Next month marks one full year with the Honda Civic Si sedan project car—and what a year it's been. Originally, I reached out to Honda about potentially getting my grubby little hands on an Si model to dive into some basic modifications to see just how much tuning potential the 8th iteration of the Si nameplate was blessed with. While many doubted the little 1.5L mill (admittedly, I too had my reservations), plenty of owners were already making impressive strides in power, handling, and aesthetic, and I wanted a canvas of my own to work on.
THERE IS A TYPE R, YA KNOW?
I'm aware. And trust me, the FK8 is incredible—packing quite a punch with its mid-$30K price tag. Undoubtedly open to performance increases, it's been the center of attention ever since it was first teased. My attention, however, was turned toward the Si, as it felt like the middle child had been somewhat neglected. The hatchback and entry-level coupe and sedans, much like the Type R, were garnering interest far quicker than the Si, most likely due to the pricing of the lower end models and their head start into the market, and the pure performance of the upper echelon CTR. At around $25K, the Si is fitted with all of the creature comforts you could want from a new car (except for power seats, which is still a little odd to me), more power out of the box as compared to lower level models, and the aftermarket in the past few years took notice and began showering it with options.
When I took hold of the keys for this Aegean Blue Metallic sedan, my first real upgrade to the car was provided by @eibachsprings. The group was in search of a stock Si sedan to test the SPORTLINE springs they'd been working on, and with this car now available, it was the perfect candidate.
In addition to the springs, Eibach also provided their front and rear anti-sway bar. The front was their replacement option for the Si and the rear was actually their Civic Type R bar, which also fits the Si chassis. A larger diameter, the idea was to tighten up the back end even more with the aggressive springs that were going in.
Adding strength to the rear is a billet aluminum subframe brace, and in order to dial in the alignment, Eibach's adjustable rear camber arms were brought into play. After a few months of testing, the SPORTLINE prototype springs proved to be a winner. Offering the lowest ride height and very crisp handling, the SPORTLINE eventually hit the market this year, but I ended up switching to Eibach's PRO-KIT in order to bring the car up a bit to play nicely with the wheel sizing and front lip I had planned. While not as intense as the SPORTLINE springs, the PRO-KIT offers a street-friendly ride height and the car is still a blast to toss into turns.
ACUITY INSTRUMENTS - @acuityinstruments
One of the things I really enjoy about working on a new platform as a project car is the chance to work with groups I've never encountered before. One such outfit is Acuity Instruments. The brand resides in Louisiana and has kept themselves busy by churning out a number of parts for the 9th generation Civic, various FIit models, and of course, the 10th gen. Civic family.
Acuity's upcoming (at the time) adjustable short shifter kit drew me into their product line-up. A complete replacement for the factory unit that, in all honesty, already seemed like a pretty good system from the factory, would completely change my mind with arguably the most precise shifting you're likely to encounter in a Honda. With each "thunk" into gear, I realized just how sharp the shift action had become. Jumping into another modified Si months later that relied on the factory shifter was a stark reminder just how good the Acuity shifter really is.
I also added Acuity's shift cable bushings, which further tighten up the throw action, and I removed the gas pedal to add Acuity's pedal spacer that offers multiple positions to give you the best fit. Raising the pedal further off of the floor to align better with the brake pedal is something I never would have thought of but after making the switch, I'll talk another 10th gen. owners ear off (I even annoy myself) about why it's completely necessary and how well it goes with that magical shifter.
No matter how good the aftermarket aero producers get, nothing fits better than OEM. I knew I wanted to add something to the sedan's flanks for a little more bulk, but nothing in the aftermarket was really tempting me. That's where Honda Factory Performance, or HFP, came into play.
Searching the Honda Genuine Parts' user-friendly app on my phone, I was able to quickly find any local dealers that had the exact parts I wanted in stock and I could even get a look at what they looked like installed. Their replacement side skirts don't require any sort of modification and installation is a breeze.
The OEM optional window visors have been copied and manipulated countless ways but like the side skirts, the fit and finish is virtually unmatched.
PRL MOTORSPORTS - @prlmotorsports
Pennsylvania's PRL Motorsports is another brand I'd never worked with before the Si program began. After hearing about the car, my old friend Bisi Ezerioha of @bisimoto sent me a message about PRL and the line of parts they produced for the 10th gen. Civic market. A few weeks later, multiple boxes from PRL arrived and it was obvious this company put some serious time and effort into their parts, with no corners cut and quite a few online reviews raving about their ability.
PRL's intercooler and charge-pipe kit went on first with its taller and thicker core supported by larger end tanks. The plastic tubing going to and from the factory intercooler was removed for PRL's reinforced 4-ply silicone couplers and upgraded charge piping. Everything fit in the bay properly and behind the bumper grill without a single issue, just like OEM.
Since I already had the massive stock bumper with its bucket-full of clips removed, I figured it was a good time to add PRL's Cobra cold-air intake. Having the bumper off made life much easier and the included instructions made this a very simple, "in your driveway" type upgrade. Offered with a Street and Race MAF option, I went with the Street MAF to get a feel for things. The open element filter, now tucked nicely under the driver's side headlight, also enhanced the "flutter" from the factory turbo between shifts—something most people like hearing.
