How Porsche Perfected Intake Manifolds

The art of engine design and optimization is a complex and nuanced topic. Porsche's approach to intake port pressure management is a prime example of how innovative thinking can lead to significant performance gains.

As we take a closer look at the intake port pressure, it becomes clear that there are two main approaches: traditional and Porscherian. The traditional method relies on a simple, linear curve, where the pressure wave backs and forth in a predictable manner. However, this approach has its limitations. When you hit peak valve lift, the engine is forced to push more air into the cylinder, which can result in a significant amount of energy being wasted.

In contrast, Porsche's method employs a smoother, more curved pressure wave pattern. This curve is carefully timed to coincide with the expansion of the turbocharger, which forces a little bit more air into the engine while maintaining optimal intake conditions. The key insight here is that by controlling the pressure wave, Porsche can actually reduce the amount of air entering the cylinder. However, this reduction comes at a price: cooler air.

The benefits of this approach are multifaceted. By reducing the temperature within the cylinder during the intake stroke, Porsche has managed to decrease the engine's operating temperature. This, in turn, allows for more aggressive spark timing and leaner air-fuel ratios, which can lead to significant power gains. The real-world results are impressive: at high-load and high-RPM scenarios, Porsche's engine achieves a 12% reduction in brake-specific fuel consumption without sacrificing performance.

So what makes this approach possible? The answer lies in the clever design of the expansion intake manifold. By carefully controlling the pressure wave pattern, Porsche has managed to optimize the airflow into the cylinder while minimizing waste energy. This is achieved by leveraging the turbocharger's ability to expand air at high pressures, allowing for more efficient energy transfer.

To visualize this effect, let's take a closer look at a graph of temperature versus crank angle for both the traditional and Porscherian approaches. As we can see, the cylinder temperatures drop dramatically with Porsche's method, from 115°C to just 95°C. This reduction in temperature has significant implications for engine performance and efficiency.

The benefits of this approach are clear: reduced emissions, improved fuel economy, and increased power output. But what really sets Porsche apart is its ability to optimize engine performance without sacrificing refinement or luxury. By combining advanced engineering techniques with a deep understanding of the engine's behavior, they've managed to create a truly exceptional driving experience.

As we explore the art of engine design, it's clear that innovation and experimentation are key. The development of new technologies and materials is an ongoing process, driven by the pursuit of excellence in performance and efficiency. And at the forefront of this journey is Porsche, pushing the boundaries of what's possible with their cutting-edge approach to intake port pressure management.

As we reflect on this topic, it becomes clear that the size of our whiteboards or screens matters little compared to the impact they have on our ability to understand complex concepts. The art of engine design is a multidisciplinary field, requiring expertise in areas such as thermodynamics, fluid dynamics, and materials science. But with dedication, passion, and a willingness to learn, even the most seemingly insurmountable challenges can be overcome.

So if you're interested in exploring this topic further or have questions about Porsche's approach to intake port pressure management, feel free to leave your comments below. We'd love to hear from you!

