FK8 Honda Civic Type R Downpipe Upgrade Guide

Honda’s top of the line Civic model, the FK8 Type R, is optimized for both speed and fuel economy. For 25 years, the Honda Civic Type R has set the standard for entry-level FWD Japanese sports cars, and the current FK8 version is widely considered to be the best yet. It has beautiful appearance, responsive handling, a silky smooth 6-speed transmission, and lots of turbocharged power.

Fans of Honda cars love the FK8 Type R and its K20C1 engine since it has all the VTEC features for which the K20 is famous and adds a turbocharger on top of it. Indeed, the two of you were meant to be together. Thus, under US spec, a factory FK8 Type R produces 306 HP and 295 lb-ft of torque. While it may be plenty for the average consumer, true fans will always be looking for something more powerful. The FK8 platform, fortunately, is very adaptable, and there are several excellent performance-enhancing upgrades available for it right now.

A better downpipe is one of the finest ways to increase the FK8’s performance. As the first piece of the exhaust system following the turbo, downpipes play a crucial role in force-induced engines. They are a component that can severely limit or significantly improve an engine’s output. There is a lot of potential power to be unleashed by replacing the stock Type R downpipe with a high-flow or catless version. This article will explain why you should upgrade your FK8’s downpipe and provide some suggestions for doing so.

What is a Downpipe?

The section of exhaust that connects your turbocharger to the rest of your system (the “cat-back”) is called a “downpipe” (DP). Turbocharged vehicles have an additional exhaust component. Catalytic converters are used in the downpipes of most turbo automobiles, including the FK8’s K20C1 engine. Flow is impeded by the strong angular bends in the downpipe design used on FK8 Type-Rs.

The exhaust gases have less momentum as they enter the catalytic converter after making a 90-degree turn in the factory downpipe. The factory FK8 downpipe has a sharp curve and short taper at the outlet, reducing flow even further. Many of the benefits of the turbocharger are lost since the exhaust flow is controlled by the cat right after it leaves the turbo. Just like that, a downpipe is complete. The exhaust system begins at the turbo and extends to the front pipe.

In a turbocharged engine, the downpipe is the most crucial component of the exhaust system because it follows the turbo directly. A downpipe provides the greatest gains in performance of any of the exhaust components installed after the turbocharger.

FK8 Civic Type R Downpipe Performance

The OEM Type R downpipe has a catalytic converter (cat) to assist cut down on pollution. In that respect, it succeeds admirably. However, catalytic converters are notoriously power- and performance-sapping due to their limiting nature. One of the most important factors in a turbo’s ability to spool is the pressure drop between the inlet and outlet. Therefore, quicker spool and increased power can be achieved by decreasing back-pressure after the turbo. The best possible performance from a turbo engine would be attained if there were no exhaust after the turbo.

But that’s not exactly a feasible plan for public transportation like street cars. The installation of a high-flow catted downpipe or a catless downpipe is a great solution for this problem. They aid in lowering the K20C1’s back pressure, which in turn frees up additional horsepower.

Catless Civic Type R Downpipe

A catless downpipe (DP) is more flexible because the catalytic converter (cat) is not included. Therefore, the best power, torque, and spool can be achieved with a catless FK8 Type R downpipe. But there are certain drawbacks to catless downpipe choices. When the Civic Type R has been modified to include catless downpipes, it will likely fail emissions testing. When compared to catted downpipes, they will also result in a somewhat louder and more pungent exhaust.

Don’t be put off by the slight olfactory and auditory variances; they’re typically manageable. Most people are probably worried about emissions first and foremost. Get a catted downpipe if you don’t want to deal with the bother. We recommend going with a catless Civic Type-R downpipe if you aren’t worried about emissions or are ready to switch back to the original downpipe for emissions testing. There is no doubt that they provide the greatest value for the money.

Even still, brand-new Type R downpipes without cats are elusive. Since the EPA started cracking down, the aftermarket industry leaders in Honda parts have stopped making FK8 catless downpipes. Thus, you may need to buy one from a resale shop.

High Flow Civic Type R Downpipe

The higher price and slightly lower performance of high-flow catted Type R DPs are why many people opt for more budget-friendly uncatted models. Even though high-flow downpipes still have a catalytic converter, their enhanced design allows for more gas flow. High-flow downpipes typically provide less power than catless downpipes because the exhaust gas still has to pass through an extra component.

