Hey gang,
I stopped by Stan’s today to ask a few questions because I have a D350 Dually that I am trying to decide what to use for an exhaust system. He is very knowledgeable, lots of facts and numbers to back up what he was telling me. I will pass on my info to you.
Stan’s 4" exhaust system starts from the turbo and goes all the way back. It has a machined part that attaches to the turbo and than a 4" piece of exhaust tubing is welded to it, and it is a real nice piece. The down pipe did not require any modifications and he uses the Donaldson mufflers. The most popular one is the 40” M085171, says that it flows real well, and it is not real loud. Had a Furd Power joke in the parking lot with one installed on it, and it didn’t sound to bad.
I have been told by a few (nameless companies) that there was no improvement between the 3” and the 4” systems. Stan showed me the flow numbers between the 3” systems and the 4” systems, big difference. I wouldn’t even consider a 3” system and he mentioned the 5” inch was a waste of money unless your pushing (lots) of horsepower.
As far as the 4x4 model, they make a special piece that goes around the t-case. Not sure what dia. size they use, I didn’t ask because mine is 2x4, and they also use the factory hangers.
If I left out anything let me know and I will try to answer. I will be installing a 16cm turbine housing in the next few weeks and I will probably install one of Stan’s kits on it at the same time.