Any thoughts on this exhaust manifold design? (Not E55/63 specific)
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Any thoughts on this exhaust manifold design? (Not E55/63 specific)
This isn't e55 related but I know a lot of guys here have other cars and are very knowledgeable on anything performance related. Feel free to move it to off topic if no one is interested... anyway. Maybe this is old news but I just came across this the other day. Mazda is using 4 to 3 to 1 merging in their turbo manifolds. This is supposed to give much more efficient exhaust scavenging by timing the exhaust pulses. They also do some other stuff but it is emmissions and fuel economy related that we probably don't care much about (EGR cooling and injection, a pseudo variable geometry design etc).
Unfortunately I haven't found much more about it. In a single scroll turbo it might be better than a log design. But compared to a tubular equal length.... more compact, maybe more efficient at least in terms of low and mid range torque. Possibly worth considering for anyone in the market for a custom design. I haven't checked the firing order of our M113 but it might even be relevant to V8's.
Unfortunately I haven't found much more about it. In a single scroll turbo it might be better than a log design. But compared to a tubular equal length.... more compact, maybe more efficient at least in terms of low and mid range torque. Possibly worth considering for anyone in the market for a custom design. I haven't checked the firing order of our M113 but it might even be relevant to V8's.
Last edited by tw2; Sep 3, 2018 at 05:49 AM.
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From: New Zealand
There must be something wrong with me, I can't get it to link.
Anyway contents of the short article is:
Automakers are obsessed with turbocharging everything at the moment, being that consumers are demanding ever more power and low-end torque feel from their cars, while attempting to meet fuel economy expectations at the same time. That low-end boost is provided a number of ways, but effectively manufacturers desire the turbocharger boost to help provide additional power from just-off-idle RPM. Mazda has proven particularly adept at the task with their advanced SkyActiv engine family.
to help us all understand how they’ve done it.
Mazda has pushed the turbocharger as close to the exhaust valve as they possibly can, though that alone isn’t unique. The turbocharger has effectively become a variable geometry by virtue of that interesting valved manifold it bolts to. By closing off much of the manifold’s cross section at low RPM, the exhaust is bottlenecked through a smaller opening, which increases the velocity of the exhaust gasses as they hit the turbine, spooling it much quicker than it would otherwise. By the time the RPMs get high enough to open that valve, the turbo is already spinning quite well.Further, by building the exhaust manifold as a four-into-three-into-one, the high-pressure exhaust gasses are paired with the cycle of a paired cylinder’s low-pressure cycle, promoting scavenging. This also helps provide a smooth and continuous flow of exhaust gasses to keep the turbine spooled.
As mentioned in the comments of this video, this 2.5-liter engine from the CX-9 would be a great one to drop into a brand new Mazda3 to create a hell of a hot hatch. And to make that even better, it’d probably get pretty decent fuel economy to go with its power.
The youtube video is "Mazda's Secret To Efficient Turbo Engines" by Engineering Explained. Last try
Anyway contents of the short article is:
Automakers are obsessed with turbocharging everything at the moment, being that consumers are demanding ever more power and low-end torque feel from their cars, while attempting to meet fuel economy expectations at the same time. That low-end boost is provided a number of ways, but effectively manufacturers desire the turbocharger boost to help provide additional power from just-off-idle RPM. Mazda has proven particularly adept at the task with their advanced SkyActiv engine family.
Mazda has pushed the turbocharger as close to the exhaust valve as they possibly can, though that alone isn’t unique. The turbocharger has effectively become a variable geometry by virtue of that interesting valved manifold it bolts to. By closing off much of the manifold’s cross section at low RPM, the exhaust is bottlenecked through a smaller opening, which increases the velocity of the exhaust gasses as they hit the turbine, spooling it much quicker than it would otherwise. By the time the RPMs get high enough to open that valve, the turbo is already spinning quite well.Further, by building the exhaust manifold as a four-into-three-into-one, the high-pressure exhaust gasses are paired with the cycle of a paired cylinder’s low-pressure cycle, promoting scavenging. This also helps provide a smooth and continuous flow of exhaust gasses to keep the turbine spooled.
As mentioned in the comments of this video, this 2.5-liter engine from the CX-9 would be a great one to drop into a brand new Mazda3 to create a hell of a hot hatch. And to make that even better, it’d probably get pretty decent fuel economy to go with its power.
The youtube video is "Mazda's Secret To Efficient Turbo Engines" by Engineering Explained. Last try
