This engine was completely off our radar until mid 2025 while researching a swap for our ZN6 Drift Car. Our E36 has a 2JZ so we didn't want to just do the same thing and more importantly didn't want a 1JZ/2JZ to throw off the balance of the ZN6 chassis with the light and low engine. In googling various H4 and H6 engines (considered a Porsche H6!) we found the Subaru H6 which is called the EZ30 / EZ36 in this video: LINK. Assuming you've watched the first few seconds, you can see why we're hooked just by sound and NA power alone. Looking up the cost got us more excited as they're $1,000 - $2,000 for the entire engine. We also see the FA24 swap is growing in popularity and as much as we love the FA24 and use it in our GR86 endurance car, they are a $5,000 dollar engine. We can get you more power and WAY better exhaust note for around the same amount of money and as seamless as the FA24 goes in.
More research uncovered a unique set of what enthusiasts call legos which means interchangeable parts across different platforms. Off the rip here is what interchanges and/or lines up with zero changes.
• Engine Mounts (ALL EZ30/EZ36 H6 engine mounts line up with 86/BRZ subframe NO CUTTING)
• Transmission, Driveshaft, and Shifter
• Clutch / Flywheel
• Heater Hoses
• Radiator (different radiator hoses, we have a product for this)
• AC Compressor (if 03-09 Phase 2 EZ30R is used)
• Engine Harness to Chassis Connector (the large square one above starter, wires do not line up...of course we have solution)
The items we're developing to make this beautifully plug and play:
• Fuel System (ALL 6AN, Filter, FPR, Flex Fuel, Stays, etc)
• Wiring / ECU (whether its a wiring guide or harness)
• Radiator Hoses
• Expansion Tank / Swirl Pot & Coolant Overflow
• Forward Facing Intake Manifold (Optional, allows for OE airbox and trimmed intake arm / elbow of your choice)
• Plus a ton of other products we'll talk about shortly to make this swap Motorsport ready (Drift, Track, Rally...)
Now that you mostly grasp the ease and awesomeness all around let's talk basic power numbers. Quick engine option rundown:
Phase 1 EZ30D - 00-02 Subaru Legacy / Outback / Lancaster 3.0
• No VVTi / AVCS
• Single Exhaust Ports
• Throttle Cable & Aluminum Intake Manifold (better plastic intake manifold bolts up)
• Bore: 89.2mm ... Stroke: 80mm... CR: 10.7:1
Phase 2 EZ30R - 03-09 Subaru Legacy / Outback / Tribeca 3.0R
• VVTi / AVCS
• 3 Exhaust Ports per side
• DBW & Plastic Intake Manifold
• Bore: 89.2mm ... Stroke: 80mm ... CR: 10.7:1
EZ36 - 08-14 Subaru Legacy / Outback / Tribeca 3.6R
• VVTi / AVCS
• 3 Exhaust Ports per side
• DBW & Plastic Intake Manifold
• Bore: 92mm ... Stroke: 91mm... CR: 10.5:1
Intake, Header, Exhaust, and Tune NA RWD approximate numbers (aka I/H/E/T). Don't forget 15-20% drivetrain loss when looking at AWD dyno #'s.
Phase 1 EZ30D - 200hp / 200tq
Phase 2 EZ30R - 255hp / 240tq
EZ36 - 265hp / 260tq
This is all the average of dozens of dyno graphs and 91-93 pump gas, there has been little to no ethanol tuning done. With the good compression ratio Chase Bays will be able to show the capability of ethanol and stand alone tuning. Can we break the 280hp mark on EZ36?!
We will make a long form video to explain the exact differences between each. For now I will keep it simple. The Phase 2 EZ30R should be and will be the most popular, the engine is balanced, great timing chain design, great AVCS to get more hp/tq in the right places, and has the most runway for expansion into turbo w/ stock internals or built. The EZ36, as beastly as it seems, has offset connecting rods to achieve 3.6 and one timing chain guide has been known to be problematic. HOWEVER...we have this engine in our ZN6 and we are going to develop and make some fixes for it. I wouldn't turbo it and expect it to take the abuse we give but we believe if left simple with I/H/E/T and the timing chain guide brace we're developing...this could be a fantastic track / road race option. Again NO turbo. People put EZ30 crank & rods in to make it 3.2 but the EZ30 has the simpler chain design and it's always going to be better for boost abuse!
