Renault R31

[Giblet]

1 inch pipe? Exhaust velocity would be lowered.

You're last sentence is not accurate. Back pressure DOES increase efficiency. And I damn well know what pulse tuning is thanks.
Tell me, what is an exhaust valve introducing. A backward resonant wave of ......?

No need to get testy or defensive this is merely a discussion about racing cars. Back pressure does increase efficiency, but like anything there can be too much of a good thing.

[PlatinumZealot]

1 inch pipe? Exhaust velocity would be lowered.

what? sorry dude...

You're last sentence is not accurate. Back pressure DOES increase efficiency. And I damn well know what pulse tuning is thanks.
Tell me, what is an exhaust valve introducing. A backward resonant wave of ......?

Hate to break it to ya but Back-pressure - does not increase efficiency nor power.

That is why modern cars use high flow catalytic converters, and high flow exhaust runners. That is why turbo diesel have expander cones behind the turbo-charger. That is why formula 1 cars have fat ass exhaust pipes.

Back-pressure increases efficiency?! Get those nasty thoughts out of your head man!

[Crafty]

grasping at straws here, but...

Would it make any sense to configure the exhaust to create a venturi effect and draw air, through a duct, from the front of the car to create a negative pressure in this area AND add volume to the exhaust flow that could be used to drive the diffuser or blow the wing?

The additional volume would also modulate exhaust gas temps.

Just a thought...

I reckon you could be on to something there.

[Crafty]

Can anyone post here a pic of R30 without Engine cover , with Exhaust system mounted?

weird thought just stroke my mind...

dunno if this helps ? I *think* its last years engine ?

[Lurk]

In your opinion, is it possible the exhaust to be under the floor, as here?

http://twitpic.com/3v8ago

http://twitpic.com/3v89cl

http://twitpic.com/3v897l

It's forbidden.

3.12.7 No bodywork which is visible from beneath the car and which lies between the rear wheel centre line and a
point 350mm rearward of it may be more than 125mm above the reference plane. With the exception of the
aperture described below, any intersection of the surfaces in this area with a lateral or longitudinal vertical
plane should form one continuous line which is visible from beneath the car.

An aperture for the purpose of allowing access for the device referred to in Article 5.16 is permitted in this
surface. However, no such aperture may have an area greater than 3500mm2 when projected onto the
surface itself and no point on the aperture may be more than 100mm from any other point on the aperture.

(Article 5.16 is about engine starter.)

[manchild]

Supercavitation?



http://en.wikipedia.org/wiki/Supercavitation

I also think that two bulb-like shapes between sidepod inlets and the floor serve for same purpose. So, the exhaust is split in at least 8 pipes (4 for each cylinder bank). Nothing can been seen clearly since car is black.



The gasses would also be kept on top of the floor, unlike suggestions that they are blown below.

Same principle as fife:

[wickerbill]

To conclude: Renault made it hell of a BLOW JOB

[mith]

But how would you make legal splitting exhaust into few exits, when it is stated in the regulations that there can be only two exits? Do you have any idea for a loophole?

[siskue2005]

i think the rules state that there should only be 2 exhaust pipe, you cannot have more than that

[spaman]

I have the impression, that the sidepods aren´t symetrical. Viewed from the front - the left one seems to be muchs slimmer than the right one.

Is it possible that the exhaust exits the car just on the right side?

Take a look at this picture:



and compare it to this one:



Strange - isn´t it?

[TURU]

I have the impression, that the sidepods aren´t symetrical. Viewed from the front - the left one seems to be muchs slimmer than the right one.

Is it possible that the exhaust exits the car just on the right side?

Take a look at this picture:



and compare it to this one:



Strange - isn´t it?

I don't think they are asymetrical. "The exhaust" in your picture is just reflection.

[luca]

Here are some relevant excerpts from the current technical regulations:

3.8.5 Once the relevant bodywork surfaces are defined in accordance with Article 3.8.4, apertures, any of which
may adjoin or overlap each other, may be added for the following purposes only :
- single apertures either side of the car centre line for the purpose of exhaust exits. These apertures
may have a combined area of no more than 50,000mm2 when projected onto the surface itself. No
point on an aperture may be more than 350mm from any other point on the aperture.
[...]

5.1.6 Engines must have two inlet and two exhaust valves per cylinder.

5.6 Exhaust systems :
Engine exhaust systems may incorporate no more than two exits.
5.7 Variable geometry systems :
5.7.1 Variable geometry inlet systems are not permitted.
5.7.2 Variable geometry exhaust systems are not permitted.
5.7.3 Variable valve timing and variable valve lift systems are not permitted.

So apparently there's no rule that says there must be just two exhaust pipes. They only limit the number of exits.

[SLC]

If the exhausts do indeed exit towards the front of the car the exhaust outlets will be just behind the bargeboard blowing fumes out and rearwards towards the leading edge of the floor. The additional mass flow provided here will increase the main floor suction peak as well as strengthen the T-tray/BBoard/Canard vortex system.

[manchild]

Perhaps they have conducted a single pipe for each bank into part of the sidepod (to one that has more outlets). So not ducted/connected/extended but with tiny space between exhaust pipe and the sidepod box - just enough to meet the regs.

Remember how Ferrari had bypassed the regs. and split multiple hot air exit into one by a tiny cut trough making it "one hole"?

I think of something like that. So, in the light of those hints let's call it (if it is at all) a blown sidepod, rather than blown front diffuser.

[bosanac1]

we will know tomorrow for sure

i am sure someone will snap picture of exhaust gases should be easy to spot or flames on down shifting