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http://photo.gp/2015/06/05/honda-rc213v-exhaust-design/
http://photo.gp/2015/08/14/repsol-ho...haust-at-brno/
http://photo.gp/2015/06/03/yamaha-yz...xhaust-design/
Repsol Honda MotoGP Exhaust at Brno
Posted on 14 Aug, 2015 by Scott Jones
Though I have photographed the Repsol Honda exhausts from many angles before, this morning I got a new perspective that shows just how different the ‘same’ exhaust systems can be from one rider’s bike to another’s. Design and length of the exhaust system are two elements that affect an engine’s characteristics. Please click on the above image to view it larger.
The media center here at Brno offers an overhead view of the pit lane. Looking down on Dani Pedrosa’s bike (shown left) and Marc Marquez’ bike (shown right), we can see that the shapes of the two versions of the Repsol Honda exhaust are quite different.
My perspective is not identical as the mechanics had moved Pedrosa’s bike farther away from the garage. You can see from the position of the rear tire that I’m looking at Pedrosa’s bike from more of an angle than Marquez’, on which I’m looking nearly straight down.
Comparison of the unprocessed photos suggests that Marquez’ seat is a bit farther back, which makes sense given that he’s taller. That there is more of the 2 into 1 section showing on Pedrosa’s bike may be accounted for by his seat being closer to the front of the bike.
The position of the seat also likely affects the position of the rear pipe hanger, which is visible on each bike and supports the pipe from above by attaching just behind the rider’s number.
You can also see the tip of the longer front-cylinder exhaust that Marquez is still using in the bottom left portion of the right side photo. Pedrosa is still using the shorter version, and that front exhaust is not visible on his bike from this perspective. This is curious because it appears from looking at these overhead views that Pedrosa’s bike has a longer exhaust path than Marquez’. The bend in this tail section seems designed to allow that straight section on the right side of Pedrosa’s bike’s pipe to exist.
Both of Pedrosa’s bikes have the design shown here, and both of Marquez’ bikes match as well.
By comparison, the Aspar Hondas of both Laverty and Hayden have identical exhaust sections that are quite different from those used on the Repsol Honda team:
UPDATE (2015-08-19): On Monday at the test, there was lots of down time related to the lousy weather. I took the opportunity to approach one of the HRC guys to ask about the differences between the Marquez and Pedrosa versions of this tail pipe section. I explained how I had viewed each from above and noted the different shapes/lengths of the pieces.
“You are very observant,” he commented with a wry smile.
I asked about why the riders had different pieces of exhaust pipe in this area and he confirmed that this is one of the ways Honda can affect the characteristics of the engine. Many things they can do with software, but physical changes such as different pipe length and design are another.
So it’s down to rider preference, I asked, Dani prefers one and Marc prefers the other? That was so.
I then rolled the dice and asked how changing the length of pipe affected what the rider felt from the engine. The smile grew, as did the degree of wry amusement, and when a slight shake of the head was added to that smile I knew I’d have to keep on wondering about this detail for myself.
But I appreciate very much the confirmation that the differences between these two versions of rear exhaust are determined by what each rider prefers when he twists the throttle.
Yamaha YZR M1 Exhaust Design
Posted on 3 Jun, 2015 by Scott Jones
After a previous post on exhaust back pressure, I’ve been watching in pit lane for how different manufacturers approach the challenge of designing an exhaust solution that maximizes engine performance.
Each solution depends on the engine layout, of course. The Yamaha YZR M1 has an inline 4-cylinder engine, so each exhaust port is adjacent to the others at the front of the engine, as opposed to a V-4 design where two ports are at the front and two at the rear.
With Yamaha’s inline 4, the exhaust pipes follow a 4 into 2 into 1 design. In this image you can see how two of the pipes join into one just below the engine block and beneath that, the other two join into a different pipe as the exhaust gases are directed toward the rear of the engine.