"WEBVTTKind: captionsLanguage: enhello everyone and welcome in this video we are talking about porsche's very clever expansion intake manifolds and an expansion intake manifold sounds like the exact opposite of what you maybe should do with an intake manifold and yet it actually works out in porsche's favor and so we're going to get into a more traditional style intake manifold why that design is cool and why it works and that kind of thing but then what porsche did differently and how they were able to improve upon it so pretty neat thing they introduced this in the 2008 911 gt2 and they have since employed it on their uh later uh turbocharged engines out there they're you know boxer engine style out there and so we're gonna get into the differences between theirs and why theirs is advantageous so starting with a traditional engine here we just have an inline four cylinder you can see the intake manifold right here here's our throttle body so you've got this large distributor and then you've got these narrow long intake runners that go into each individual cylinder so the first thing that happens you've got your intake stroke of course that intake valve is open allowing for air to come into the cylinder now once that intake stroke is finished you close that intake valve and you still have air that's trying to get into that cylinder it's running through this intake runner and it's coming up to that intake valve and that valve has now closed so all that air bunches up up against that intake valve and you have this high pressure area that's created well pressure doesn't like to be unevenly distributed it likes to be even so that pressure wants to equalize with the area around it so now you have this pressure wave that starts bouncing back and forth as that pressure attempts to equalize and so you have this pressure wave and ideally what you want to do is the next time you open up your intake valve you want to open it up so that pressure wave is coming back so when this is fully open you have that pressure wave force in additional air into your cylinder by forcing in that additional air you can inject more fuel and you can make more power and so that's tuned for a certain rpm region uh this length of the intake runner so that you know you know depending on how quickly that pressure wave is bouncing back and forth and know what distance it has to travel you know exactly at what rpm opening that intake valve you're going to be maximizing power and so it is a very clever thing i don't want you to think that this isn't a thing that you should do it's a it's a clever way of increasing power especially with naturally aspirated engines where you know you can force in a little bit more air than you otherwise thought would be possible just using atmospheric pressure and so you make more power it's a clever setup but porsche on the other hand did something very different so while this engine is trying to maximize pressure going into the cylinder this engine is actually trying to decrease the pressure of the air going into the cylinder so why are they doing this well what they did is they took a design of this intake manifold right here and they played around with all the different dimensions so you know they change the runner lengths they change the distributor length these pipe lengths their widths how long how short how wide how narrow and they played around with it to maximize it for brake specific fuel consumption what does that mean well basically they wanted to make the most amount of power using the least amount of fuel that's what we all want it's a great thing so what happens in this one differing from this one well we have boosted air these porsche engines are turbocharged and so you're pushing that air into the intake manifold so it comes in right here it goes down these long narrow runners and then it enters into this expansion area right here and so when you compress air you heat it up if you expand air you can actually cool it and so what happens with this air is as it goes into these expansion areas that air actually cools down and so it's actually under expansion when your intake valve opens up so the air is expanding and cooling as it goes into the cylinder now cooler cylinder temperatures mean you have a less likelihood of having knock which is destructive for engines you don't want to have that happen and so by having those cooler cylinder temperatures they're able to use either higher air fuel ratios or a combination of higher air fuel ratios and more spark advance so by using uh more air to at less fuel that means they're able to get better fuel economy if they're able to advance the spark more that means you're able to make more power so you're making more power and you're using less fuel simply by having that air expand and cool before it enters the cylinder now that sounds a bit strange because obviously you want more air and by expanding it you're going to have less air going into the cylinder so they compensate for that by using a turbocharger and forcing in additional air which sounds like in the end you know it might all balance out but it turns out it does not it turns out it works out in porsche's favor so looking at intake port pressure here so here on the left we have pressure here on the bottom we have the crank angle so your engine has two rotations of the crankshaft for every intake stroke you've got your four strokes on the left side we've got pressure we're looking at the pressure right outside this intake valve right here so that intake port pressure right about to go into the cylinder what is that pressure there and so kind of a baseline uh you kind of see that uh back and forth pressure wave that's occurring in there and so porsche changed that and so looking here this is our valve lift this dotted black line so with kind of a more traditional approach you have this pressure wave backing going up and down up and down and when you hit peak valve lift you try and have that peak uh pressure occur right there so you force in as much air into the cylinder as possible and you can see that that traditional way actually past that point is forcing more air into the engine versus porsche's method and then here we have porsche's method which has you know kind of a smoother curve of these pressure waves that's going on but as that air is forced in from the turbocharger it's of course high and then it expands out in this area right here and so that's where you have it dropping and