High-flow Civic Type R downpipes take away some of the trouble of going catless without sacrificing much performance. For instance, you can get through emissions testing without having to constantly replace your downpipe. For those who don’t need or want a louder engine or turbo (though why would you want either of those things? ), they are the greatest option. The catalyst in a stock downpipe absorbs much of the odor produced by the exhaust, so a high-flow downpipe should have a similarly muted effect.

FK8 Civic Type R Downpipe Tuning Considerations

Most of the power increase from a new downpipe is not due to the downpipe itself, so keep that in mind. There are many reasons why tuning is so important when installing a new FK8 Type R downpipe. The first is that the engine’s electronic control unit (ECU) needs to be adjusted so that it can sense the higher airflow. There won’t be any power gain unless the engine is aware that the downpipe has been upgraded to one with less restriction.

The second reason is that if you replace the stock downpipe on an FK8 Civic Type R without a tune, you may get a check engine light. To be more specific, the FK8 Type R is picky about changes to its exhaust or downpipe. A CEL may be triggered by various catted downpipe options on the FK8 without the appropriate tuning, according to some of the vehicle’s current owners.

However, the O2 sensor bung on the OEM downpipe is calibrated to a specific airflow, and most aftermarket downpipes won’t work. The O2 sensor receives a different value when the downpipe’s airflow parameters are altered, thereby causing an error. Tuning or a defouler installation can solve this issue.

Honda FK8 Civic Type R Downpipe Pros

A few benefits to running upgraded downpipes on an FK8 Type R include:

  • 15-30whp (10-20whp w/ high-flow cats)
  • Similar torque gains
  • Quicker turbo spool
  • Lower back-pressure & EGT’s
  • Louder exhaust

The most appealing feature of downpipe improvements for the FK8 Type R is the substantial increase in output. The aforementioned benefits are shared by both catted and catless alternatives. But catless downpipes are superior to catted DPs in every way imaginable. With catless downpipes, you can gain between 15 and 30 hp. Gains could be increased with more modifications and fine-tuning. Power improvements for the Type R with a catted downpipe are capped at around 5-10whp compared to what can be achieved without a cat. Power and torque increases will be almost equivalent.

Once again, the reduced back pressure brought on by the pressure decrease will speed up the turbo’s spooling process. This decrease in pressure aids in maintaining manageable exhaust gas temperatures (EGTs). There is a cumulative effect of the improved performance from each component of an enhanced downpipe. There aren’t many upgrades that can offer the same amount of performance improvement for the same price.

FK8 Honda Civic Type R Upgraded Downpipe Sound

It’s no secret that this one can divide opinions. With an enhanced downpipe, the increased loudness is one of the most noticeable differences in day-to-day driving. Increasing the downpipe’s diameter and flow rate makes the exhaust system louder because of the increased exhaust gas velocity. That’s a huge plus in the eyes of most fans. However, it may not be the best option if you regularly drive your Type R and are sensitive to increased interior noise.

A catless or high-flow downpipe is an excellent choice for individuals seeking enhanced noise levels. An improved exhaust note is one of the most common desires of car fans, and a performance downpipe will deliver just that. When the downpipe of an FK8 is improved, the car’s interior bass tone deepens and the turbo induction sounds are amplified, according to several drivers. With a catless downpipe, the volume increase is to be expected. Crackles and pops from the K20C1 are more audible through catless Type R downpipes, which is a lot of fun.

A high-flow catted downpipe is your best bet if you don’t want your Civic Type R to be noticeably louder inside and outside the car. A catless downpipe is the way to go if you’re down with a bit more turbo and induction noise.

FK8 Honda Civic Type R Upgraded Downpipe Options

Now that we’ve gotten that out of the way, let’s talk about some of our favorite downpipe improvements for the Civic Type R. We’ll outline both catless and catted DP possibilities. Remember that this is not meant to be an all-inclusive list. The FK8 may be fitted with a variety of aftermarket downpipes from a variety of manufacturers. These are merely some examples of solutions we’ve found to be very effective in terms of cost, quality, and utility.

