You can’t design good intercooler piping that fits a particular application for wide-scale production willy-nilly. Without the use of the proper tools, time, and R&D, the resulting product will be met with negative feedback from the surrounding automotive community. With the overall tight engine bay clearances of this 2016+ Honda Civic 1.5L Turbo, working around the space to design piping that will fit with a larger diameter than stock is a priority. Even slight miscalculations in the design parameters will result in ill-fitting pipes. I’ve already shown you that the factory piping isn’t necessarily the simplest, so to make a great product, there are steps to take.

We have a nifty tool to scan tricky design space into a computer file, easily manipulated by the engineer to create whatever part they want with pinpoint accuracy. Our engineer decided to use our scan tool for these pipes, but here is where it gets interesting.

A common industry trade when it comes to fabrication is the design and construction of a “jig” for automotive piping applications (things like intercooler piping, exhausts, downpipes, etc.). This jig is essentially a basic framework for piping structure. The pieced together jig is created in a CAD (computer-aided design) program by the engineer and printed out for our fabricator, giving an idea of exactly how the pipe will look. Each fixture is a part we cut out using our waterjet. Once all pieces are cut and assembled, it’s a matter of fitting the proper size, length and angles of the pipe sections through the jig and welding it together. We’ve done this for previous intercooler piping and exhaust projects, but this was my first time seeing the entire process from start to finish, up close. It’s like watching a form of automotive scaffolding take shape.

With both pipes finished, it’s time to move on to how we plan to connect them to the intercooler. That might sound simple and mundane, but it’s quite the opposite. Honda has connected their factory piping to their factory core using flanges sealed with inner O-rings, a relatively uncommon feature in factory turbocharged applications, and this presents a problem.

For either our upgraded intercooler core or intercooler piping to attach to the end tanks, we need adapters to accommodate the different sizing. We want everyone to be able to use our intercooler, so the core will start out having adapters to work with the stock piping. The upgraded piping is where fitment will be a challenge.

Honda turned a new leaf with the new Civic. The days of DIY forced induction projects are over and enthusiasts can roll off the lot with the help of a TD03 turbo. Owners of these new boosted Hondas can make full use of ECU tunes, turning up the workload of the single-scroll turbo, and cramming more boosted air into the cylinders. While this is a quick way to put some extra pep in the Civic’s step, these tweaks to the system come with the added side effect of increased heat throughout the intercooling system. Since we’ve already figured out how to keep the charged air cool, naturally the next step was to upgrade the mode of transportation for that air.

If you recall from our last update, our engineer had already figured out the best way to improve the flow through the piping, and worked with our master fabricator to develop a prototype. Now, we haven’t been cutting, scanning, and welding since April, but rather we’ve finalized our design and received the first sample of the new pipes.

This is typically the part where we break down our kit, cold side vs. hot side. However, for this kit, the pipes work best together. During our development, our engineer determined that there wasn’t any clear advantage to installing one side over the other. They operate most efficiently as a complete kit. We also determined that the complete kit wouldn’t add much of an advantage when combined with the stock intercooler, so we designed these pipes with our improved bar-and-plate core in mind.

The reason for upgrading the intercooler is pretty clear. The larger volume and improved construction allows for much more efficient heat dissipation, and will allow the charged air to pass through much easier, all important characteristics to consider for anyone who does anything more than commuting, especially for those who drive in hotter climates. The same sort of thinking goes into upgrading the piping, especially once the boost starts to get cranked up. The stock piping quickly becomes a restriction since the combination of plastic and rubber weren’t designed to handle much over the stock tuning.

We started by replacing the flimsy stock construction materials. Plastic and rubber are a god-send when it comes to mass production on the scale that Honda operates, but it can quickly become a weak link as the performance of the car increases. We replaced the plastic lengths of piping with mandrel-bent aluminum, along with increasing the inner diameter from 42 mm to 55 mm, giving these pipes a 30% increase in size over the stock components.

The piping wasn’t the only part of the system that received a makeover. The stock rubber couplers were replaced with 5 layers of durable silicone. Our couplers have a few tricks up their sleeves as well. The first is that we’ve embedded heat resistant fibers within each coupler during the layering process to keep any heat from the engine bay from seeping into your intercooling system. Each piece features reinforced steel wire to make sure that it’s shape holds true no matter how much boost is thrown at it.

The only quandary that remains is how to attach these new and improved pipes to the intercooler. By now, you should be quite familiar with the bolted flange method Honda used to seal the stock piping to their intercooler. This is not a common practice when it comes to fastening the intercooler pipes to the heat exchanger, so our engineer had to add some extra creativity into the intercooler’s design and our piping.

Much like the adapter plates that are included with our intercooler, the piping kit also comes with a pair of specialized adapters that convert Honda’s flange-style mount to a method that is better suited for our silicone couplers. These converters are specially designed for their designated side, and as a bonus, the hot-side adapter is visible through the port on the front bumper.

With the design finalized, and the full kit assembled, it’s time to take our loaner Civic Sport Hatch off the lift and the piping out of the photo studio, and then hit the dyno to see what sort of gains we can produce from Honda’s first take at a turbocharged engine.

