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 forumn are running a 3.5" DP with their stock exhuast. What have you all done to remedy this? Any advice would be much appreciated. Thanks!

Chris

Early '99 F350 XLT CC LB SRW 6sp
Mods: Straight pipe, CCV, Ford AIS w/Zoodad, Oilguard bypass, SS Hpx, Autolite Pyro & boost

Future Mods: Dp tune & ITP regulated return

 

You should be able to find a piece of 3.5" i.d. pipe and slip it over your dp in order to make up the 12 inch difference remove the 3-3.5 adapter and just clamp it all together or if you have access to a weld smoke em together

 

After looking closer at the DP and measuring, it's set up to go into a 4" mid-pipe. Maybe the best thing to do is to have it and a custom 4" exhaust exiting before the rear wheel at a muffler shop. Thoughts?

 

If you can find a shop that can/will bend 4 inch tube feel free to.
You may have to go to a big rig shop to find 4 inch stuff to do it yourself.
As to the style I have a side exit too. stock dp to 3.5 pipe to a 6 inch tip

 

I canot believe that MBRB makes a DP that is shorter or will not fit with what you have under there. Anybody else? I know many folks have gone that route. Not me though.

 

I can't believe it either. I thought it would be a straight bolt in deal. I was under the impression that the stock DP's were 3" at the turbo and flared out to 3.5". Mine is a constant 3" all the way to where the cat used to be. Maybe I'll should consider getting the rest of MBRP 4" system, only with the muffler delete. I've been straight-piped now for 2 months and will never go back.

Chris

Early '99 F350 CC LB SRW 6sp
Mods: CCV, SS hpx, Ford AIS w/Zoodad, straight-pipe stock exhaust, Oil Guard bypass, Grill Gutter Mod

Future: DP tune, ITP regulated return

 

the stock downpipes go past the transmission cross member. so, to remove it without cutting it, you need to remove the cross member. stupid idea. the MBRP downpipe is shorter, and it's in front of the cross member, as you can remove it and install it without touching the cross member.