guess the first two runs were race setup and the last qualifying.
- I would assume that changing the bar setups for lower weight (qual) would indicate the CoG isn't on the fuel tank as I thought.
- Fuel strategy info was great. Who did better out of the two?

Cant even read the engineers comments!

Edit: Didn't Burti race for Jag in the 2001 Spanish GP?

16.7 not 76.7

ffat bastard driver 94 kg

Ah my bad, shocking writing!

You sure that is a 74 and not a 94? A few sites said 69 kg, so 74 kg with helmet etc?

Even thats heavy, wasnt Button 73kg post Imola? and he's one of the tallest drivers. I thought Burti was your typical 5'6 weighs-nothing driver

The way I read it, the scrutineering check page shows car weight of 523.5, plus a driver weight of 74kg.

This total of 597.5 is only just over the legal limit of 595 (presuming it was a practise session), so the Prost team can thank their lucky stars the FIA didnt decide to 'hoover' their fuel tank like they did to the BAR team!


Reading further down the page, the right side "flip height max" appears to be illegal.

yes, the ballast is only around 20 Kg. At that time, the top teams were said to have about 60-80 Kg of ballast !

Did anyone take some time to look at the time sheet and follow the progression of changes?

High speed understeer and loose/rear stability problems on corner entry. Classic problems with about every open-wheeled racecar ever made. The poor engineer is painted into a corner. He's got high speed understeer (apparentlly a lot of it), so he wants to be able to stick some front flap into it or something of that nature. The problem is that he can't do that, because the rear isn't stable on corner entry.

He tried to drop the rear ride height 3mm, but that made too much understeer, so he's written, "R R/H Not Good". On the top of the page we see the front ride is 26mm and the rear is 75mm. I'd say 50mm of rake is a damn fine chunk of rake in just about any car I've ever run across. You end up running more on a flat bottom car to make more downforce, but that's a bunch. My guess is, that's a place where the car is aerodynamically producing the most downforce. I'd say even if it puts me at a place on the aeromap that is a lower overall downforce, I'd take a bunch out of that, just to get rear stability. Once you've gotten the rear secured a little bit on entry, then you can throw some front flap in it to get your high speed balance back.

The designations on suspension geometry and all that are pretty much meaningless....they're just meant for internal use. We don't know anything about the dampers, either, other than they're Sachs. He's running 1mm of toe out in the front and 4mm of toe in in the rear...pretty standard fair, if anything that's a little low on the front toe-out, but it doesn't sound like turn-in is a problem.

Does anyone know anything about a Moyen differential? I've never heard of one, but that seems to be what they're running. Again, the setup nomenclature is for internal use only, so we don't know what they're running. I'd say a little preload would go a long way. Anything to help grip the rear end on entry.

So, long story short, If it were my car I would pretty much increase the rear grip of the car with about every change I could come up with. The only thing I would do to add front grip is increase front flap/wing extension/gurney/etc. Everything else would be to help the rear.

Bingo, Alain, all you needed was me, and you woulda been on pole!

yes, that is a French 7, not a 9 on the driver weight.

Humm...in the scruteneering papers...there are a few minimum sizes of 100mm....and they have them under the minimum size....has anyone noticed it?

Originally posted by Fat Boy
Bingo, Alain, all you needed was me, and you woulda been on pole!

Great post FB. I could barely read the setup sheet. Cheers

Originally posted by Lukin
- Is that front camber is -2.5 deg and rear camber -0.5 deg (seems about right I guess).

Sounds good for the front. Based on my limited knowledge, I would've guessed the rears would want a touch more in corner exit. I mean the car probably rolls at least a half-a-degree, although I don't know how much their suspension geometry would translate that to at the wheel. On the other hand, any more camber makes it even worse for the inside rear and they don't want that spinning either.

Originally posted by Fat Boy
Does anyone know anything about a Moyen differential?

I believe "moyen" in French means "average". Considering Prost's results in 2001, I think that's a bit optimistic.

