Ford Powerstroke Diesel Forum banner

1 - 20 of 22 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter #1
Ok what size downpipe are you running and how's it work for you?

I want to know cause I'm looking at getting exhaust, I've had some people telling me to leave my stock size downpipe and go from catback... I am looking at 4" and 5" straight pipe systems from turbo back or catback, any info and personal experiences is greatly appreciated!
 

·
Premium Member
Joined
·
20,293 Posts
You'd have a hard time getting a 5" DP stuffed in there. My 4"DP barely fits, and is dented up from hitting the up-pipe when the truck articulates :doh:
 

·
Registered
Joined
·
4,816 Posts
Yea I really dont think a 5in Dp will fit in between the firewall and engine. Maybe if it was in three pieces vice two. A 4in DP will be the largest that will fit right. I have a 4in DP to a 5in as soon as it gets underneath the truck then strait to an 8in stack. I like it a lot.
 

·
The Silent Service
Joined
·
5,390 Posts
As stated before, 5" aint really going to fit up without banging something out of the way. 4" will fit ok, as long as you have the 5R110 Automatic. 3.5" is the most common in the aftermarket kits because it will fit in there with the ZF6 Manual trans.

I'm running a 3.5" down to the CAT, and I don't have any issues.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #5
Thanks for the feedback guys, really good info!

I was looking at some of the MBRP systems, you know if there turbo backs come with the 3.5" DP?

I am interested in the offroad system with no cat and no muffler
 

·
Registered
Joined
·
303 Posts
i have a 4inch turbo back with a flow master muffler and i love it. i think 4inch is plenty big enough for a dp.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #8
Thanks Raul! Like the price, looks like I will be ordering from you!
 

·
Premium Member
Joined
·
5,700 Posts
running a 4" with my magnaflow kit, wouldn't have it any other way. took a little tapping with a dead blow but it went in place okay and doesn't hit anything now
 

·
Premium Member
Joined
·
11,966 Posts
I have a Magnaflow 4" and a 4" downpipe. I wouldn't have it any other way. It takes a little work to make sure that it isn't hitting anything but the difference between stock and 4" is huge.



 

·
Registered
Joined
·
2,116 Posts
Stock downpipe is like 3" max with a lot of crush in the bends. I just got a 3.5" MBRP downpipe to install and it is HUGE compared with the OEM. Absolutely no reason to go larger with the stories of firewall contact causing so much noise.
 

·
Registered
Joined
·
18 Posts
Discussion Starter #15
holy moly there is a huge difference!!!
 

·
Registered
Joined
·
5,351 Posts
I had a 4" DP on my 6.0l. And it's a manual.
Stick shifts have less room and mine still fit just fine. You have to make sure you get the clamp and pipe centered perfectly.
If not, it scares the crap outta you. lol
 

·
Premium Member
Joined
·
11,966 Posts
Mine fits right up in there and doesn't rattle on anything. I strongly recommend the use of band clamps.
 

·
Premium Member
Joined
·
11,966 Posts
Stock downpipe is like 3" max with a lot of crush in the bends. I just got a 3.5" MBRP downpipe to install and it is HUGE compared with the OEM. Absolutely no reason to go larger with the stories of firewall contact causing so much noise.
The output of the turbo to the downpipe is 4". Absolutely no reason to neck it down to 3.5" because you don't want to take the time to fit it right.
 

·
Registered
Joined
·
2,116 Posts
The output of the turbo to the downpipe is 4". Absolutely no reason to neck it down to 3.5" because you don't want to take the time to fit it right.
No it's not, the output is almost exactly 3.5". The exducer diameter is 88mm, divide that by 25.4 mm/in and you get 3.46". Either way, 3.5" is a huge improvement over stock, and there will be very little benefit to going larger unless you're pushing over 550-600hp.
 

·
Registered
Joined
·
279 Posts
Is there any noticable differance in power or anything when going to a bigger down pipe from stock?
 
1 - 20 of 22 Posts
Top