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Heavy Breathing – 2017+ Honda Civic Type R Performance Intake R&D, Part 2 – Design and Prototype Fabrication

Intakes are typically the first modification that any automotive enthusiast would recommend in the name of quick power gains. It’s really no surprise either. If you take a look at any modern vehicle on the road today, including the Civic Type R, stock intakes are full of silencers, restriction points, and accordion-style hoses. Those are three things that I know every gearhead doesn’t want, and in fact it’s quite the opposite when looking to add some power, so we’ve been researching solutions to get rid of them.

The top view of the airbox once it’s removed from the car. The slim width of the box might lead to some creative solutions once we get into designing our box.

To start, let’s briefly revisit our stock air intake. While the Type R is based on the return of the Civic hatchback to the US, it’s no regular Civic hatchback. The beefed up aerodynamics on the exterior, and bright red racing seats, have the 305hp K20C1 to match, which includes a well-thought-out intake system. From the factory, Honda included a cast aluminum runner which not only accounts for 2/3 of the stock system, but also does most of our jobs for us. We only needed to focus on what was attached to that piping. The downside is that these are the tricky bits to redesign. The engine bay is like an ecosystem. Every component under the hood relies on another in order to push you back in the driver’s seat and hurl you around the track at record speeds. The intake system in the Type R is no exception.

Design

So how do you design a new intake system for a vehicle like the Type R? Well, the answer is carefully. The reason why this end of the stock air box is challenging to improve is not because of the original design, but because of all the systems and sensors incorporated in that small area. Like I said, the components all depend on each other, and one of the most important sensors is built right into the top of the stock air box, the MAF.

Catering to the MAF sensor is always one of the toughest parts of designing a new intake system.
Catering to the MAF sensor is always one of the toughest parts of designing a new intake system.

Like many modern vehicles, the Type R uses a mass airflow, or MAF, sensor to monitor the amount of fresh air entering the engine. The ECU uses this data to determine just how much fuel to spray into the cylinder for each cycle. The challenge is that these sensors are calibrated to work with the housing where it’s originally mounted. Any sort of adjustment to the size or placement of the housing could throw off the air/fuel mixture and cause an unwanted check engine light. While it would be beneficial in the name of speed and power to increase the size of this housing, we strive to design our intake systems to work on the stock tune, meaning that Ye needed to come up with new housing as close to the factory specifications as possible.

Since Honda incorporated their MAF housing into the lid of their airbox, we have to start from scratch. Ye will have to design a new housing that matches the diameter and location to keep the ECU from throwing a check engine light.
Since Honda incorporated their MAF housing into the lid of their airbox, we had to start from scratch. Ye will have to design a new housing that matches the diameter and location to keep the ECU from throwing a check engine light.

If you remember from the stock review, Honda’s French horn-shaped airbox came partially from their decision on a specific size and shape of the panel air filter. The other factor was just the open space in the engine bay. Two very important factors that Ye needed to work around when developing the new airbox design. Once the MAF housing size is determined, she can pick the best filter for that opening and build the box around it using the 3D models created from our Faro scan data.

Thanks to our gracious loaner, Ye was able to get a jump start on this project by collecting scan data days before our CTR arrived in New Castle.
Thanks to our gracious loaner, Ye was able to get a jump start on this project by collecting scan data days before our CTR arrived in New Castle.

After moving on from the air box, we found ourselves at an impasse with the rest of the intake system. What should we make this from? Typically, from what we’ve found, aluminum is the answer. There’s a clear reason that it’s been used for years in Honda performance intakes along with many others, including a few of our own. Aluminum piping has good flow characteristics, great durability, and generally looks great under the hood. However, we discovered a few hurdles in this type of construction during our research. We only have to span a short distance from the airbox to the rest of the intake, which includes a few bends and ports, and on top of that, with the amount the K20C1 moves around in the engine bay, we would have to include a serious silicone coupler. Which begs the question, why not just make it completely from silicone?

Ye works diligently testing the flow characteristics of our prototype on our flow bench using 3D printed components.
Ye works diligently testing the flow characteristics of our prototype on our flow bench using 3D printed components.

The short answer: that’s what we did. After Ye spent some considerable time between crunching numbers, simulations, and testing an early stage 3D printed model on our SuperFlow flow bench, she determined that the status quo wasn’t necessarily the best option. The new silicone design proved to not only have a marginal increase in flow, but also resist the heat generated from the turbo better than its aluminum counterpart. In our research, we found that keeping this coupler as an aluminum construction would also transfer that heat to the MAF housing, potentially frying one of the more important sensors under the hood. On top of that, the silicone construction would be able to match the K20’s movement in the bay while you’re thrashing your CTR around the track.

Fabrication

It goes without saying that the only way to test  our designs on any project like this is to make it come to life. Once the designs for each of our CTR performance intake components were completed we promptly began creating prototypes to be used for real world testing. By way of our fabricators, and machinery, the new intake design began to take shape.

