Short answer: On a G20 M340i, G22 M440i or G42 M240i, an intake is mostly about sound. You hear the turbo spool and the blow-off. Power gains are small, and the makers' own claims run from about 9 to 19 hp. For the cheapest change, use a drop-in filter in the factory box. For the most turbo noise for the money, get a turbo inlet pipe. For the best heat control, get a sealed carbon box. The install is a hand-tool job under the hood. Plan on 30 to 60 minutes for most kits, and up to 2 hours for a sealed carbon box the first time. The part that matters most is the turbo-end O-ring and spring clip.
Parts in this guide are for off-road / competition use only. Not legal for use on public roads in the United States, including California.
I'm Gleb Blekher. I run B58 Racing out of Dallas, TX. An intake is usually the first part people put on a B58, and we get more "which one?" questions about it than almost anything else. This guide uses the intake makers' own install instructions (Eventuri, Dinan and CTS Turbo) plus the specs they publish for their parts. Where they disagree, or don't say, I'll tell you.
Who this guide is for
| Car | Chassis | Engine | Notes |
|---|---|---|---|
| M340i / M340i xDrive | G20 sedan, G21 Touring | Gen 2 B58 (B58TU) | Most kits list the G20. Check the listing for the G21 Touring. |
| M440i / M440i xDrive | G22 coupe, G23 convertible, G26 Gran Coupe | Gen 2 B58 (B58TU) | Many G20 kits are also listed for it. Check each listing. |
| M240i / M240i xDrive | G42 coupe | Gen 2 B58 (B58TU) | Fewer kits list it. Check fitment. |
2025 and newer cars: BMW added a 48V mild-hybrid system to the B58 in these cars. Eventuri sells a separate intake for them. Check your production date before you order any intake.
Z4 M40i (G29) and GR Supra: same engine family, different engine bay. The airbox is different, so most G20 intakes won't fit. A few inlet pipes and drop-in filters do cross over, and each listing says so. Supra owners should read our A90 Supra mods guide.
F-chassis M240i, 340i, 440i: that's the Gen 1 B58, with different intakes. Not sure which engine you have? See B58 Gen 1 vs Gen 2.
The four types of B58 intake
1. Drop-in filter. A washable filter that goes in the factory airbox in place of the paper element. The box, the inlet tube and the sound stay mostly stock. It takes five minutes. It's the cheapest option and has the smallest effect.
2. Open or semi-open cone intake. The factory box comes out. A cone filter sits behind a heat shield or in a partly open box. These are the loudest full intakes. The trade-off is heat. A filter that can see the engine bay can pull warm air when you're stopped in traffic.
3. Sealed carbon box. A fully closed airbox that still breathes through the factory front duct. Most add a second feed from the wheel-arch area. Eventuri says the stock intake sits right next to the exhaust manifold. Its box adds a reflective heat shield on that side and is sealed against engine-bay air. These cost the most.
4. Turbo inlet pipe. This replaces the factory plastic inlet between the airbox and the turbo. The stock inlet has a built-in resonator (Dinan calls it the "turbo muffler"). It's there to quiet the turbo. Remove it and you hear a lot more spool and blow-off. Inlet pipes work with the stock airbox or with most aftermarket intakes.
What an intake actually changes
- Sound. This is the big one. Every maker we read talks about more turbo and intake sound. The resonator in the factory inlet is there to hide it.
- Power. Small. The numbers below are the makers' own figures. They come from different dynos and test methods, so don't compare them directly.
- Dinan says its G2x intake is at least 58% less restrictive than stock. It claims up to 9 wheel hp and 8 lb-ft on an otherwise stock car.
- Injen claims up to 19 hp and 18 lb-ft for its SP short ram, and up to 13 hp and 11 lb-ft for its sealed Evolution box.
- aFe claims up to 9 hp and 10 lb-ft for its Momentum GT with the Pro DRY S filter.
- do88 measured about 15% more airflow than stock for its intake on a flow bench, and about 23% with its turbo inlet added.
- Forge says independent dyno testing showed over 9 bhp and 7 Nm from its inlet hose alone.
- Intake air temps. Sealed boxes and heat shields are designed to keep engine-bay heat away from the filter. An open cone can do the opposite in stop-and-go traffic. We did not find a published, independent back-to-back intake temperature test for these cars that we'd trust. Treat "cooler air" as a design goal, not a measured number.
