Every fuel injector set we carry for the 2012-2015 Honda Civic fits the Si with the 2.4L K24Z7, and you only need one once you add boost or ethanol. For a mild turbo build on pump gas, the DeatschWerks 650cc set is plenty. For most boosted Si builds, we'd run the DeatschWerks 750cc set. For big turbo or E85 builds, our pick is the Injector Dynamics ID1050X, with the DeatschWerks 1000cc Bosch EV14 as the other big-flow option. The 1.8L base cars don't take any of these.
Which 2012-2015 Honda Civic do you have?
This matters more than the brand you pick. The 9th gen Civic came with two very different gas engines, and every injector set in this post is listed for the Si's 2.4L K24Z7 only.
The Si is the one with the 2.4-liter (2354 cc) DOHC i-VTEC four. It makes 205 hp at 7000 rpm and 174 lb-ft at 4400 rpm, revs to a 7000 rpm redline and comes with a 6-speed manual. The Si coupe rolls on 225/40R18 tires and the Si sedan on 18-inch alloys, so the wheels are a quick tell along with the Si badges.
Everything else is a different animal. The DX, LX, EX, EX-L and HF use a 1.8L SOHC 16-valve four with 140 hp and 128 lb-ft, on 15-, 16- or 17-inch wheels. The Hybrid and CNG sedans aren't Si cars either.
| Version | Engine | Power / torque | Factory tires | Takes these injectors? |
|---|---|---|---|---|
| Civic Si coupe and sedan | 2.4L DOHC i-VTEC (K24Z7) | 205 hp / 174 lb-ft | 225/40R18 (coupe), 18" alloys (sedan) | Yes |
| DX, LX, EX, EX-L, HF | 1.8L SOHC 16-valve | 140 hp / 128 lb-ft | 195/65R15, 205/55R16 or 215/45R17 | No |
| Hybrid, CNG | Not the Si engine | n/a | 195/65R15 | No |
Not sure what's under the hood? Your registration, window sticker or owner's manual lists the engine. If it says 2.4L, you're in the right place.
That Alabaster Silver EX sedan above is a clean daily, but it's a 1.8L car. None of the sets below will fit it. The full fuel injectors category covers other engines.
Best fuel injectors for the 2012-2015 Honda Civic Si (2.4L K24Z7)
From the factory, the 9th gen Si runs multi-point fuel injection, 11.0:1 compression, drive-by-wire throttle and an 87 x 99 mm bore and stroke. Honda requires premium. It's a torquey, happy NA motor, and on intake, header and exhaust the stock injectors have room to spare.
Things change when you add a turbo or start pouring in ethanol. Boost means more air, more air needs more fuel, and the factory injectors run out of headroom. "Duty cycle" is how much of each engine cycle the injector stays open. Once you push it toward the limit, the tune runs out of fuel to add, and a lean K24 under boost is an expensive noise. If you're still deciding whether boost is even your path, read our turbo K20 vs NA VTEC reality check first.
Here's every injector set we carry for this car.
DeatschWerks 650cc: the mild-boost pick
The DeatschWerks 02-15 Honda Civic Si K20/K24 650cc Injectors (17U-08-0650-4) are the smallest step up we sell for the Si. You get a set of four, made by a company that built its name on high-flow drop-in fitment injectors back in 2004. If you're running a low-boost kit on pump gas and want a safety margin over stock, this is the sensible move. Don't buy more injector than you need. Oversized injectors on a mild build just give your tuner more low-end work to do.
DeatschWerks 750cc: our pick for most boosted Si builds
The DeatschWerks 02-15 Honda Civic Si K20/K24 750cc Injectors (17U-08-0750-4) flow 750 cc/min. DeatschWerks sells them as a matched set of four with a USCAR connector, an ethanol-compatible rating and a limited lifetime warranty. That ethanol rating is the difference from the 650 set. You have room to blend ethanol or turn up the boost later without buying injectors twice. For a typical street turbo Si, this is the set we'd buy.
DeatschWerks 1000cc Bosch EV14: big flow, DW flavor
The DeatschWerks Civic Si / RSX K20/K24 & S2000 F22 1000cc Bosch EV14 Injectors (17U-08-1000-4) are a Bosch EV14-based set rated at 1000cc. This set is for big turbos and serious fuel demand, not a weekend bolt-on. It suits the owner building toward real boost who wants to stay in the DeatschWerks family alongside their pump and fuel system parts.
Injector Dynamics ID1050X: the no-compromise pick
The Injector Dynamics ID1050X 12-15 Honda Civic Si 14mm (Grey) Adaptor Top Injectors (1050.07.21.48.14.4) are listed specifically for the 12-15 Si. Injector Dynamics rates them at 1065 cc/min at 3.0 bar (43.5 psi) on gasoline at 125°F, with a maximum differential fuel pressure of 10.0 bar (145 psi). ID says they're compatible with all known fuels, were developed with Bosch Motorsport and are "not a modified production component." They use a USCAR connector and a 14mm grey adaptor top for the Si rail. If you're running E85 or flex fuel on a big turbo, this is the set we'd put in our own car.
