Hows that work then?

[mondeoman]

Simple question really - once you've got a car set up ie its handling is balanced, the aero works, the engine and gearbox are good etc... how is it that simply moving it from one circuit to another can cause so many problems? Talking about F1 here really and the way cars work one week then dont the next - why is this?

All the circuits have tarmac surfaces, they are all smooth (compared with our roads at any rate), the tyres are all the same ie you can't mix hard/soft on a car, its either all soft or all hard (oooer missus)so I assume the respective levels of grip are the same, the spring rates don't change, the weight of the car is constant, air doesn't suddenly change its characteristics ie if a wing combination works, it works - French air doesn't flow differently to German air, it all follows the same rules.

So what changes?

[egomeister]

what actually stays the same?

everything changes! ambient temp, track temp, track abrasiveness, corner types, amount of braking, kerbs etc etc etc.

All of the factors that make an F1 car work properly as so dependent on each other that when one is changed, many others have to be tweaked to compensate.

[zac510]

Of course the really good cars work everywhere despite that

[HiRich]

The simplest way of answering this is that all the things you think stay the same do change. The closer you go to the limit, the more important these changes become. Pretty much everything about car set-up is a compromise. If we consider the extremes of Monza and Monaco, some examples:

• At Monaco, the car will be geared for about 160mph, at Monza 210. Intermediate gears need to be wider spread, and this may mean you don't have the ideal gear for a corner, or too large a gap between gears (so less power for an instant)
• With the same aero, the car would produce 70% more downforce at top speed (assuming elements don't stall). You would sacrifice some for less drag (or vice versa)
• Cooling would be excessive at Monza. Trim it out to reduce drag.
• The different downforce levels would force you to change spring rates significanty. Geometry may be forced into different areas of camber, changing how the tyres work with the tarmac.
• Hotter air changes power levels, cooling requirements (engine, and brakes)
• Track surface varies considerably: temp, surface friction, minor variations (or major if you include kerbs) in level which your suspension needs to accomodate.
• Tyre temperature (which is influenced by many things) changes the instantaneous grip and wear rate dramatically. You need to chase a set-up that optimises that grip round the three-odd miles.
• Corner speeds vary dramatically. If the bulk of corners are slow, you want to exploit maximum downforce, and look for a suspension set-up that seeks mechanical grip. On the high speed corners of Monza you would sacrifice mechanical grip for a stable patform of downforce (aero grip).

And all of these affect each other. Change the suspension and it changes the aero - you are chasing the optimum all the way. When (on an F1) downforce is senstive to 1mm variation in ride height (and the instantaneous ride height, say mid-corner verus entry), the engineers are chasing an incredible level of fine tuning and compromise.

One car may perform better at a particular circuit. But if a second car, designed on significantly different principles is more suited to the other circuit, favours the other, the difference will be magnified.

[mondeoman]

HiRich said:

The simplest way of answering this is that all the things you think stay the same do change. The closer you go to the limit, the more important these changes become. Pretty much everything about car set-up is a compromise. If we consider the extremes of Monza and Monaco, some examples:

• At Monaco, the car will be geared for about 160mph, at Monza 210. Intermediate gears need to be wider spread, and this may mean you don't have the ideal gear for a corner, or too large a gap between gears (so less power for an instant)
• With the same aero, the car would produce 70% more downforce at top speed (assuming elements don't stall). You would sacrifice some for less drag (or vice versa)
• Cooling would be excessive at Monza. Trim it out to reduce drag.
• The different downforce levels would force you to change spring rates significanty. Geometry may be forced into different areas of camber, changing how the tyres work with the tarmac.
• Hotter air changes power levels, cooling requirements (engine, and brakes)
• Track surface varies considerably: temp, surface friction, minor variations (or major if you include kerbs) in level which your suspension needs to accomodate.
• Tyre temperature (which is influenced by many things) changes the instantaneous grip and wear rate dramatically. You need to chase a set-up that optimises that grip round the three-odd miles.
• Corner speeds vary dramatically. If the bulk of corners are slow, you want to exploit maximum downforce, and look for a suspension set-up that seeks mechanical grip. On the high speed corners of Monza you would sacrifice mechanical grip for a stable patform of downforce (aero grip).

And all of these affect each other. Change the suspension and it changes the aero - you are chasing the optimum all the way. When (on an F1) downforce is senstive to 1mm variation in ride height (and the instantaneous ride height, say mid-corner verus entry), the engineers are chasing an incredible level of fine tuning and compromise.

One car may perform better at a particular circuit. But if a second car, designed on significantly different principles is more suited to the other circuit, favours the other, the difference will be magnified.

Ok - I kinda see what you're saying. Are they really that temperamental and finely tuned? Maybe its just a question of me not fully understanding the loads and numbers involved.. or indeed the percentage changes in these.

As an example, when it comes to changing suspension, are you talking about doubling spring rates circuit to circuit or is it more in terms of percentages like 5%-10%. Its always interesting to learn something new ....

[Ahonen]

mondeoman said:

Ok - I kinda see what you're saying. Are they really that temperamental and finely tuned? Maybe its just a question of me not fully understanding the loads and numbers involved.. or indeed the percentage changes in these.

Driven at 70% the cars would, largely, feel the same all the time, but you're dealing with something that's operating right at the edge of its performance at all times, so a minor change makes a big improvement.

It's not just F1 - all racecars are affected like that. If they weren't, teams wouldn't need people like me...

[Scuffers]

consider that in Q2, the top 10 places were covered by 0.397 of a sec (in a 1:15.XXX lap)

that's 0.5% difference between 10th and 1st...

we are talking chassing very small gains here to get on top.

