Red Bull RB7 – Open Fronted Exhaust Blown Diffuser

When the RB7 was launched the cars apparent lack of any innovation was surprising.  Yet the car ran in its launch guise during the first day of testing.  Then, in only the tests second day, the RB7 evolved with a new diffuser and exhaust system.  Despite rule changes Newey has found the loophole that allows exhausts to blow inside the diffuser for more downforce.  Although the rules were revised for 2011 to try to prevent double diffuser and openings to allow the exhaust to blow inside the diffuser.  The rules did permit openings in the outer 5cm of the diffuser, an area where teams have recently split the floor and created raised lip, coincidentally a practice first exploited by Newey on the RB5.

In my 2011 trends and solutions post (see https://scarbsf1.wordpress.com/2011/01/27/2011-trends-and-solutions/) I proposed this area could be exploited if the exhausts could be routed there:  ” The only openings in the diffuser are the starter motor hole and a 5cm area on the outer section of floor. Exhausts could be routed to this outer section of floor, but routing the large diameter exhausts across the floor could create their own blockage effect in-between the rear wheels. Offsetting the benefit they are supposed to provide.”

It appears Newey had the same idea and has presented the modified RB7 with flattened exhausts reaching rearwards under carbon overs (shown yellow in the above picture)  these reach towards the outer 5cm of floor and blow under the raised lip in the floor.  The fast moving exhaust gas then curves inside and blows out via the sidewall of the diffuser (shown below with the red arrow).  Blowing inside the  diffuser this way helps accelerate the airflow out of the diffuser and increases downforce.  As with last years EBDs they will be sensitive to throttle openings and Renault have assisted as much as possible in accommodating the aerodynamics with a special overrun strategy, to keep the exhausts gas velocity as high as possible without overheating the engine (see https://scarbsf1.wordpress.com/2010/07/10/red-bull-map-q-the-secret-to-the-teams-q3-pace/).  Renault were also understanding in developing an engine mapping that would work with far longer secondary exhaust pipes, without losing power or drivability.

In a strange coincidence with the Lotus Renault team, the exhausts has been extended by up to 1 meter and equally has a flattened oval exit, with the central separator (https://scarbsf1.wordpress.com/2011/02/01/renault-r31-front-exit-exhausts-fee-explained/).

20 thoughts on “Red Bull RB7 – Open Fronted Exhaust Blown Diffuser

  1. fantastic article scarbs

    you really are a wizard😀
    maybe red bull got the idea from your article.

    do you think renaults engine mapping will require to run much richer at the expense of fuel mileage to compromise for power and driveability?

  2. Thankyou very much for all your work. With f1 teams developing their cars at a frantic rate throughout the it’s great to have a site that not only publish the developments but explains them in plain English with drawings. Keep up the good work.

  3. Very interesting that Renault and Red Bull both have similar exhaust requirements…

    This could simply be coincidence; a gradual move towards the needs of the blown diffusers in a different way, but the fact that both the exhausts have vertical dividers and also are so flattened is a little odd.

    This surely is an innovation which other teams could implement relatively, by that I mean it would require less work than the Renault system? Who knows, it may also be more efficient than the Renault system!

  4. I love the way you spot these things and then explain them with great drawings to support the text. Now who inspired whom here?
    Is it possible RBR asked around at Renault about longer exhausts and the works team got the tip to have look at that as well?
    Or did the Renault outfit have the same idea, or possibly it’s part of the intensive service provided by the Renault engineers to their customers. In that case, look forward to Team Lotus turning up with long exhausts as well at the next test!

  5. Brilliant again scarbs, thanks.

    Do you think the rear tyres/rear break ducts will need shielding from the exhaust gases if they are exposed as in the diagram above? I would have thought that this could be an over heating issue.

    Cheers.

    • Yes Red Bull have fitted a fence and of course the cabron shrouds over the exhausts to protect the tyre. they also ran with an infrared sensor looking at the inside face of the tyre, most likely to detect any heat problems with the tyre.

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  8. scarbsf1,

    Do you have any idea which exhaust design should theoretically be better between the Lotus Renault and Red Bull? I’m totally non technical, so don’t listen to me, but won’t it be the case that on the Renault the exhaust gases will be a colder by the time they get to the back of the car because of the distance they are travelling? Does that make the design less effective?

    The speed that the gases flow back on the Renault is going to be a function of the speed the car is moving through the air isn’t it? is this a problem? Does downforce in anyway become a function of speed?

    Nick🙂
    (I apologise if these are silly Q’s.)

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