Turbo Hp/TQ #'s is a different approach, it's more of how much boost can it take and approximately how much will it make. Something that is extremely frustrating to me is when companies overstate the capability of an engine when selling engine swap products. This was a MASSIVE issue with the K24 RWD platform, companies were saying 400hp stock internals no problem and as a Honda guy I was saying noooo don't do it. The next few year all I saw was blown K24's over and over. Not cool. There is nothing wrong with saying they were happiest at 325hp that's still great power. So it's important you know we are not going to do that here.
The Phase 2 EZ30's at 10psi are making approx. 450hp RWD...which is extremely impressive. In our research we have found the head lifts over time with hard driving at 10psi and above. So let's stay safe with 8psi stock internals and assume 400hp RWD, still very impressive and extremely usable power. WAY more than FA20 can do obviously, my built FA20 makes 410hp at 22psi. We are currently building a ZN6 Drift Car that will be Garrett G30-900 0.82AR turbo'd Phase 2 EZ30 with stock internals and we are working with a company to make upgraded head studs to pop in and will go 10psi. I drive drift cars hard as heck so we develop and find its true boundaries.
Last stop before we build, engine weights. This will blow your mind.
FA20 / FA24 Engine Weight - 320 lbs
EZ36 Engine Weight - 344 lbs
2JZGTE Engine Weight - 496 lbs
Stock 86/BRZ Transmission - 92 lbs
R154 Transmission - 112 lbs
Engine stand weighs 57 lbs and pallet weighs 29lbs
EZ30/EZ36 Dimensions:
25” height bottom of oil pan to top of intake manifold
18.5” height bottom of oil pan to top of block
32.125” width at timing chain cover
30” width center of VCs
18.5” Center length
17.25” back of cyl head to timing chain cover
FA20/FA24 Dimensions:
24” height bottom of oil pan to top of intake manifold
19” height bottom of oil pan to top of block
32” width at timing chain cover
30” width center of VCs
17.25” Center length
15.25” back of cyl head to timing chain cover
Now, finally time to build! We are building this FR-S in two stages. First stage is NA EZ36 with I/H/E/T plus E90 ethanol as an easy track car. We're developing all the swap parts on this one, tuning it, then taking it to Barber Motorsports Park and Polecat Training Center to drive the crap out of it and get lap times. Then we're putting a Phase 2 EZ30 w/ upgraded head studs in, turbo'ing, and it'll turn into a drift car. Of course yes we have a vision board:
Exciting day, EZ36 received! Immediately stripped down.
Under the intake manifold, most of this will be deleted and blocked off.
Lovely chassis that volunteered to be test mule. What I love about the ZN6 chassis is they're very easy to work on. We own every popular chassis and have built them all...there is no car easier to work on.
Now, all the engine prep before it goes in. First thing we're doing is stock oil cooler delete. We do this because they are not very effective and the header is going to run along where the hose routes, plus of course we're adding the Chase Bays Oil Cooler Kit. Ignore the blue hose, this is not final form. It was just considered before we figured out the final method (more on that later).
An easy wire tuck we do on the ZN6 and ZN8 cleans the firewall up a ton, so here is how you can do it too.
Lightly heat gun the plastic to make it easier to cut. Then very carefully without hitting any wires trim this plastic piece so the harness can route differently.
You'll push the harness down like this, the driver side will be a tad stubborn but its okay wires are flexible and the chassis isn't old enough to crack all the brittle jacketing like an 89 Honda.
Throw a big clamp over the harness plastic, then a clamp over the stubborn side to an existing bolt hole. We kept this on when putting the engine in, but you may want to undo it since the trans could smack it from your friend being a little too drunk while assisting the install. It's could to do it now though to "train" the harness to sit this way.
Now, we have to trim the block to fit the starter. The EZ30 / EZ36 Subaru's have the starter on the opposing side. I have seen people doing this swap cut the trans up to fit the starter over there and it is a terrible idea that is way more labor intensive. More cutting and extending wiring, don't do it! There are two studs on the lower side of the engine that will no longer be used, remove those. Yes the transmission will be fine it will still have 5 bolts. Then bolt the transmission on to mark for cuts. It will come off so don't put clutch / FW on yet.
We may develop a beauty cover plate for this area down the road, just focused on the core swap products for now!
Look at our built FA20 ZN6! 420hp. Our EZ30/36 swap will look wayyyy better. There is a lot to the FA20 so its hard to clean them up.
Next up...