- Boost and spool. The engine computer controls boost, so a freer intake doesn't raise peak boost by itself. Smoother airflow can mean the turbo works a little less to make the same boost.
My honest take: if you want power, the tune comes first. Get an intake because you want to hear the turbo, or because you're running a big tune and want less restriction ahead of it. See our M340i and M440i mods guide for where the intake fits in the order.
Do you need a tune?
In general, no. Most intakes here are sold to run on the stock engine software. Injen says this about both of its kits. These cars measure airflow with a factory sensor that moves over to the new intake housing, so the engine still sees the air coming in.
There are exceptions. do88 says its turbo inlets have no crankcase heating element, so that connector is left unplugged. do88 recommends a custom tune to avoid a check engine light. Read the "Good to know" notes on any listing. If you're already tuned, tell your tuner what intake you fitted. Some maps assume a specific intake.
Strut brace, fitment and xDrive notes
- Strut brace. Many G20s, G22s and G42s have a factory brace across the engine bay, and it sits over the intake area. Check that your kit works with it.
- Dinan's G2x intake (D760-0069) comes with two spacers that go under the factory brace when you put it back.
- Dinan says its carbon G20/G22/G42 intake (D760-0058) works with or without factory bracing.
- Eventuri and do88 say their boxes leave room for a brace.
- Dinan's earlier G20-only carbon intake (D760-0052) is listed by at least one retailer as for cars without the factory brace. Ask us before ordering it for a braced car.
- Build date. Eventuri makes two G20 M340i versions: one for cars built before November 2018 and one for cars built after. Eventuri's GXX instructions also include two turbo-end flanges, one marked "B58 LCI", and say to choose by car. Check your build date.
- xDrive. Everything on this job happens from the top of the engine bay. We didn't find any maker's instructions with extra steps for xDrive, and Injen's Evolution listing names xDrive cars. Expect the same job on both.
- Factory sensor screws. Several kits come with their own screws for the airflow/temperature sensor. Eventuri says "DO NOT use the stock screws." Dinan says the stock screws aren't reused. CTS says to use its supplied washers.
Which intake to buy: what we sell for these cars
Every part below is listed for at least one of the G20 M340i, G22 M440i or G42 M240i. Fitment is per our listing, so confirm your exact car before you order. Browse the full range in B58 Intakes.
Drop-in filters (factory airbox stays)
| Filter | Listed for | Notes |
|---|---|---|
| FTP Motorsport High-Flow Air Filter | G20, G22, G42 | Washable, rubber frame |
| VTT B58TU Drop-In Filter | G20, G22, G42 | Pre-oiled cotton |
| Pipercross PP2020 Panel Filter | G20, G22, G42 | Pipercross claims 30–40% more airflow than paper |
| Dinan High Flow Drop-in Filter | G20, G22 | Oiled cotton gauze |
| aFe Pro 5R Filter | G20, G22 | Five-layer oiled gauze |
| Fabspeed BMC F1 Filter | G20 | BMC claims close to 40% more flow than paper |
| ProRam drop-in filter | G20 | Choose your engine on the listing |
Turbo inlet pipes (most sound per dollar)
| Inlet | Listed for | Notes |
|---|---|---|
| Dinan Carbon Fiber Turbo Inlet | G20, G22/G23/G26, G42 | Dinan quotes 14% more internal volume than stock |
| CTS Turbo Aluminum Turbo Inlet | G20, G22, G42 | Cast aluminum. CTS puts the install at about 10 minutes. |
| FTP Motorsport Turbo Intake Pipe | G20, G22, G42 | Viton O-ring included |
| Forge Motorsport Inlet Hose | G20, G22 | Five-ply silicone. Forge estimates about 30 minutes. |
| B58 Silicone Inlet Pipe (Intake Resonator Delete) | G20 | Our cheapest bolt-on |
The Wagner Tuning turbo inlet is made for Lader Manufaktur or Turbosystems hybrid turbos, not the stock turbo.
