BMW 325i / 330i N52 E90 / E91 / E92: the naturally aspirated straight-six, the exhaust system guide
Saloon, Touring or coupé, the E90-generation 325i and 330i are among the last 3 Series with a naturally aspirated inline-six. The N52 that powers them is smooth and fierce at high revs, but its factory exhaust is tuned so that you forget about it. This guide sets out every option of the ROG exhaust, so that you know which one will give the N52 back its full personality: material, valves, tips and fitting.
Written by ROG Motorsport · Updated
Your ROG exhaust for the BMW 325i / 330i N52 E90 / E91 / E92
From €2,190 in stainless steel, €2,690 in titanium
Configure my exhaust- Vehicles
- BMW 325i / 330i N52 E90 / E91 / E92 (2005-2007)
- Engine
- N52 · 218 to 258 hp · 250 to 300 Nm, depending on the version
- Exhaust
- Valved cat-back, built for your VIN
- Material
- 304 stainless steel or titanium
- Front section
- Optional: catted front pipes with 200 or 100 cells, or decat
- Valves
- ROG remote, or factory control if your vehicle has it
- Lead time
- 20 working days from order confirmation to delivery
- Warranty
- 3 years, parts and workmanship
Closely related versions have their own guide: BMW 335i N54 E90 / E92 / E93 3.0T, BMW 335i N55 E90 / E92 / E93 3.0T, BMW M3 E90 / E92 / E93 4.0L, BMW 320i / 330i GT F34 2.0T.
The N52: a naturally aspirated inline-six that lives for revs
The N52 is a naturally aspirated inline-six whose block combines magnesium and aluminium to lighten the front of the car. It features Valvetronic variable valve lift and double variable camshaft timing. In the 325i it produces 218 hp and 250 Nm; the 330i, with its larger displacement, offers more. Either way, the power arrives progressively, with a real eagerness to rev.
With no turbo to filter the sound, the exhaust is the only thing between the N52 and your ears. The factory exhaust takes the opportunity to smooth everything over, and the car seems tamer than it really is. Fitted in its place with no work on the engine or the ECU, the ROG valved exhaust gives it back its texture: a full bass note at low revs, a clean climb towards the top of the rev counter, and the option of returning to factory calm on demand.
What makes up the exhaust on your BMW 325i / 330i N52 E90 / E91 / E92
An exhaust system is best understood in two parts. Here is what each one does, and what ROG replaces.
The cat-back is the complete exhaust system
It is everything you can see under the chassis of your BMW 325i / 330i N52 E90 / E91 / E92, from the outlet of the front section to the tips: pipes, silencer, valves. Routing, silencer, valves: this is where the sound is shaped, and where we focus our research and development.
The front section, where the catalytic converter sits
On your BMW 325i / 330i N52 E90 / E91 / E92, that means the front pipes, just after the manifolds. They contain the factory catalytic converter: the second restriction in the exhaust, after the silencer. Changing this part remains a choice: it pays off mainly with an ECU remap, which turns the freed-up flow into power.
The figures for your BMW 325i / 330i N52 E90 / E91 / E92
What an exhaust changes straight away is the sound, the engine's breathing and the weight at the rear. For more power, add an ECU remap.
Power
Torque
Published factory and Stage 2 figures. Factory figures vary by version; Stage 2 figures published for the 258 hp version.
With or without an ECU remap, the exhaust fits and works. But it is an ECU remap at an approved tuning centre that truly unleashes your BMW 325i / 330i N52 E90 / E91 / E92, and that is what we recommend.
On a naturally aspirated engine like the N52, an ECU remap does not have the reserves that a turbo offers: it refines injection, ignition and throttle response. The gains remain more modest, felt more in driving pleasure than on paper. The ROG exhaust is the logical complement, since it lets you hear the extra liveliness the engine gains.
Configuring your exhaust, step by step
4 choices, in the same order as the product page configurator.
