How big is a stock LB7 downpipe?
Aftermarket 3-inch Downpipe The most common aftermarket downpipe for the LB7 is a 3-inch diameter version, available from manufacturers such as MBRP, Flo-Pro and ProFab Performance.
What size is the stock exhaust on a LB7?
Registered. And yes stock exhaust is 3.5 inch. 150k miles and counting!
How do I choose a downpipe?
Measure the length and width of each roof plane. If the surface area is less than 50 m2 then gutters with a width of 100 mm and downpipes with a diameter of 75 mm should be used. If the surface area is from 50 m2 to 100 m2 then gutters with a width of 125 mm and downpipes with a diameter of 90 mm should be used.
Does a 2004 Duramax have a catalytic converter?
In 2001, the Duramax turbo diesel was introduced to the GM 3/4 ton, 1 ton trucks and commerical trucks. In 2004.5, the EPA required a catalytic converters (Cat) and exhaust gas recirculation (EGR) on the LLY engines.
What size is the exhaust on a LBZ?
3.5"Typical factory exhaust size of 3.5" on 2001-2007 LB7/LLY/LBZ and 4.0" on 2007.5-2010 LMM.
What size downpipes do I need?
To calculate the minimum number of downpipes, divide the roof catchment area by the allowable maximum catchment per downpipe. To calculate the average catchment per downpipe, divide the roof catchment area by the number of downpipes.
How much horsepower does a downpipe add?
It's generally accepted that installing a downpipe will add just 10 to 20 horsepower, but that gain is noticeable when the engine is revved up.
Do I need a tune for a downpipe?
Registered. Less backpressure from a less restrictive downpipe = turbo builds boost faster = more air into the engine from the turbo = you absolutely need a new tune to compensate for that.