Thanks Fat Boy for the analysis!

Here are some telemetry datas, it compares the best lap of both drivers, Alesi and Burti, in qualification. Did not find what it means ?!

The top one is gear, the next is speed, the next is brakes, the bottom one is throttle position or MAP, almost certainly throttle position.

Throttle....the printout is from Barcelona look at the distances at the bottom of the the sheet and imagine yourself going through the diferent parts of the circuit and check the various parametres.....and if you pay attention the brake is only "activated" when the throttle isn't being used!

Quite interesting!

Silly question, but I guess that's throttle demand at the pedal? I'd love to see throttle demand vs. what the drive-by-wire actually does to the throttle bodies.

Ben

That's an interesting question, somehow I'd assumed the trace was pedal position. If any data sheets existed with the two I'd expect they've been shredded, then incinerated.

Hi,

I suspect the throttle trace is the engine butterfly's rather than the pedal, as you can see the downshift throttle blips (e.g. between 700 and 800m).

These will have been done by the ECU, rather than the driver's foot.

Cheers
Andy

Originally posted by Lukin
Edit: Didn't Burti race for Jag in the 2001 Spanish GP?

He was replaced with Pedro de la Rosa, went to Prost.;)

Originally posted by zoom_the_loom
Hi,

I suspect the throttle trace is the engine butterfly's rather than the pedal, as you can see the downshift throttle blips (e.g. between 700 and 800m).

These will have been done by the ECU, rather than the driver's foot.

Cheers
Andy

Yes, if one looks at the right margin of the sheet one can see "Angle Papillon".

You can see on the data that Throttle is never a zero! there is allways some throttle. So since 2001, F1 have engine management specialy design for brake balance as it seems to be a problem for Villeneuve in the Sauber!

Actually, I think it's more of a Ferrari thing than it is an F1 thing. Villeneuve has driven Honda's and Renault's since 2001, and said he has never encountered this kind of engine management. I wouldn't say it's unique to Ferrari, but it doesn't seem to be something that it universally adopted by the Manufacturers. If it is tho, then Ferrari might be the most extreme case.

"You can see on the data that Throttle is never a zero! there is allways some throttle."

well, that's one interpretation. Mine would be that the pot or encoder used to send butterfly position was not necessarily set so that zero=zero. It isn't on a production car.

Greg, you can see that throttle or butterfly potentiometer as you want is not set to zero during the decceleration but this value decrease with the braking as an anti lock system will do it (for my opinion)!

I can show you a lot of data acquisition that have fixed "zero position" butterfly on different racecar from F3000 to LMP car, I never see this kind of zero position which decrease during the braking!

Originally posted by Antoine
Greg, you can see that throttle or butterfly potentiometer as you want is not set to zero during the decceleration but this value decrease with the braking as an anti lock system will do it (for my opinion)!

I can show you a lot of data acquisition that have fixed "zero position" butterfly on different racecar from F3000 to LMP car, I never see this kind of zero position which decrease during the braking!

I'm assuming you mean the downward slope (punctuated by downshift blips) after the throttle drops when the brakes are applied?

I suspect this slope is what is controlled when they talk about engine braking settings. I would say this comes under the general heading of traction control rather than being anything fundamentally new.

Ben

Yes it was what I search to explain with my poor english speaking!

You said that it's now fondamentally new Ok in 2005 but in 2001, I don't think you will say that!

For sure it's what I said because when I take a look on the set up sheet you can see for brake Balance 51.3% so a lot of brake on the rear and some anti lock via throttle on the rear...

Originally posted by Fat Boy
So, long story short, If it were my car I would pretty much increase the rear grip of the car with about every change I could come up with. The only thing I would do to add front grip is increase front flap/wing extension/gurney/etc. Everything else would be to help the rear.

So, basically, add mechanical grip in the rear and move downforce forward, right? I am also thinking about stiffer springs. They would keep the downforce from shifting back at high speed and from shifting forward during braking.

