Exhaust blown diffusers and FIA restrictions/ban

[bgroovers]

The James Allison article is the most specific public information we've had about the new engine mapping rules.

Based on public information, if the driver pushes the throttle pedal at least 1% into its travel then there is no restriction on throttle position, ignition timing, or anything else. Therefore, there is no change to blown diffusers IF the driver pushes the pedal 1%. All drivers use left foot braking which means the right foot is available for this throttle-cracking excercise during braking and turn-in.

I assume drivers and engineers are spending a lot of time practicing this technique on driving simulators at the factories. I assume teams will try it out on the cars during Friday morning practice in Valencia in advance of it becoming the new norm at the British GP.

Therefore, blown diffusers will not really be eliminated or significantly changed. The only difference is that drivers will have to do the silly keep-the-throttles-cracked thing during braking. This will be inconvenient, but if blowing the diffuser makes you faster then you really don't have a choice.

If I was strongly against blown diffusers then I would still wonder what the point of the new rules was. They seem too intentionally inept to make sense as an anti-Red-Bull plot. Therefore I assume they are a way for the FIA to remind people of its power and show that FOTA is submissive, sort of a probe into enemy lines ahead of the Concord negotiation battle.

Having a driver throttle on in the braking zone as your are suggesting will not work as you think as it will create torque at the rear wheels and drive the car forward which is not what hot or cold blowing is. Hot and cold blowing is to do with burning fuel in the exhaust so no torque is created but exhaust gas is driving the diffuser whilst off throttle.
Why do you think this is anything to do with the FIA reminding people of its power to fight in the concord negotiation battle? Its just trying to eliminate using engine mapping to effect the areo... It far from an inept way of stopping blowing diffusers and should stop cars being changed electronically under parc ferme conditions.
I just dont understand why a team cant enter its extreme quali down force map as one of its race maps and only run it in quali as driver change between about 6-10 maps through a race anyway with no need to reprogram with a laptop...

[Pandamasque]

yup, but you'd need three feet.

Not if you're Scott Speed.

*crickets*



Seriously though, clutch is controlled by 2 paddles on the back of steering wheel. HOWEVER, disconnecting rear wheels from the drivetrain may lose you a lot of stability in the corners.

[timd]

Dropping the clutch would make the car very unstable. If the FIA hear blowing again they will move to stop it. I think the most sensible thing for the teams to do is stick to 10% blowing and spend their money elsewhere. Its only likely to get banned if they come up with a work around and last a race or two.

[machin]

Surely this part of the statement made today means that the car will stall if the car is sat stationary (on the grid/pitlane etc) if the driver takes his foot fully off the pedal?

"Furthermore, when the driver lifts fully off the throttle, the ECU maps must be configured to cut off the fuel supply to the engine – this is intended to prevent so called “hot blowing” where the energy of the exhaust gas is increased by combustion."

[lotus7]

+1 on your avatar , Machin !

[gridwalker]

Surely this part of the statement made today means that the car will stall if the car is sat stationary (on the grid/pitlane etc) if the driver takes his foot fully off the pedal?

"Furthermore, when the driver lifts fully off the throttle, the ECU maps must be configured to cut off the fuel supply to the engine – this is intended to prevent so called “hot blowing” where the energy of the exhaust gas is increased by combustion."

"Cut" doesn't necessarily equate to "kill" : Lifting your foot off the throttle should "cut" the fuel supply to the maximum level mandated by the FIA (soon to be 10% of WOT). Naturally some fuel will still be required to keep the engine ticking over.

[hardingfv32]

"Surely this part of the statement made today means that the car will stall if the car is sat stationary (on the grid/pitlane etc) if the driver takes his foot fully off the pedal?"

Presently when car is on pre-grid or pit-lane the engine map being used (switch to) does not have off throttle mapping.

The driver can switch engine maps and there are multi-able maps available.

Brian

[hardingfv32]

"Couldn't a driver brake, go full throttle, and full clutch all at once during heavy braking? That would kind of "simulate" off throttle blowing, no?"

You need to keep the KERS (thus engine) engaged during braking to charge the system. Now that is not to say you couldn't move the KERS to the transmission, but that is not going to happen this season. Next season there is no blow diffusers.

