How to Modify a 10th Gen Honda Civic Si: The Ultimate Guide

How to Modify a 10th Gen Honda Civic Si: The Ultimate Guide

The 10th Generation Civic Si (2017–2021) is the perfect blend of practicality and performance. Powered by Honda’s turbocharged L15B7 1.5-liter engine and paired with a slick 6-speed manual, this front-wheel-drive platform responds incredibly well to modifications. From simple bolt-ons for daily driving to some serious power builds. Its balance of reliability, aftermarket support, and enthusiast community makes it a favorite daily driver or weekend track weapon.

 

Getting Started: Ideal Order of Operations

A sensible build starts with mods that improve drivability and performance. Of course you’re free to start anywhere you like on this list, but this is the order we would typically take.

1. Suspension upgrades – Dialing in your fitment and overall handling at the same time. Suspension upgrades give you the best of both worlds.
2. Wheels and Tires – Improving safety and handling. As these cars get older every year so do their tires and other wear items. Upgrading to a new set of tires that makes sense for your goals is a great way to start. It’s also a great excuse to snag the set of wheels you like!
3. Bolt on Performance – Unlocking some more power and of course the sounds that you are probably after.
4. Tuning – Making the most of your bolt on performance parts. Unlocking the full potential of the parts you’ve added to your car.
5. Aesthetic upgrades – rounding out the build with your own personal style.

Best Suspension Upgrades For The 10th Gen Honda Civic Si

It’s hard to name a car that can’t benefit from a drop in ride height and some suspension component upgrades. Here is what we would recommend for this car.

Coilovers

The go to choice for diving into an adjustable suspension setup. Check out our top choices of coilovers for the 10th Gen Honda Civic Si.

1. BC Racing BR Series – BC Racing gives you a great bang for your buck when it comes to an aftermarket coilover solution for your car. A drop in system coming in at a good price and giving you a ton of adjustability.
2. Fortune Auto 500 Series – Looking for more performance that’s ready for the track? The Fortune Auto 500 series is the route we recommend you take. With its digressive piston and other customization options, the Fortune Auto 500 comes in at a higher price, but we can confidently say that it’s worth it.

Lowering Springs

If you’re on a bit of a budget or don’t need the full adjustability of a coilover system, lowering springs are a fantastic option for lowering your ride height. Here are some options you can choose from.

1. Eibach Sportline – Offering a lower ride height with ease.
2. Eibach Pro-kit – Offering a less aggressive drop in ride height compared to the Sportline spring.

What Wheels And Tires Fit The 10th Gen Honda Civic Si?

That’s a great question my friend, and I’m glad you asked. We happen to know a thing or two about aftermarket wheel and tire fitment and can provide some real world experience with multiple brands. That being said, here are some of our top choices for wheels and tires.

Recommended Wheel Sizing

Diameter: 18”
Width: 8.5” – 9.5”
Offset: +40 – +35

Recommended Tire Size

Width: 225 – 255
Aspect Ratio: 35 – 40

Recommended Wheels

The best wheels for the 10th Gen Honda Civic Si are the ones that keep things simple yet purposeful. Because that’s what this car does best. Here is a list of our top wheel choices for this car.

1. Konig Hypergram – A lightweight flow form wheel option that offers a decent lip and available in the perfect sizes for the Honda Civic.
2. Enkei RPF1 or NT03 +M – Honestly, I couldn’t choose one or the other, so I did both. Sorry. The iconic Enkei RPF1 is good for many reasons. Availability, lightweight, strong, and just looks good. However, the NT03 +M does all of that as well, just in a different looking wheel that looks incredible on this platform.
3. Work Emotion ZR10 – A 10 Spoke Japanese flow form option that flows perfectly with the body lines of the 10th Gen Civic Si.

Recommended Tires

1. Continental ExtremeContact DWS06+ – Our top choice for the do-it-all tire. The DWS06 is an amazing all season tire that gives you the performance you need for your Civic Si all year round.
2. Michelin Pilot Sport 4S – Looking to step things up a bit? Can’t go wrong with the PS4S. Giving you more grip during those warm summer days while giving you peace of mind whenever the random rain shower hits.
3. Falken Azenis RT615K+ – A budget friendly “Sticky” option for those of you looking for something that not only looks aggressive, but can hold its own when it comes to the track or back roads.

Bolt On Performance For the 10th Gen Honda Civic Si

Intake Systems

Cold air intakes increase airflow while reducing intake temperatures, a good way to get a few extra horsepower and throttle response.

1. PRL Motorsports Cold Air Intake System
2. aFe Takeda Cold Air Intake System

Exhaust Systems

An aftermarket exhaust improves overall exhaust flow and of course tends to make our cars sound sick. On top of that a bump in horsepower is also a nice benefit. Here are some of our top choices for exhausts for the 10th Gen Honda Civic Si.

1. AWE Tuning Track Edition Exhaust
2. aFe Takeda Cat-Back Exhaust System
3. Borla Cat-Back Exhaust System
4. Greddy Supreme SP Cat-Back Exhaust

Tuning

Nothing scarier than a Honda with a laptop in the passenger seat. Jokes aside, tuners optimize air/fuel and boost for more power and a better throttle response. Pairing bolt on modifications with a tune is especially popular in the 10th generation thanks to the turbocharged platform.

1. Hondata CANFlex – Honda Civic Si Tune – A flexible tuning solution that works with various fuel blends and builds.
2. COBB Accessport V3 – A simple plug-n-play tuning solution that has been proven among many different vehicle platforms

The Biggest Mistakes When Modifying the 10th Gen Honda Civic Si

The 10th Gen Civic Si is a great platform, but it’s also easy to damage if you don’t understand its weak points. At MartiniWorks, we’ve seen plenty of avoidable mistakes on these cars.

First: don’t floor it at low RPM

These engines are prone to LSPI (low-speed pre-ignition). Always keep the revs above 3,000 RPM before heavy throttle and downshift instead of lugging the engine.

Second: don’t ignore the factory head bolts

Once you add basic bolt-ons like an intake, intercooler, exhaust, or tune, the weak factory head bolts can lead to head gasket issues. If you plan to modify the car, upgrading the head bolts should be part of the plan.

Third (and most important): don’t install a blow-off valve

The Civic Si is designed for a recirculating diverter valve. A blow-off valve throws off air calculations and can cause misfires and drivability issues. If you want an upgrade, use an aftermarket metal diverter valve, not a BOV.

Finally, don’t chase parts without a plan

Some intakes can cause fueling issues, the Si doesn’t require TPMS sensors, and bigger isn’t always better. Focus on proven upgrades that improve balance, reliability, and how the car actually drives.

Build smart, and the 10th Gen Civic Si will reward you.

Conclusion

The 10th Gen Honda Civic Si is a versatile and rewarding platform that welcomes enthusiasts of all levels. Whether you’re into spirited canyon runs, track days, or a subtle street build, the aftermarket support makes it easy to craft a car that’s uniquely yours.

MartiniWorks has a full catalogue of Civic Si parts to support every stage of your build. From performance to suspension to wheels and tires. Mod your car with your friends at MartiniWorks.