Damn, that's a lot of rake! Maybe the engineer has already done what I am suggesting...

Philip

This set up may be the result of a complex aerodynamic problem, known as the pitch sensitivity (see Joseph Katz - Race car Aerodynamics: designing for speed). This problem occurs at Le mans a few years ago when the Mercedes took off. It is a big instability problem.

To face this problem, the race engineer has to use stiff front spring which will lead to understeer at high speed. But this problem is really important during braking. Indeed the car pitches his nose down, which increases the down force due to ground effect at the front at the expense of the rear. This may explain why the the driver looses the rear of the car on corner entry on heavy braking

A solution to solve the problem would be a better aero package. When aerodynamics is concerned in race car the level of downforce is the first key point. The second is the pitch sensitivty which a phenomena really important on planes. Therefore the race engineer has to make a compromise to tune the performance of the car.

I hope this small explanantion helps

Well, I just got back from a trip, and since I'm being a bum today I thought I'd take a stab at decifering the data on the data overlay between Alesi and Burti.

1. On the shift to 7th gear, JA's motor seems to pull a bit cleaner. Either he is getting a bit of a draft, or he's just got a little bit better 'plant.

2. Both guys really spike the brake pressure hard at the beginning of the brake zone which is what you have to do to minimize the braking distance on a heavily aerodynamic car. LB has a very controlled brake pressure trace where as JA's brake pressure is a bit 'noisy'. He seems to be releasing brake pressure during downshifts. This is fairly common for a right foot braker in a 'normal' car, but with a semi-auto gearbox and computer controlled blipping, it seems a little strange. Does anyone know the particulars on JA's braking? I don't know a hell of a lot about that car, but it looks like to me, that the blips might be the driver's doing (as God intended!). Also, both guys hit the brakes at the same time, but LB let's off the gas just a bit later...he seems to be overlapping his throttle & brakes a little. It's hard to tell by the trace, but if so, that's a no-no as it puts a lot of extra heat in the brakes.

3. The throttle trace is definitely bizarre. It must be some sort of computer controlled throttle release in an effort to reduce rear tire lockup under braking. Both cars have the same rate of release from about 10% throttle on down. It doesn't look like any driver controlled thing I've ever seen. Incidently, if the throttle is open a good chunk through all of these low speed corners, that could very well be a big contributor to the understeer in the car.

4. JA short-shifts to 3rd gear where LB dabs at the brake with his left foot to get through Turn 2. They both lift the throttle. I'll take JA's approach since it's a little easier on the car. There's no real speed difference.

5. JA goes much deeper into T3. He carries something like an extra 15kph on the entry. That's a big deal. LB is off the gas earlier and is again dabbing at the brake to settle the car. I'd like to see the steering trace here. My guess is that JA is real busy. LB gets back to throttle early and probably picks up a good portion of the time he lost on entry down the next straight. We need to have a 'time compare' channel to really know for sure.

6. LB is later to the brakes for T4. He seems to really stove it into the corner. JA is much better at getting off the brake and rolling speed into the corner. Getting off the brake pedal early is a very tough thing to do. They get to throttle at about the same point on the track, but since JA is at a higher speed, he carries that advantage all the way down the next straight. You would kind of expect the traces to come together as the speed goes up, but I think JA has a little bit of an engine advantage, and the staight isn't that long. This corner is a good gain for JA.

7. Braking for T5 is basically identical. Again, JA's trace shows signs of coming off and getting back on the pedal, as if he were blipping the throttle. Could that be it? I don't know. I don't think he's modulating the brake pedal to reduce locking. Not at 250kph, at that speed, you just hit the pedal for all you've got and have a lot of faith in aerodynamics. Any modulation to reduce locking is going to be at the end of the brake zone. They run this corner fairly different. LB goes to first gear where as JA only goes to 2nd. They carry the same corner minimum speed, but LB goes to throttle first. Even though LB goes to throttle first, JA is the guy who accelerates away from the corner a little cleaner. I'm guessing wheelspin/traction control is a problem for LB in the lower gear where at JA is able to put power to the ground a little better in the higher gear. Again, JA gets a bit higher top speed for no apparent reason.

