It's been about 4 months behind the wheel of the 10th gen. Si and, as expected, I'm becoming more and more attached to it. Peppy in stock form, a blast to rip through the turns, especially with the addition of Eibach's complete suspension makeover and far more connected with the Acuity Instruments additions, the boosted sedan has proven to be a great daily driver. With suspension and a few driver-centric upgrades checked off the list, I aimed at addressing the intake side of the equation—something most enthusiasts do early on with their builds.
PRL Motorsports -
Over a decade ago, the doors to PRL Motorsports opened officially and the performance-driven brand that's become very well known for a bevy of effective upgrades for 's SR20 family, as well as 's 8th and 9th generation Civics, transitioned heavily into making a major impact on the 10th gen. Civic chassis.
When I first got the keys to the Si from Honda, PRL's Patrick Linn reached out and offered a full line of products to install and test, including their front-mount intercooler with charge piping upgrade that fits both Si and non-Si models.
In the past, when people were piecing together a turbo kit for their build, many would opt for the largest intercooler that would fit (or not fit, let's be honest) in the front of their car. Like almost anything with engine building, bigger isn't always better, and sizing the intercooler properly can help avoid issues with additional turbo lag and overall response. PRL is well aware and though their version proudly stands taller and deeper than the factory cooler, they put some serious R&D and countless hours of road testing into play to make sure there were no performance trade-offs. The result is a jump in cooling performance packaged within a true bolt-on system that requires no additional modifications. For those doing mods one step at a time, you won't need a tune to support the new intercooler; it's a plug-and-play affair.
Based on a 500hp-capable bar-and-plate design, the intercooler's hot side is 2.00 inch, its cold side 2.5 inch, compared to the factory 1.5-inch openings on both ends, and as mentioned the PRL unit is both taller and thicker but doesn't weigh much more than the factory offering. The factory plastic plumbing is replaced by PRL's 4-ply silicone hoses, which are stronger and put up a better fight against the under hood heat your boosted Si is going to be producing.
Since I'd be pulling the bumper off to install the intercooler anyway, it seemed like the perfect time to get rid of the factory air box. Spend a few minutes searching online for intake systems for the 2016+ Civic line-up and you're guaranteed to come across PRL's COBRA cold-air intake kit.
Available in street or race versions, it replaces the factory airbox and plastic plumbing and snakes a high-flow filter just outside of the engine bay, right under the driver's side headlight. The Street MAF version doesn't require any tuning, while the much larger Race MAF does require some sort of ECU support, like Hondata's FlashPro, which is pre-loaded with a tune specifically for an Si with PRL's Race MAF setup.
The kit includes everything you need for installation and, like their intercooler, is fully reversible, meaning no cutting or major changes are needed to make it happen or return back to stock if desired.
I won't take you through the bumper removal but suffice to say it's my least favorite chassis to unmask. A large number of plastic clips under the front bumper have to be removed along with the typical fender well screws, as expected, but then you have to address the plastic mask that surrounds the headlights and clips into the top of each headlight housing and the center grill portion—it's involved, so I took my time to avoid having to replace any clips and laced the headlights with painter's tape to avoid scratches during the process. To make things a little easier on my back, I lifted the Si up with our Quickjack system and got to work.
With the bumper finally removed I started by unbolting the piping that connects directly to the intercooler on both sides first, along with the brackets that anchor it to the car.
From there, I started on the hot side, using a ratchet to free up each connection. Being a brand new car, the OEM hardware wasn't rusty or corroded, and other than the initial "snap" you get with breaking each bolt free for the first time, they came off without any issue. To get organized, I matched the shape of the original piping with PRLs and began the assembly process, loading the clamps onto the piping but not tightening them so I had some space to rotate and wiggle for a proper fit.
Space gets quite a bit tighter as you get closer to the turbo itself.
On the driver's side, I started by removing the factory airbox upper and lower portions entirely to gain better access to the piping and also because I'd have to remove it anyway to make room for the cold-air intake.
With the huge airbox out of the way, the factory piping is easily accessible, and within a few minutes it was removed.
The sensor and line on the OEM piping are to be reused and the PRL hard pipe includes fittings that match up perfectly for a pain-free install.
A look at the majority of OEM parts removed to make room for the PRL upgrades
With everything lined up and no signs of anything in danger of making , I tightened all of the hardware and the PRL intercooler kit was complete.
I first mounted the high-flow air filter, then added the lower frame bracket to the COBRA intake but left it loose in order to allow some adjustment once everything was added. The lower mount uses a factory threaded hole and a nut and bolt combo for a non-threaded factory hole—no drilling required.
PRL supplies this billet bracket to slightly relocate the clutch line's anchor on the driver's side rail.
That piece frees up a little space to fit PRL's aluminum bracket that, again, uses factory holes.
The upper portion is then assembled with your choice of Street or Race MAFs. I went with the Street version for now to get a feel for it but will be moving up to the Race MAF in the next installment.