Open and semi-open intakes
| Intake | Listed for | Notes |
|---|---|---|
| Dinan Cold Air Intake (D760-0069) | G20, G22/G23/G26, G42 | Semi-open. Strut brace spacers included. |
| Dinan Carbon Fiber Cold Air Intake (D760-0058) | G20, G22, G42 | Carbon version. Dinan rates the install at about an hour. |
| Dinan Cold Air Intake, 2020–2024 M340i (D760-0052) | G20 | Earlier carbon kit. See the strut brace note. |
| Injen SP Short Ram | G20, G22/G23/G26, G42 | Aluminum tube and heat shield. Not CARB exempt. |
| Injen SP Aluminum Short Ram (SP1140) | G20, G22 | Red or polished |
| aFe Momentum GT, Pro DRY S | G20, G22/G23/G26, G42 | Dry filter with a sight window |
| Ramair Pleated Intake Kit / Ramair Foam Intake Kit | G20, G22, G42 | Heat shield, MAF housing and silicone inlet |
| Pipercross Intake Kit PK419 | G20, G22 | Confirm fitment with us |
Sealed carbon boxes
| Intake | Listed for | Notes |
|---|---|---|
| Eventuri Carbon Intake, built after Nov 2018 | G20, G22, G42 | Second feed from the wheel arch, gold heat shield |
| Eventuri Carbon Intake, G20 built before Nov 2018 | G20 | Early cars only |
| Eventuri Carbon Intake, 2025+ 48V | G20, G22, G42 (2025+) | Mild-hybrid cars only |
| do88 Intake System | G20, G42 | Optional matching turbo inlet |
| Injen Evolution | G20, G22/G23/G26, G42 | Molded plastic sealed box. Not CARB exempt. |
| Forge Carbon Induction Kit | G20, G22 | Includes Forge's inlet hose. Intake-only version also listed. |
My picks:
- Sound on a budget: an inlet pipe with a drop-in filter.
- Best heat control: the Eventuri, if your build date matches.
- Most kit for the money on all three cars: the Dinan D760-0069, with the spacers if you have the factory brace.
Difficulty, time and tools
- Difficulty: 2 out of 5. Everything is done from the top. No lift, no jack stands.
- Time: 30 to 60 minutes for most kits. CTS puts its inlet at about 10 minutes, and Forge puts its hose at about 30. Dinan rates its carbon intake at about an hour. Eventuri's GXX instructions say 1 to 2 hours. A first-timer should plan on the longer end.
- Work on a cold engine with the car switched off. CTS says not to work on a hot motor.
Tools
These are the sizes the makers list. Have a basic metric set on hand too.
- 6 mm and 7 mm sockets with a ratchet (Eventuri, Dinan). The sockets fit the hose clamps.
- 8 mm socket (Dinan D760-0052).
- Long extension. Dinan says you need one for the upper clamp on the turbo inlet hose.
- T20 and T25 Torx bits (Eventuri lists both, Dinan lists T20). These fit the sensor screws.
- 2.5 mm and 3 mm hex keys (Dinan D760-0052), plus a 3 mm hex bit (Eventuri). These fit the kit hardware.
- Flat screwdriver or pick (Eventuri, Dinan) for the spring clip and the breather connector.
- Side cutters or snips. Dinan says to cut the factory crimp clamp on the inlet hose.
- A clean rag to cover the turbo inlet.
Torque values: none of the instructions we read (Eventuri, Dinan, CTS) gives a torque spec for the clamps or the sensor screws. Eventuri says to secure the clamp on the carbon tube without overtightening. Use the value in your own kit's instructions if it gives one. Otherwise go snug, and don't crush carbon or plastic.
Step-by-step install
This is the common sequence from Eventuri's G20 and GXX B58 instructions, Dinan's D760-0052, D760-0069 and D760-0062 instructions, and CTS Turbo's G20 M340i guide. Your kit's sheet comes first if it differs.
Removing the factory intake
- Open the hood and locate the airbox. It's on the passenger side of the engine bay (CTS). Dinan's turbo inlet instructions start by taking off the engine cover, which gives you more room at the turbo.
- Unplug the sensor on the airbox outlet. CTS calls it the MAF sensor and Dinan calls it the air temperature sensor. It's the plug-in sensor held on by two screws. Press the tab and pull the connector straight off.
- Loosen the band clamp between the airbox and the inlet hose. CTS, Dinan and Eventuri all start here.