1) While you have your cutter out, there is a spot on the lower cylinder where the exhaust will route that will get in the way. Easy cut.
2) Remove the black coolant hardline that goes from lower thermostat housing up to top of engine (for heater core)... we will not be reusing this since it would hit the header and routes wrong.
3) Lastly, we believe in clean engine bays and clean engines, so pressure wash that engine! Make it look good so more people swap their ZN6's and more cool products can be made. The grime on the engine is stubborn we brush on
Star Brite Ultimate Aluminum Cleaner & Restorer and pressure wash off. Takes about 4 cycles to get it looking perfect (see photos below).
Now we MAINTENANCE! Easy but very important. Not something you want to do with the engine in. This engine is extremely simple with very few gaskets which is great. The timing covers are known to leak after 75k+ miles and we need to do stuff under there anyhow. All of this is in the Master Parts List with SKU's at the top of the page, so we'll just list component / action.
• Valve Cover Gaskets
• Intake Manifold Gaskets
• EGR Gaskets + Block Off Plates (we sell the block off plates, the OE gaskets are replaced and reused with them)
• Water Pump (chain driven / behind timing chain cover)
• Front Main Seal
• Timing Chain Tensioners (if the engine looks beat, you can make a decision to replace chain and guides. We didn't on our EZ36 NA build but we are on our EZ30R Turbo Build)
• Rear Main Seal
• Spark Plugs
• Thermostat (Rock Auto sells lower temp opening ones)
• Reseal Oil Pan or get
RSD Cork Gasket.
• Do the best work you've ever done resealing the timing chain cover and follow OE instruction to a T
•
Variation - If you're running AC, you'll do Idler Pulley and Belt Tensioner. If you're not you can get our Alternator Relocation Kit which has the adjuster to apply tension built in, which is better for Motorsport Use.
• Clutch and Flywheel - The OE Clutch / FW works but the level of power and torque the OE / Stage 1 clutch supports isn't enough for increased power. Do not use a Twin Disk unless you have an upgraded trans, it will put too much stress on the stock trans and break...even with our Clutch Line Delay Valve Kit. We recommend a Stage 2 or 3 Exedy or Spec.
Exedy Stage 2 Cerametallic - 15956
Exedy OE Flywheel - TYF001
Exedy Lightweight Chromoly - TF02
• Clutch Throwout Bearing Release & Sleeve - MAJOR Upgrade. The input shaft bearing support is Aluminum and can wear out under heavy use very quickly, we know from personal nightmares on our GLTC ZN6 race car. This solves it entirely and very affordable. Don't skip this one!
Final step, Fuel Rails. If you're running ethanol you'll upgrade injectors too. We really wanted to create an option to reuse stock rails and fuel lines but there are some complications and it ended up being best to upgrade rails and run new AN lines. The Phase 2 EZ30 and EZ36 are similar to the 86/BRZ in that they regulate pressure at the tank and are return-less aka "deadhead"...unfortunately it's a major pressure difference (40-45psi vs 60psi) so we need to add a Fuel Pressure Regulator. The stock fuel rails are single input on each side so there is no way to cross over fuel to properly add an FPR so the lovely fuel rails were added to the list. Hard to be mad about it when they look so dang good along with our AN Hose and Hose Ends, I love the countersunk allens that is very simpatico with Chase Bays product design language. Our engine was in when we did this but it would have been easier out.
Now with our ID1050's
NOW PUT THE ENGINE IN!! We installed it with the trans attached and two people. Was very simple. You can see we immediately got to work on Upper Radiator Hose and Intake Design.
Again, ignore the blue hose and coolant hardline we had you remove, hadn't made that decision yet.
We will move mountains to design a great sounding header for this that doesn't require cutting the subframe.
Side tangent. More love for the designers of the ZN6 chassis. This shell was hit on the passenger fender and bent some of the core support. I assumed we'd spent half a day drilling spot welds to replace the whole thing. Nope. 2 spot welds and the rest bolts on.
Current state. This is both a build thread and EZ30 / EZ36 swap guide!
Let's focus on getting fuel delivery complete. We are making an entire 6AN Tank to Rail Fuel Line Kit with everything needed for complete install. Pump Hanger, pre-made 6AN Hose / Hose Ends, Fuel Filter, Flex Fuel Sensor, Bracket for Filter/Flex, FPR, FPR gauge, Stays...EVERYTHING. Let's start at the tank and work our way forward. Install the Fuel Pump Hanger, use
Radium instructions for how to do that.
