Resonator Nissan Sunny FB15: how to choose, replace and upgrade

Resonator in the exhaust system Nissan Sunny FB15 - this is not just a “can” under the bottom of the car, but a key element responsible for reducing noise, stabilizing the flow of exhaust gases and even influencing engine dynamics. Owners FB15 (especially with motors GA15DE And GA16DE) often encounter problems: from body corrosion to burning out of internal partitions, which leads to unpleasant hum, vibration and even lambda probe errors. In this article, we will look at how to diagnose resonator malfunctions, select a high-quality replacement (including original and analogues), and also consider tuning options to improve sound and performance.

Feature Sunny FB15 — a compact exhaust system with an integrated catalyst in the exhaust pipe, which imposes restrictions on the choice of resonators. For example, installing sports models without modifications can lead to error code P0420 (low catalyst efficiency) due to changes in back pressure. We've analyzed owner reviews, technical data and dyno test results to provide up-to-date information - without the myths and marketing gimmicks.

Signs of a resonator malfunction on a Nissan Sunny FB15

The first signal about problems with the resonator is change in exhaust sound. On FB15 With a mileage of over 150 thousand km, a metallic ringing or wheezing often appears at idle, which intensifies during acceleration. This is due to the destruction of internal partitions or cracks in the housing. Unlike a burnt-out muffler, a faulty resonator reveals itself resonating hum at medium speeds (2500–3500 rpm), which can be confused with problems in the gearbox.

Other symptoms:

• 🔥 Body vibrations when driving, especially at speeds of 80–100 km/h - a sign of depressurization of joints or loosening of the resonator fastenings.
• 🚨 Check Engine light on with errors P0420 or P0430 - may indicate a disturbance in the flow of gases and false readings from the lambda probe.
• 💨 Exhaust smell in the cabin — cracks in the resonator can allow gases to pass under the bottom, and through the door seals they get inside.
• 🛑 Power reduction at high speeds - due to increased back pressure in the system (relevant when the catalyst is clogged or the resonator is deformed).

On Sunny FB15 the resonator is located between the exhaust pipe (with catalyst) and the main muffler. Its corrosion is accelerated by condensation that accumulates during short trips in the cold season. Models with resonators without internal anti-corrosion coating are especially vulnerable - their service life rarely exceeds 100 thousand km in Russian conditions.

⚠️ Attention: If you hear a loud pop from the exhaust pipe after starting the engine, this may be a sign that the inner tube of the resonator has failed. Ignoring the problem will lead to fragments getting into the muffler and clogging it.

Original vs analogs: which resonator to choose for FB15

Original resonator for Nissan Sunny FB15 has an article number 20520-4M000 (for 1995–1999 models) or 20520-4M001 (for restyled versions). Its average price is 8-12 thousand rubles, but the quality justifies the cost: stainless steel with aluminum coating and welded seams treated with anti-corrosive agent. However, the original is not always available, so let’s look at proven analogues:

Manufacturer	Article	Material	Average price (RUB)	Features
Bosal	255-121	Aluminized steel	4 500–6 000	Light weight but prone to corrosion after 3-4 years
Walker	20946	Stainless steel	7 000–9 000	Full compatibility with the original, resource 150+ thousand km
SASIC	4020520	Galvanized steel	3 000–4 500	Budget option, but requires additional anticorrosive treatment
Magnetti Marelli	675126350121	Stainless steel	8 000–10 000	Optimized for Euro regulations, reduces the risk of lambda probe errors

When choosing an analogue, pay attention to:

• 🔧 Pipe diameter - must match the original (45–50 mm for FB15). A reduced diameter will increase back pressure.
• 📏 Resonator length — a deviation of more than 5 cm will lead to tension or sagging of the system.
• 🔊 Internal structure — cheap models often have simplified perforations, which worsens sound insulation.

