Newey offers insight into why FIA exhaust ban was suspended
Red Bull Racing
Newey offers insight into why FIA exhaust ban was suspended
Posted By: James Allen  |  27 May 2011   |  11:02 am GMT  |  54 comments

Buried deep in the transcript of yesterday’s FIA press conference at Monaco is an explanation from Red Bull’s Adrian Newey of why the FIA had to row back on the off-throttle exhaust ban they tried to introduce in Spain.

Newey: Reliability concerns

Newey says that the Renault system is set up as it is to provide exhaust valve cooling and that to ban it with immediate effect would introduce a reliability issue, which would unfairly disadvantage them. He says that the methods others have used to get the same aerodynamic effect, do cross the line.

Clearly the exhaust valve cooling was Renault’s argument that persuaded the FIA to relent on the ban on a technology that is known by F1 engineers as “TD015”.

Other rival engineers tell me that this argument doesn’t really stack up, but here’s how Newey explains it,

“The key to 3.15 (the article in the rules which the FIA says the system violates) is that it talks about ‘driver over-run then the throttle should be closed’ then in brackets ‘idle speed’ so it seems to be implying that the throttle should be closed at idle, which it clearly is,” said Newey.

“What the throttle does on over-run at other times is not clear in the regulations, not as expected.

“Certainly, in the case of Renault, then they open the throttle to full open on the over-run for exhaust valve cooling, and that’s part of the reliability of the engine. It has been signed off through the years for dyno testing and for them to change that would be quite a big issue, because the engine’s not proven that it would be reliable if the throttle remained closed in that situation.

“Obviously if other people are going further and perhaps firing the engine on the over-run then clearly exhaust valve cooling is not part of that and that would be something that presumably they would need to explain to keep Charlie (Whiting, technical delegate) happy.”

Last I heard the teams had been given until Silverstone to phase it out.

Newey also admitted in the same press conference that he has underestimated the value of KERS and hasn’t staffed the team appropriately to deal with it. In races this season KERS has been unreliable, with the effect that the drivers have really only had it at the starts and not much more of the time. As McLaren close in on pace, this is becoming a big problem for Red Bull,

“It is not our forte, we are an aero chassis manufacturing group rather than a KERS group,” Newey said.

“The department is quite small, with hindsight probably a little too small, and there is a lot of inertia to these things. It’s quite difficult to react quickly to a problem.”

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Otherwise, they should be cool and comfy without having to be tough on the skin. You would really love your sweet princess to have fun with full enthusiasm.

Direct sun drying is to be avoided; instead, you should dry it in an airy place not directly in the sun.


Just a thought, but doesn’t throttle application affect the pitch of the car, which as we know, has quite a significant effect on aerodynamics? So, independent of the blown diffuser debate, doesn’t the throttle already constitute a driver operated device that affects aerodynamics?

Oh, and while we are talking about it, doesn’t the brake pedal do the same thing by inducing a pitch change (dive)?

And, of course, we have heard multiple times how the angle of the front wheels in a turn affects the aerodynamic performance of the front wing, so I guess the steering wheel is also a driver operated device that influences aerodynamics?

Sounds like the next step will be mandating zero dive and zero squat suspension and not allowing steering on the cars as these are clearly in contravention of the article 3.15.

Just a thought 😉


As mentioned elsewhere in these comments, in ‘overrun’ the momentum of the car is causing the wheels to drive the engine.

If the throttles remain open on the overrun, the engine will be a simple air pump — air being sucked in through the inlet and being blown out through the exhaust. There is no requirement to inject fuel or to ignite it in order to get a mass flow of air to enable the blown diffuser.

Now, you could inject some fuel, ignite it very late in the engine cycle (i.e. during the exhaust stroke with the exhaust valve open, not during the compression stroke when all valves are closed) and create combustion as the mixture exits the exhaust. There is no doubt that this would create more exhaust energy and blow the diffuser harder. Based on their exhaust note, I suspect the McLarens are doing this.

In summary:

– you can get some blown diffuser benefit from running open throttles on the overrun.