GREDDY - @greddyperformanceproducts
Another item added to the install list while the bumper was already off was GReddy Performance Products' front bumper lip. Multiple nut and bolt combos insure it's not going anywhere, and with a low, aggressive look, it really enhances the angular front bumper. Gauging the ground-to-lip clearance, the PRO-KIT springs I moved onto definitely made sense.
SSR WHEELS - @ssrwheels
Wheels are usually a tough decision for most enthusiasts. There's a balance between style and functionality that has to be met (at least, in most cases). Add to that, color options, offset, other parts already on the car or that will be added later, and it's enough to drive you a little crazy.
Right after I started modifying the Si, SSR Wheels dropped their Formula AERO MESH design, which has a retro feel with a touch of modern aesthetic.
Sized in 18x9.5-inch, +43 offset, the new wheels required rolling the front fenders and as previously stated, the prototype springs I had on the car originally would not have allowed sufficient clearance for a wheel and tire package of this width.
TOYO TIRES - @toyotires
About those tires...This project relies on Toyo Tires Proxes R1R in 245/40-18, a step up from the factory rubber. After digging into some of the forums and what other enthusiasts were putting on their 10th gens, I noticed most were using wider wheels, sometimes much wider, but transferring the stock tires over with some stretch to make them fit—which doesn't make much sense if you're looking to improve the cars handling or up the level of traction.
This is a true wheel and tire upgrade that you can actually feel in the turns and upon heavy acceleration. Again, the style vs. functionality relationship is something I wouldn't ignore.
HONDATA - @hondata_inc
Not only was Hondata on the front lines of 10th gen. Civic tuning development early on, they've remained there, constantly finding new ways to improve driver experience and power production. Their insanely popular FlashPro unit is available in a California-compliant C.A.R.B. version and a Race version with even more options.
Acting as the link between a laptop and your vehicle via the OBDII diagnostic port, you can check and clear codes, quickly upload multiple off-the-shelf programs, write your own (best left to a professional), datalog, and much more. In terms of bang for your buck, it's undeniably at the very top of the list of must-haves for someone looking to increase performance on their 10th gen. both short and long-term.
With Hondata installed and using a basic program combined with the PRL Street MAF-fitted intake and intercooler kit, the Si put out 223hp/245lbs-ft of torque at the wheels on GReddy's dyno—up from the factory 193/219 measured on the exact same dyno a few months prior. For someone looking to add some kick while still sending exhaust notes through the factory catalytic converter and exhaust, this combination is ideal, affordable, and can be done in your driveway in a few hours.
GREDDY - @greddyperformanceproducts
With the car up on the lift, the stock exhaust came out and GReddy's DD-R 3-inch cat-back system went in. Using the factory hangers, the GReddy kit hangs in the rear bumper's original center-exit but uses dual canisters in place of the "HDMI port" OEM version.
Back onto the dyno after the exhaust was bolted in place, I also swapped out the Street MAF for PRL's Race version, then I uploaded another Hondata program intended for that specific MAF along with a few more PSI and we did another dyno run, which brought power up to 229/264. This is where some will want more, and others would prefer to keep things closer to a factory look. More power is just a few bolt-ons away, but keep in mind things will get louder and unless you're going to rely on the stock exhaust, the car will visibly stand out a bit more (Flex-fuel is an exception, but not everyone has access to the E85 pumps). In my case, I wanted to install PRL's down pipe with high-flow cat and front pipe, and since I'd be removing the turbo's heat shield and basically getting into a full procedure, it was the perfect time to look at a turbo upgrade.
27WON - @27won
Again, keeping a mostly factory look can still be achieved as under the hood, we've only added an intake and intercooler piping that are black and blend into the rest of the bay. The factory heat shield covers the downpipe for the most part and unless you know exactly what you're looking for, you'd never even notice that nice 27WON W1 turbo upgrade bolted in place.
Designed from scratch, the 27WON crew put countless hours of R&D into making their W1 upgrade a true bolt-in replacement that fits just like OEM, but far outperforms the factory snail. Multiple CAD designs and extensive street and track testing later, the W1 features a much larger compressor wheel, larger turbine shaft and bearings that all team up for a potent performer that's packaged so nicely that it blends right into the car's bay.
While the turbo was going in, we also added 27WON's billet rear engine mount to help control engine movement with the new-found power. Well out of sight, the increase in cabin vibration is apparent, but also a welcome co-pilot as it adds a layer of "feel" when in the driver's seat. Not too much to be obnoxious, yet enough to remind you that it is, in fact, on duty.
Still on the stock clutch, we plugged in a Hondata-supplied program based on the 27WON turbo upgrade and the car took on a whole new feel. Any potential shortcomings you can conjure up about adding a larger turbo simply don't apply here. There's essentially no bottom end loss, the mid-range is dramatically improved, and where the factory turbo seemed to take a nap as you approached the higher RPM range, the W1 shines, with a punch to the gut that doesn't let up until you do. If there was ever an "Si+" made available from Honda, it would rely on the W1.