Bolted in place, the PRL logo draws a little attention, but overall the look is subtle, which I really appreciate. Having a shiny chrome pipe sprawled along the front of the bay, in my opinion, doesn't suit this car. Overall fitment of both the intercooler and intake couldn't possibly be any better. There were no adjustments needed and no issues with any sort of interference.
On the road, the intake without a tune will make some additional power that can be felt but I imagine many will be too pumped on the sound to realize it. The "whoosh and flutter" you get from the factory turbo amplifies significantly with the open element filter and Si owners get that blow-off sound that (whether they admit it or not) they've been craving.
GReddy Performance Products -
Another piece of the Si project puzzle that would benefit from having the bumper off already was this GReddy Performance Products FRP front lip. Also available in carbon fiber, I opted for the fiberglass version since I had planned to have it painted. The crew at Signature Auto Body in Anaheim, Calif. were able to get a perfect match and had it back to me in no time.
Using a pair of boxes, I propped the bumper up sideways in order to get enough space to mount the lip without interference from the ground. Turning it upside down would have been ideal but the awkward shape wouldn't allow it.
There are 2 sets of hardware included with the lip, the first of which is a number of self-tapping screws. These go through the FPR lip and directly into the plastic OEM undertray via these access holes.
The idea is to work your way across all of the holes and secure the lip in place, exactly where you want it. Then, one-by-one you remove each screw and drill a slightly larger hole to accept the 2nd set of hardware comprised of a nut and bolt combo with washers. It's a simple and effective way to mark all of the holes and you really don't need a second set of hands to hold it in place; the self-tapping screws do that for you. Since the lip mounts under the factory bumper, you determine exactly how much you want it to protrude forward or tuck underneath and you can center it perfectly. It makes life much easier for someone like myself, with sausage fingers.
The lip fully installed and the bumper re-attached to the car moments before adding the finishing touch with GReddy's titanium logo.
SSR Wheels -
The last and perhaps biggest aesthetic change to the Si at this point is the wheel and tire package. It's always a tough decision for me, trying to choose a wheel that looks right on whatever chassis I'm dealing with. For the Si, it's a big car and I've seen quite a few relying on the wheels that most everyone relies on. Nothing wrong with that but we've already seen it dozens of times and I wanted something a little different. My timing couldn't have been any better (also known as just getting lucky) because our friends at SSR Wheels had just announced a new wheel called the Formula AERO MESH.
Available in 16-, 18-, and 19-inch versions, the design pulls inspiration from the past, combines it with SSR's signature lip design and ties it all together in a very unique look that's as modern as it is old school. It's a lot to pack into a wheel design but as soon as I caught a glimpse at the teaser on Instagram, I ordered a set for the Project K24 build that's also currently underway and reserved a set for the Si.
The disk that runs around the center cap is available in red or blue, and like most SSR Wheel offerings, there are a ton of customization options. Want a gunmetal face and polished lip? How about red anodized hardware or a matte black outer lip? No problem, SSR gives you plenty of options to create a wheel that suits your needs specifically. For this project, I requested a standard polished lip and silver face along with a blue ring surround. It seems like silver wheels with a highly polished lip aren't as common these days, which pulled me toward this set up even more.
To complement the car's blue paint and the blue wheel ring, SSR also supplied a set of their GT Forged lug nuts to tie it all together. Cold forged and produced using a spline design that adds a level of security, the blue anodized, ultra-light lug nuts have the SSR logo on the face of their closed end and use a thin body that gives you plenty of space during installation or removal. I can't think of a more perfect combination with the Formula AERO MESH.
One of the interesting things I've seen in the 10th gen. Civic community is many reaching for a wheel set up wider than stock but opting for the factory or factory-spec tires. This often means a wider wheel accompanied by a stretched tire, in no way improving the amount of rubber put to the pavement for an increase in traction. With the 18x9.5-inch, +43 offset square setup of the SSRs, I chose a 245/40 R1R from Toyo Tires as a step up from the factory 235s to increase the car's footprint.
Toyo's R1R is a favorite of mine, having used them on a personal build in the past. Labeled as an extreme performance summer tire, the R1R is also really good in the wet, though heading into June here in SoCal, I doubt they'll see much rainfall. In terms of handling, however, they're awesome with their silica-reinforced tread compound that offers excellent grip, and that cool cross-pattern you see, referred to as an arrowhead tread design, along with the uniform slits help with the tire's rigidity under load and when you're hard on the brakes—giving you a solid balance regardless of dry or wet status.
Available for 15- to 18-inch applications, this is a great tire for the street as well as weekend track fun.
I finished up with this portion of the build just a few days prior to the Eibach Meet's 15th anniversary. Though I didn't have time to enjoy the inside of the event since I was running traffic duty up front, I parked the Si next to the D.J. booth on display.
Next up, it's time to hit the dyno to see where the car sits currently, followed by a switch to PRL's Race MAF and Hondata's off-the-shelf program for that setup using their FlashPro before I put the car back in the air to work on the exhaust system. Stay tuned!