Blown
Elite Explorer
- Joined
- December 6, 2007
- Messages
- 1,211
- Reaction score
- 965
- City, State
- Montrose, CO
- Year, Model & Trim Level
- 2017 Sport
My antics! Jeez, I think I have been chasing power that the current exhaust set-up won't support? Duh
My butt dyno was not reading 400HP!
A recent post made me look at my exhaust again, rethink it, research it as I had not considered how much power the exhaust would take. In building this, I was doing the best with what was stock in getting it done as it's my daily. Calculating it, I think my exhaust is good to about 350 horses??? I want 400 and have the boost, but am not getting 400. I have detuned to 350 horse from 9.1lbs to 5.7lbs of boost till I get more exhaust work done.
What I am running: TMH's into the stock downs with all 4 cats. I cut-off the neck-downed pipe after the second cats and put a high flow chamber muffler on (two 2 1/2" in and 3" out) with 3" tail pipe.
I am going to start searching, might modify something larger for an F150 or something. It will likely take some custom work. I would keep the TMH's. I believe they are good to 400-425HP? I am thinking most of the restriction is in the stock downpipes and cats? I think 2 1/2" downpipes and two high flow cats would be large enough? Then comes the single 3" which is a little small, but I would try it first before I went to a bigger muffler and tailpipe. I think I can give a little power on the top end, with a 3" muffler and pipe restriction for those brief moments at high RPM. However, a mandrel bent piece would be nice.
The downpipes and cats should make for a big improvement and I think I will try that first. No hurry, spring weather is much nicer to work in at the earliest.

A recent post made me look at my exhaust again, rethink it, research it as I had not considered how much power the exhaust would take. In building this, I was doing the best with what was stock in getting it done as it's my daily. Calculating it, I think my exhaust is good to about 350 horses??? I want 400 and have the boost, but am not getting 400. I have detuned to 350 horse from 9.1lbs to 5.7lbs of boost till I get more exhaust work done.
What I am running: TMH's into the stock downs with all 4 cats. I cut-off the neck-downed pipe after the second cats and put a high flow chamber muffler on (two 2 1/2" in and 3" out) with 3" tail pipe.
I am going to start searching, might modify something larger for an F150 or something. It will likely take some custom work. I would keep the TMH's. I believe they are good to 400-425HP? I am thinking most of the restriction is in the stock downpipes and cats? I think 2 1/2" downpipes and two high flow cats would be large enough? Then comes the single 3" which is a little small, but I would try it first before I went to a bigger muffler and tailpipe. I think I can give a little power on the top end, with a 3" muffler and pipe restriction for those brief moments at high RPM. However, a mandrel bent piece would be nice.
The downpipes and cats should make for a big improvement and I think I will try that first. No hurry, spring weather is much nicer to work in at the earliest.