We started by creating a 3D print of our MAF housing design:

Using our 3D printer we were able to produce a prototype of the new MAF housing using nylon and later coating it with XTC-30. The extra coating of epoxy seals the prototype print from any gaps in the filament left during the printing process, and also shields it from the heat of the engine bay.
Using our 3D printer we were able to produce a prototype of the new MAF housing using nylon and later coating it with XTC-30. The extra coating of epoxy seals the prototype print from any gaps in the filament left during the printing process, and also shields it from the heat of the engine bay.

Once the MAF housing was printed and cured, the next step was creating the airbox. Much like how Honda designed their original box around a filter, we had to do the same. Luckily, we already had one ready and shipped to us.

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We used our Waterjet to cut the individual sections of the new airbox before shaping and tacking it together.

Our *Wardjet* makes quick work of cutting the different sections of the prototype airbox.
Our *Wardjet* makes quick work of cutting the different sections of the prototype airbox.
Using our selection of different presses and bending machines, we are able to bend each component for the airbox into its exact shape.
Using our selection of different presses and bending machines, we are able to bend each component for the airbox into its exact shape.
Our director of innovation, Eric, filled in for our fabricator the other week to tack the sections of the new airbox design into place.
Our director of innovation, Eric, filled in for our fabricator the other week to tack the sections of the new airbox design into place.

One of the most challenging aspects of this prototype is creating the silicone hose section. With the drawings complete, we could have one of our suppliers rush a sample, but thanks to the skills of our fabricator, Mike, we created our own prototype in-house.

The process of creating a silicone hose starts with the mold. While this might look very similar to the 3D printed hose from above, but this mold is an adapted version of that design. Ye decreased the diameter for this version to compensate for the silicone that will be layered on top, and will cure at the correct dimensions. You might also notice a series of raised edges through out this print. These are cut lines. Once the silicone is cured on the mold, these raised edges will give Mike a template on where to cut excess material.
The process of creating a silicone hose starts with the mold. While this might look very similar to the 3D printed hose from above, this mold is actually an adapted version of that design. Ye decreased the diameter for this version to compensate for the silicone that will be layered on top and cured at the correct dimensions. You might also notice a series of raised edges throughout this print. These are cut lines. Once the silicone is cured on the mold, these raised edges will give Mike a template on where to cut excess material.
For the most part, silicone hoses incorporate several layers of material. Mike starts laying the first layer directly on to the mold before adding the other necessary layers and materials.
For the most part, silicone hoses incorporate several layers of material. Mike starts laying the first layer directly on to the mold before adding the other necessary layers and materials.
A metal reinforcement wire is added to the hose between layers to keep the hose from collapsing under a heavy vacuum created by the turbo. Specifically, the wire is added on the straight points around the ports.
A metal reinforcement wire is added to the hose between layers to keep the hose from collapsing under a heavy vacuum created by the turbo. Specifically, the wire is added on the straight points around the ports.
Before the hose gets cured in the oven, Mike wraps it using a binding tape. This tape makes sure the hose holds its shape around the mold while it cures. The tape is removed after the curing process, which gives the final product that tightly bound texture.
Before the hose gets cured in the oven, Mike wraps it using a binding tape. This tape makes sure the hose holds its shape around the mold while it cures. The tape is removed after the curing process, which gives the final product that tightly bound texture.
The hose goes through two curing processes. The first cure is to vulcanize the silicone. By being heated in the oven for an hour at 225°F, the silicone will go from a soft malleable material to a solid, holding its shape enough that the mold and binding tape can be removed. The second cure is more of an aging process, where after 4 hours at 350°F the silicone will not degrade or discolor, even after repeated pulls on our dyno.
The hose goes through two curing processes. The first cure is to vulcanize the silicone. By being heated in the oven for an hour at 225°F, the silicone will go from a soft malleable material to a solid, holding its shape enough that the mold and binding tape can be removed. The second cure is more of an aging process, where after 4 hours at 350°F the silicone will not degrade or discolor, even after repeated pulls on our dyno.
After the silicone is cured, Mike uses the cut lines that are now imprinted on the inside of the hose to trim the excess material. Once the edges are trimmed, Mike just needs to grind down the edges and it’s ready for testing.
After the silicone is cured, Mike uses the cut lines that are now imprinted on the inside of the hose to trim the excess material. Once the edges are trimmed, Mike just needs to grind down the edges and it’s on to testing.
Once it's cured and aged, our prototype hose is ready for testing.
Once it’s cured and aged, our prototype hose is ready.

After some serious shop-hours, our prototype fits like a charm and is ready for a long day on the dyno. For those of you wondering just how much faster you can make your Type R, our next installment will let you know just that.

Our fully assembled prototype installed on our Type R and waiting to be put through the paces on the Dyno.
Our fully assembled prototype installed on our Type R and waiting to be put through the paces on the Dyno.

Thanks for Reading!

-Nick

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