Remove the two feed hardlines from tank to rail, these will not be reused. DO NOT REMOVE the fuel tank vent. It's the middle one but always follow the lines to triple check. We find it easier to cut them halfway up the firewall to make it easier to come out.
Let's get the Filter and Flex Fuel Bracket installed on the car as shown. Don't worry Fuel Lines are next step. For this install you're going to want the
Chase Bays AN Wrench Set to keep the aluminum hose ends safe from scratches!
Now to install the Tank to Rail Feed and Return. Take the two longest lines in the Chase Bays Fuel Line Kit, the longest one that is a 45º to Straight, attach the 45º to Fuel Pump IN and the other side to the Flex Fuel Sensor. The remaining longer line that is 90º to Straight will attach the 90º to Fuel Pump OUT and the other side to the Fuel Filter. Make sure the 45º sits over the 90º as shown.
For proper routing make sure the return hose / the hose running to the flex fuel is sitting closer to the trans side before installing our Billet Stays so it all aligns properly.
For the engine bay side there are 3 hoses. Filter to Rail, Rail to Rail, and Fuel Rail mounted FPR to Flex Fuel (return). Make sure the Chase Bays FPR is installed on the rear of the right side / bank 1 Fuel Rail.
• Starting from the longest that is 45º to Straight, Straight to FPR and 45º on Flex Fuel Sensor. Make sure the firesleeve is against the block as show as this serves vibration resistance.
• Next longest line that is 90º to 90º, connects from rail to rail on the front.
• Shortest line that is 45º to 45º, connects from back of left side / bank 2 rail to the Filter.
In our Stage 2 Motorsport Ready Kit we will provide a Bosch Motorsport Pressure / Temp Sensor Combo. This will be installed on the right side / bank 2 rail via our 8AN ORB adapter. After this your fuel system is DONE.
Cooling System! This will include Upper and Lower Hoses, Heater Hose Mod, OE Oil Cooler Loop, and optional Cyl 5 & 6 Cooling Mod. Let's start with upper hose. This was something we had a specific vision for, we wanted it to look super badass. Other swaps we've seen fell short. It's one of the first things you see and it's just important for a high end feel. The EZ30/EZ36 have two upper ports. On the Subaru's they came from they have two ports on the radiator. We want to use the stock radiator shape (aluminum obviously). The outlets on the engine are 28mm and the ZN6 radiator is 38mm so merging the two in a Y shape for best flow is perfect.
We start with some bends and a then Engineer Evan & Fabricator Hunter fashioned this piece.
We really wanted it to use a silicone 45º at the radiator but barely visible from overhead, this makes it easier to install / uninstall and just better looking. So Hunter got this made and we're stoked on where it's going. We also wanted to eliminate the stock fill point since we're adding our Swirl Pot / Expansion Tank as the standard. So don't panic that we've eliminated the fill point.
The 45º coupler idea worked and bam we've got ourselves a vision achieved. We painted the intake manifold cast aluminum looking...not sure if I like it. Also you can see our stock intake manifold intake design coming together. There's so many different options here but we'll just pick one and move on. Later we can test different designs for optimal power.
Lower hose was much easier. This is two piece now but production will be one piece of course.
Heater Hose Mod & OE Oil Cooler Loop. As mentioned before, the heater hose hardline that goes from lower thermostat housing to heater hose routes right where we need to put the header plus aims the wrong way once it gets to the top of the engine. Furthermore with Motorsport build, you should always get creative to route cooling lines as far away from heat as possible. These things add up. The header also will hit the stock oil cooler lines even after we loop them since we're changing from the water cooler design. First thing you will do, using a 3/8 extension you'll slowly turn the exit tube to clock toward the firewall. Some people heat them up first but we never do, they turn and retain sealing capacity.
Now you'll install the new heater core hose connection, in our kits we provide a 5/8 - 16mm Barb Joiner. The production piece will be welded with an M8 hole instead of clamped as shown.
Before we final install heater hoses, just a pro tip of something we do to clean up the engine bay a little bit and open up working space. Cut off 1.5" inches off the top portions that connect to the firewall. You will also trim 2.5" inches off the opposing side of the hose with the bleeder valve for proper fitment.