Brian

[hardingfv32]

"With reference to the long throttle : Why should a driver struggle to find the point where the throttle switches from blowing to acceleration? It is relatively easy to set a point on the pedal movement where it requires a little more pressure than usual to continue moving (possibly giving a slight tactile click to indicate when the pedal moves past that point) so drivers have some feedback to indicate the pedal position."

1) Any aid in the throttle or clutch mechanism to indicate an intermediate position is clearly not allowed by the rules. The context of this rule relates to launch/starting aids.

2) The driver simply is not going to be able to accomplish all this trick foot/hand work you are asking of him.

Those in doubt: Take your street car on a small, WET, tree lined, two lane country road and do a 0-120 km/h (75 mph) braking test. Now tell me do you have ANY attention left to notice where the throttle is? The brakes are getting most of your attention and what is left over is concentrating on the steering and those BIG trees!

Watch the in car videos, this stuff is happening REALLY fast.

Brian

[raymondu999]

yup, but you'd need three feet.

I calculated 2 feet and a finger. How do you figure 3 feet?

[machin]

+1 on your avatar , Machin !

Similar (but bigger) picture on the front page of my website if you're interested!!!

http://www.competition-car-engineering.com

[bill shoe]

2) The driver simply is not going to be able to accomplish all this trick foot/hand work you are asking of him.

Those in doubt: Take your street car on a small, WET, tree lined, two lane country road and do a 0-120 km/h (75 mph) braking test. Now tell me do you have ANY attention left to notice where the throttle is? The brakes are getting most of your attention and what is left over is concentrating on the steering and those BIG trees!

Watch the in car videos, this stuff is happening REALLY fast.

Back in the day when drivers reached their fingers around to the back of the steering wheel they found... nothing!!! There were no paddles for shifting, clutching, engine map changes, etc.

Gears were changed with a little mechanical lever called a "gearshift". This operated a rube-goldberg mechanical linkage all the way to the shift forks in the transmission. As the driver downshifted into a corner he often only had one hand free to operate the steering wheel during this critical moment of car control.

The clutch was disengaged with a "clutch pedal". This meant there were more pedals than feet. As the driver downshifted into a corner he often had to operate three pedals simultaneously during this critical moment of car control. A really rube-goldberg technique, called "heel-and-toeing", was developed to do this in the most competent way possible. Good drivers mastered this heel-and-toe technique. It's an imperfect workaround to an awkward driving situation but it got the job done.

It's astonishing to watch a really good heel-and-toe driver work the pedals and shifter while driving a car at the limit. You would not think it's possible but it is. Compared to this I am really not concerned about the ability of drivers to keep the throttle pedal slightly cracked during braking.

Again, if the throttle pedal is 0.1% into its travel then there is (based on public information) no limit to engine mapping. This means full hot blowing with no net torque delivered to the drive wheels. Cracking the throttle pedal during braking is awkward and artificial, but it's very do-able from a driver control point of view.

feynman gives a good description and picture (previous page) of how to set up the throttle pedal on a practical level.

[hardingfv32]

A heel toe jab on the throttle is not the same as holding the throttle 1-20% off fully closed.

Watch an in car clip. These braking actions are every short, at the traction limit and require the majority of the drivers attention to keep it at the limit. Now if you will allow him some lower level of braking performance, sure he could fine attention for your throttle positioning task. What good is extra grip from the blown diffuser if the driver can't perform a optimum braking application?

Brian

[raymondu999]

I think something that some people are kind of forgetting here, is that the off-throttle EBD blowing ADDED to the braking stability of the cars. Taking this away will mean they'll be at 2009-like pre-ddd braking stability. ie still safe.

[Lurk]

Throttle pedal already are like that, more or less.

Rules do not specify if the throttle must have a linear reaction or not. So throttle pedal are already configure to be more precise at the beginning. For example: 50% pedal = 25% throttle. It only depends of driver preference.
If they want to use that system to keep their hot blown diffuser, they don't have to much to do.


@Raymond: +1. They only have to change their setup to keep a good balance. But the car would not become undriveable as though by magic.