Berk Test Pipes vs. Stock Catalytic Converters: Complete Comparison

Test pipes are straight-through exhaust pipes that replace your factory catalytic converters. Unlike cats, which restrict exhaust flow to reduce emissions, test pipes allow exhaust gases to flow freely.

Stock Catalytic Converters:

• Reduce harmful emissions (CO, NOx, HC)
• Restrict exhaust flow
• Required for emissions testing
• Quieter exhaust note
• No performance gains

Test Pipes:

• Remove catalytic converters
• Maximum exhaust flow
• Significant power gains
• Louder, more aggressive sound
• May not pass emissions testing

Not all test pipes are created equal. Here's why Berk Technology dominates the VQ market:

What Makes Berk Special:

Resonated Design:

• Eliminates raspy drone
• Deep, aggressive tone
• No highway drone
• Perfect sound quality

CEL Fix Included:

• Built-in O2 sensor bungs
• Prevents check engine light
• No need for spacers or tuning
• Plug-and-play solution

Quality Construction:

• 304 stainless steel
• Mandrel-bent piping
• Perfect fitment
• TIG welded
• Made in USA

Fitment:

• 2009-2019 Nissan 370Z
• 2007-2008 Nissan 350Z (VQ35HR)
• 2007-2015 Infiniti G37
• 2007-2008 Infiniti G35 (VQ35HR)
• 2014+ Infiniti Q50/Q60 (VQ37VHR)

Let's talk numbers. Here's what you can expect:

Dyno-Proven Gains:

370Z (VQ37VHR):

• Horsepower: +15-20 HP
• Torque: +10-15 lb-ft
• Peak Gains: Mid-range (3,500-6,000 RPM)

G37 (VQ37VHR):

• Horsepower: +12-18 HP
• Torque: +8-12 lb-ft
• Peak Gains: Mid-range

350Z (VQ35HR):

• Horsepower: +12-15 HP
• Torque: +8-10 lb-ft
• Peak Gains: Mid-range

Real-World Performance:

• Improved throttle response
• Better acceleration (0-60 mph)
• Reduced backpressure
• Smoother power delivery
• More aggressive exhaust note

Combined with Cat-Back Exhaust:

• Total Gains: 25-35 HP
• Torque Gains: 15-25 lb-ft
• Maximum flow potential

Sound is subjective, but here's what to expect:

Stock Catalytic Converters:

• Quiet, refined
• Minimal exhaust note
• No drone
• Boring (let's be honest)

Berk Resonated Test Pipes:

• Deep, aggressive tone
• VQ "trumpet" sound enhanced
• No raspy drone (thanks to resonators!)
• Louder on cold start
• Perfect volume for daily driving

Non-Resonated Test Pipes (Other Brands):

• VERY loud
• Raspy, tinny sound
• Highway drone (annoying!)
• Too loud for daily driving

Sound Level Comparison:

• Stock: 70-75 dB
• Berk Test Pipes: 85-90 dB
• Non-Resonated: 95-100 dB

Pro Tip: Berk's resonated design is the sweet spot - aggressive without being obnoxious.

Difficulty: Moderate

Time: 2-3 hours 
Tools Needed:

• Jack and jack stands
• Socket set (metric)
• Penetrating oil (WD-40, PB Blaster)
• Torque wrench
• New gaskets (recommended)

Installation Steps:

Step 1: Preparation

1. Lift car and secure on jack stands
2. Spray all bolts with penetrating oil
3. Let sit for 15-30 minutes

Step 2: Remove Stock Cats

1. Disconnect O2 sensors (4 total)
2. Remove bolts connecting cats to headers
3. Remove bolts connecting cats to mid-pipe
4. Drop catalytic converters

Step 3: Install Berk Test Pipes

1. Install new gaskets
2. Bolt test pipes to headers (hand-tight first)
3. Bolt test pipes to mid-pipe
4. Reconnect O2 sensors to Berk bungs
5. Torque all bolts to spec (35-40 ft-lbs)

Step 4: Check for Leaks

1. Start engine
2. Listen for exhaust leaks
3. Check all connections
4. Tighten if needed

Common Issues:

• Stuck bolts (use penetrating oil!)
• Stripped threads (use thread repair kit)
• Exhaust leaks (replace gaskets)

Pro Tip: Professional installation costs $150-$300 if you're not comfortable doing it yourself.

One of the biggest concerns with test pipes is the dreaded check engine light (CEL).

Why CEL Happens:

Your car has downstream O2 sensors that monitor catalytic converter efficiency. When you remove the cats, these sensors detect the change and trigger a CEL (P0420/P0430 codes).

How Berk Fixes It:

Berk test pipes include specially designed O2 sensor bungs that:

• Position sensors at optimal angle
• Reduce sensor exposure to exhaust flow
• Trick ECU into thinking cats are present
• Prevent CEL in 95% of cases

What If I Still Get CEL?

In rare cases (5%), you may need:

• O2 sensor spacers ($20-40)
• ECU tuning to disable codes
• Uprev or ECUtek tune

Most customers report: No CEL with Berk test pipes!

Important: Test pipes are for off-road/track use only.

Emissions Testing:

• Will NOT pass: Visual inspection
• Will NOT pass: Sniffer test
• May pass: OBD-II scan (if no CEL)

State Regulations:

• California: Illegal for street use (CARB)
• Most States: Illegal if emissions testing required
• Track/Off-Road: Legal

Alternatives for Emissions States:

• High-flow catalytic converters
• CARB-legal cat-back exhausts
• Keep stock cats for inspection

Disclaimer: Check your local laws before purchasing. Revline Performance does not condone illegal use.

Berk Test Pipes:

Price: $349.99 Installation: $150-300 (or DIY free) Total: $350-650

Value Breakdown:

• Performance: +15-20 HP ($17-23 per HP)
• Sound: Priceless
• Quality: Lifetime durability
• Resale: Holds value well

Compared to Alternatives:

High-Flow Cats:

• Price: $600-1,200
• Gains: +8-12 HP
• Legal: Yes (CARB-approved)
• Sound: Moderate improvement

Cheap Test Pipes:

• Price: $150-250
• Gains: +15-20 HP (same as Berk)
• Quality: Hit or miss
• Sound: Often raspy/drone

Verdict: Berk offers best value for performance and quality.

Option 1: High-Flow Catalytic Converters

Best For: Emissions-legal states 
Pros: Legal, still improves flow 
Cons: More expensive, less gains 
Recommended: Fast Intentions, Motordyne

Option 2: Cat-Back Exhaust Only

Best For: Budget builds 
Pros: Legal, good sound 
Cons: Limited power gains (5-10 HP) 
Recommended: Invidia, Tomei

Option 3: Full Exhaust System

Best For: Maximum performance 
Pros: Best gains (25-35 HP total) 
Cons: Most expensive ($1,500-2,500) 
Recommended: Headers + Test Pipes + Cat-Back