CUSCO USA - @cuscousa
While the car was still in the air, a few Cusco chassis braces were bolted in place. Each features a precision fit, using factory holes, which didn't require any adjustments to be made. Powder coated for long-term durability against the elements, all three under-chassis bars went on in just minutes.
In the engine bay, their polished shock tower bar with powder coated mounts went right on and I think this bar, which sits in a more traditional position as compared to the last few Civic generations, is a welcome addition to Civic fans.
With just two weeks left before the SEMA Show, some of the folks with much higher pay grades than me were pleased with the progress but wanted to see more. Being that the car was to park in the Honda booth at the big show, the almost factory look under the hood wasn't going to be enough to display. With no time to even get the car on the dyno for a new baseline, it was back on the lift at our office Tech Center so I could install yet another turbo upgrade—this one a leap away from the factory-like appearance.
PRL Motorsports - @prlmotorsports
PRL had already introduced their Big Turbo Kit for the 10th gen. and offered to ship one out which would leave me with about a week to get everything installed. The kit included a new downpipe, a new portion of the silicone that runs to the intercooler, a crossover pipe, and in my case, a Garrett GTX2860R Gen2.
Having pulled the factory turbo out previously, revisiting the process a second time around was much quicker. This kit is certainly a big step for someone interested in dramatically upping the power and isn't glued to keeping a factory look. Along with the PRL Flex-fuel kit, power is expected to land in the mid-300s, a huge increase from the original factory sub-200 dyno result. As you're reading this, a new clutch should be arriving so I can finally upgrade it and get back on the dyno for some final numbers with the new PRL kit.
CHAPMAN CONCEPTS - @chapmanconcepts
To complement the new turbo kit, Chapman Concepts, a specialist in the Cerakote coating world, mixed up a custom grey hue to transform the crossover pipe, charge pipe, heat shield, and that pesky factory plastic valve cover. The sleek grey adds a more cohesive, custom look, and plays well against the Aegean Blue Metallic paint.
Cerakote adheres to various metals as well as plastic, is heat resistant, and with plenty of color options available, is a great alternative to purchasing a one of those painted covers that carry a pretty steep price tag. (Note: OEM Si valve covers from the Honda dealer are only about $75.)
DOWNSTAR INC. - @downstar
To bolt in that newly coated valve cover, Downstar supplied a set of their prototype (at the time) 10th gen. hardware in raw aluminum, and also included their 10th gen. engine bay hardware kit in gunmetal to match the Cerakote parts.
It seems minor, adding these tiny hits of color, but added up, Downstar's unique bolts and beauty washers make a huge impact on the overall look. It's the easiest install you'll ever do and there are a number of colors to choose from to suit your needs.
BRIDE - @lot_usa
I worked with Lot USA, the Master U.S. Distributor of BRIDE Japan seats, to get my hands on a set of Stradia II bucket seats and mounts/rails for the FC chassis.
The new seats slide right into place and take up less space that the airbag-equipped factory seats while offering a much firmer hold on the thigh and torso, not to mention they look absolutely amazing, especially with the Kevlar backing. Though more aggressive, the bolsters still allow a street-free dismount when getting out of the car.
AEM - @aemelectronics
To add a little more technology to the cabin, AEM Electronics supplied their CD-5 digital cluster along with an adapter kit that makes things simple, plugging right into the OBDII diagnostic port on one end and, for power, the cigarette lighter on the other end. I bent a few simple brackets to hang the unit and it "floats" right in the center of the cluster opening. The customizable, full color, highly-visible readout can display a ton of information from your factory ECU or using AEM's precision sensor line-up.
BUDDY CLUB - @buddyclubusa
I wanted to go with an aftermarket steering wheel to finish off the cabin but 10th gen. Civics carry quite a bit of convenience on the factory wheel. Giving all of that up on a street car didn't seem like a good idea, but fortunately Buddy Club offers their version, which replaces the outer portion of the wheel and maintains the airbag and all steering wheel controls. Red stitching, a bright red horizon marker, hints of carbon fiber and a sporty flat-bottom give you the aftermarket look and feel, without sacrificing those factory goodies or safety.
DTM AUTOBODY - @dtmautobody
Those faux bumper grills. It seems nothing upsets this fanbase more than those 4 bits of thick, surprisingly heavy, solid plastic inserts. DTM Autobody came up with a solution so good that the moment I saw it, I pulled off both bumpers and drove straight to their El Monte, Calif. shop.
In no time they had all four grills trimmed, cleaned up, and ready for their new thick gauge, powder-coated mesh replacement. The change is incredibly clean and looks almost factory. Of all the exterior upgrades made thus far, the DTM grills have been the most asked about.
Stay tuned for an additional article once I get my hands on the new clutch and jump back on the dyno!
For a complete rundown of each section of this build, here's the story directory:
Pt II Complete suspension makeover
Pt. III HFP upgrades, adj. Shifter, bushings and pedal spacer
Pt. IV Intercooler, intake, front lip, wheels/tires
Pt. V Turbo, full exhaust, chassis bars
Pt. VI SEMA prep