8. Braking for T6 is very similar. In this corner JA isn't 'pumping' the brakes. It makes me wonder even more what's going on there. They both get off the brakes at the same time, but JA is able to get back to throttle just a bit earlier, which gives him the advantage down the next straight. His car seems to have just a touch more rear grip, especially in a power-down situation.

9. T7 is a big difference between the two. JA slows the car just a touch more on entry. He has a bigger brake pressure spike, but is off the brakes much sooner. He gets to throttle a lot ealier and has a big advantage down the next straight.

10. T8 is very close between the 2 drivers. They both brake well into the corner, but I'd say the advantage has to go to Burti. The bigger brake spike early in the brake zone let's him be a little more efficient and go a touch deeper. JA is again playing around too much with the pedal. JA initiates throttle a little ealier at exit, but LB actually gets to 100% first. There's no real clear advantage for either guy in this corner.

11. They brake similarly into T9, but JA looks like he overcharged the brake zone and had to over slow the entry. My guess is that the rear started to break free on him in this corner at about the time he shifted into 2nd gear (maybe it was the downshift locking the rear tires a touch). Regardless, JA seems to be able to gather it up and get down the next straight at least as good as LB.

12. JA again shows that he's brave in high speed corners, but his bravery seems for naught. He goes to 5th gear at the entry of the corner and then gets completely off the throttle and slows to a much lower minimum than LB. Also, since his minimum is later than LB, he gets a bad shot onto the next straight. LB comes off the throttle earlier and less, and also brakes with his left foot. He seems to keep the car more settled and is able to carry more speed across the apex and get to earlier throttle. He holds his advantage down the next short straight.

13. In the last corner, T13, JA goes the brakes a little later, but pays for it by having to overslow the apex a little. LB backs up the entry just a little, uses less brake and more gas. He carries more mid-speed and has about the same corner exit shot. Slight advantage to LB.

All in all, I'd say that JA has a little better low speed corner technique and LB is a little better at the more flowing corners. It's really hard to compare the 2 when you don't know the differences in the cars (which could be pretty massive). Both guys seem to be fighting the car. It would be easier to make that call if we had a steering trace to look at as well, but just judging from the shape of the speed trace it looks like they are having to overslow the corner entries. JA shows he's pretty fast in most the corners, but LB shows the way a little here and there as well. LB has a better throttle application trace in general....it's smoother. I don't know what's up with JA's brake pressure pumping. He needs to get rid of that. He tends to play around with the throttle pedal in a similar manner. That's just not the fast way around the track.

Both guys look like they really have their hands full. I don't remember JA having a lot good to say about the Prost. I do remember his comments on the aerodynamics of the car. They weren't too flattering. I'm sure everyone was trying the best they knew how, but judging from what we've seen here I'm going to go back to what I said about getting some mechanical rear grip in the car.

Originally posted by tom62
This set up may be the result of a complex aerodynamic problem, known as the pitch sensitivity (see Joseph Katz - Race car Aerodynamics: designing for speed). This problem occurs at Le mans a few years ago when the Mercedes took off. It is a big instability problem.

To face this problem, the race engineer has to use stiff front spring which will lead to understeer at high speed. But this problem is really important during braking. Indeed the car pitches his nose down, which increases the down force due to ground effect at the front at the expense of the rear. This may explain why the the driver looses the rear of the car on corner entry on heavy braking

A solution to solve the problem would be a better aero package. When aerodynamics is concerned in race car the level of downforce is the first key point. The second is the pitch sensitivty which a phenomena really important on planes. Therefore the race engineer has to make a compromise to tune the performance of the car.

