I talked to Magnuson today and the guy told me he had to change the standard 3.40 inch pulley to a 3.60 inch pulley to lower the boost because he said my flowmaster exhaust was too restrictive. He said there were too many "squeeze bends." Does this make sense? Its a 3 chamber flowmaster: single in / dual out. Not sure what my options are, especially since I live in California. What exhaust system are you guys running and how are they working for you? I want true duals with an x-pipe and two mufflers. I heard things about magnaflow and borla. Opinions well accepted here please!

 

Are you building extra boost because your exhaust is restrictive?It could really happen,but I don't think I'd change the pulley.I run a 3" pulley on my Radix setup with no problems it makes about 9.5lb of boost.The guys at Magnuson go a little overboard when you tell them you are making over 7lb of boost.I guess they think you are going to pull a 15000lb trailer up a mountain at full throttle in 110 degree heat.

 

What motor do you have? Where in cali are you? And do you have the radix installed already?

 

just sent you an email brian

 

i have the 5.3, live in san francisco, and the radix is already installed on the truck with a 3.60 pulley

 

That would make sense .... squeeze bends are more restrictive. If you have a restrictive exhaust it would tend to build up more. I haven't watched my boost gauge with the y-pipe or headers uncorked ... I'll have to take note of that next time I'm at it.

 

My flowmaster exhaust actually lowered my psi about 1/2 a lb or so over the stock exhaust. My setup is a single 3" inlet and dual 2.5" outlet with 2.5" pipes out the back. custom fabed by my exhaust guy. Not a cat back kit.