In mid-2020, we announced that we were beginning development on a K24 swap package for the 2013-2020 BRZ/FRS/86 chassis. For over a year, our team has poured countless hours into all aspects of development, with a lofty goal of taking a much-needed engine swap to the next level.
The potential of the K24 in an 86 chassis has already been seen by a few highly skilled DIY enthusiasts, but we wanted to bring a proper “FA20 delete kit” to the masses.
Thanks to the popularity of our previous product releases and our amazing loyal customers, we’ve been able to scale the size and scope of our company and put together an incredibly talented crew. Armed with in-house machining, fabrication, wiring production, and more, we took to the task of building a 100% complete K24 86 swap.
The goal was a lofty one. We wanted complete OEM functionality in this modern chassis. All electronics needed to work like stock, down to the gauges, air conditioning, cruise control, ABS, traction control, and more. We also wanted to retain the smooth shifting 86 transmission, particularly for customers doing naturally aspirated builds.
Additionally, we wanted compliant rubber engine mounts to keep NVH to a minimum. In short, the car needed to function as though this incredible chassis came fitted with a proper K24 engine right off the showroom floor.
The good news is that we exceeded our high expectations, and the end result is something truly special. The ability to easily convert an 86 chassis to operate with K series power under the hood breathes new life into a very capable car that has always suffered from an underwhelming and often unreliable engine.
Our test vehicle, a 2013 BRZ, has been thoroughly tested for the last several months. We’ve clocked over 3000 miles on track alone—at Barber, NCM, Putnam Park, Gingerman, Autobahn Country Club, and Mid-Ohio. Data has been logged and reviewed, and our products were tweaked and refined until perfection was reached.
At the moment, our car runs a stock K24A2 engine, outputting a healthy 230whp and 190wtq thanks to our intake, header, exhaust, and tune. But since this is only the beginning, we’ve already acquired another BRZ and an FR-S, with plans to develop an upgraded transmission option, turbo parts, and do some endurance racing along the way.
Our completed car also benefited from a whopping 140-pound weight drop thanks to the lighter K24 and our lightened components, even with all accessories and A/C!
Best of all, our K24 swap parts will be on sale TOMORROW, 8/31. So until then, here is a breakdown of the major components that will be available, along with package options to suit the needs of any K swap project.
Engine Adapter Plate and Flywheel
At the heart of our swap is an adapter plate and flywheel that are quite different from the rest of our catalog. Due to the dimensions of the 86 bellhousing and input shaft, our adapter is twice as thick as the lineup of our other steel adapter plates. Because of the added thickness and increased thread depth, we were able to machine this adapter out of 6061 aluminum instead of steel and still maintain the durability we needed, but with added lightness.
The unique shape and thickness of this plate allows any factory style 86 clutch, fork, release bearing, and slave cylinder to be used without any modification. It also allows the K series starter to fit without modification. Significant R&D resources went into this piece, and our proprietary shape and design features are patent pending.
Although the adapter thickness has been increased, we were able to design an aluminum flywheel that is much thinner than our other offerings, resulting in a flywheel that looks a lot like your typical lightweight OEM replacement, weighing in at just 9 pounds.
For customers more interested in mild street manners than lightning quick revs, we also have a 14.5-pound steel unit available that is dimensionally the same size and price, but has a more refined feel.
Engine and Transmission Mounts
When designing our engine and transmission mounts, we had two main goals:
- Relocate the engine as low and as far back towards the firewall as possible for the best weight distribution, and to create hood clearance.
- Maintain an OEM style design that accepts mild-mannered rubber engine mount pads that could also be upgraded for more extreme applications.
The end result is the laser-cut, tig-welded, and powder-coated engine mount brackets you see here. They are welded in-house by our fabricator to the tightest possible tolerances.
Not only do they drop the crankshaft centerline 2.5” lower than stock and move the engine back about 4”, but they also position the engine in the perfect location, so the stock hood closes without modification, and the factory undertray fits down below the oil pan with room to spare, so factory ground clearance is retained.
