After years of testing, the FKF 2017-2023 L5P Duramax S400 Turbo Kit is a complete, street-proven single turbo kit for the 6.6L L5P. Developed in early 2024, with 20+ kits now on the street and track at up to 1000+ hp.

Key features

Billet turbo pedestal

CNC machined from a brick of steel for years of crack-free use — a well known failure point in other L5P S400 kits. The pedestal also has a 45mm wastegate provision.

5" 6061 aluminum intake

True 5" mandrel bent intake, TIG welded. Billet MAF bung with correct placement for easy MAF scaling, tested through all the major L5P tuning names. No need to choke your S400 down to a 4" intake. A fabricated ram air airbox is included on the 2017-2019 kit.

3" 6061 aluminum Y bridge

Full mandrel bent 3" tubing to both intake runners, jumping immediately to 3.5" at the split. No section of this kit's cold side sees less than 3.5" tubing. Integrated billet MAP bung and 2x 1/8 NPT ports. Port matched billet intake flanges make for a smooth transition into the head.

3.5" cold side tubing

Mandrel bent with integrated IAT bungs. Includes a billet intercooler adapter proven to hold 80+ psi that works with most aftermarket intercoolers.

3" two-piece hot side pipe

Two piece design for ease of install, with integrated NPT ports for pre-intercooler charge system monitoring.

3.5" stainless steel downpipe

Full mandrel bent TIG welded 304 stainless. Port matched flange and tubing size proven to make 1000+ hp without becoming a restriction.

Additional components

• Couplers and boots — only multi-layer 4-ply reinforced aramid fibre boots and stainless steel clamps. You will not be fighting blown pipes when the truck makes full boost.
• Oil feed and drain lines — all required plugs and fittings for a reliable, well thought out oiling system.
• Coolant plugs — billet coolant plate to plug the VGT feed at the source, plus the heater lines needed to properly reroute the coolant lines without a mid-install hardware store run.

Turbo sizing options

• S467 83x74 .9 A/R — the smallest turbo we recommend for the L5P. The L5P has a strong stock fuel system and this turbo has made 700+ hp on stock fuel with our kit and proper tuning, multiple times. Retains good drivability. Best with stock fuel up to 100% injectors / 12mm pump. Max 800 hp.
• S472 87x82 1.0 A/R — best suited to fuelling and transmission upgrades. Pairs well with 100s / 12mm. Still works well on the street with a higher hp threshold. Max 1000+ hp.
• S476 87x82 1.0 A/R — more performance forward, requires large injector and pump combinations. Intercooler and converter mods recommended. Max 1200+ hp.
• S480 96x88 1.25 A/R — a strictly performance turbo. 200% / 14mm fuel system and supporting mods recommended. 1300+ hp.

Note: on S400-frame turbos, the two digits after S4 are the compressor inducer diameter in mm. The "400" is the frame size, not the wheel.

Fitment

2017-2023 GM 2500HD / 3500HD trucks with the 6.6L L5P Duramax.

Powder coat options

We offer complete customisability with powder coat combinations, and we coat the compressor cover for free with the purchase of a kit.

If a custom powder coat colour is desired, select “Custom Colour” and state the colour in the cart notes.

Colour link — https://www.prismaticpowders.com/canada

Frequently asked questions

What is the lead time on the L5P S400 turbo kit?

Current lead time is 4-8 weeks from the time of order. We know that is a long wait. This is not a mass produced turbo kit — every kit is built and welded by the same two people at FKF and undergoes a rigorous QC process. We guarantee these kits are worth the wait.

Which turbo size should I choose?

S467 for stock to mild fuel up to 800 hp, S472 for fuel and transmission upgrades up to 1000+ hp, S476 for large injector and pump combinations up to 1200+ hp, and S480 for a dedicated performance build at 1300+ hp. If you are unsure, contact us and we will help you choose.

Do I need to drop to a 4" intake with this kit?

No. The kit uses a true 5" mandrel bent intake with a billet MAF bung placed for easy MAF scaling, so there is no need to choke the S400 with a 4" intake.

Will the intercooler adapter work with my aftermarket intercooler?

The billet intercooler adapter has been proven to hold 80+ psi and works with most aftermarket intercoolers.

Is the compressor cover powder coated?

Yes. We coat the compressor cover free of charge with the purchase of a kit.