so porsche has it timed so that that expansion is then occurring while your valve lift is peaking and so that air is expanding in here while it's going into your intake valve and so it's actually dropping in pressure as it goes in which means yes you have less air going in but you have cooler air going in and as i mentioned you compensate for that by using the turbocharger to force a little bit more air in now why does this work well porsche found that their intake manifold strategy resulted in lower cylinder temperatures during the intake stroke so if you think about the temperature within the cylinder during the exhaust stroke as you're pushing out those hot exhaust gases of course it's going to be very hot within the cylinder and then as you start your intake stroke you pull in that fresh new air that intake charge and you start cooling the cylinder and so that's what we're looking at a graph of right here so we have temperature here on the left in celsius 75 to 150 and then we have our crank angle here on the bottom and so we're looking at our intake stroke right here and so this is our valve lift for the intake valve and then you can see the cylinder temperatures for the two different engines and red the base engine and in blue the porsche engine you can see those cylinder temperatures dropping as that intake valve opens and you pull in that new air now they saw that versus the base style engine which came down to about 115 degrees celsius by employing this method using these expansion intake manifolds they were able to drop that cylinder temperature down to just 95 degrees celsius so 20 degrees celsius drop in temperature and as a result that means they can use more spark advance they can use a leaner air fuel ratio meaning they can create more power using less fuel exactly how much well they found at high load and high rpm scenarios they were able to reduce the brake specific fuel consumption meaning the amount of power made uh versus the amount of fuel used by 12 so same amount of power using 12 percent less fuel very cool thing that they were able to do uh using this expansion intake manifold strategy now you may have noticed the whiteboard it's bigger it's better it's awesome it's the whole screen uh very cool i actually did get a good number of comments of people saying hey it'd be cool if your whiteboard was larger and you know i think that's cool i think it's great i do like having it as a full screen my one small counter is that you know it's not the size of my whiteboard that matters this isn't some motion in the ocean joke it is not the size of my whiteboard that matters it is in fact the size of your screen that matters so if you can't see it i guess like hold the phone a little closer uh maybe like watch it on a big screen i do film in 4k so that's the good news if you do watch it on a big screen uh you know a nice 4k screen then you can take advantage of that hopefully a couple of you out there but uh the size of my whiteboard is relative to the size of the screen that you're watching on that's the unfortunate bit uh but i do appreciate you all so much for watching if you do have any questions or comments of course feel free to leave those below and happy watching on the new full screen whiteboardhello everyone and welcome in this video we are talking about porsche's very clever expansion intake manifolds and an expansion intake manifold sounds like the exact opposite of what you maybe should do with an intake manifold and yet it actually works out in porsche's favor and so we're going to get into a more traditional style intake manifold why that design is cool and why it works and that kind of thing but then what porsche did differently and how they were able to improve upon it so pretty neat thing they introduced this in the 2008 911 gt2 and they have since employed it on their uh later uh turbocharged engines out there they're you know boxer engine style out there and so we're gonna get into the differences between theirs and why theirs is advantageous so starting with a traditional engine here we just have an inline four cylinder you can see the intake manifold right here here's our throttle body so you've got this large distributor and then you've got these narrow long intake runners that go into each individual cylinder so the first thing that happens you've got your intake stroke of course that intake valve is open allowing for air to come into the cylinder now once that intake stroke is finished you close that intake valve and you still have air that's trying to get into that cylinder it's running through this intake runner and it's coming up to that intake valve and that valve has now closed so all that air bunches up up against that intake valve and you have this high pressure area that's created well pressure doesn't like to be unevenly distributed it likes to be even so that pressure wants to equalize with the area around it so now you have this pressure wave that starts bouncing back and forth as that pressure attempts to equalize and so you have this pressure wave and ideally what you want to do is the next time you open up your intake valve you want to open it up so that pressure wave is coming back so when this is fully open you have that pressure wave force in additional air into your cylinder by forcing in that additional air you can inject more fuel and you can make more power and so that's tuned for a certain rpm region uh this length of the intake runner so that you know you know depending on how quickly that pressure wave is bouncing back and forth and know what distance it has to travel you know exactly at what rpm opening that intake valve you're going to be maximizing power and so it is a very clever thing i don't want you to think that this isn't a thing that you should do it's a it's a clever way of increasing power especially with naturally aspirated engines where you know you can force in a little bit more air than you otherwise thought would be possible just using atmospheric pressure and so you make more power it's a clever setup but porsche on the other hand did something very different so while this engine is trying to maximize pressure going into the cylinder this engine is actually trying to decrease the pressure of the air going into the cylinder so why are they doing this well what they did is they took a design of this intake manifold right here and they played around with all the different dimensions so you know they change the runner lengths