Now that there are two pipes instead of four, they are routed around the oil sump. The image atop this post shows the right side of
- - - Updated - - -
this section. (Click on the top image to see a larger version.) The topmost image also shows the two pipes joining into one. The final section of single pipe is pretty short. It ends in an aerodynamic grilled opening that is much different from previous designs.
Up until Catalunya 2014, the pipe sported a traditional silencer like this and you can see that this exhaust design used a much longer section of single pipe.
After Catalunya the silencer design changed to this non-round shape. The single pipe section grew shorter, but there still appeared to be some silencing going on based on the thickness of the final section of the pipe.
The current design looks like this and similar to Honda’s pipe ends, does not appear to have any silencing properties as in previous versions.
As we will see in coming posts, exhaust designs can be radically different based on engine layout and the ideas of the engine designers.
To follow up on our look at the Yamaha YZR M1 exhaust, here is a look at how Honda routes exhaust on its RC213V.
As the RC213V uses a V4 rather than an Inline 4 like the Yamaha, the exhaust design is fundamentally different. With two exhaust ports on opposing sides of the engine, the RC213V does a pair of 2 into 1 pipes rather than the Yamaha’s 4 into 2 into 1. With the Yamaha’s exhaust we saw some noticeable changes over the past year, both in terms of the shape and design of the end piece and the length of the final section of the pipe.
The RC213V’s exhaust has remained fundamentally the same for the past several years at least, but there have been more subtle changes within the basic design.
Photos of a naked RC213V are exceedingly rare, as no manufacturer in pit lane is more diligent about making sure their machine never appears in public without side fairings on. Even shots such as the one below of Scott Redding’s 2014 RC1000V are rare, but I managed to find the bike uncovered at Phillip Island last year. I believe that the basic design of the exhaust is very similar on both bikes, so we’ll look at this image to speculate about what is going on with the RC213V.
There is a lot to look at in this photo! Notice first how the forward cylinder head, though not visible behind the frame and beneath the air box, must be very close to the upper radiator, leaving little room for the two forward pipes to attach to the exhaust ports. But attach they do, descending and becoming visible behind (from our view, in front of) the lower radiator.
The forward pipes then wind around the oil sump before joining into a single pipe and rising past the swing arm. Notice that the two pipes are not perfectly parallel, since the right side pipe has a longer route to the left side of the oil sump. The pipes are designed to end up the same exact length, which is necessary to keep the back pressure even on each of the two front cylinders.
The rear two exhaust ports are much closer to the rear of the motorcycle, which again presents the problem of how to keep back pressure even between the front and rear pairs of cylinders.
As the two rear pipes rise together, they join at the top of their climb into a single pipe, then wind around in order to make the 2 into 1 unit the same length in the rear as the unit coming from the front. The main image above shows another perspective of this, as does the next.
The design of this final section is one area where I have noticed changes over the past few years. Changing the back pressure is one thing the engineers can do to affect engine performance even in this age of sealed engines and frozen development.
I have noticed changes in the where the two sections of pipe join into a single pipe. Sometimes the join has been closer to the rear cylinders, thus reducing the distance the exhaust gases travel before being forced into a single pipe, and sometimes the join has been farther. The size of the megaphone section at the end also appears to vary, at least to the naked eye. This of course is very difficult to verify, even with the ability to photograph the bikes in pit lane. I hardly ever shoot the bikes from exactly the same perspective and distance, which is what I’d need to do to be able to prove that one day’s megaphone section is larger than another’s.
But some changes are so obvious that they make plain the degree to which the engineers play around with how the exhaust design affects engine performance. This is the rear section from Bradl’s RC213V at Silverstone last season. Notice that the 2 into 1 join is much closer to the bodywork, and the shape of the pipe’s bend is dramatically different. It’s a longer loop, thus lengthening the single pipe section both by joining the two pipes earlier and by lengthening the final section.