– you can get more benefit if you also inject fuel and ignite it during the exhaust cycle.


The rules should apply to ALL team equally, no exceptions.


Well if it is just for cooling purposes then I’m sure Adrian won’t mind making a quick modification to the engine map so that the injectors are always closed on the overrun.

He then gets nice cool air without wasting any fuel or the inconvenience of the fuel ‘accidentally’ igniting.

It would only take a few minutes to put that into the map and he still gets his ‘cooling’ that was probably added for ‘reliability’ reasons after the engine was homologated.

I think Adrians latest comments should go with my other all time favorite ‘our wings don’t flex, it is all due to the rake’


As I understand it this has nothing to do with variable valve timing. Just regarding the ignition so that so that the cylinders charge expands through the exhaust system & not in the cylinder itself. Thereby keeping the speed of the exhaust flow at a level where it can positively influence the level of downforce.

Michael Prestia

Fine Mr. Newey, keep Valves open for cooling if that is why they were designed that way but then move your exhaust pipes away from blowing on diffuser. That has nothing to do with cooling… just has everything to do with creating downforce!!!


exhaust valve cooling can be achieved without retarding the ignition timing, in fact it will be cooler. The extra exhaust gases that add downforce is a result of dumping fuel and retarding the ignition timing on off throttle with the throttle butterfly not actually fully closed for air to enter and burn the excess fuel. In the rally world this is called anti-lag. when this happens the exhaust gas temperatures are actually higher ergo the exhaust valve is actually hotter as compared to when extra fuel is dumped without retarding the ignition timing and fully closing the throttle.


The overrun isn’t something the teams have come up with and has nothing to do with hot diffusers etc., it is simply the condition that happens when the car is not being driver by the engine, such as when the driver lifts off the throttle and the momentum of the car keeps the engine turning.

On a normal road car no fuel is injected during the overrun, but on an F1 car with a hot diffuser this would mean no exhaust gasses to power the diffuser and therefore a sudden drop off in downforce right when you need it. To counter this they are continuing to let fuel and air into the engine during the overrun with the ignition retarded to the point when the exhaust valve is opening and therefore the hot gasses produced are being sent straight out of the exhaust.

Newey seems to be claiming that Red Bull allow fuel and air into the engine on the overrun but don’t fire the ignition in order for the cool fuel to help protect the exhaust valves, but not to generate additional gas flow.

Sounds like a load of old rubbish to me as presumably the fuel/air mixture ignites anyway as in enters the red hot exhaust…



Ok so when the other teams use the over run ie leaving the exhaust valve open it causes more heat. but when renault does it, it cools the values. According to scarbs as teams have become more comfortable with this heating effect they have been able to use it more in races. SO how is it that renault is getting a “cooling” effect from this?


If the Renault engine does need to be at full throttle on the overrun to cool the valves then that is fine.

They just need to stop blowing it somewhere that affects the aerodynamics.

Then they would comply with the wording of the regulations (if not the spirit). Although I’m not sure I agree with the premise of banning this tactic in in the first place.

The Kitchen Cynic

That big fan at the back of the Brabham was for engine cooling as well, of course…


Ah the problem here with the regs I think is that we mortals only get to see the FIA published “Summary” of the regs. Whist what Adrian said is clearly not in the version we can see, indeed over-run and throttle are not mentioned at all, it is possibly in the “Full” version. (which it would be great for some of us pedantic types to see)

However I would suggest that hot blowing might come under Article 5.7.3 vis:

5.7.3 Variable valve timing and variable valve lift systems are not permitted. This is assuming that the exhaust valve is held open for a greater percentage of the rev than it is under power.

My search of the tech regs (Summary) revealed no instance of over run (or overrun or over-run).


Is it just me to think he is a step ahead of the game?


Yes but it’s great for F1 – a smaller funded team winning out against the mighty Ferrari and Mclaren teams. Long may it continue imho!


While the Red Bull company may be an oddity in that it’s not primarily a motorsport organisation I suspect calling them smaller funded might be a bit of a stretch especially over the last year or two. You don’t get a team and car like what they’ve put together when you are running on the smell of an oily rag.


