F1 Exhaust System

[godlameroso]

I haven't read the whole thread, but has anyone asked or answered as to why there is a 180 degree bend after the collector in the exhausts of the cars this year? Is it supposed to serve the same function as in conventional plumbing? In other words is the bend supposed to help scavenge exhaust gases?

[hardingfv32]

I would say it is a packaging issue. It is probably helpful for proper vortex formation to have the exhaust traveling straight before it leaves the collector.

All things being equal, a 180 bend is not helpful for exhaust tuning/performance.

Brian

[strad]

Man...I wish I was as smart as you guys..Then I would know exactly how long and big to make the exhaust for a big block Chevy at 8500 RPM.

[MIKEY_!]

Correct me if i'm wrong (and i probably am) but ignoring external aerodynamics don't you want as little back pressure in the pipes as possible and therefore want the shortest pipes, even no pipes if possible?

[spacer]

In a utterly simplified and steady-state situation? I guess so.

But tuning exhausts lengths allows you to tune the timing of positive and negative pressure waves travelling through the exhaust system. This is an important factor in engines with any valve-overlap, it aids the intake proces (you actually use the exhaust flow to "suck in" an extra amount of intake charge), and at the same time prevents the fresh mixture to escape into the exhaust during the overlap period.

Try googling some articles on two-stroke exhaust design, the effects are more noticable and actually crucial on those engines.

[MIKEY_!]

Thanks

[olefud]

Man...I wish I was as smart as you guys..Then I would know exactly how long and big to make the exhaust for a big block Chevy at 8500 RPM.

If it would help you, I can run some numbers for you.

[ringo]

I know this sounds like blasphemy becuase of the implications on the car's volumetric efficiency and power, but can there be a case where the packaging and and thus aerodynamic benefits of a certain manifold design, (for example log manifold ) actual give it precedence on an F1 car over an equal length manifold?

There would be a noticeable loss in power, but how much power really?
The log manifold has some things going for it if we think about cooling flow through the packaging etc. Yes there are issues with tuning and pressure waves etc.

After seeing renault and their front exhausts you cant help but think engine power can be sacrificed for other benefits.



these do take up quite some space. To be clear I'm not endorsing the log manifold to be used any time soon, just going out on a limb on this one.

There must be a way to package an equal length manifold more efficiently, even with the use of oval sections for aero benefits.

The log, or something close to it would be the desperation move. Especially for an engine with power to spare like the Mercedes.

ringo,

A modern, stepped F1 header design produces lots of additional torque at its design point. It's more than worth the additional weight and space it occupies.

With regards to a "log" manifold design, it would have one serious drawback, in that there would likely be unacceptable flow interferences and short circuiting between adjacent cylinders with the long duration valve timings that an F1 engine uses. With 4 exhausts discharging into the log manifold at 180deg intervals, and an exhaust period of maybe 320(?) crank degrees per cylinder, there would always be two cylinders interfering with each other. The header avoids this problem by isolating the flows with individual primary tubes.

Of course, another alternative is using individual primaries and no collector. It would not be as efficient as a merged header, but it sure looks cool on Top Fuel and Funny Car drag racers.



riff_raff

Riffraff, now that we have V6 with midbank turbo. The log manifold is looking like a good design path.



We could be looking at something like this.

[matt21]

If I remember correct, the 2014 regulations mandate the exhaust to be located on the outside of the v.

[ringo]

Sure?
I remember reading that the turbo has to be between the V.

[matt21]

5.1.6 Pressure charging may only be effected by the use of a sole single stage compressor linked to a sole single stage exhaust turbine by a common shaft parallel to the engine crankshaft and within 25mm of the car centre line.

5.1.9 Engine exhaust gases may only exit the cylinder head through outlets outboard of the cylinder bore centre line and not from within the “V” centre.

[Edis]

Riffraff, now that we have V6 with midbank turbo. The log manifold is looking like a good design path.



We could be looking at something like this.

Those are not log type manifold.

And as already mentioned, the exhaust ports have to be on the outside of the V.

[MIKEY_!]

Wonder why they made that rule.

[ringo]

That means the turbo has to be behind the engine with the width of the V, 25mm from center line, and with the pipes running round back to it.
This engine wont be shorter than the V8.



This is one example. There are some other layouts, but not far from this.

[ringo]

Riffraff, now that we have V6 with midbank turbo. The log manifold is looking like a good design path.



We could be looking at something like this.

Those are not log type manifold.

And as already mentioned, the exhaust ports have to be on the outside of the V.

I know, this is just to demonstrate the location of the turbo. Either way you cannot say that these are equal length.