MBRP 3" LLY Downpipe

The downpipe is the second biggest restriction on the Duramax LLY, behind the turbo inlet. The factory downpipe is crushed throughout which restricts exhaust flow, causing backpressure that leads to excess heat and reduced turbo spool. The LLY is known to run hot and overheat - upgrading the downpipe is one of the most important mods to prevent overheating and subsequent head gasket failure.

MBRP has a 3" stainless steel downpipe that offers the best value on the market, at $189. It is a direct bolt-on and maintains 3" piping throughout the whole downpipe, increasing exhaust flow and reducing all the restrictions of the factory unit.

A downpipe is the most important part of the exhaust to upgrade, but it also pairs well with a 4" cat-back exhaust. Combining the two will maximize power gains and EGT reduction which results in a healthier and more reliable turbo. The LB7 exhaust is also bolts directly up to the LLY and turbo-back versions can be had for half the price of downpipe and cat-back combo's.