MBRP 3.5" DP Install

[cvdenson]

Hello everyone,
Having some problems installing a 3.5" downpipe to my stock straight-piped exhaust. My truck is a early '99 F350 CC LB SRW 6sp manual trans. When I bought the truck I noticed the catalytic converter had been removed for a straight pipe with a ford serial number stamped on it. My problem is: It appears the stock downpipe is 3" from the Turbo to where the catalytic converter would've been. There is a collector that appears to go from 3" to 3.5". My MBRP 3.5" DP is much shorter than the stock DP and seems to end about 12" on the turbo side from the collector.

I noticed a few on this forum are running a 3.5" DP with their stock exhaust. What have you all done to remedy this? Any advice would be much appreciated. Thanks!

 

[jvencius]

I noticed a few on this forum are running a 3.5" DP with their stock exhaust. What have you all done to remedy this? Any advice would be much appreciated. Thanks!

IMO, running a good 3.5" downpipe into the stock exhaust is like trying to fart through a straw. While it's technically possible, you'd be much better served by installing a proper high-flow exhaust while you're that far into things.

 

[police stroker]

Go by an exhaust shop and have then fab a piece to connect the down pipe and exhaust pipe together. Or save some cash and buy a full mbrp or magnaflow exhaust kit 3.5" down pipe to 4" pipe to the rear.