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Step 1 of 4: Material: stainless steel or titanium
For your BMW 325i / 330i N52 E90 / E91 / E92, the exhaust costs €2,190 in stainless steel and €2,690 in titanium.
304 stainless steel
2 190 €
- Weight
- Baseline
- Sound
- Full and rounded
Durable, corrosion-resistant, with a rounded, full sound: the most popular option.
Titanium
2 690 €
- Weight
- Around 40% lighter
- Sound
- Metallic, crystal-clear
For the same design, it weighs around 40% less than stainless steel. A more metallic note at high revs and a look all of its own, from brushed to blued.
Both materials age well: 304 stainless steel copes with winter and salt, and titanium does not rust. Stainless steel or titanium: what really changes.
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Step 2 of 4: Front section: front pipes and catalytic converter
Optional: the front pipes on your BMW 325i / 330i N52 E90 / E91 / E92, with the catalytic converter. Sound rating out of 10, valves open: the factory exhaust sits at 3.
Cat-back only
Included
7/10Factory emissions control
Nothing changes at the front: the cat-back alone is already enough to change the car.
200-cell sports catalytic converter
+1 250 €
8/10Road use and French MOT
The everyday compromise: emissions control is still there, and breathing improves noticeably.
100-cell sports catalytic converter
+1 250 €
9/10French MOT pass not guaranteed
One step further: more flow, a more aggressive sound, reduced emissions control.
Decat
+1 010 €
10/10Track use only
Everything unleashed: maximum flow and unrestrained sound, for the track.
Sound intensity, on a scale of 0 to 10
- 10/10Decat front pipes + ROG cat-back
- 9/10100-cell sports catalytic converter + ROG cat-back
- 8/10200-cell sports catalytic converter + ROG cat-back
- 7/10ROG cat-back only, factory catalytic converter retained
- 3/10Factory exhaust, for comparison
Valves open. With the valves closed, every configuration becomes discreet again.
What about the engine warning light? It can appear with a sports catalytic converter: the downstream oxygen sensor reads a different level of cleaning from the factory unit. It is not an engine fault, and it is dealt with by an ECU remap or a diagnostic tool. With a decat, an ECU remap becomes necessary. If it happens to you, call us and we will point you in the right direction. Passing the French MOT with a sports exhaust.
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Step 3 of 4: Valves: ROG remote or factory control
Two ways to control the valves on your BMW 325i / 330i N52 E90 / E91 / E92.
ROG remote
The simplest solution: a control unit in the boot and a remote, open or closed at the press of a button, whatever mode you are in. A question while fitting? We will get back to you.
Factory control
- Only for vehicles fitted with factory valves
- Controlled by the drive modes
Does your vehicle have factory valves? The exhaust keeps their existing control: the drive modes operate the valves, as before, with no added electronics.
On a long journey, what matters is the absence of drone at a steady speed. With the valves closed, the exhaust keeps the cabin calm; the show is still there whenever you ask for it. More about exhaust drone.
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Step 4 of 4: Tips: the visual signature
Match the tips to the style of your BMW 325i / 330i N52 E90 / E91 / E92, understated or bold. A particular finish in mind? Send us a photo and we will look at it together.
- Stainless steel
- Black
- Carbon
- Blued titanium
- M Performance style carbon
The ROG sound signature on the N52 in the E90 3 Series
The N52 has the typical sound of a BMW inline-six: a muted purr at idle, then a round, even song that turns higher-pitched towards the red line. It is a very pleasant voice, but the factory exhaust strips out almost all of its depth, so much so that both the 325i and the 330i seem to change gear in a whisper.
With the ROG exhaust and the valves open, that song comes back without turning into a din: the six-cylinder makes itself heard every time you accelerate, with a more metallic tone at high revs. With the valves closed, your 3 Series keeps the discretion expected of a saloon or Touring used every day.
From order to fitting
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Configuration
You choose the options for your BMW 325i / 330i N52 E90 / E91 / E92 and enter its VIN, found in box E of the registration certificate.