1) PRL Motorsports High Volume Downpipe Upgrade

The moniker PRL Racing Limited (PRL) comes up frequently when discussing the best Type R downpipes among FK8 owners and the greater Honda tuning community. That’s for a fantastic cause, trust me. PRL Motorsports has made it their mission since 2007 to supply the Honda aftermarket with premium components at affordable costs. Their high-volume catted downpipe for the FK8 Type R is similarly impressive.

Among the more notable aspects of the PRL downpipe is the massive 5.0″ GESI G-Sport high-flow catalytic converter installed smack in the middle. To match the diameter of the remainder of the piping, most competitors use a cat with a lower internal diameter, which can limit flow more than is ideal. When it comes to a catted downpipe, the huge cat design not only delivers the highest flow rates, but also reduces the amount of turbulence created inside the pipe.

With regards to the PRL Type R downpipe’s form and build, it is made entirely of 304 stainless steel and is formed to offer the least amount of resistance to gas flow possible. The PRL downpipe’s redesigned shape is arguably the most performance-enhancing feature. Because of the large inlet, the turbine’s exhaust and the wastegate’s gases are mixed together without turbulence. When compared to the stock downpipe, the reduced angle of the outlet facilitates the rapid release of exhaust gases.

2) RV6 Catless Civic Type R Downpipe Upgrade

Despite widespread elimination of catless FK8 downpipes, RV6 remains one of the most well-known and acclaimed fabrication companies in the Honda sector. RV6 is well-known for its thorough design attention to detail, employing cutting-edge CAD and laser scanning technology to guarantee a snug and secure fit. That’s to be expected, given that their downpipe doesn’t have a catalytic converter.

The RV6 catless downpipe, like the PRL Motorsports downpipe, is manufactured entirely from 304 stainless steel. Thus, the downpipe is able to survive long-term exposure to its own scalding temperatures without deteriorating. For improved exterior heat management, the RV6 downpipe keeps the factory heat shield mounting locations. Because there is no catalytic converter, a defouler is included with the RV6 package to keep the CEL from lighting up. Argon back gassed TIG welds are used throughout the whole downpipe, making the joints nice and clean.

RV6 meticulously designed a catless system for optimal flow dynamics and performance. Advanced flow analysis was utilized throughout the design of the turbo output, downpipe, and front pipe connections to ensure the best possible flow characteristics. When compared to the other downpipes on our list, the RV6 is clearly the most powerful because it has the greatest flow numbers. Those of you living in a CARB-compliant state may want to know that you cannot legally purchase a downpipe without a catalytic converter. Know that you cannot pass an emissions test while operating one.

3) MAPerformance FK8 Civic Type R Downpipe

Finally, we’ll suggest one more excellent high-performance catted solution. For nearly two decades, the MAPerformance crew has provided top-tier components to the Japanese tuner scene, demonstrating their expertise and dedication to the industry. One particularly impressive product they provide is a catted FK8 performance downpipe.

The MAPerformance downpipe, like the others on this list for the FK8, is constructed from 304 stainless steel for exceptional strength and heat resistance. If you want to further improve thermal dispersion and maintain a cool cabin environment, you can buy the MAPerformance downpipe with ceramic coating. MAPerformance provides the option of selecting the downpipe catalytic converter type. You can go with the factory cat, which is less expensive but produces less power, or you can upgrade to a GESI cat that can handle 500 HP.

The MAPerformance catted downpipe just requires a few simple tools and the included components to install. Cottage Grove, Minnesota is where everything is hand-built and welded, so you know it will be of the highest quality and workmanship.

FK8 Downpipe Upgrades Summary

Downpipes that have been upgraded are a great mod for almost any turbo engine. The Civic Type R is the same way. A downpipe without a catalytic converter can give you about 10 to 20whp more power. High-flow catted DPs will give you about 5 horsepower less. You’ll also notice quicker turbo spool and a better all-around power curve. Also, downpipes with or without cats will make your Civic sound a little bit deeper and more aggressive.

Those looking for a catless downpipe will enjoy the great price, quality, and performance from the RV6 catless downpipe. If you’re concerned with emissions, check out the catted downpipe option from PRL as well. MAPerformance, Skunk2, and tons of other companies have some solid choices as well but they are quite a bit pricier. Regardless of your choice, it’s hard to go wrong with a Civic Type R downpipe upgrade. As always, safe driving!

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