Next is to set up and install the rest of the Heater Hose Mod / OE Oil Cooler Hose Loop. This connects the lower thermostat heater hose outlet, the former oil cooler hose, up to the heater core hose. The Oil Cooler Hose is 1/2 and the rest is 5/8 but we're able to stretch the 1/2 hose over the 5/8 WYE. This is shown without clamps for clarity but of course spring clamps are provided, which are the best clamps for cooling hoses. Don't use worm gear.
The 90º portion runs around the engine mount and under the trans with ample room. The engine movement is the opposite way so pinching the hose won't happen.
Swirl Pot / Expansion Tank. This is such an exciting and overlooked modification that is useful with every engine but especially flat H4 and H6 engines. The wonderful part of these engines is all the weight sits so low which is priceless for handling. This also puts the heater hoses a lot higher than the fill point. It works okay for street driving and there is a bleeder valve in the heater hose but under heavy Motorsport high rpm use and hitting limiter causes water/coolant cavitation, bad. This causes the progressive increase in water temps that don't bring themselves down even with airflow and fan speed.
My personal example of this is hot lapping in a drift car. This is all assuming a very efficient Radiator/Fan and Oil Cooling setup is used. At the end of Lap 1 your temps are 220º F / 104º C, you have a long straight to cool with 80mph of airflow and you're down to 190º F / 88º C. Each lap the delta increases from unresolved cavitation...
Lap 1 - 220º F / 104º C...cools to 190º F / 88º C
Lap 2 - 230º F / 110º C...cools to 200º F / 93º C
Lap 3 - 240º F / 115.5º C...cools to 210º F / 99º C
Lap 4 - Your engines blown. You get my point.
This happened to me all the time, until we developed our Swirl Pot / Expansion Tank. A Swirl Pots internal design spins the coolant like a whirlpool. Air bubbles get pushed to the middle and rise out the top to escape, while the heavy air bubble free coolant gets pulled to the outside. The water pump pulls its coolant only from that clean, air bubble free outer ring...so during high-g cornering, acceleration, and high rpm / rev limiter conditions...the water pump never pulls in air and can’t cavitate. With our proper swirl pot design this rising temp condition goes away and our Swirl Pot does just that.
It's such an easy install you question how it can work so well. It's got a Radiator Cap and Overflow like a traditional fill point. The two upper inlets go to two separate corner high points. Our upper radiator hose has a provision for one 1/4 hose and for the other hose we replace the factory bleed point elbow on the heater hose with an added 1/4 hose provision. The lower outlet connects to the lower hose Y connection so the water pump pulls air bubble free coolant.
Chase Bays Clutch Line w/ Tilton Delay Valve installed. Such a crucial piece to eliminate drivetrain shock. Drift, Track, Rally, Street cars...they all benefit from this. By allowing the clutch to "slip" slightly during quick engagements or clutch kicks, the flow control valve reduces shock loads to the driveline. There is no delay in clutch kicks or shifts and you will still be able to drive aggressively. The OEM ones are very slow and not built for Motorsport use, they do delay quick shifts and clutch kicks. So they are not the same and not recommended. Shown is the upgraded
Chase Bays Master Cylinder Adapter. It is not needed for the swap but it is recommend.
Wiring / Sensors
Intake
Front Facing Intake Manifold
Alternator Relocation
EZ30 / EZ36 Swap Package Stage 1 - Bare Essentials
• Link G4 PnP w/ Wideband
• Link IAT
• Bosch Motorsport Combined Temp / Pressure for Oil
• M12x1.25 to M10x1.0 Adapter for Above Sensor
• Chase Bays Intake for Stock Intake Manifold
• Option to add Chase Bays Intake Manifold w/ Stock Airbox (Alternator Relocation Kit included)
• Chase Bays Oil Cooler Kit (Needed for Header Clearance (option to add Cooler)
• Chase Bays x NAS 6-2-1 Headers
• Chase Bays EGR Block Offs
• Option for Chase Bays EZ36 Timing Chain Arm Brace
EZ30 / EZ36 Swap Package Stage 2
• Chase Bays Oil Catch Can Kit
• Chase Bays 48mm Motorsport Radiator w/ 12” Ultra High CFM Fans & Upper Radiator Relocation Brackets
• Chase Bays Cyl 5 & 6 Cooling Mod
• Chase Bays Oil Pan Baffle (Option for Rally Sport Design Oil Pan)
• Chase Bays Right Side VC Vent Adapter
Transmission Options
Coilovers and Spring Rates
Torque Solution Diff & Subframe Inserts
