Ford Powerstroke Diesel Forum banner

Why no 5 inch down pipe?

15K views 13 replies 7 participants last post by  Ipkyss 
#1 ·
So, why does nobody make a 5 inch downpipe? Is the Turbo outflow only 4inch? This must be the case, right??
 
#2 ·
I'm guessing there is a clearance issue between cab and engine.
 
#5 ·
So, if I were to cut into the cab to make room, and re-plate a tunnel such that I will have enough room to fit a 5" DP, will this affect the current tuners available? In other words, if I were to place a 5inch downpipe will this have an untoward effect on individual tunes??

What is the diameter of the stock turbo outlet?
 
#7 ·
I can't see the reason for a 5" down pipe. Getting rid of the stock one is a great Idea. Its amazing these motors make any power with the stock one. The turbo is a 4" outlet I believe. Or really close to that. My truck is 5" from the down pipe back. I really don't see a need for more size than that.
 
#11 ·
With as much room as I have around my 4" down pipe, I could see a 5" fitting with not too much work. I just don't see the reason for it when the turbo is not a 5" outlet...
 
#13 ·
Sean (Powerstroker67) said he has tried a 5" before and the fitment was not good at all. I have had issues with my 4" rubbing on the firewall. I just don't see a 5" working at all. Plus you would have to go from 5" to 4" and then back to 5" because of the transmission crossmember.
 
#12 ·
Thanks, guys. So, that was my big question: is the turbo outlet at 4 or 5 inch. Assuming it's a 4inch out, then you are right, it does not make sense. Just trying to maximize flow characteristics out the turbo. Turbos in general do not like any backpressure and the exhaust flow is not laminar, ie, the exhaust coming out of the turbo is actually a swirl. so, it would be of great advantage to have the exact same diameter downpipe, if not larger, but not smaller.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top