Best Spark Plugs for Audi RS4 B8/B8.5 (2013–2017)
Meta Description:Find the best spark plugs for the 2013–2017 Audi RS4 B8/B8.5. Keep your high-revving 4.2L V8 running crisp and clean with…
Meta Description:
Find the best spark plugs for the 2013–2017 Audi RS4 B8/B8.5. Keep your high-revving 4.2L V8 running crisp and clean with these plug upgrades.
If you’re lucky enough to own a 2013–2017 Audi RS4, you’ve got one of the last naturally aspirated V8s Audi ever made. The 4.2L FSI high-revving engine in the B8/B8.5 RS4 Avant is an 8,250-RPM symphony of intake noise, exhaust scream, and precision engineering. But even the most advanced engines rely on one basic thing to keep them running perfectly: spark plugs.
If your RS4 is misfiring, feeling sluggish, or overdue for service, replacing or upgrading your plugs is one of the simplest and most important maintenance steps you can take. And if you’re running carbon-cleaning mods or light tuning? Choosing the best spark plugs for the Audi RS4 B8/B8.5 becomes even more critical.
Let’s break down your best options, whether you’re staying stock or revving harder than ever.
🔧 Engine Overview – Audi RS4 B8/B8.5 (2013–2017)
- Engine: 4.2L FSI Naturally Aspirated V8
- Code: CEUA
- Horsepower: 450 hp @ 8,250 rpm
- Compression Ratio: 12.3:1
- Ignition Type: Coil-on-plug direct fire
- Plugs Needed: 8
This isn’t a turbo engine, so it doesn’t need cold plugs to handle boost. But with such high RPMs and high compression, a high-quality iridium or platinum plug is still essential.
🧰 OEM Spark Plug Specs for RS4 B8
Audi fitted the B8/B8.5 RS4 with NGK PFR7S8EG plugs from the factory:
- Type: Iridium
- Heat Range: 7
- Gap: ~0.028″ (0.7 mm)
- Recommended Replacement Interval: ~30,000–35,000 miles
These are great plugs and can be reused for stock performance, but there’s room for improvement—especially with age, aggressive driving, or any engine modifications (carbon cleaning, porting, intake/exhaust upgrades, etc.).
🏆 Best Spark Plugs for Audi RS4 B8/B8.5
1. NGK PFR7S8EG – OEM Replacement
This is the stock plug, and still one of the best for most RS4 drivers.
- Iridium center electrode
- Excellent longevity
- Direct fit—no gapping required
- Audi-approved, high quality
Best For: Stock cars, OEM reliability
Replace Every: 30,000–35,000 miles
Gap: Pre-gapped (~0.028″)
2. NGK BKR8EIX – 1-Step Colder for Aggressive Driving
Want slightly better knock resistance? Running it hard, tracking, or living in a hot climate? This 1-step colder plug is a solid upgrade.
- Iridium tip = strong spark
- Slightly colder heat range = extra knock margin
- Must gap to ~0.026–0.028″
- Improves response on aggressive throttle
Best For: Aggressive driving, canyon runs, track days
Replace Every: 20,000–25,000 miles
Gap: ~0.026″–0.028″
3. Denso IK24 – High-Rev Track Use
A colder racing plug that shines in high-rpm heat or heavily modded NA builds.
- Iridium racing-grade electrode
- Requires gapping
- Shorter lifespan
- Only needed if you’re doing sustained redline use (track or very hot climate)
Best For: Track builds, heat management
Replace Every: 15,000–20,000 miles
Gap: ~0.026″
4. Bosch FR6KPP332S – Reliable OEM-Style Option
Bosch is another Audi OEM supplier. This is a direct-fit platinum plug with long life and solid ignition performance.
- Cheaper than NGK
- Works well in bone-stock RS4s
- No tuning required
- Decent heat tolerance
🛒 Buy Bosch FR6KPP332S – Amazon
Best For: OEM+ daily drivers
Replace Every: 35,000–45,000 miles
Gap: Pre-gapped
🔧 Spark Plug Gapping for the RS4 V8
Because this engine isn’t boosted, it’s not ultra-sensitive to small gap changes—but you still want to stay within spec for best ignition under load.
| Build Type | Recommended Gap |
|---|---|
| Stock RS4 | 0.028″ (0.7 mm) |
| Aggressive NA Mods | 0.026″–0.027″ |
| Track Use | 0.024″–0.026″ |
Always check the gap even if it says “pre-gapped.”
🧰 Tools You’ll Need for DIY
- Spark plug socket (14mm with magnetic insert)
- Torque wrench
- 3/8” ratchet and extension
- Anti-seize compound (optional)
- Dielectric grease for coils
- Torque Spec: 18–21 ft-lbs (cold engine)
⏱ Install time: ~2 hours (includes coil removal)
🛒 Full DIY Spark Plug Kit – Amazon
💡 Bonus Tip: Coil Packs
If you’re changing plugs, consider swapping out ignition coils too—especially if you’re past 50k miles or experiencing misfires.
Audi red coils are a fan favorite and drop right in.
🛒 Audi RS4 Coil Pack Set – ECS Tuning
🛒 Red Coil Upgrade Kit – Amazon
📊 Quick Comparison Table
| Spark Plug | Heat Range | Best For | Lifespan | Price (Set of 8) |
|---|---|---|---|---|
| NGK PFR7S8EG | 7 (stock) | Stock/maintenance | 30k–35k miles | $$ |
| NGK BKR8EIX | 8 (colder) | Aggressive use | 20k–25k miles | $$ |
| Denso IK24 | 8 (cold) | High-rev/track | 15k–20k miles | $$$ |
| Bosch FR6KPP332S | Stock | OEM+ daily drivers | 35k–45k miles | $ |
🛒 Where to Buy
- Amazon – Great plug bundles
- FCP Euro – Lifetime warranty
- ECS Tuning – Full ignition kits
- AliExpress – Budget options (double check quality)
- GermanCarMods.com/blogs – Upgrade guides + DIYs
✅ Final Thoughts – Best Spark Plugs for Audi RS4 B8/B8.5
The B8 RS4’s naturally aspirated 4.2L V8 doesn’t need exotic race parts to run strong—but it does demand high-quality spark to stay razor-sharp.
If you’re stock, NGK PFR7S8EG or Bosch FR6KPP332S will last you years. But if you’re squeezing every RPM and adding mods like intakes or lightweight pulleys, step up to NGK BKR8EIX or even Denso IK24.
Changing plugs on schedule helps your engine rev smoother, throttle harder, and avoid misfires that can dull the whole experience.