Step-by-step instructions for replacing the resonator

Replacing the resonator with Nissan Sunny FB15 does not require special tools, but will require an inspection hole or a lift. Operating time: 1.5–2 hours. Here's what you'll need:

Open-end wrenches 12 and 14 mm

14 mm socket with extension

Penetrating lubricant (WD-40 or equivalent)

New gaskets for flanges (part number 20680-4M000)

Torque wrench (optional, for precise tightening)

Rubber hangers (if the old ones have lost their elasticity) -->

Step 1. Dismantling the old resonator

1. Stop the engine and allow the system to cool (exhaust gas temperatures may exceed 100°C).
2. Apply penetrating lubricant to the flange threads and wait 10–15 minutes.
3. Unscrew the nuts securing the resonator to the exhaust pipe and muffler (usually 2-3 bolts at each joint).
4. Remove the rubber hangers supporting the resonator. If they are sour, cut them off with a knife.

Step 2. Installing a new resonator

1. Check the integrity of the gaskets on the flanges. Replace them at the slightest damage.
2. Install the new resonator, lining up the bolt holes. Do not fully tighten the fasteners.
3. Secure the rubber hangers, making sure that the resonator does not touch the body or suspension components.
4. Tighten the bolts crosswise with a force of 30–40 Nm (without a torque wrench - “by hand” until it stops plus 1/4 turn).

Step 3: Check

Start the engine and check:

• 🔊 No extraneous noise (knocking, whistling).
• 💨 Tightness of joints (put your hand to the joints - there should be no flow of gases).
• 🚗 No vibrations on the body when driving.

⚠️ Attention: If after replacing the resonator the Check Engine with an error P0420, reset it with a scanner and drive 50–100 km in mixed mode. The error may be false due to altered gas flow. If the code appears again, check the catalyst.

Resonator tuning: improving sound and performance

Standard resonator Sunny FB15 designed for quiet and economical operation, but many owners strive to give the exhaust a sporty character. Upgrade options:

1. Installation of a direct-flow resonator

Direct flow models (for example, Sprint or Fox) remove internal partitions, reducing back pressure. This gives:

• 🔊 More dull and bassy sound (resembles an exhaust Nissan Silvia S14).
• 🚀 Increase in power by 3–5 hp. due to improved gas removal.
• ⚠️ Risk of error P0420if the catalyst is worn out.

2. Perforation of a standard resonator

A budget option is to drill holes in the resonator body (3–5 mm in diameter) to change the sound. However, this reduces the life of the part due to corrosion and may compromise the seal. On an FB15 with a GA16DE engine, perforation of the resonator without modification of the exhaust manifold often leads to a “wheezing” sound at high speeds.

3. Replacement with a resonator from Nissan Primera P11

Resonator from Primera P11 (article 20520-4M200) has a larger volume and improved sound insulation. Its installation requires modification of the mounts, but gives a more balanced sound without loss of power. Suitable for those who want to keep the "stock" look, but improve the acoustics.

What happens if the resonator is completely removed?

Removing the resonator will lead to an extremely loud exhaust (over 100 dB), which contradicts GOST R 52230-2004 (maximum 96 dB for passenger cars). In addition, the operation of the lambda probe will be disrupted due to the altered gas flow, which will cause constant errors P0420 And P0430. In practice, this also impairs acceleration at low speeds due to the lack of back pressure.

Common mistakes when working with a resonator

Even experienced car owners make mistakes that lead to repeated breakdowns or deterioration of performance. FB15. Here are the most common:

1. Ignoring gaskets

Reusing old flange gaskets leads to air leaks and lambda probe errors. For example, a gasket with the article number 20680-4M000 costs only 200–300 rubles, but its wear and tear can result in expensive diagnostics.

2. Incorrect bolt tightening

Over-tightening the fasteners deforms the flanges, and loose tightening leads to vibrations. Optimal torque for resonator bolts Sunny FB15 — 35–40 Nm. Without a torque wrench, aim for a "tight fit" with no play.

3. Installation of the resonator without anticorrosion treatment

Even stainless steel analogues rust over time at the welds. After installation, it is recommended to treat the resonator anticorrosion agent for exhaust systems (For example, Liqui Moly Auspuff-Spray). This will extend its service life by 30–50%.

4. Neglecting to check the catalyst

If the catalyst is clogged, installing a new resonator will not solve the problem of reduced power. On FB15 signs of a clogged catalyst:

• 🔥 The engine stalls at idle.
• 🚗 Maximum speed drops to 120–130 km/h.
• 💨 The smell of sulfur from the exhaust pipe.

Cost of work and spare parts: where is it cheaper?

