SALEEN961
Well-known member
- Joined
- Jan 1, 2023
- Threads
- 4
- Messages
- 86
- Reaction score
- 99
- Location
- Radnor, PA
- Vehicles
- 2021 F150 XLT 302A
- Occupation
- Automotive Technician
- Thread starter
- #1
Initial Testing
I recently added a FactionFab resonator delete pipe to my truck, and before I installed it, I decided to weld in an O2 sensor bung about 6" back from the flange so I could easily measure the back pressure in the system. I did this because I wanted to determine if there were any real gains to be had by replacing the factory muffler and tailpipe assembly on my single exhaust 3.5EB F150. What I found was that the back pressure gauge barely registers more than 0psi during light throttle driving as you would expect in a good system. When you go WOT the back pressure immediately jumps up to 2.5psi which isn’t terrible, but as you continue to accelerate the back pressure will climb and peak in the range of 3.5-4.0psi.
To be clear, this is 3.5-4.0psi of back pressure after the cats and before the muffler. It is possible that this reading would be a few psi higher had I measured directly in front of the cats at the turbo outlets. During my testing I also noted that exhaust manifold pressure peaked at 40psi during my WOT pulls but it quickly cycled between roughly 20.5 and 40psi as it seems to be greatly impacted by the exhaust valves opening and closing. My peak boost during the WOT pull was 18.65psi so the pressure ratio for the peak numbers is 2.14:1.
My Conclusion and Concerns
At this point I’ve decided that I do want to replace my exhaust system because of how restrictive it is, but finding anything that genuinely sounds good on the 3.5EB is a real challenge, especially when you limit yourself to full 304 stainless exhaust systems. I’ve had very loud exhausts in the past and I’m not afraid of some added noise, but I’m very concerned about how this truck will sound with the 3.5EB and I would like to err on the side of caution and go with something “too quiet” and not something “too loud”.
Trying to Pick an Exhaust System
Initially I thought that the obvious answer to reducing back pressure would be to build my own 3.5” single exhaust, but at that pipe size controlling noise and drone can be difficult. Going with a true dual 2.5” exhaust would be much more expensive, but with 2 resonators and 2 mufflers it should be very easy to keep things quiet while keeping roughly the same flow potential as the single 3.5” system.
As I continue to debate what I want to do, I noticed that Corsa advertises an 83% increase in flow with their single 3” exhaust system (#21166). In the past their F150 single 3” systems only offered modest 9%-18% increases in flow, but it seems that Ford has made the stock exhaust on the 2021+ F150 much more restrictive than it was on 2011-2020 F150s. I’m still not sure how I feel about the sound of the Corsa on the 3.5EB, but they have shown that a single 3” or dual 2.25” system should be sufficient when designed properly.
If anyone has a recommendation on an exhaust system for my 3.5EB I would love to hear it, I’m still very far from making a decision on exactly how I’d like to proceed with upgrading my exhaust.
I recently added a FactionFab resonator delete pipe to my truck, and before I installed it, I decided to weld in an O2 sensor bung about 6" back from the flange so I could easily measure the back pressure in the system. I did this because I wanted to determine if there were any real gains to be had by replacing the factory muffler and tailpipe assembly on my single exhaust 3.5EB F150. What I found was that the back pressure gauge barely registers more than 0psi during light throttle driving as you would expect in a good system. When you go WOT the back pressure immediately jumps up to 2.5psi which isn’t terrible, but as you continue to accelerate the back pressure will climb and peak in the range of 3.5-4.0psi.
To be clear, this is 3.5-4.0psi of back pressure after the cats and before the muffler. It is possible that this reading would be a few psi higher had I measured directly in front of the cats at the turbo outlets. During my testing I also noted that exhaust manifold pressure peaked at 40psi during my WOT pulls but it quickly cycled between roughly 20.5 and 40psi as it seems to be greatly impacted by the exhaust valves opening and closing. My peak boost during the WOT pull was 18.65psi so the pressure ratio for the peak numbers is 2.14:1.
My Conclusion and Concerns
At this point I’ve decided that I do want to replace my exhaust system because of how restrictive it is, but finding anything that genuinely sounds good on the 3.5EB is a real challenge, especially when you limit yourself to full 304 stainless exhaust systems. I’ve had very loud exhausts in the past and I’m not afraid of some added noise, but I’m very concerned about how this truck will sound with the 3.5EB and I would like to err on the side of caution and go with something “too quiet” and not something “too loud”.
Trying to Pick an Exhaust System
Initially I thought that the obvious answer to reducing back pressure would be to build my own 3.5” single exhaust, but at that pipe size controlling noise and drone can be difficult. Going with a true dual 2.5” exhaust would be much more expensive, but with 2 resonators and 2 mufflers it should be very easy to keep things quiet while keeping roughly the same flow potential as the single 3.5” system.
As I continue to debate what I want to do, I noticed that Corsa advertises an 83% increase in flow with their single 3” exhaust system (#21166). In the past their F150 single 3” systems only offered modest 9%-18% increases in flow, but it seems that Ford has made the stock exhaust on the 2021+ F150 much more restrictive than it was on 2011-2020 F150s. I’m still not sure how I feel about the sound of the Corsa on the 3.5EB, but they have shown that a single 3” or dual 2.25” system should be sufficient when designed properly.
If anyone has a recommendation on an exhaust system for my 3.5EB I would love to hear it, I’m still very far from making a decision on exactly how I’d like to proceed with upgrading my exhaust.
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