Our pick for the 9th gen Si
Most boosted street Si builds should run the DeatschWerks 750cc. It's sized right, rated for ethanol and leaves room to grow. If you're going full E85 or chasing big boost, skip the middle ground and get the ID1050X. If you're staying NA, keep your money for now and spend it on the stuff in our mod order guide.
2012-2015 Civic Si fuel injectors compared
Here's every set side by side. Flow rate, part number and fitment are all in one place.
| Part | Fits | Years | Type | Price |
|---|---|---|---|---|
| DeatschWerks 17U-08-0650-4 | Si 2.4L K24Z7 | 2012-2015 | Fuel injector set | $405.06 |
| DeatschWerks 17U-08-0750-4 | Si 2.4L K24Z7 | 2012-2015 | Fuel injector set | $455.06 |
| DeatschWerks 17U-08-1000-4 | Si 2.4L K24Z7 | 2012-2015 | Fuel injector set | $485.06 |
| Injector 1050.07.21.48.14.4 | Si 2.4L K24Z7 | 2012-2015 | Fuel injector set | $597.60 |
All four sets are listed for the 2012-2015 Si 2.4L K24Z7. None of them is CARB legal, and none can be sold in California.
DeatschWerks vs Injector Dynamics for the 9th gen Civic Si
This comes down to how far you're going.
DeatschWerks gives you a ladder: 650cc, 750cc and 1000cc, all for the same car. You can buy the size your build needs today. DW designs, builds and tests its parts in-house and also makes in-tank and in-line pumps, regulators, rails and lines. That makes it easy to keep a whole fuel system from one maker.
Injector Dynamics sells one big set for this car and publishes exactly how it's rated: flow at a stated pressure, fuel and temperature, plus a 145 psi differential pressure ceiling. Tuners like that kind of detail. The "all known fuels" rating makes it the cleanest pick for E85 and flex fuel.
Our take: DW for most street builds, ID for big ethanol builds. If you're choosing between the DW 1000cc and the ID1050X, the ID's published specs and fuel rating usually win, unless you're already running a DW fuel system and want everything to match.
What size injector for your power goal?
Neither DeatschWerks nor Injector Dynamics puts a horsepower number on these sets, and we won't make one up. Injector headroom depends on boost, fuel type, fuel pressure and how your tuner sets the car up. What we can tell you is how builds usually line up.
- Stock or bolt-ons (intake, header, exhaust, tune): keep the factory injectors. Our best cold air intakes for the 9th gen Civic post covers the intake side, and none of those need bigger injectors.
- Mild turbo, pump gas: DeatschWerks 650cc.
- Street turbo with room to grow, or ethanol blends: DeatschWerks 750cc.
- Big turbo, high boost, heavy ethanol: DeatschWerks 1000cc Bosch EV14 or Injector Dynamics ID1050X.
- Full E85 or flex fuel on a big turbo: ID1050X.
Talk to your tuner before you buy. They'll tell you what duty cycle they want to see at your boost target, and that settles the size faster than any forum argument.
A Crystal Black Pearl Si sedan like this one makes a great sleeper ("looks stock, isn't"). Budget matters on builds like this, so our budget Civic Si build breakdown covers where the money actually goes once fueling enters the picture.
Can you run E85 on a 9th gen Civic Si?
Yes, with the right parts. E85 is a high-ethanol pump fuel that turbo guys love for its knock resistance. It takes a lot more fuel volume than gasoline, so the injectors have to grow.
Of the sets we sell, two carry an ethanol claim from their makers. The DeatschWerks 750cc is rated ethanol compatible, and the Injector Dynamics ID1050X is rated for all known fuels. For a full E85 or flex-fuel Si on boost, we'd go straight to the ID1050X so flow is never the bottleneck.
Injectors are only one part of an E85 setup. Plan on fuel pump capacity to match, and get a tune built for ethanol. Bigger injectors on a stock pump just move the bottleneck down the line.
Do you need a tune for bigger injectors?
Yes, every time. The factory ECU is calibrated for the factory injectors. Bolt in a set that flows more and the car will run rich, idle badly and throw codes until it's retuned.
Your tuner needs the injector's flow and characterization data. That's one reason the ID1050X's published rating conditions matter. Book the tune before the injectors go in, not after the car won't idle.
If you're doing injectors as part of a turbo kit, the tune is happening anyway. Just make sure your tuner knows which set you bought.
How to install fuel injectors on a 2012-2015 Civic Si
This is a driveway job if you can turn a wrench and respect fuel. Here's the flow we follow.
- Kill the fuel pressure and power. Relieve fuel system pressure the factory way, then disconnect the battery. Work cold, with rags handy and no open flames.
- Unplug the injectors. Release each electrical connector (3 in Figure 1). The DW 750 and ID1050X both use USCAR plugs, so check that your harness matches or that you have the right adapters before you start.
