O.k., so I assume you are *SIGH*'ing at me, assuming you are calling me the ignorant one, if not, my apologies for the below specific explanations, but before we start (and again, assuming you are *SIGH*'ing at me), that lump in your seat, it's your head-please pull it out so you can read all of the details.
A few things, but let's start with the air filter capacity. Below is a simple spreadsheet that shows the limitation of the OE filter vs. a S&B filter (easy, since S&B publishes all of their filter dimensions in detail, and I happen to have purchased one because it is the best value). Now below, this shows the truck at stock stated Hp rating of 450 Hp at 5000 rpm based on published Ford Technical Specifications for a 2020 Ford F-150 Raptor:
S&B Calculated filter efficiency losses:
RPM | Pressure Loss (percent) | Horsepower Loss |
3,000 | 0.00 % | 0.01 |
3,500 | 0.00 % | 0.02 |
4,000 | 0.01 % | 0.03 |
4,500 | 0.01 % | 0.04 |
5,000 | 0.01 % | 0.04 |
5,500 | 0.01 % | 0.04 |
| | |
OEM Calculated filter efficiency losses:
RPM | Pressure Loss (percent) | Horsepower Loss |
3,000 | 0.76 % | 2.06 |
3,500 | 1.13 % | 4.04 |
4,000 | 1.52 % | 6.45 |
4,500 | 1.87 % | 8.59 |
5,000 | 2.12 % | 9.55 |
5,500 | 2.20 % | 8.50 |
Now the above shows a lot of difference in filter losses between a performance filter with enlarged dimensions in oiled felt/gauze and an OEM paper filter media.
Quick note, since someone else noted that a larger intercooler in the stock location is a great idea, I did not mention that, but it is a great improvement...especially if you are holding a lot of throttle for extended or repeated times, like in the dunes or towing.
Let's move on to the exhaust:
Here is a nice little article that explains many of the nuances of exhaust systems, specific to both turbo charged and naturally aspirated (they are more specific to turbos, which is good, since we are talking Gen 2-but if you like, I can explain more details about why some backpressure in naturally aspirated engines is a good thing). https://dsportmag.com/the-tech/bolt-basics-exhaust-systems/
Speaking of downtubes (after you read at least a little of the above article, I remember years ago from a BMW owners group that the single best improvement to a turbo engine is better downtubes. Keep in mind, these were referencing small-mid displacement 6 cylinder BMW turbo engines.
Efficiencies of piping, bends, diameters, etc. in General:
Suffice it to say that you want to try to keep the internal diameter of any flowing pipe consistent and seek the optimal flow velocities without going too fast, as that leads to friction losses, and not too slow-that can lead to pour cylinder filling on the intake side and pour exhaust scavenging on the exhaust side.
General rules, keep the internal diameter consistent and with the lowest radius bends possible, this is for both intake and exhaust tubing. When you look at piping for either you don't want sudden changes in internal cross-sectional area or pipe diameters, as this causes hydraulic jumps (both positive and/or negative). In a lab, the way to measure this is to have a pressure transducer before the change in diameter, at the change in diameter, and after the change in diameter. You can do this with both a smooth transition pipe, or a rapid transition in pipe (think exhaust cone pipe adapter vs. the rapid jump adapter like you find at auto parts stores). At a rapid change in diameter you will have a large pressure fluctuation (if going from larger pipe to smaller it will be a high pressure increase; if going from a smaller diameter pipe to a larger diameter pipe it will be a large pressure drop/vacuum). If you are seeing the writing on the wall here...yeah, either a pressure drop/vacuum or pressure jump, both cause a big disturbance in the flow stream in the pipe, that equals horsepower....horsepower the engine has to sacrifice to your pipe diameter change rather than power to the wheels.
The above explains why you should do things like eliminate the resonator (as long as you are o.k. with the trade off of sound quality), pipes that are mandrel bent vs. pinch bent, intake tubes that have smoother bends and larger/more consistent diameter.
In Summary, my list of potential upgrades provides a basis for making efficiency improvements that when added up have a cumulative positive impact, typically better drivability (smoother turbo spool with less lag; minor mpg potential improvement; durability) without impacting your warranty (the downtubes are iffy). So with these improvements, and good amount of cost savings from going with the bigger ticket items like different mufflers, etc., you can add a noticeable amount of power while you are at it without a tune. If you end up going with a tune, this will promote even better improvements over having all stock items.
If you would like to see more specific methods to calculate the potential friction/Hp losses or gains with piping, whether exhaust or intake, let me know and I can start scanning pages from my fluid dymanics design manuals, or you can even check out www.engineeringtoolbox.com and get some simple methods from there to see some of these differences and how they can affect your performance.
BONUS---you chair has been more comfortable this whole time!
