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2008 Exige S240
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Discussion Starter · #1 ·
The standard Veyron has two exhaust pipes exiting above the diffuser and 2 existing through the diffuser. I find this strange. Why does the Veyron have 4 exiting pipes while it really only needs 2 that would ideally exit above the diffuser.?

The SS version (1st and last picture) has all four pipes exiting above the diffuser. I guess someone has a brain fart or maybe thought the pipe exiting through the diffuser may produce more downforce.

Do you guys have any idea why Bugatti would have 2 pipes exiting through the diffuser?

The reason for asking is I have the Silent Touch exhaust that exits through the diffuser and was thinking of cutting the outlet completely flush with the diffuser. Then I would cut a hole in the difflow block off plate to create the same effect as the standard Veyron design. I like the hidden exhaust look. I had the naked rear above the diffuser exhaust setup on my Elise (sold). The stock s240 setup has grown on me.


-Robert
 

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I guess someone has a brain fart or maybe thought the pipe exiting through the diffuser may produce more downforce.
It's a blown diffuser, a borrowed aerodynamic trick used in F1 racing.

As you may know, diffusers work by producing a low pressure between the diffuser and the road that pulls the diffuser downward (ie. down force). It's basically an an aerofoil (albeit inverted)..

(an aerofoil)


And so the principle at work here is that by routing the exhaust out through the diffuser, it speeds up the air passing through back of the diffuser, thereby increasing the negative pressure that is responsible for downforce. So lower pressure = increased down force.

Not sure why they removed it though.. could be that the implementation was ineffective or maybe they just wanted to a different aesthetic for a newer model.
 

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does it mean the US exige with the bottom exhaust has blown diffuser too??? I guess as long as people shave off the pipe flush with the diffuser
 

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I'm sure it has less to do with the airflow and more to do with the exhaust on the Bugatti.

If I was to guess (I have no idea on the new Bugatti) it could be 2 exits (2 dual exits, 4 pipes total). One dual exit could be for quiet cruising and emissions. The the other dual exit pipes could be for loud, cat bypass. I always wanted to do this on the Lotus, by having a switch inside the car and going from quiet to loud mode. One pipe direction could route through the cats, hit a switch and then it could route through a straight pipe. Could be something wastegate related too.
 

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I'm sure it has less to do with the airflow and more to do with the exhaust on the Bugatti.

If I was to guess (I have no idea on the new Bugatti) it could be 2 exits (2 dual exits, 4 pipes total). One dual exit could be for quiet cruising and emissions. The the other dual exit pipes could be for loud, cat bypass. I always wanted to do this on the Lotus, by having a switch inside the car and going from quiet to loud mode. One pipe direction could route through the cats, hit a switch and then it could route through a straight pipe. Could be something wastegate related too.
Yeah my thought was wastegate bypass or a cutout, but that doesn't look to be the case... In the pics 2 posts up there's one of what looks like an aftermarket veryon exhaust and it looks to just be 2 in > 4 out on the muffler assembly.
 

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Discussion Starter · #6 ·
I initially thought the two exiting through-diffuser were also turbo waste gates but wouldn't that be an emission violation?

The waste gates merge before the muffler because there are not 4 pipes leading into the muffler, unless there are two housed within the larger pipe.

The Elige diffusers, even the most track-minded ones, are not producing any significant downforce. They are much too high off the ground and there aren't venturi gates/tunnels along the mid-area leading to the diffuser so much of the flow bleeds out the sides.

I haven't seen any manufacturers place pipes above and below on the same car.
 

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The Veyron went through literally years of development to get a car that could safely and reliably do 250mph. Exhaust and heat extraction were a major part of the development delays. Suffice it to say that the design directive for the Veyron is very different than that for the Elise. I'm not sure that there's much applicable crossover. I am certain that there were no brain farts on the part of the Bugatti engineers. The technical accomplishments with that car are staggering.
 

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Discussion Starter · #8 ·
The brain fart comment was a bit of a joke.
 
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