To get the most accurate and comprehensive results during our dyno-days, we lined up several different testing configurations to compare our improved intercooling components and gauge how well our equipment plays with others. Before we dive into the nitty-gritty of our range of tests, take a look at what our video team captured during our dyno day.

We’re fortunate enough to have a thermal imaging camera here, which is ideal for capturing exactly what we are aiming to prevent: heat-soak. We started our series of tests with a baseline of the Civic’s stock intercooling system. The baseline test consists of a series of pulls on the dyno from which we can determine how well the air flows through the system, the pressures related to that flow, and the temperature before and after the intercooler. As a part of the baseline, we also run a heat-soak test, which involves a series of back-to-back runs to test how long until the intercooler core soaks with heat from charged air and residual heat from the engine bay. From the last shot in the video, it’s clear that it doesn’t take much for the stock core to fill with heat.

As we ran the test, the inlet temperatures spiked to around 240°F, and the outlet temperatures peaked at around 80°F. Not too bad from the relatively small tube-and-fin cooler. On our standard set of pulls, we slightly lowered inlet temperatures, but the outlet temperature neared 100°F, showing the effect of heat-soak on the intercooler.

 

After recording the baseline results on the stock intercooling system, we started our parts swap. In order to obtain the best results, we started by first testing with the stock piping and our new intercooler design, and then installed our pipe kit for a final full system test. Here is how our upgraded intercooling system faired when put through the dyno torture test.

Right away, it’s plain to see that our new construction is much more efficient at dissipating heat buildup than the stock unit. If you compare the two sets of graphs, you’ll notice that the inlet temperature begins to have an influence on the outlet temperatures. This is the telltale sign of heat-soak. Now, with our system installed, no matter the inlet temperature, the outlet remains at a rock steady 75°F. This is a much better temperature for compressing into the cylinders of your turbo-Civic.

Since we’re all enthusiasts here at Mishimoto, we know that one of the first modifications that anyone who just bought a turbocharged car seeks out is a tune. So, naturally we had a Hondata FlashPro shipped to New Castle in preparation for our Sport Hatch loaner. We programed the FK7 with Hondata’s off-the-shelf +9psi tune, bumping the Sport Hatchback’s peak wheel horsepower from 174 to 190 and a remarkable 40ft-lb increase in torque. There’s even more potential from a custom tune. The downside is the rising temperatures.

With the boost turned up, the effects of heat-soak are much more apparent, especially when we ran several back-to-back runs. The effects of cooking your intercooler will ripple through the rest of the system. On top of robbing your engine of power, the air passing through your intercooler will transfer that heat into your radiator, in turn putting an extra strain on your cooling system. While we’re all about turning up the boost on your Civic, we always recommend making sure the charged air is properly cooled, and here’s why.

During our dyno pulls with the tune and stock intercooler equipment, we saw almost a 100°F jump in the inlet temperatures with a peak of about 340°F, the outlet temperatures hovering right around 115°F. What sounds like a typical ambient temperature in the southwest, and relatively cool considering the heat of the air entering the stock intercooler, the fact remains that the hotter the air, the harder it is to compress into the cylinders.

Once we had the tune set and our intercooler and piping installed, Dan jumped back into the driver’s seat to test just how well our new core design stood up to the heat of increased boost. For the inlet temperatures, we saw similar numbers during our previous test, with peaks in the low-to-mid 300°F’s. As for the outlet temperatures, well, I’ll let our graphs speak for themselves:

Even with the boost pressure turned up, our new core design was able to shrug off the heat with ease, keeping the charged air temperature comfortably under 100°F. In fact, when we averaged  the intercooler outlet temperatures between the stock tune and Hondata tune, we saw a 20-40°F temperature drop across the board all while retaining the same air pressure throughout the system. In most cases, with our intercooler installed, you could see near ambient air temperatures being crammed into your Civic’s intake manifold, no matter how hard you push it.

There is a benevolent side effect to this increased flow and super cooling throughout your intercooler system, which is power. The perfect storm of an increase in volume, minimal pressure drop and the cool charged air yields max gains of 3 whp and 8 wtq with the intercooler alone, and picks up another horse when coupled with the piping kit on the stock tune. As with all turbo vehicles, the potential always increases once a tune is involved. The combination of the full Mishimoto intercooler kit and the Hondata +9psi remap will ramp your 1.5T powered Civic’s max gains to 10 whp and 8 wtq on top of the reprogramming results. This jump in power could bring the power figures of a Sport Hatch up to the likes of the Si.

If you just bought an Si and you’re worried about the standard Civics keeping pace with your sporty Civic, we made sure to test fit our components on this variant as well. While we didn’t have the opportunity to record the power gains of our intercooler installed on the 10^th generation Si, we can confidently state that it will keep the tuned up L15B7 just as cool.

As intrigued as we all were when inspecting every angle of the Civic Sport hatchback, hearing it bellow through the shop on the dyno, we were just as impressed with the sheer potential of Honda’s first take on a production turbo engine. Many would question why it took them so long to unveil their engineering skill with the 1.5T, but they must’ve been doing their research. The 10^th generation Civic is a remarkable platform. It isn’t perfect, and suffers once the heat is turned up, but luckily our improved intercooler design turned out to be just as impressive and will help your turbo-Civics strive for perfection.