Since the stock 86 engine mounts are pretty large, we tried a number of other options, and ultimately decided to build our mount brackets to accept an OEM Subaru Impreza mount. The stock transmission mount is retained, but we supply a Whiteline transmission mount insert to eliminate the sloppy movement in the factory mount.
While OEM STi mounts can be dropped right into this setup, we tested them for a couple events and found no performance gain, but we did pick up a large amount of vibration throughout the entire vehicle. Because of this, OEM style rubber mounts are standard in our packages, and we won’t offer any substitutions.
Baffled Oil Pan
Our K24 86 oil pan offers some big advantages compared to any other pan solution available. Specifically:
- The pan clears the stock subframe without any modification.
- It includes thoroughly tested oil baffling for all road race and drift applications.
- An entire K20 oil pump and pickup can be used. No need to use an oil pump adapter and modified pickup tube like other swaps!
- The factory K series A/C compressor fits in the stock location without modification.
It’s also built out of .100” thick aluminum, tig welded inside and outside, and even has the drain in the stock 86 location, so the oil can be drained through the factory undertray window. It’s these little details throughout the product line that make all the difference.
Since the transmission is relocated, the shifter also required some modification. We took this as an opportunity to make this already silky-smooth transmission even more crisp by eliminating some slop.
We deleted the stock shifter carrier and have replaced it with a solid-mounted shifter plate. However, the stock shift lever is detained, along with the internal damper, so the end result is a more direct feel that still has some of the “give” of the OEM setup. The Whiteline transmission mount insert is a requirement when running the solid-mounted shifter plate.
We also paired the plate with our own dual shear selector rod of the appropriate dimensions to make shifting more precise and direct. This piece will be available separately for those looking to run an aftermarket race shifter like an IRP and won’t need the shifter plate.
Intake Manifold, Throttle Body, and Piping
Our legendary cast KPower intake manifold needs little introduction, as it has become the gold standard for all RWD K swaps over the last couple of years.
We’ve added it to our 86 swap with a throttle body that allows the factory 86 drive-by-wire throttle body to be retained, and we also developed our own 3” cold air intake that reaches in front of the radiator and into the bumper at a precise length that we optimized on the dyno for peak horsepower and torque. Our production intake pipes are CNC mandrel bent out of a single piece of 3” tubing.
Huge throttle bodies are often overdone in the K series world and are overkill for many applications. The 86 unit is larger in diameter than all factory K series throttle bodies, and our dyno testing hasn’t shown any significant gains by playing with larger throttle body size, aside from on the wildest applications. Very often, OEM is best.
For those truly needing something larger, our existing Bosch 74mm throttle body adapter can be used with a custom 3.5” intake pipe. A jumper wiring harness will also be available for this soon.
Header and Exhaust
Our 86 swap header maximizes the space available in the engine bay and provides the best all-around header for both stock and modified engines.
It’s built from 304 stainless steel, and features a 4-2-1 runner design, with 1-4 and 2-3 cylinder pairing. Thanks to the width of the engine bay, runner lengths and diameters have been optimized for both peak and midrange horsepower and torque. Thanks to these dimensions, this is the best performing header out of our entire lineup.
The header terminates with a 3 bolt flange, which transitions to a small 3” midpipe section that fits around the lowered transmission. It also includes a port for the Haltech CAN wideband, and then ends with a two bolt 3” universal exhaust flange in the exact location as the stock midpipe. Pair up our midpipe with any aftermarket 3” 86 exhaust for a straightforward exhaust solution.
All necessary hardware is included.
Since our swap relocates the stock transmission, the stock driveshaft is no longer compatible. We took this as an opportunity to provide another nice upgrade. The two-piece, 29-pound factory driveshaft is replaced by a shorter 3” aluminum driveshaft weighing in at 16 pounds.
They are built by the best local driveshaft shop in our area using a Sonnax slip yoke and U joints, and are precision balanced.
Instead of leaving the fuel system up to the end user, we’ve added a clean and inexpensive fuel system to our 86 product line. The centerpiece is our beautiful KPower Industries fuel rail, as well as a custom 5/16” quick disconnect inlet.
We’ve also included a simple e85 compatible fuel hose, fitting, and clamp that connects to the main feed line in the engine bay. A machined aluminum plug is also included to delete the fuel line for the second set of FA20 injectors. Lastly, a couple of connectors are used to delete the factory fuel pump ECU for seamless operation with the Haltech.