Sure but I think you’ll find Ferrari (and Mclaren) operate on significantly higher budgets and at the level the teams are at, that makes a big difference.


I don’t see how a retarded ignition and overfuelled engine can help to cool the exhaust valves, its only going to create more heat around the valve.

To run the engine with no fuel injected (i.e. a fuel saving method under braking, as Ducati used in Motogp when fuel limitations were introduced) would mean that the mass flow rate of gas past the valve is achieved, how the heating of this gas with combustion can assist the cooling of this valve is beyond me, unless the increase in veolcity of the gases assist cooling, but the mass flow rate would be similar (assuming the fuel injection is not significant).


James – can you help out with something please?

Is throttle over-run a very recent phenomenon?

My understanding is that the technology was devised using smart engine mapping, in order to harness the effect of a blown diffuser, even when a driver is off-throttle.

Blown diffusers have been around for a little while but exactly how long? I thought that McLaren and Ferrari only got in on the act in 2010, through copying the Red Bull exhausts. Prior to 2010, exhaust gases weren’t blown onto the diffuser were they?

If engine development has been frozen since 2008 and Adrian Newey is claiming that throttle over-run is fundamental to engine cooling and reliability, then it means Red Bull and Renault must have been using the over-run since 2008.

I suppose it’s a moot point, as Renault allegedly have the most efficient exhaust solution, hence stand to lose the most from the ban, so they’d clearly say ‘yes’ in order to support Adrian.

Personally, I can’t see Adrian Newey knowing about throttle over-run in 2008 and not thinking of exhaust blown diffusers until 2010.

I think he’s a very canny chap, using every possible (including tenuous) means of keeping an advantage.

NB: this could all be garbage – I need to do more research into how long blown diffusers have been in action!


Exhaust blown diffusers have been around since 1983 when Renault pioneered them in the RE40. Adrian Newey has always been a big fan of them and used them in many of his cars, starting with his Leyton House CG901 in 1991. Several of his Williams designs also had them. The last cars to have them before their recent comeback were Newey’s McLaren MP4/17 and the stillborn MP4/18. A number of factors made EBDs fall out of favour when Ferrari pioneered the “chimney” exhausts in 2002 which persisted until the recent comeback for EBDs.


Well there you are – my previous post is founded on utter rubbish.

I still don’t believe that the over-run is key to Renault’s engine reliability, although it would make things very interesting if that were the case and it was banned from Silverstone.

I suppose we’ll find out in due course.


Yep it seems a little convenient that RBR need to keep it for reliability. I used to like Newey but there’s something about him that has changed this year that doesn’t sit well with me. I think he’s adopted the RBR arrogance that runs through the rest of the team. If Ferrari or McLaren were to come up with an answer like that it would be thrown out immediately as a load of rubbish.


I dunno, it’s not like it’s being allowed indefinitely – just a few more weeks for teams to rectify it. Certainly I think if they had banned it effective last race as originally suggested I believe it would have had a negative effect on more than just the RBR team.

To me it’s a measured response from the FIA, in many ways they are probably more worried about where further development of this solution leads to than where it is now.


Surely this would be the case for all Renault engined powered teams then?


So Adrian Newey’s almost as good at making up nonsense as he as at aero design. Who knew!


I appears as though Newey means the second way (from the list below)to cool the exhaust valve.

But it still sounds convenient.

Like his non-flexing flexible front wing?

Following ways can cool exhaust valve,

01) By providing a suitable number of jets on the channel through which cold water directs from the radiator are pumped. The water flowing from these jets or nozzles in contact with the areas adjacent to the exhaust valve and exhaust port, which are thus cooled.

02) An improved Cooling can also be achieved if cooling jackets are provided more elaborately near exhaust valve and exhaust port.

03) By filling a part of the stem of the exhaust valve by sodium, we can achieve better Cooling. The solid melts at high temperature (Near about 750 degree centigrade) and is thrown up and down due to the motion of the exhaust valve. The heat from the hot region is thus conveyed to the comparatively cold region. Sodium is good conductor of heat and has a high boiling point. (750 degree centigrade)

I am just an engineering student so….