Coming up: The Aprilia RS-GP exhaust design makes both the Yamaha and Honda designs look like models of simplicity.
http://photo.gp/2015/06/05/honda-rc213v-exhaust-design/
http://photo.gp/2015/08/14/repsol-ho...haust-at-brno/
http://photo.gp/2015/06/03/yamaha-yz...xhaust-design/
Repsol Honda MotoGP Exhaust at Brno
Posted on 14 Aug, 2015 by Scott Jones
Though I have photographed the Repsol Honda exhausts from many angles before, this morning I got a new perspective that shows just how different the ‘same’ exhaust systems can be from one rider’s bike to another’s. Design and length of the exhaust system are two elements that affect an engine’s characteristics. Please click on the above image to view it larger.
The media center here at Brno offers an overhead view of the pit lane. Looking down on Dani Pedrosa’s bike (shown left) and Marc Marquez’ bike (shown right), we can see that the shapes of the two versions of the Repsol Honda exhaust are quite different.
My perspective is not identical as the mechanics had moved Pedrosa’s bike farther away from the garage. You can see from the position of the rear tire that I’m looking at Pedrosa’s bike from more of an angle than Marquez’, on which I’m looking nearly straight down.
Comparison of the unprocessed photos suggests that Marquez’ seat is a bit farther back, which makes sense given that he’s taller. That there is more of the 2 into 1 section showing on Pedrosa’s bike may be accounted for by his seat being closer to the front of the bike.
The position of the seat also likely affects the position of the rear pipe hanger, which is visible on each bike and supports the pipe from above by attaching just behind the rider’s number.
You can also see the tip of the longer front-cylinder exhaust that Marquez is still using in the bottom left portion of the right side photo. Pedrosa is still using the shorter version, and that front exhaust is not visible on his bike from this perspective. This is curious because it appears from looking at these overhead views that Pedrosa’s bike has a longer exhaust path than Marquez’. The bend in this tail section seems designed to allow that straight section on the right side of Pedrosa’s bike’s pipe to exist.
Both of Pedrosa’s bikes have the design shown here, and both of Marquez’ bikes match as well.
By comparison, the Aspar Hondas of both Laverty and Hayden have identical exhaust sections that are quite different from those used on the Repsol Honda team:
UPDATE (2015-08-19): On Monday at the test, there was lots of down time related to the lousy weather. I took the opportunity to approach one of the HRC guys to ask about the differences between the Marquez and Pedrosa versions of this tail pipe section. I explained how I had viewed each from above and noted the different shapes/lengths of the pieces.
“You are very observant,” he commented with a wry smile.
I asked about why the riders had different pieces of exhaust pipe in this area and he confirmed that this is one of the ways Honda can affect the characteristics of the engine. Many things they can do with software, but physical changes such as different pipe length and design are another.
So it’s down to rider preference, I asked, Dani prefers one and Marc prefers the other? That was so.
I then rolled the dice and asked how changing the length of pipe affected what the rider felt from the engine. The smile grew, as did the degree of wry amusement, and when a slight shake of the head was added to that smile I knew I’d have to keep on wondering about this detail for myself.
But I appreciate very much the confirmation that the differences between these two versions of rear exhaust are determined by what each rider prefers when he twists the throttle.
Yamaha YZR M1 Exhaust Design
Posted on 3 Jun, 2015 by Scott Jones
After a previous post on exhaust back pressure, I’ve been watching in pit lane for how different manufacturers approach the challenge of designing an exhaust solution that maximizes engine performance.
Each solution depends on the engine layout, of course. The Yamaha YZR M1 has an inline 4-cylinder engine, so each exhaust port is adjacent to the others at the front of the engine, as opposed to a V-4 design where two ports are at the front and two at the rear.
With Yamaha’s inline 4, the exhaust pipes follow a 4 into 2 into 1 design. In this image you can see how two of the pipes join into one just below the engine block and beneath that, the other two join into a different pipe as the exhaust gases are directed toward the rear of the engine.Now that there are two pipes instead of four, they are routed around the oil sump. The image atop this post shows the right side of- - - Updated - - -
this section. (Click on the top image to see a larger version.) The topmost image also shows the two pipes joining into one. The final section of single pipe is pretty short. It ends in an aerodynamic grilled opening that is much different from previous designs.