Our 86-specific upper coolant neck for RBB cylinder heads routes coolant to the right side of the engine bay, so the upper radiator hose can be routed to the factory radiator inlet location.
This piece makes hose routing a breeze. We also include two 1.25” to 1.50” radiator hose couplers and clamps, so off-the-shelf OEM hoses can be used. Four-ply silicone hoses are also coming soon for all of our applications!
Wiring and Electronics
This was the area of the 86 swap that took the most time and research to perfect, and we’re thrilled with the final product.
At the center of our swap is a Haltech Elite 1500 ECU. We chose Haltech for a number of reasons, including its broad range of functions, ease of use, and attractive price point. However, most importantly, the folks at Haltech already did the work of adding the CAN protocols from the 2013-2016 BRZ and FR-S into the software. This allowed us to build our wiring in such a way that all OEM vehicle functions could be controlled by the Haltech ECU. We’ve also partnered with Haltech and a nearby customer to compare the CAN protocols from the 2017-2020 cars, and thankfully we can confirm that they are 99.9% identical, as are the wiring connector pinouts.
Armed with an ECU that’s up to the task, we designed a motorsports-grade K series engine wiring harness that connects directly to the same engine harness connector as the FA20 harness once did. It’s built from all-new OEM connectors, Teflon insulated wire, and Raychem DR-25 loom. It’s as pretty and as durable as it is functional.
Under the dash sits the Haltech ECU, and a custom ECU jumper board and harness, as well as a Haltech CAN wideband controller. All of this is installed by only moving the glovebox, and at no point does new wiring need to be passed through the firewall.
Our engine harness also is pinned to accept a Bosch oil pressure and temperature sensor (included) and a connector for a 2006-2008 K24A2 A/C compressor.
The end result is a beautiful thing: a 100% plug-and-play wiring solution. No splices, no dash removal, and no drama.
And when you purchase an Elite 1500 from us, it will come with our base calibration pre-loaded, so everything works just like it should. Just plug everything in correctly and fire it up!
Air Conditioning and Heat
Since our goal was to provide customers a 100% functional vehicle, A/C had to be addressed. This is usually a daunting task for many DIY engine swappers, as A/C hose fittings are often unavailable, so building custom hoses isn’t easy, not to mention the wiring.
Not so with our 86 swap! Our oil pan is specifically designed so a factory K24 A/C compressor fits in the stock location. As mentioned above, our engine wiring harness is already pinned to connect directly to the compressor, and our Haltech basemap has all A/C functions pre-configured.
At the heart of the A/C setup are three custom A/C hoses that mate the 86 condenser, evaporator, and pressure switch with the K series compressor. Simply bolt up the A/C hoses, have the system charged and you’re done! No wiring, no guesswork.
Our A/C hoses intentionally route up and away from the exhaust and along the firewall to keep clear of the header or a turbo and downpipe.
Heat is added to our swap by using two OEM Honda heater hoses that happen to be the exact shape we needed, as well as a ⅝” barbed fitting and appropriately-sized clamps.
OEM Honda Parts
Obviously, some OEM Honda parts and accessories are needed and/or recommended to complete the swap. Because of this, we also are offering an 86-specific OEM parts package that includes the following:
- K20 Type S oil pump (required to run our oil pan)
- K20 oil pump chain
- K20 oil pump chain guide
- K20 windage tray
- K20 pump hardware
- K20 50-degree intake cam gear
- EP3 idler pulley kit
- K20 manual flywheel bolt set
- Replacement timing chain tensioner
- Replacement water pump
- Replacement thermostat
- Valve cover gaskets
- Spark plug tube seals
- New NGK spark plugs
- Oil filter
Ready to Get Started?
If you’re ready to take your BRZ, FR-S, or 86 to the next level with a K series swap, check back tomorrow and learn about our swap packages designed to meet every builder’s needs. Individual parts will also be available. And if you need any help planning out your project, please call or email us at email@example.com.
You can also expect to see much more to come from KPower for this product line and others. Thanks for reading!