I hope this small explanantion helps

The pitch sensitivity that effected the cars at Lemans and this car are not really the same thing. What this car seems to exhibit is pretty serious aerodynamic balance changes due to front ride height. The thing doesn't just take flight at random. It just picks up a lot of front aero percentage as the front gets close to the ground. In addition, my guess is that when the front get very, very close to the ground (a few mm), the front aero drops off. Basically, a driver wants to drive something that acts in a linear manner, and that is not what is going on here.

Stiff front springs do not lead to understeer in high speed corners in my experience. They can lead to understeer in low speed corners due to raising the front roll couple percentage, but this track has a lot of corners at or over 200 kph. If you're going that fast, the wings are going to make a much bigger difference in the handling of the car than the roll couple. The stiffer front springs will reduce the change in front ride height around the track. The aero balance will be more stable while braking and tend to give the driver a piece of equipment that acts in a more linear manner.

Having the rear ride height 50mm above the rear is probably inclining the roll axis a pretty severe amount, which would make the car twitchy on the brakes and make the rear load quickly at corner entry. It's hard to really know, because our info on the suspension geometry is nill, but I'll bet that's what's going on. It's hard to argue with the comment of 'make a better aero package'. I think that's probably a good piece of advice to anyone. Once you're at the racetrack, though, you have to optimize what you have. My feelings on this one is that they had a ways to go before they were really using all of what they had available because the mechanical grip on the car was not very good. It's amazing how if you cure the mechanical problems of the car, all of the sudden the aerodynamics fall into place.

I don't think JA have a better Engine that LB! at this speed the aero drag is lot more important than engine power. For LB have more aero down force than JA and pay it in straight!

Fatboy you have a very good analyse of the data but your conclusion is a bit too quick to my opinion. As you explain in your last post their are a lot of thing that we don't know about car and driver.

to conclude, I remenber that JA have a very special braking! with a very high and quick attack! it's probably why JA can overtake where nobody do it!

For some reason I can't get the thumbnail in post 15 to open up, in any browser, on high speed or dialup. Grrr. Sounds interesting...from the description there could be some throttle bounce.

Jeeez, 50mm is lot of rake I would tend to think. I think we may have the wrong info here. Could we have the 2001 Ferrari data now please?

Originally posted by Antoine
I don't think JA have a better Engine that LB! at this speed the aero drag is lot more important than engine power.

That could very well be. 90% of what I wrote was conjecture and the other 1/2 was B.S.! It's really hard to make concrete statements when you know so little about the car.

I guessed that the 2 cars were on a similar aero package due to the simulation work that the team must have done. I've got nothing really to back that up. I will say that the trace 'looks' like JA has a little better engine. I don't even know how to describe that other than I've seen it before, and that's kinda what it looks like. You can see that even below 120kph JA seems to pull a little better than LB. I wouldn't think that they would give a different specification engine to JA, but even if 2 engines are meant to be identical, there will always be little differences.

What would support your theory is that at high speeds, JA's advantage seems to hold steady or even increase. Even if one engine is a little soft, 2 cars with the same drag tend to arrive at top speeds that are very, very close. The one with the better engine will just get there quicker. This could very well be an aero package with less downforce/drag that we're seeing.

Originally posted by Fat Boy
Stiff front springs do not lead to understeer in high speed corners in my experience. They can lead to understeer in low speed corners due to raising the front roll couple percentage, but this track has a lot of corners at or over 200 kph. If you're going that fast, the wings are going to make a much bigger difference in the handling of the car than the roll couple. ...

... It's amazing how if you cure the mechanical problems of the car, all of the sudden the aerodynamics fall into place.

I needed these two ideas 2 months ago. Back then I could not understand what was going on until the testing day was almost over. Also, wind/rain/snow/hail at the track were not helping the thinking process. I am learning.

Thanks, Fat Boy! You rock when you get those days off. When is your next one?

Philip

I know it's very difficult to resist when you see some data! You want to analyse and conclude about set up! I do the same!
but for sure it's a diffcult exercise when you don't know every thing!