Up until Catalunya 2014, the pipe sported a traditional silencer like this and you can see that this exhaust design used a much longer section of single pipe.After Catalunya the silencer design changed to this non-round shape. The single pipe section grew shorter, but there still appeared to be some silencing going on based on the thickness of the final section of the pipe. The current design looks like this and similar to Honda’s pipe ends, does not appear to have any silencing properties as in previous versions.As we will see in coming posts, exhaust designs can be radically different based on engine layout and the ideas of the engine designers.
To follow up on our look at the Yamaha YZR M1 exhaust, here is a look at how Honda routes exhaust on its RC213V.
As the RC213V uses a V4 rather than an Inline 4 like the Yamaha, the exhaust design is fundamentally different. With two exhaust ports on opposing sides of the engine, the RC213V does a pair of 2 into 1 pipes rather than the Yamaha’s 4 into 2 into 1. With the Yamaha’s exhaust we saw some noticeable changes over the past year, both in terms of the shape and design of the end piece and the length of the final section of the pipe.
The RC213V’s exhaust has remained fundamentally the same for the past several years at least, but there have been more subtle changes within the basic design.
Photos of a naked RC213V are exceedingly rare, as no manufacturer in pit lane is more diligent about making sure their machine never appears in public without side fairings on. Even shots such as the one below of Scott Redding’s 2014 RC1000V are rare, but I managed to find the bike uncovered at Phillip Island last year. I believe that the basic design of the exhaust is very similar on both bikes, so we’ll look at this image to speculate about what is going on with the RC213V.
There is a lot to look at in this photo! Notice first how the forward cylinder head, though not visible behind the frame and beneath the air box, must be very close to the upper radiator, leaving little room for the two forward pipes to attach to the exhaust ports. But attach they do, descending and becoming visible behind (from our view, in front of) the lower radiator.The forward pipes then wind around the oil sump before joining into a single pipe and rising past the swing arm. Notice that the two pipes are not perfectly parallel, since the right side pipe has a longer route to the left side of the oil sump. The pipes are designed to end up the same exact length, which is necessary to keep the back pressure even on each of the two front cylinders.The rear two exhaust ports are much closer to the rear of the motorcycle, which again presents the problem of how to keep back pressure even between the front and rear pairs of cylinders.
As the two rear pipes rise together, they join at the top of their climb into a single pipe, then wind around in order to make the 2 into 1 unit the same length in the rear as the unit coming from the front. The main image above shows another perspective of this, as does the next.The design of this final section is one area where I have noticed changes over the past few years. Changing the back pressure is one thing the engineers can do to affect engine performance even in this age of sealed engines and frozen development. I have noticed changes in the where the two sections of pipe join into a single pipe. Sometimes the join has been closer to the rear cylinders, thus reducing the distance the exhaust gases travel before being forced into a single pipe, and sometimes the join has been farther. The size of the megaphone section at the end also appears to vary, at least to the naked eye. This of course is very difficult to verify, even with the ability to photograph the bikes in pit lane. I hardly ever shoot the bikes from exactly the same perspective and distance, which is what I’d need to do to be able to prove that one day’s megaphone section is larger than another’s. But some changes are so obvious that they make plain the degree to which the engineers play around with how the exhaust design affects engine performance. This is the rear section from Bradl’s RC213V at Silverstone last season. Notice that the 2 into 1 join is much closer to the bodywork, and the shape of the pipe’s bend is dramatically different. It’s a longer loop, thus lengthening the single pipe section both by joining the two pipes earlier and by lengthening the final section. Coming up: The Aprilia RS-GP exhaust design makes both the Yamaha and Honda designs look like models of simplicity.
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