I mentioned that we are going for height over depth with this design in the last update, making for a unique change compared to other intercoolers. There are two reasons for choosing height. First, if a core is going to be thicker, it will add weight. While a thick core is great, we do want to keep in mind that this is a Honda Civic, and they aren’t known for upgrades that add a lot of weight. We want things light to keep this car nimble, so our core won’t be too thick. Second, fin surface area for the air to interact with is important. These fins are responsible for the cooling during the heat transfer process. The more fins the air directly hits, the more efficient the heat transfer. With a tall core, it improves the heat transfer and creates more space in the back to keep the core further away from the combined heat of the A/C condenser and radiator.

If an intercooler stays closer to those components, it will heat the core quicker, negatively affecting heat transfer, thus making your air warmer than it should be. There also won’t be any space for the air to move behind it and cycle some of that radiating heat. By moving our core forward to clear the front core support, we were able to make it taller and slimmer, negating the effects of a core that is deeper and closer to that radiating heat.

Since the core is moved forward, fitment is also something we need to pay attention to. The Sport version has a slightly different bumper than the sedan, so we also ordered a spare EX-T bumper from our local Honda dealership to be sure that our core frame fits. All systems go!

Emphasizing height means having to manipulate the movement of airflow. The use of ducting functions within our design to funnel air into the core. Our engineers want to be sure that every morsel of air is directed right at our core. A pair of ducts will come with our end tanks to ensure that happens. These ducts will seal against a part of the bumper to direct the air to the core and prevent air from moving around the end tanks.

We 3D printed end tanks to mimic our intended design, now that it’s clear ducting will be involved. The end tanks will be cast with a bar-and-plate core. Honda also did something interesting with how they connect their charge pipes to the stock end tanks. They bolt to the intercooler with an O-ring seal, a rare design feature, as most designs use a boot or a coupler. We want this intercooler to work with stock piping and our intercooler piping, so adapters will come with the kit for both versions.

With our complete design plans set in motion, we need to get a functioning prototype in here to see how our theory holds up. It’s now a waiting game until we get to dyno this Civic with our intercooler and find out the results.

Stay tuned. (Typical sendoff, or could I be foreshadowing something this time?)

When it comes to intercoolers, the old saying “bigger is better” almost always rings true, and even with the spatial restrictions we faced during the design process, we were still able to deliver on that mantra. To start, we added three more rows to our cooler to increase the fin surface area by 97%, almost doubling the amount of area being directly exposed to airflow. This might not come as a surprise to those who saw our design in the last update, but we decided the best direction to go was up. We opted for taller over thicker, but that’s not to say we didn’t add thickness to this cooler as well, a full extra inch to be exact. The combination of this extra depth and the additional rows means an increase of internal volume from 315in³  to 637in³, equating to a 102% increase. While it might not look it from the outside, our new core design is double the size of the stock unit.

On top of nearly doubling the size of the intercooler for your 1.5T powered Civic, we’ve also ditched a few other aspects of the stock intercooler to increase the airflow and improve cooling characteristics. The first aspect was all the plastic in the original design. While plastic is beneficial for producing hundreds of thousands of units, it is easily damaged and can degrade over time. We’ve equipped our much larger core with cast aluminum end tanks that allow for increased and smoother airflow. Flow diverters integrated into the design of the end tanks ensure that we’re making use of the full core.

Speaking of the core, we chose to differentiate from Honda’s tube-and-fin design. This construction makes for a lighter intercooler and provides adequate cooling for the stock system, but it is vulnerable to heat-soak and has trouble shedding the heat even after freeing yourself from a traffic jam. Our new core will have no trouble rejecting heat with a bar-and-plate assembly. This construction combined with the volume increase means that it will not only take much longer to effectively heat-soak, but will also easily shrug off any acquired heat, the only downside being a few extra pounds to your Civic.

Doubling the size of the stock intercooler meant fitment was still a concern. We initially designed this new intercooler to fit any of the 10^th gen. Civics equipped with Honda’s brand new turbocharged system without any modification. The last thing we want is for you to have to void any warranties. The first item on the list for when our Rallye Red Civic Sport returned was to double-check the fitment.

Rest assured, our much bigger design fits like a glove. We took the extra step to confirm that our bigger and better core fits across the Civic lineup as well.

Perhaps second to fitting the core into its mounting position is coupling it with the piping. If you look back to our review of the stock equipment, Honda’s stock piping attaches via a bracket rather than the standard rubber hosing and clamps. This put us in a bit of a predicament when trying to design a new core that will be compatible with both the stock piping and our improvements.

Since our design features both a larger inlet and outlet, designing the end tanks to be a direct fit for the stock piping flanges wasn’t an option. Going down this route would restrict the airflow, and lower the horsepower rating on the new design. What our project engineer, Dan, came up with instead was a set of adapter flanges specifically for the stock piping. Each side is tapered to accommodate the difference in diameter between the piping and the larger diameter inlet or outlet. On top of adapting to the stock piping without sacrificing airflow, Dan added a splash of color to these adapter flanges, making it hard to mix up the hot and cold side of the intercooler.

Satisfied with the build of our new intercooler design, we took our loaner FK7 from the lift and moved it over to our dyno for baseline and comparison tests between the two designs. With the amount of data we collected in the numerous different configurations, it must be saved for its own post, coming very soon. Also, be on the lookout for an in-depth coverage of our intercooler piping for the L15B7 powered Civics.

There are two things that are guaranteed to get just about everyone at Mishi HQ away from their desk for at least a few minutes. The first is as soon as something new or unique rolls into one of the bays. It doesn’t matter if it’s a massive diesel truck, C6 Corvette, or one of the 10^th Gen Civic Hatchback Sports. Nearly everyone wants to get a close look at what we’ve brought in for R&D. The second thing that gets people shuffling through the shop is when that new car makes its way to our Dynapack system. Our conspicuously red FK7 was no exception. Everyone here was curious about how the scrappy L15B7 performs with a little help from Mishimoto, and I’m going to venture to guess that you are too.

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.