Цена замены резонатора на Nissan Sunny FB15 varies depending on the region and type of service station. On average:

Service/Spare part	Cost (RUB)	Where to order
Original resonator (20520-4M000)	8 000–12 000	Official dealers Nissan or Exist.ru
Analogue (Walker or Bosal)	3 500–7 000	Online stores: AutoDoc, PartReview
Replacing the resonator (work)	1 500–3 000	Any service station with a pit or lift
Flange gaskets (set)	200–500	Any auto parts store
Anticorrosive treatment	500–1 000	On your own or at the car wash

It’s not worth saving on work - an unqualified replacement can lead to:

• 🔧 Resonator skew and friction against the body.
• 🔥 Fire danger due to improper attachment to the exhaust manifold.
• 💸 Additional expenses for rework.

The most budget option is to buy a used resonator in good condition (price 1,500–3,000 rubles). However, the risk of running into a part with internal damage is high - inspect it for:

• 🔍 Cracks in welds.
• 💧 Traces of condensation inside (noise is heard when shaking).
• 🔊 Extraneous sounds when tapping (a sign of detachment of internal elements).

Owner reviews: real experience

Analysis of reviews on forums (Drive2, Nissan-Club.ru) shows that most owners Sunny FB15 encounter resonator problems at 120–180 thousand km. Here are typical stories:

Positive experience:

👍 "I installed Walker 20946 two years ago - the sound became quieter, there were no vibrations. The mileage is already 220 thousand km, no corrosion is visible. The only thing is that during installation I had to modify the suspension mount, since the hole did not coincide with the original." — Alexey, Nissan Sunny FB15 1.6 GA16DE.

Negative experience:

👎 "I bought SASIC for 3 thousand rubles. — within a year it was rusty at the seams. I had to install Bosal, but after six months it also started whistling at high speeds. Now only original or Walker." — Dmitry, Nissan Sunny FB15 1.5 GA15DE.

Tuning experience:

🔧 "I installed a direct-flow resonator from Sprint + removed the second can. The sound became aggressive, but on the highway there was an unpleasant resonance at 3,000 rpm. I had to return the stock muffler. Conclusion: on the FB15 it is better to limit yourself to replacing the resonator with a sports one, but leave the standard muffler." — Igor, Nissan Sunny FB15 1.6.

FAQ: Frequently asked questions about the Nissan Sunny FB15 resonator

Is it possible to drive without a resonator?

Technically, yes, but this violates traffic rules (excessive noise) and leads to:

• 🔊 Unpleasant roar at all speeds.
• 🚨 Constant lambda probe errors (P0420).
• 💨 Gases entering the cabin through cracks in the body.

In practice, traffic police inspectors rarely stop you for a noisy exhaust, but they will refuse you if you undergo maintenance.

How to check the resonator for leaks?

The easiest way:

1. Start the engine and close the exhaust pipe with your hand (for 1-2 seconds).
2. If you feel strong pressure, the system is sealed. If air escapes through the joints, look for cracks.

For an accurate diagnosis, use smoke tester (supplies smoke to the exhaust system under pressure).

Which resonator is better for FB15 with HBO?

On cars with gas equipment, the resonator experiences increased temperature loads. Recommendations:

• 🔥 Choose models from stainless steel (For example, Walker 20946).
• 🔧 Increase the frequency of checking fasteners - vibrations are stronger on gas.
• 💨 Give preference to resonators with reinforced welds.

Avoid cheap galvanized analogues - they burn out in 1-2 years.

What should I do if vibration appears after replacing the resonator?

Vibration is usually caused by:

• 🔧 Incorrect installation of hangers — the resonator touches the body or protection.
• 🔨 Deformed flanges - check their geometry with a ruler.
• 🚗 Exhaust system imbalance — perhaps the new resonator is heavier than the original.

Solution: Inspect the system on a lift and install additional hangers if necessary.

Is it possible to repair the resonator instead of replacing it?

Repair is only possible if minor damage:

• 🔧 Cracks on the body are welded using argon welding.
• 🔥 Burnt holes are covered with stainless steel patches.

If the internal partitions or perforated pipe are destroyed, the resonator must only be replaced. The cost of repairs (3-5 thousand rubles) is often comparable to the price of a new analogue.