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4" mbrp exhaust problems

5K views 16 replies 12 participants last post by  Zaairman 
#1 ·
No matter what i do i cant the down pipe to bolt up to the turbo if it is connected to lower pipe. if i bolt the down pipe up i cant get the other pipe even close to fit. what do i gotta do??? i have worked two days on it and still nothing but alot of aggervation.
 
#2 ·
Check the kit and make sure they sent you the right one.

I assume you are leaving the connections loose so they can me moved around
for connecting.
 
#4 ·
:whs That's what I had to do to get my system to fit...
 
#6 ·
Depending on whether your engine sits a little more forward than back, if you trim off the seam and push the fire wall in towards the cab with a 2x4 and sledge it'll fit but if it rubs she'll be a noisy one!!
 
#7 ·
A 3.5" downpipe on those trucks takes a lot of beating to fit. I can't imagine what a 4" would take.
 
#8 · (Edited)
MBRP does not make a 4" down pipe for the OBS trucks as it will not fit without a bunch of firewall modifications. Only down pipe I am aware of from MBRP is 3" that expands to 3.5" after it gets past the firewall. But I could always be wrong as there may now be one I do not know about.

All I have ever done to install one of these is make two slits in the pinch weld about 1" out from both sides of where the pipe will run. Then I take a tire bar and pry the pinch weld over flat against the firewall. Once that is done the down pipe falls rite into place.

I do not understand why no one can make a down pipe for these trucks that will fit without modifying the firewall?? I made one out of a SD down pipe about 4 years ago and it fit perfectly without modifying anything.

I guess no one will take the time refine the bends to make them work.
 
#10 ·
You will be good to go with 4" on your Super Duty...;)
 
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#12 ·
I have had hell with the mbrp exhaust on my obs and it is to the point where I cant hardly make myself get motivated to finish my build . I think I have finally got the firewall pushed in and ready to try again . Wish me luck .
 
#13 ·
How did it go? did the downpipe fit? :thumbsup
 
#14 ·
the mbrp kit for the obs deos not fit a 5 speed without extensive modification.
 
#15 ·
Yeah, it's a pain in the ***. I spent 5 hours trying to get the down pipe in. Once it was in i got the rest put in and started it up and my entire cab was shaking. The part of the exhaust right after the down pipe will rub against the tranny brace, and it will make a lot of noise. Also, mine was rubbing the tranny after the new clutch went in. I got pist off and took it to an exhaust shop, and he called MBRP and ended up removing the a part off the tranny brace that is apparently only on the 5 speeds, not on the autos.
 
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