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Check
We confirm compatibility with your car before we build it.
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Manufacturing
Made to order, for your BMW 325i / 330i N52 E90 / E91 / E92.
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Delivery
Free, insured delivery, with tracking sent on dispatch.
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Fitting
Clamps and gaskets, no welding: two hours on average at the garage of your choice.
20 working days from order confirmation to delivery
- Warranty
- 3 years, parts and workmanship, from the date of delivery
- Payment
- In instalments with Klarna
- Installation
- At the garage of your choice
What about the manufacturer's warranty? In Europe, fitting a part from another brand is not enough on its own to void it; the manufacturer has to prove the link between that part and the fault. Our article on the manufacturer's warranty.
Our recommendations for your BMW 325i / 330i N52 E90 / E91 / E92
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Daily driving
2 190 €
- Stainless
- Cat-back only
- ROG remote
Your BMW 325i / 330i N52 E90 / E91 / E92 stays easy to live with, the factory emissions control is retained, and you open the valves whenever you choose.
View this configuration -
Fast road
3 940 €
- Titanium
- 200-cell front pipes
- ECU remap
For great roads: more voice and more response, while staying road-friendly.
View this configuration -
Track
3 700 €
- Titanium
- Decat front pipes
- Stage 2
The most extreme configuration, for track use only.
View this configuration
These profiles are starting points. The right choice is often made in five minutes on the phone.
BMW 325i / 330i N52 E90 / E91 / E92: your questions
How much power does an exhaust system add to the BMW 325i / 330i N52 E90 / E91 / E92?
From the factory, the BMW 325i / 330i N52 E90 / E91 / E92 produces 218 to 258 hp and 250 to 300 Nm depending on the version. Without a remap, the exhaust transforms the voice and lightens the rear; it is the ECU remap that increases power.
Stainless steel or titanium: which material for the BMW 325i / 330i N52 E90 / E91 / E92?
For the BMW 325i / 330i N52 E90 / E91 / E92, the ROG exhaust costs €2,190 in stainless steel and €2,690 in titanium. Choose stainless steel for value for money and a rounded sound, titanium to save around 40% in weight and get a clearer tone.
Do you need to replace the catalytic converter on the BMW 325i / 330i N52 E90 / E91 / E92?
No, the cat-back alone already does most of the work on the BMW 325i / 330i N52 E90 / E91 / E92. The front pipe option is for those tuning the engine: 200 cells to stay road-friendly, 100 cells or decat for the track.
Does the BMW 325i / 330i N52 E90 / E91 / E92 pass the French MOT with a ROG exhaust?
The cat-back only and the 200-cell sports catalytic converter both keep emissions control: that is the configuration to present, with the valves closed. The 100-cell converter makes a pass uncertain, and with the decat the BMW 325i / 330i N52 E90 / E91 / E92 fails the emissions test.
How is the ROG exhaust fitted to the BMW 325i / 330i N52 E90 / E91 / E92?
Fitting needs no welding or cutting and takes two hours on average on a lift. We check compatibility with the VIN of your BMW 325i / 330i N52 E90 / E91 / E92 before manufacturing.
What does a ROG exhaust for the BMW 325i / 330i N52 E90 / E91 / E92 cost, and how long does it take?
From €2,190 to €3,940 depending on the configuration. Allow 20 working days from order confirmation to delivery. Free delivery in Europe, 3-year warranty.
Unsure about your configuration? Give us a call.
Between stainless steel and titanium, between the cat-back only and the full system, the right choice depends on how you drive and on your BMW 325i / 330i N52 E90 / E91 / E92. We take the time to talk it through before you order, with a reply within 24 hours. We are not here to sell to you over the phone: we help you choose, even if that means a cheaper option because it suits the way you drive.
Behind every ROG exhaust is a French team you can actually reach, who know the cars they talk about. More than 500 exhaust systems fitted and a rating of 4.9 out of 5.
Further reading
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