(compare this with club racing grids and you will get the point)

[anonymous-user]

Ahonen said:

mondeoman said:

Ok - I kinda see what you're saying. Are they really that temperamental and finely tuned? Maybe its just a question of me not fully understanding the loads and numbers involved.. or indeed the percentage changes in these.

Driven at 70% the cars would, largely, feel the same all the time, but you're dealing with something that's operating right at the edge of its performance at all times, so a minor change makes a big improvement.

It's not just F1 - all racecars are affected like that. If they weren't, teams wouldn't need people like me...

Very true. The car I'm responsible for is set up purely for straight line acceleration (see profile pic) yet the amount of variables are immense. We can have the optimum setup for a certain venue, yet return there later on in the year, try the exact same settings and be a mile off. Suspension geometry & pre-load, wheelie bar height & stagger, anti roll bar shock compression and rebound, clutch base pressure and centrifugal weight, tyre pressures, wing angle, launch RPM, shift points, ignition timing & mapping, nitrous oxide pressure & jetting, fuel system pressure & jetting to name a few all need optimising on a run-to-run basis to maintain competitiveness. And that's just for a drag car, the amount of variables for a Formula One car that need to be at 99% and over for competitive race pace must be mind blowing to say the least.

Edited by anonymous-user on Monday 23 June 16:35

[SlipStream77]

Rat_Fink_67 said:

Ahonen said:

mondeoman said:

Ok - I kinda see what you're saying. Are they really that temperamental and finely tuned? Maybe its just a question of me not fully understanding the loads and numbers involved.. or indeed the percentage changes in these.

Driven at 70% the cars would, largely, feel the same all the time, but you're dealing with something that's operating right at the edge of its performance at all times, so a minor change makes a big improvement.

It's not just F1 - all racecars are affected like that. If they weren't, teams wouldn't need people like me...

Very true. The car I'm responsible for is set up purely for straight line acceleration (see profile pic) yet the amount of variables are immense. We can have the optimum setup for a certain venue, yet return there later on in the year, try the exact same settings and be a mile off. Suspension geometry & pre-load, wheelie bar height & stagger, anti roll bar shock compression and rebound, clutch base pressure and centrifugal weight, tyre pressures, wing angle, launch RPM, shift points, ignition timing & mapping, nitrous oxide pressure & jetting, fuel system pressure & jetting to name a few all need optimising on a run-to-run basis to maintain competitiveness. And that's just for a drag car, the amount of variables for a Formula One car that need to be at 99% and over for competitive race pace must be mind blowing to say the least.

Edited by Rat_Fink_67 on Monday 23 June 16:35

In addition to the sheer number of permutations of setups (F1 wings are adjusted in 0.5 degree increments I believe), there is also the issue of how a change in one area will affect others. A simple example is increasing wing settings overall to achieve higher cornering speeds, the additional downforce will press the car into the track more and will require stiffer suspension and/or an increase in ride height to prevent grounding. The top speed will also be reduced because of the extra drag so the gear ratios may need changing.

Try a motor racing simulator such as rFactor or GTR2 to experience how different setups affect a car.

Yesterday in a Le Mans prototype at Le Mans (Using the rFactor sim ), I had problems with oversteer at the Porsche Curves, I didn't want to increase wing as I wanted to maintain the high speed on the Mulsanne. I thought I would reduce the rear ride height a little to lower the rear C of G and reduce lateral weight transfer at the back. When I tried it, the oversteer was worse, it turned out that reducing the rear ride height had reduced the venturi effect caused by the front ride height being lower than the rear. This reduction in venturi effect had reduced downforce at the back, causing more oversteer.

You really need a Phd in engineering to master setting up high end race cars in my opinion.

Edited for spelling.

Edited by SlipStream77 on Tuesday 24th June 23:22

[NeilBeforeZod]

Something that you also have to bear in mind is that these guys are constantly chasing that last 0.1% all of the time. That's going to come from a combination of continuing developments as well as set-up changes. As mentioned before, all of these will impact the overall effectiveness of each car differently depending on a million different factors and will change depending on many outside factors too. The on-going testing these guys do will also ensure that each car is probably different in configuration each time it hits the track, so you'll see differences in lap-time for the same car on a different day/session.

McLaren stated recently that they were looking for 1/10th of a second gain per race. That's a huge amount, meaning they want the car to gain 1.8 seconds per lap from start to finish of a season.

They are also very driver dependant, based on not only what each driver prefers in the way a car handles, but also how their input into the car will affect it's performance.

I still find it amazing that with all of the different manufacturers, engine suppliers, drivers, aero kit, circuits, etc that they all manage to be so damn close to each other.

[mondeoman]

So basically the car that finishes in Canada is a completely different car to the one that starts in France?

Sounds like a bloomin minefield......

[FourWheelDrift]

mondeoman said:

the tyres are all the same.

So what changes?

The tyres funnily enough, they are produced by Bridgestone for each track and will differ from track to track to take in to account the abrasive nature of the circuit, lack of grip or other characteristic.

Plus they bring 2 dry compounds to the tracks, the main tyre and the option (white stripe).

At one circuit a hard compound tyre might be the main tyre and a medium tyre could be the option. But at the next track the same medium tyre could be the main tyre and a softer compound the option.

[Finchy172]

mondeoman said:

So basically the car that finishes in Canada is a completely different car to the one that starts in France?

Sounds like a bloomin minefield......

You got it

With F1 every track will have a new aero package generally to specifically match the requirements of the circuit. This will be small alteration to wings like vanes and planes, angles etc.

These aero mods will have been researched months in advance using CFD and tunnel testing then applied to a setup in programmes such as chassis sim and Adams.
The analysis from each GP along with the simulation data will be coupled to produce a setup for a particular circuit.

Most high spec formula or Prototype cars are extremely sensitive to any change in any variable.
Setting a car up is generally a trade off between certain areas!