- Lift the airbox straight up and out. It sits on rubber grommets. CTS, Dinan and Eventuri all warn that the grommets sometimes come out with the box. If they do, push them back into the chassis. Your new intake needs them.
- Take the sensor off the old airbox. Remove the two screws and set the sensor somewhere clean. You'll reuse the sensor but not the old screws.
- Disconnect the breather line from the inlet hose. Eventuri calls it the breather connector and Dinan calls it the PCV line. Dinan also unclips a wiring harness from the lower part of the inlet.
- Release the inlet at the turbo. On the factory part there's a spring clip around the flange at the turbo end. Eventuri says to pull the spring clip away from the flange, and then the tube pulls off the turbo. If your kit keeps the factory lower section and replaces only the hose, Dinan says to cut the crimp clamp instead. Its G2x instructions say the clamp "may need to be cut" depending on the car.
- Cover the turbo opening right away. Dinan's warning is clear: anything that falls in can do severe damage to the turbo. Stuff a clean rag in it and leave it there until the new inlet goes on.
Swapping the turbo-end seal (inlet pipe and sealed-box kits)
- Move the O-ring and spring clip if your kit tells you to. Dinan's carbon inlet and Eventuri's GXX flange reuse the factory O-ring and spring clip.
- Eventuri says the factory O-ring is orange on earlier cars and grey on LCI cars. The flat face of the orange seal faces the turbo. The grey seal isn't sided.
- Dinan says to keep the factory orientation and warns that getting it wrong "may result in significant engine damage."
- Take a photo before you remove it.
- Fit the new inlet or flange to the turbo. Pull the rag out first. The Eventuri GXX flange clicks into place. Dinan says to make sure the spring clip is fully seated. Kits that use a silicone coupler at the turbo work differently: Dinan's G2x intake and Eventuri's G20 kit go onto the turbo inlet with a hose clamp. Tighten the turbo-side clamp and leave the top clamp loose for now. Eventuri says to point the clamp screws to the side so you can reach them later.
Building and fitting the new intake
- Assemble the intake on the bench. Attach the inlet tube to the box with the supplied screws and washers. Then fit the filter on the tube and tighten its clamp. Dinan says its filter only goes on one way, with the logo upright. Eventuri says the sealing plate's "INSIDE" label faces the filter.
- Mount the sensor on the new tube with the supplied screws. Dinan says it only fits one way. Don't reuse the stock screws (Eventuri). Use the supplied washers (CTS).
- Lower the assembly into the car.
- Most boxes snap into the factory rubber grommets. Dinan's D760-0052 uses three.
- Eventuri's box has to sit squarely inside the factory front duct, and its second scoop drops into the gap at the wheel arch. Eventuri says to bring it down at a slight angle with the tube pointing down, then press it firmly into both mounts.
- On CTS's open kit you install the heat shield first. Leave the bracket with the upper mounting pin slightly loose until it seats in its grommet, then tighten it.
- Join the tube to the inlet hose. Rotate the tube into the coupler and make sure it goes in deep. Dinan says to leave "plenty of engagement" for the clamp. Then tighten the top clamp. Dinan needs the long extension here. Eventuri says not to overtighten.
- Reconnect the breather line to the new inlet (Eventuri, Dinan).
- Plug the sensor back in until it locks.
- Fit the lid. Dinan's lids use push rivets. Line up the holes and push each rivet in until it engages.
- Refit the strut brace and engine cover. If you have the factory brace and Dinan's D760-0069, put the supplied spacers under the brace first.
- Check your work. Look over every clamp, the breather and the sensor plug. Start the car and listen for whistles or hissing at idle. Check for warning lights. Recheck the clamps after your first few drives.
Common mistakes
- Dropping something into the turbo. Cover the inlet the moment it's open. A clamp screw or a broken bit of clip in the compressor is an expensive mistake.
- O-ring in the wrong way, pinched, or missing. Note how the factory O-ring sits before you move it. Eventuri and Dinan both put this front and center.
- Spring clip not seated. If the clip isn't fully home, the inlet can pop off under boost. Tug on the inlet after fitting it.
- Losing the airbox grommets. They come out with the old box more often than you'd think. Without them, the new box rattles or won't sit right.
- Reusing the stock sensor screws. Use the screws or washers that came with the kit.
- Tightening clamps before everything lines up. Hang it all loose, line up the tube with the coupler and the sensor housing, then tighten. CTS, Dinan and Eventuri all use this order.