they change the distributor length these pipe lengths their widths how long how short how wide how narrow and they played around with it to maximize it for brake specific fuel consumption what does that mean well basically they wanted to make the most amount of power using the least amount of fuel that's what we all want it's a great thing so what happens in this one differing from this one well we have boosted air these porsche engines are turbocharged and so you're pushing that air into the intake manifold so it comes in right here it goes down these long narrow runners and then it enters into this expansion area right here and so when you compress air you heat it up if you expand air you can actually cool it and so what happens with this air is as it goes into these expansion areas that air actually cools down and so it's actually under expansion when your intake valve opens up so the air is expanding and cooling as it goes into the cylinder now cooler cylinder temperatures mean you have a less likelihood of having knock which is destructive for engines you don't want to have that happen and so by having those cooler cylinder temperatures they're able to use either higher air fuel ratios or a combination of higher air fuel ratios and more spark advance so by using uh more air to at less fuel that means they're able to get better fuel economy if they're able to advance the spark more that means you're able to make more power so you're making more power and you're using less fuel simply by having that air expand and cool before it enters the cylinder now that sounds a bit strange because obviously you want more air and by expanding it you're going to have less air going into the cylinder so they compensate for that by using a turbocharger and forcing in additional air which sounds like in the end you know it might all balance out but it turns out it does not it turns out it works out in porsche's favor so looking at intake port pressure here so here on the left we have pressure here on the bottom we have the crank angle so your engine has two rotations of the crankshaft for every intake stroke you've got your four strokes on the left side we've got pressure we're looking at the pressure right outside this intake valve right here so that intake port pressure right about to go into the cylinder what is that pressure there and so kind of a baseline uh you kind of see that uh back and forth pressure wave that's occurring in there and so porsche changed that and so looking here this is our valve lift this dotted black line so with kind of a more traditional approach you have this pressure wave backing going up and down up and down and when you hit peak valve lift you try and have that peak uh pressure occur right there so you force in as much air into the cylinder as possible and you can see that that traditional way actually past that point is forcing more air into the engine versus porsche's method and then here we have porsche's method which has you know kind of a smoother curve of these pressure waves that's going on but as that air is forced in from the turbocharger it's of course high and then it expands out in this area right here and so that's where you have it dropping and so porsche has it timed so that that expansion is then occurring while your valve lift is peaking and so that air is expanding in here while it's going into your intake valve and so it's actually dropping in pressure as it goes in which means yes you have less air going in but you have cooler air going in and as i mentioned you compensate for that by using the turbocharger to force a little bit more air in now why does this work well porsche found that their intake manifold strategy resulted in lower cylinder temperatures during the intake stroke so if you think about the temperature within the cylinder during the exhaust stroke as you're pushing out those hot exhaust gases of course it's going to be very hot within the cylinder and then as you start your intake stroke you pull in that fresh new air that intake charge and you start cooling the cylinder and so that's what we're looking at a graph of right here so we have temperature here on the left in celsius 75 to 150 and then we have our crank angle here on the bottom and so we're looking at our intake stroke right here and so this is our valve lift for the intake valve and then you can see the cylinder temperatures for the two different engines and red the base engine and in blue the porsche engine you can see those cylinder temperatures dropping as that intake valve opens and you pull in that new air now they saw that versus the base style engine which came down to about 115 degrees celsius by employing this method using these expansion intake manifolds they were able to drop that cylinder temperature down to just 95 degrees celsius so 20 degrees celsius drop in temperature and as a result that means they can use more spark advance they can use a leaner air fuel ratio meaning they can create more power using less fuel exactly how much well they found at high load and high rpm scenarios they were able to reduce the brake specific fuel consumption meaning the amount of power made uh versus the amount of fuel used by 12 so same amount of power using 12 percent less fuel very cool thing that they were able to do uh using this expansion intake manifold strategy now you may have noticed the whiteboard it's bigger it's better it's awesome it's the whole screen uh very cool i actually did get a good number of comments of people saying hey it'd be cool if your whiteboard was larger and you know i think that's cool i think it's great i do like having it as a full screen my one small counter is that you know it's not the size of my whiteboard that matters this isn't some motion in the ocean joke it is not the size of my whiteboard that matters it is in fact the size of your screen that matters so if you can't see it i guess like hold the phone a little closer uh maybe like watch it on a big screen i do film in 4k so that's the good news if you do watch it on a big screen uh you know a nice 4k screen then you can take advantage of that hopefully a couple of you out there but uh the size of my whiteboard is relative to the size of the screen that you're watching on that's the unfortunate bit uh but i do appreciate you all so much for watching if you do have any questions or comments of course feel free to leave those below and happy watching on the new full screen whiteboard\n"