Fatboy is it your job?

Job? Yup. Sometimes it seems more like my life than just my job.

You've said it almost all. All i can add is that Jean said that year that the car wasnt any good because of the problem LB was reporting with oversteer on corner entry(straight line braking and he was chasing Kimi's Sauber in Canada) + they had problems because of not much testing data on the TC.
Btw, though I'm a fan of JA, I'm really not sure which pedal he's using for braking!

P.S. A HUGE 10X to MODE!!!

JA brake right foot!
you can see a small time between throtle off and brakes, not for LB who can brakes with throtle!
Usually this time is around 0.1sec!

little bit too quick!
LB brakes left foot, you can esilt see that in fast corner where he help the car by using left foot braking (two corner before the end of the lap)
It's why you can see LB lifted throttle always after JA, but they take brakes at almost the same time!

Some other datas from Prost team with set up and comments from drivers to their race engineer on a GP. Jean Alesi and Nick Heidfeld, Imola, 2000, first day. http://www.gurneyfla.../prostap03.html

And this one, Nick Heidfeld, Monza, 2000 :


[IMG:152:120]http://img59.imageshack.us/img59/9856/heidsetup10lc.th.jpg[/img]


[IMG:152:150]http://img59.imageshack.us/img59/7550/heidsetup21lz.th.jpg[/img]

In a slightly similar vein, I dont know if anyone would be interested in a brief document from Jock Clear discussing his season at Lotus.

http://ross.stonefel...otus/Jock Clear's%20report%20of%201994%20season.doc


Thats a kind of crappy link, but you can find it in http://ross.stonefeld.com/lotus

Ross,
You've got some very VERY interesting stuff in there. At the risk of coming off sounding a bit nosey, do you have any other goodies on your website (other than the lotus page)?

Not really, my webpage became a sort of lost and found for various people. Those files were given to me by an old TNF guy (forget his nick atm) who used to work for Lotus and needed hosting space so he could share them to the forum.

The only other relevant racing things are http://ross.stonefeld.com/martini/ which is some leftover artwork from a Martini-Audi proposal I worked on, and http://ross.stonefeld.com/Minardi/ has some of their old presentation stuff, which is interesting if for no other reason than to see how well put together a file it is for a perennial backmarker, it really shows just how much of a step above the rest of the racing world F1 is.

And for giggle factor, any original Nintendo users will enjoy http://ross.stonefeld.com/mario/

Just having another look at the tracking sheet .

Look at the tyre temps front and rear (AV/AR). Considering the outing he did 8 laps, the tyre temperatures are all over the place:

86 85 69 / 72 66 60
119 107 94 / 88 92 90

Does anyone find that alarming? I am assuming it's pyro probe when he pits (I was always told start on the tyre that works the hardest and move anti-clockwise around the car) the temp spread seems quite horrible.

The pressures's arent too bad, but those temps seem to be very strange. And for the following runs (5 laps, 6 laps) it doesn't get much better.

Any thoughts/explanations?

Originally posted by Lukin
Just having another look at the tracking sheet .

Look at the tyre temps front and rear (AV/AR). Considering the outing he did 8 laps, the tyre temperatures are all over the place:

86 85 69 / 72 66 60
119 107 94 / 88 92 90

Looks like they forgot to adjust the cambers for the predominantly clockwise circuit and then tried to use some positive camber in the rear to get the car to rotate.

Philip

Originally posted by Lukin
Just having another look at the tracking sheet .

Look at the tyre temps front and rear (AV/AR). Considering the outing he did 8 laps, the tyre temperatures are all over the place:

86 85 69 / 72 66 60
119 107 94 / 88 92 90

...dont worry, just a typing error... , lh temps just inverted inner/outer..

as car is running 2.5 degrees neg cambers on front would be very surprised to see inner shoulder temps that low... spread looks very typical for Barcelona, with rear left taking a beating...

note LHRR peak inner shoulder temp on new tyre runs (first two)...