- Overtightening clamps on carbon or plastic. Snug is enough. Eventuri warns against overtightening.
- Forgetting the breather line. Left off, it leaves an open port in the intake. On do88's inlet, the crankcase heater connector is meant to stay unplugged. That's a different part.
- Ordering the wrong build-date version. Pre- and post-November 2018 Eventuri kits are different, and 2025+ cars need their own.
- Ignoring the strut brace. Check before you start that the brace goes back on, or that you have the spacers.
FAQ
What is the best intake for the M340i?
It depends on what you want. For heat control, the Eventuri sealed carbon box is the strongest design. For value across the G20, G22 and G42, the Dinan G2x intake is a good pick. If you mainly want turbo sound, a turbo inlet pipe with a drop-in filter gets you most of it for much less money.
How much horsepower does an M340i intake add?
Not much. Maker claims for these cars run from about 9 hp (Dinan, aFe) to 19 hp (Injen's SP short ram). Each maker tests on a different dyno. Expect a small change on a stock car and a lot more sound.
How long does an M340i intake install take?
About 30 to 60 minutes for most kits. CTS says its turbo inlet takes about 10 minutes. Eventuri's instructions allow 1 to 2 hours for its sealed carbon box. Your first one will take longer than a shop's.
Do I need a tune after installing an intake on my M340i?
Usually not. Most intakes here are sold to run on the stock software, and the factory airflow sensor moves to the new housing. Some turbo inlets are an exception. do88 recommends a custom tune with its inlet to avoid a check engine light. If you're already tuned, tell your tuner.
Will an aftermarket intake fit with the factory strut brace?
Many do, but check the listing. Dinan's G2x intake includes spacers for the factory brace. Dinan says its carbon D760-0058 works with or without bracing. Eventuri and do88 say their boxes leave room for a brace.
Is the intake install different on xDrive cars?
No. The whole job is done from the top of the engine bay. We found no maker instructions with xDrive-specific steps.
Does the same intake fit the M340i, M440i and M240i?
Often, but not always. Dinan's D760-0069, Eventuri's post-November 2018 kit and Injen's Evolution are listed for all three. Some kits list only the G20 and G22, or the G20 and G42. Check each listing.
What torque do the intake clamps need?
The Eventuri, Dinan and CTS instructions we read don't give one. Use your own kit's value if it lists one. Otherwise tighten clamps snug and don't overtighten carbon or plastic parts.
If you're planning the next step, start with our M340i and M440i mods guide and the best B58 mods, in order. Not sure which B58 you have? Read B58 Gen 1 vs Gen 2. Supra owners should go to the A90 Supra mods guide. Doing more under the hood? See the B58 charge pipe install and the B58 downpipe install.
Sources
- Eventuri G20 B58 intake steps (silicone coupler at the turbo, sealing plate, secondary scoop, supplied sensor screws, don't overtighten): Eventuri G20 B58 installation instructions
- Eventuri GXX B58 tools (6/7 mm, T20/T25, 3 mm hex), 1–2 hour time, click-in turbo flange, orange/grey O-ring and LCI flange: Eventuri EVE-GXXB58-CF-INT installation guide
- Dinan G20 tools (6/7/8 mm, extension, 2.5/3 mm hex, T20), cutting the crimp clamp, covering the turbo inlet, three grommets, push-rivet lid: Dinan D760-0052 installation instructions
- Dinan G2x/G4x intake steps, sensor screws not reused, clamp engagement, strut brace spacers: Dinan D760-0069 installation instructions
- Dinan turbo inlet steps, removing the engine cover, "turbo muffler", PCV line, O-ring orientation warning: Dinan D760-0062 installation instructions
- CTS G20 M340i intake steps, airbox grommets, supplied MAF washers, loose-then-tighten clamp order, don't work on a hot motor: CTS Turbo G20 B58 M340i intake installation guide
- Dinan D760-0052 listed for cars without the factory strut brace: retailer listing (turnermotorsport.com)
- Maker flow and power claims (Dinan, Injen, aFe, do88, Forge, Pipercross, BMC), CTS and Forge install times, do88 tune note, Injen stock-calibration and CARB notes, Eventuri build-date and 2025+ versions: manufacturer product information on our listings