Mbrp downpipe

[pa05stroker]

I just got a mbrp 5" turbo back exhaust. And I was just wonderin if there was a reason why they only make 3.5" down pipes instead of a 4"

[Tuscany]

Because you have to beat your firewall in to get the 4" dp to fit. Also the 4" is overkill unless you have supporting mods necessary for a bigger dp. Eg; injectors, turbo, exhaust headers etc.

[pa05stroker]

That would make sense. Thanks for the reply.

[Tuscany]

Lol no problem.

[U235a4]

I just wanted to add that I have a 4" DP on my Magnaflow exhaust and I didn't have to beat or modify anything to get it to fit...

[Tuscany]

I have a 4" on mine and I didn't either but some people I know personally had to beat theirs in to get it to fit but they also had 2003's and 2004's so maybe it was different then.

[BucOff]

4" DP on my 04 Excursion with literally no issues at install.

[L&B]

My '04 has a ZF6 and the 3.5" MBRP pipe is VERY tight between the back of the starter boss on the bellhousing, frame, and firewall seam. I think that if a manufacturer could be bothered to make a special downpipe for the manual transmission trucks, a 4" might be OK. Problem is that it's a small market segment, so volume would probably be too small to make it worthwhile. It's so much easier to market a 3.5" downpipe that fits everything poorly, and a 4" labeled "automatic transmissions only." At only a little over $200 for the whole system I can't complain too loudly, but will probably try to do something different if/when it needs to be replaced.

[SharkDiver]

My 4" diamond eye went in without any problems and so did the rest of my 5" exhaust.

[HeavyAssault]

Motor placement, cab placement from the factory will make a difference. MBRP could have the bend off the turbo just a tad less then other exhausts. FWIW I doubt anyone has a setup that will not flow properly with a 3.5" exhaust.