Tell me if any one really knows….

Happy to learn….



There are two issues here.

1/ Engine exhaust valve cooling – one of the ways Renault has enabled itself to have a high torque with good driveability is by allowing the incoming charge to overlap the outgoing exhaust. This ensures optimum cylinder filling but perhaps means that because of fuel consumption issues they use a much leaner burn and generate more heat? However it of course promotes aero performance in lower speed corners.

2/ The effect of exhaust gases can be two fold – Red Bull don’t use ‘Hot’ exhaust gas blowing off throttle. That is they don’t retard the ignition and then ignite the mixture remaining in the exhaust to speed up gas flow and pressure to energise the diffuser.

Other teams are doing this and this is the area which teams such as Williams are asking for clarification on. Hot Blowing doesn’t effect engine performance so it causes the driver no problems in driveability terms but does ensure the diffuser remains energised giving worthwhile aero effect.

So using the exhaust gases to blow the diffuser is fine but to deliberately create off throttle ignition in the exhaust to promote gas velocity and pressure is something that is questionable.

That is why Red Bull feel the Renault solution is legal because it doesn’t ignite the gasses in the exhaust.



I really don’t understand what Adrian is saying when he says:-

“Obviously if other people are going further and perhaps firing the engine on the over-run then clearly exhaust valve cooling is not part of that and that would be something that presumably they would need to explain to keep Charlie (Whiting, technical delegate) happy.”

Because it was his team who started this, but he suggests that all they do is use this off-throttle technique to cool the exhausts, when everyone knows they use it for aerodynamic benefit? Isn’t he taking everyone for a mug?


what is bizarre here is that Jean Louis Moncet said the same thing since May 23rd and gave exactly the same explanation Newey gave yesterday (26).

But it’s very hard to agree with because without over-run ignition, exhaust gas can’t be as much energized. On the other hand Renault declared that blown diffusers were costing them 20% more fuel, which James mentioned in this blog.


What a load of hogwash… Exhaust valve cooling???

He’s basically saying they need the throttle wide open on overrun because thier engine is rubbish and overheats, therefore the extra downforce they generate is just a side effect of cooling the engine!!!!

He then says if anyone else is doing it then it might be illegal because it’s not for cooling…

And what does he mean by “others go further and firing the engine on overun”? if renault have the throttle open full on overun isn’t that exactly the same thing??? surely the engine is firing if the throttle is open!!!


I’m not so sure, for the engine to fire it needs fuel to be put in. Who’s to say that on the over-run they don’t use techniques employed by the engines elsewhere. So on the grid most of the engines run on 4 clyinders, who’s to say that on overrun they don’t limit supply of fuel to just 4cylinders and stick plain old ait (minus fuel) through the others? To enable that to happen you may well want WOT to prevent stalling. A similar principle is used on road cars when they start to overheat, e.g. some will start just putting air through a cylinder or two if they detect overheating (e.g. some Ford Focus’s).

I’m wondering if the fuel conservation in F1 is pushing them right to the edge of the envelop with regards leaning out the engine (as lean = hot!) and thus they need additional cooling? It’s well known that the Renault engine is pretty fuel efficent compared to some (like Ferrari) and carrying less fuel than a rival is a huge advantage.

Just a thought…


They retard the timing with the throttles wide open. What’s the point of retarding the timing unless you use it to ignite fuel!?


Adrian Newey is indeed a clever chap. His over run throttle is for engine cooling and reliability – the others are not. Red Bull can keep their system, the others can’t. Hmmm… Yeah, right…


I think this is a ruse by Newey to get them enough points by Silverstone so that it wont matter!



Agreed. He is trying his luck. Now lets see what the FIA does.


The exhaust topic certainly keeps everyones attention diverted from those RedBull low slung (at certain times) front wings eh.



Indeed! Perhaps the FIA will permit the other engine manufacturers to downgrade their engines, so they need to throttle on the overrun to remain reliable too 😉


cooling an engine by burning the exhaust gas is similar to try to make ice cream out of a microwave. cmiiw.


