FITMENT
- 2007.5-2010 6.6L Silverado & Sierra Duramax 2500HD/3500HD LMM engine.
- Fits Crew Cab Short Bed and Crew Cab Long Bed models. Does NOT Fit: Cab & Chassis truck models.
DESCRIPTION
Product Overview
- The 2007.5–2010 Chevrolet Silverado and GMC Sierra 2500HD/3500HD 6.6L Duramax LMM marked General Motors' introduction of factory DPF emissions technology. However, this early DPF system is notorious for high backpressure, frequent fuel-wasting active regens, and dangerous thermal heat build-up right behind the turbo.
- The 4" Downpipe-Back DPF & DOC Delete Race Exhaust Kit is engineered specifically to liberate the LMM engine. By removing the choked emissions core at the source, it sharply drops towing EGTs, restores crisp throttle response, improves fuel economy by 2–3 MPG, and delivers that deep, unmistakable Duramax V8 rumble.
Key Features
-
Premium T409 Stainless Steel: Full 4-inch mandrel-bent T409 stainless steel tubing built to withstand extreme exhaust temperatures, road salt, and harsh off-road environments.
- Sharply Lower Towing EGTs: Eliminates intense exhaust backpressure right behind the downpipe, allowing exhaust gases to flush out rapidly to lower Exhaust Gas Temperatures (EGTs) under heavy towing.
- Permanently Kill Active Regens: Stops fuel-wasting active regeneration cycles that inject raw diesel during exhaust strokes, protecting crankcase oil from fuel dilution and bearing wear.
- Direct Bolt-On Fitment: Connects directly to the factory downpipe outlet flange and mounts using stock rubber hangers—no custom welding required.
FAQ
Q: Do I need a custom delete tuner to run this 4" Downpipe-Back pipe on an LMM Duramax?
A: Yes. The LMM ECM closely monitors differential DPF pressure and EGT sensors. Removing the DPF and DOC will trigger Check Engine Lights and lock the truck into Limp Mode. A compatible delete tuner (such as EFI Live, HPTuners, or Quadzilla) is required to disable emissions codes.
Q: How does deleting the DPF on an LMM engine protect my engine oil?
A: The factory LMM performs active regeneration by injecting extra diesel fuel directly into the cylinders during exhaust strokes to heat up the DPF. Unburned fuel washes down cylinder walls and dilutes crankcase oil. Deleting the DPF allows your tuner to stop regens, keeping engine oil clean and protecting engine bearings.
Q: Does an LMM Duramax use DEF (Diesel Exhaust Fluid)?
A: No. The 2007.5–2010 LMM engine uses a DPF and DOC only. DEF (SCR systems) was not introduced by GM until the 2011+ LML Duramax. You do not need to worry about DEF tanks or fluid errors on an LMM.
Q: Will this 4" kit fit both Short Bed and Long Bed models?
A: Yes. The kit includes modular extension pipe sections designed to accommodate all cab and bed lengths. You simply trim the straight extension pipe during installation based on your specific wheelbase.
