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TruckTok 2011-2015.5 Chevy/GMC 6.6L Duramax LML Turbo Diesel 3Inch Downpipe Exhaust
Brand TruckTok

TruckTok 2011-2015.5 Chevy/GMC 6.6L Duramax LML Turbo Diesel 3Inch Downpipe Exhaust

SKU DP-0013
$134.25 - $134.25
$134.25
$134.25 - $134.25
$134.25

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Availability:
in stock, ready to be shipped

Installation Discussion & Community Support

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FITMENT

  • 2011-2015.5 6.6L Silverado & Sierra Duramax 2500HD/3500HD with LML Diesel engine pickup.
  • This downpipe features a V-Band connection flange at the turbo outlet.
  • NOT directly fit 2015.5-2016 models with the 3-bolt flange exhaust system unless the downstream system is modified.

DESCRIPTION

Product Overview

  • The factory downpipe on 11-15.5 Duramax LML trucks is a major performance bottleneck. To squeeze past tight engine bay clearances, GM engineers severely crushed and flattened the stock pipe.
  • This restricted "pancake" design chokes exhaust flow, traps excessive thermal energy right at the turbo charger, and spikes EGTs under heavy towing loads.
  • Upgrading to smooth, 3-inch mandrel-bent downpipe maximizes exhaust flow right from the turbo outlet, rapidly dropping EGTs and allowing the turbo to spool up much faster.

Key Features

  • Heavy-Duty Wrapped Protection: Crafted from high-grade 304 stainless steel and wrapped in premium heat-insulating sleeve to safeguard surrounding engine bay components.
  • TIG-Welded Construction: All joints are precision TIG welded and jig-built to prevent cracking under high thermal cycling and aggressive vibration.
  • Unrestricted 3" Bore: Replaces the restrictive, "crushed" factory oval pipe with a true, consistent 3“ mandrel-bent round diameter through every turn.
  • Drastic EGT Reduction: Smooths out exhaust flow to quickly draw extreme heat away from the turbo, reducing under-hood temperatures and protecting engine health.

FAQ

Q: Will this fit my 2015 or 2016 model?

A: It fits 11-15.5 models that use a V-band style turbo connection. In 15.5-16, GM switched the LML to a 3-bolt flange style downpipe. Please inspect your truck's connection before buying.

Q: Does this pipe have the necessary sensor ports?

A: Yes. Unlike older generations, the LML downpipe requires sensor ports. This downpipe is precision-engineered with 3 factory-location bungs to house your stock EGT sensor, NOx sensor, and 9th injector dosing valve flawlessly.

Q: What happens to the sensor bungs if I delete my truck?

A: If you are doing an emissions delete and removing these sensors, you must buy a standard LML downpipe plug kit (or sourcing matching bolts/plugs) to cap the 3 bungs off so exhaust gas doesn't leak out.

Q: Will this 3" downpipe work with my stock exhaust or an aftermarket 4"/5" delete pipe?

A: Yes, it fits both perfectly. The OEM-matched flanges bolt directly to the stock turbo and factory exhaust. If you upgrade to a 4" or 5" delete pipe, it still fits flawlessly—all downpipe-back systems neck down to bolt directly to this factory location without adapters.

  • 5 stars: 3 (50%)
  • 4 stars: 3 (50%)
  • 3 stars: 0 (0%)
  • 2 stars: 0 (0%)
  • 1 star: 0 (0%)
R
Rusty Hargrove
2014 LML — check your V-band clamp condition

Pipe itself is 5 star quality — thick 304 stainless, clean welds, perfect fit on my 2014. The reason for 4 stars is that the factory V-band clamp on these trucks is single-use from the factory. If your truck has over 100K there is a good chance the clamp will snap when you remove it. I had to overnight a new clamp and the truck sat on jack stands for a day. TruckTok should offer an option to include a new V-band clamp with the pipe. Other than that, flawless.

S
Shaun Russell (United States)

TruckTok 2011-2015 Chevy/GMC 6.6L Duramax LML Turbo Diesel 3Inch Downpipe Exhaust

B
Bo Hightower
Throttle response improved — less lag off the line

2011 LML with 155K. The factory downpipe was still intact but I wanted better flow before doing a full exhaust. This 3-inch pipe made a real difference in throttle response. The truck used to hesitate for a half-second when you punched it from a stop — that lag is gone now. The turbo gets on boost about 200 RPM sooner according to my CTS monitor. Combine this with a tune and an intake and the LML wakes up.

D
Dusty Prather
Direct bolt-on — no welding, no adapter

2013 Silverado 2500. I replaced the downpipe in my driveway with basic tools — 13mm socket, 15mm wrench, and a pry bar to pop the old one off the hanger. The turbo flange lined up perfectly and the pipe cleared the firewall and transmission bellhousing with room to spare. Took about 90 minutes. The hardest part was getting the factory V-band clamp to release after 130K miles of heat cycling.

C
Colt Boudreaux
Factory LML downpipe is a bottleneck — this fixed it

2012 Silverado 3500. The factory downpipe necks down at the bend near the firewall — you can see the crush marks from the factory mandrel. This TruckTok 3-inch pipe is a true constant-diameter mandrel bend all the way through. Turbo flange is CNC-machined flat and the exhaust side uses a standard 3-bolt gasket. EGTs dropped about 90 degrees and the turbo spool is noticeably faster off idle. The LML should have come with this pipe from the factory.

W
Waylon Fontenot
Made my turbo whistle audible — in a good way

2015 GMC Denali HD. After installing this downpipe the turbo whistle is finally audible through the exhaust — not obnoxiously loud, just a clean VGT whistle when you roll into the throttle. The factory downpipe has so much sound deadening cast into it that you can't hear the turbo at all. The 304 stainless construction gives a nice crisp tone. If you want to actually hear your Duramax without straight-piping it, start with the downpipe.