I think what Newey is saying re cooling the exhaust valves is that the ignition is retard and unburnt fuel flows over the exhaust valves, cooling them. The fuel then ignites in the exhaust pipes and provides exhaust gases for generating downforce. Also, the driver actually is taking no action to control this except getting off the throttle; one could argue that this is not under the drivers control.

The argument that pistons are moving aerodynamic devices is, in my opinion, really a stretch. If this is so then everything in the car is an aerodynamic device; the wheels aid in extracting hot air from the brakes, they are moving aerodynamic devices (they are certainly moving when the car is); the car pitches under braking, changing the angle of the wings, that’s a moving aerodynamic devices, etc. etc. This can be carried to absurdity (and seems to be, if pistons are aerodynamic devices).


in the turbo era the idea of allowing fuelling during the overrun would have been disallowed as it would have made an illegal gas turbine – it was a trick used by some teams to keep the turbo spinning fast when not on the power to reduce lag.


That’s not what the article says, he is claiming that they pump fuel into the cylinder on the overrun and it is the cooling effect of the fuel that protects the exhaust valve.


Something seems to have got a bit confused in Newey’s comments. Regulation 3.15 reads

‘3.15 Aerodynamic influence :

With the exception of the driver adjustable bodywork described in Article 3.18 (in addition to minimal parts

solely associated with its actuation) and the ducts described in Article 11.4, any specific part of the car

influencing its aerodynamic performance : 2011 F1 Technical Regulations 16 of 73 8 March 2011

© 2010 Fédération Internationale de l’Automobile

– must comply with the rules relating to bodywork ;

– must be rigidly secured to the entirely sprung part of the car (rigidly secured means not having any

degree of freedom) ;

– must remain immobile in relation to the sprung part of the car.

Any device or construction that is designed to bridge the gap between the sprung part of the car and the

ground is prohibited under all circumstances.

No part having an aerodynamic influence and no part of the bodywork, with the exception of the skid block

in 3.13 above, may under any circumstances be located below the reference plane.

With the exception of the parts necessary for the adjustment described in Article 3.18, any car system,

device or procedure which uses, or is suspected of using, driver movement as a means of altering the

aerodynamic characteristics of the car is prohibited.’

This is indeed the rule in relation to which the hot-blown exhausts are being challenged, but Newey’s ‘“The key to 3.15 (the article in the rules which the FIA says the system violates) is that it talks about ‘driver over-run then the throttle should be closed’ then in brackets ‘idle speed’ so it seems to be implying that the throttle should be closed at idle, which it clearly is,” does not seem to refer to the rules. Perhaps, he is rather referring to the document by which the FIA wanted to clarify the rules.

There is clearly quite a strong argument that the hot-blown exhausts fall within the letter Article 3.15 (and, indeed, any sort of mechanism to artificially keep the throttle open in order to influence aerodynamics), although as drafted Article 3.15 is wide enough to include any moving part – including the parts within the engine itself – which affects the aerodynamics (e.g. by the hot exhaust gasses produced). One cannot ban the aerodynamic effect of the hot exhaust gasses, the real mischief here is the break in the link between the driver’s foot and the engine throttle position.


There’s a subtle change these days. In prior decades the airflow from throttle determined the fuel delivery and from that the torque of the engine. Not the “throttle” pedal is connected to a computer and that computer cuts the fuel flow.

In the Renault case, taking Newey at face value, the throttle was being kept open while the fuel was cut off, so the engine was still cutting torque as the driver wanted, but allowed the engine to have improved performance.


It could be banned, the exhaust exit would just have to move to the rear of the car.


Spot on. I would only question the comment about, “One cannot ban the aerodynamic effect of the hot exhaust gasses…”

One can easily control the position the exhaust gasses exit by adding a rule that they must exit at the extreme rear of the car — say, in pipes that terminate flush with the rearmost piece of bodywork (including aerodynamic devices).


“Last I heard the teams had been given until Silverstone to phase it out.” – Yes, me too, it was initially suggested by Auto Motor und Sport, I believe. Let’s see what happens in the middle of June with TWG.

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