- Pull the rail. Unbolt the fuel rail and lift it with the injectors attached. Expect a little fuel to drip from each fuel inlet (2 in Figure 1).
- Swap the injectors. Pull each old injector body (4 in Figure 1) from the rail and the head. Check that the old lower seals came out with them and didn't stay stuck in the ports.
- Lube the O-rings. Put a light film of clean engine oil on the upper O-ring (1 in Figure 1) and the lower O-ring (5 in Figure 1). Dry O-rings tear, and torn O-rings leak.
- Seat and reassemble. Press each injector straight into the rail, then guide the spray nozzle (6 in Figure 1) into its port with no twisting or forcing. Bolt the rail down evenly.
- Leak check before you start it. Reconnect the battery and cycle the key a few times to prime the system. Look for wet spots at every O-ring, then start it only with your tune loaded.
On the ID1050X, the 14mm grey adaptor top is what lets it fit the Si rail, so leave it on. If you're doing the injector swap as part of a bigger weekend, our Civic Si coilover install mistakes post is worth reading before the car goes on stands for round two.
Where injectors fit in a 9th gen Si build
Injectors are a supporting mod. They don't make power on their own. They let your turbo, ethanol and tune make power safely. On a 9th gen Si, wheels, tires, brakes and suspension usually come first, then intake and exhaust, then boost and fueling together.
Our 9th gen Civic Si build guide lays out a canyon-ready plan. If you've got a TSX sitting next to your Si, our Acura TSX K24A2 build guide covers that K24 cousin.
Honda Civic fuel injectors FAQ
What fuel injectors fit a 2012 Honda Civic?
It depends on the engine. If your 2012 Civic is an Si with the 2.4L K24Z7, all four sets we carry fit: DeatschWerks 650cc, 750cc and 1000cc Bosch EV14, plus the Injector Dynamics ID1050X. If it's a DX, LX, EX, EX-L or HF with the 1.8L, none of these will fit. Check your engine size before you order.
What are the best fuel injectors for a 2012-2015 Honda Civic Si?
For most boosted street builds, the DeatschWerks 750cc set. It flows 750 cc/min, carries an ethanol-compatible rating and comes with a limited lifetime warranty. For E85 or big-turbo builds, step up to the Injector Dynamics ID1050X, rated at 1065 cc/min at 3.0 bar. For light boost on pump gas, the DeatschWerks 650cc is all you need.
Do these fit a 2017, 2018, 2019 or 2020 Civic Si?
No. The 2017-2020 Civic Si is the 10th gen, a different generation of car. Every set in this post is listed for the 2012-2015 Si 2.4L K24Z7 only. Don't put them in a 10th gen expecting a fit. Browse the full fuel injectors category for other models.
Do these fit older Civics like a 1998, 2000 or 2004?
This post covers only the 2012-2015 car, and we list these sets for that generation's Si. Older Civics from the '90s and 2000s used different engines and fuel setups. Some DeatschWerks part names mention a broader year range, but check the fitment for your exact car before you buy. Don't go by the product title alone.
Do I need bigger injectors on a stock or bolt-on Civic Si?
No. The factory Si makes 205 hp at 7000 rpm, and an intake, header, exhaust and tune don't push past what the stock injectors can feed. Bigger injectors make sense once you add a turbo or switch to ethanol. Before that, spend the money on tires, brakes or a tune instead.
What size injector do I need for a turbo 9th gen Si?
Mild boost on pump gas: 650cc. A street turbo with room to grow or ethanol blends: 750cc. Big boost or heavy ethanol: the DeatschWerks 1000cc or the ID1050X. Your tuner will make the final call based on your boost target and the duty cycle they want to see.
Are these injectors E85 compatible?
The Injector Dynamics ID1050X is rated by its maker as compatible with all known fuels, which covers E85 and flex fuel. The DeatschWerks 750cc carries an ethanol-compatible rating. For a full E85 Si, we'd run the ID1050X. Upgrade the fuel pump and get an ethanol tune too.
Are they plug-and-play?
Physically they bolt into the Si, and the ID1050X comes with the 14mm grey adaptor top for the factory rail. The DW 750 and ID1050X both use USCAR connectors, so confirm your harness plugs match or have adapters ready. Electronically, no injector upgrade is plug-and-play. You need a tune with the new injector data before the car will run right.
Do I need a tune after installing bigger injectors?
Yes. The factory ECU expects the factory injectors, so more flow without a retune means rich running, rough idle and fault codes. Give your tuner the exact set you bought so they can load the right data. Get the tune lined up before install day.
Are these legal in California?
No. None of the four sets is CARB legal, and none can be sold in California. That goes for the DeatschWerks 650cc, 750cc and 1000cc and the Injector Dynamics ID1050X. Check your local rules if you're in another state with strict emissions testing.
Shop every 2012-2015 Honda Civic Si fuel injector
Every set below fits the 2012-2015 Si 2.4L K24Z7. For other cars, browse our full fuel injectors lineup.