5" Downpipe Back Dual 2017-2021 L5P 6.6L Duramax DPF Delete Race Pipe GM 2500/3500 |SPELAB

This high-performance L5P 6.6L Duramax dual-pipe design eliminates restrictive factory bottlenecks, slashing exhaust backpressure for faster turbo spool, reduced EGTs, and instant throttle response. Precision mandrel-bent stainless steel piping ensures maximum flow efficiency, while the dual-exit configuration enhances scavenging for optimized power delivery. Built for heavy-duty performance, this system delivers deeper torque curves, aggressive diesel acoustics, and improved fuel efficiency—all while shedding excess heat and preventing turbo lag.

Specification

Benefits

Expect to see a significant increase in fuel mileage. If your DPF is plugged up your probably averaging about 13-14 mpg. More or less depending on the severity of the restriction. After deleting the DPF/CAT expect to get a combined mileage of 18-19 mpg.

• It removes the need to service the DPF at regular intervals (cleaning, replacement)
• A DPF delete will remove the possibility of a DPF failure which could cause expensive diesel repairs
• Due to less exhaust backpressure, the DPF delete increases exhaust flow and therefore increases the performance of your motor!
• Paired with an ECU remap, the DPF delete is proven to increase power and torque for all vehicles

Installation

Install takes about 1hr with basic hand tools done on the ground of your driveway or garage. Quicker if you have automotive style lift. Cutting may be be required to fit shorter wheelbase bed/cab configurations. Clamps, hangers and hardware are included. You may have to re-use some factory hardware.
Tuner Required: Removal of the DPF, CAT, SCR, and/or DOC involves removing and eliminating emission related sensors. A DPF delete capable tuner is required to prevent any check engine light or diagnostic trouble codes from setting.

• 2017-2021 L5P 6.6L Duramax Diesel GMC Sierra 2500 HD
• 2017-2021 L5P 6.6L Duramax Diesel GMC Sierra 3500 HD
• 2017-2021 L5P 6.6L Duramax Diesel Chevrolet Silverado 2500 HD
• 2017-2021 L5P 6.6L Duramax Diesel Chevrolet Silverado 3500 HD

* IMPORTANT NOTE: These kits will only fit models equipped with the OEM style 4-bolt flange off the turbo direct pipe!

Spelab 6.6L Duramax L5P DP-Back must be used together with our downpipe. The factory downpipe has an integrated SCR assembly and cannot connect directly. Ours must be installed first to allow proper attachment of the subsequent exhaust section.

These parts are for use on non-registered race vehicles on closed-course competition events *Installing or using this part on any emission-controlled vehicle ("street" or "off-road") may violate federal and/or state emissions laws and regulations.

What is the DPF and is it worth doing a DPF Delete?

Most post-2007 diesel vehicles are fitted with a Diesel Particulate Filter (DPF) for emissions reasons, however there are a few disadvantages to this device; including constant maintenance and repairs.

Because the DPF clogs up, it increases backpressure. Due to this pressure, the fuel flow is hugely disturbed and slowed down. Therefore, when you remove this filter, the fuel flows much easily and faster, increasing the overall fuel mileage.

FAQ

Q1. Will a magnet stick to this pipe? Is it really stainless steel?

Yes – This pipe uses T-409 stainless steel, which is still magnetic (unlike T-304). It offers excellent corrosion resistance while being more affordable than T-304.

Q2. How thick is the pipe? Will it last?

2mm thick T-409 stainless steel – Durable enough for long-term use without excessive weight.

Q3. Will this improve performance?

• Yes! Benefits include:
• Lower EGTs (Exhaust Gas Temperatures)
• Faster turbo spool
• Better fuel efficiency (with proper tuning)
• No more DPF clogging issues

Q4. Is this street legal?

⚠ Off-Road Use Only – DPF removal is illegal for on-road vehicles in most regions. For competition/racing use only.