Add 5-7whp to your Stillen Gen 3 intake :) for the daring only...
 

Firstly, I lay claim to being the 1st with balls to try this, and now I am rollin (har har.. cough)

So... if you have some cash to spend, which I did recently, you can add another 5-7whp from 3000rpm's up (dynos coming soon) to your Stillen Gen 3 setup.

As they sit from the normal install, the bottom and front facing (towards front bumper) side and the top are all partially obstructed due to the chassis support beam, the front bumper curvature and the black top piece for the under hood area. They are not 100% choked off, but airflow in the area is very poor. Only one side is truly open to breathe effectively. There are a few details for intake systems that, as a whole, can add up to make a substantial difference in performance and results. The first is circumferential flow, aka, allowing the filter to breathe from all sides. It has been documented before that more power is found when the Stillen Gen 3's are dyno'd with the bumper off, so I took that and another step to max out the possibilities of this intake system.

This is discussed below....

Due to the curvature of the bumper, if the bottom bar was not in the way, you can angle the Stillen Gen 3 pipes downward just a bit away from the obstruction at the top and on the side from the bumper. This allows for a decent bit more airflow all around the Stillen filters. The black bar is no longer touching the top of the filter. The bottom bar is not there to obstruct flow around the bottom part. The bumper cover is no longer extremely close to the filter since it is angled down and away. Hence, all of the filter breathes better. This does help, but probably only 2-4whp by itself at max, but it helps nonetheless.

Luckily the Stillen Gen 3 intakes are long enough for the air to straighten out by the time it hits the MAF sensor. I have no doubt this places a key part in the performance of their intake, aside from pipe sizing and routing. Secondly, the real key to a performing intake is elimination of boundary layer separation. This is easily accomplished by adding full diameter flow stacks to the end of the intake tube. The "choke" is eliminated from the end pipe from the Stillen filter which has no smooth, large radii to guide the airflow. BPI Initiatives sells 6" round flow stacks that transition to a 3" outlet to mate to your Stillen Gen 3 intakes. If you buy flow stacks, get them from BPI as Bryan is the one who originally produced and did the homework to build these awesome pieces. As you might have guessed, there is no way to fit this in that area where the Stillen Gen 3 filters are. Therefore, I pulled off the metal brace and foam support to make room and angled my pipes and filters down a notch (still above the direct airflow from the bumper grill area). In return, I am building an alternate bumper support crossbeam that will fit with the filters and new alignment of the intake piece. More on that coming soon.. I am all about chassis rigidity so its essential. That being said, I went ahead and took the beam out and have not yet replaced it. There have been zero ill effects, obviously since I havent crashed the car. The alternate beam will fix the risk soon.

With the beam gone and the intakes angled down a bit, I added the BPI Initiatives flow stacks with the full size K&N filters (cost.. $200 ish from BPI). I had to bend the stock horn assembly a bit and turn the horn upward to make room, it is indeed a tight fit. However, it all now fits very well with no rubbing or concerns. The airflow coming in now has no concern for the flow on all sides of the filter or from the boundary layer separation. The result is impressive, see below for what I found.

Results:

To be brief, here we go (flaming is welcomed wholeheartedly b/c you havent tried this and have nothing to prove me wrong, those who are interested, I can share more and will have dynos soon :tup:)

• Throttle response is faster and more consistent
• Power is MUCH better
• Sound is not changed much
• It takes the car about 20 miles to adjust but is smooth as butter after
• Power is 5-7whp better now across the board, ESPECIALLY MID RANGE TORQUE
• I'm in love
• But it aint cheap
• And if you dont put in a bumper cross beam replacement to fit around the filters, your front end is TRASH if you get wrecked :happydance:

Comments are welcome. I am sharing this despite my want to keep it "secret" and be unique, b/c the community deserves to know! :) I will have pics soon for everyone and dynos eventually of course.

I'm a little leery mainly because I'm concerned about the front bumper support thing from a crash-safety and chassis-rigidity aspect, and also about whether your new setup changes the risk of sucking water on the Gen3 (which is about zero with the normal setup).

But either way, major kudos to you for even trying this stuff out, and I can't wait to see your pics and results.

My best thoughts in the past about freeing up airflow (with the stock Gen3 filter/pipe setup) was to cut some holes in the upper front bumper, line them with shallow ducting (e.g. Mine's, but not so deep in the back and cheaper), and make some plastic plugs to cover them for driving in the rain. It still wouldn't get nearly as much improvement as what you're looking at though, and involves a ton of custom plastic work that has to fit just right.

Also, here's a link to the flow stack / filter setup he's talking about: BPI - Filtered Flow Stack Kits

Oh and links to the two different K&N filters for the flow stack (full size and short):

RF-1048 - K&N Universal Air Filters, Universal Air Filter

RU-4600 - K&N Universal Air Filters, Universal Rubber Filter

in for pics...

OP,Not sure if you're aware that rebar plays a larger role than you think on a front end hit. Granted it doesnt do much to absorb, but directs energy to proper crush/crumple zones in the front end. + rep for trying to maximize a current mod. Sub'd

the foam absorber plays a huge role in airbag timing as someone who has worked in collision repair for over half his life i ask you to please re install it on the vehicle you are honestly playing with your life as well as anyone who trusts you and gets in your car with you. 5~7 hp not worth the possible tragic outcome. remember it takes 2 people usually to get into a big wreck but only 1 idiot cause it. how many idiots do you see driving daily?

Interesting and logical -- but sounds like a replacement bumper support needs to go there...

Also, how much $$ we talking for another 5-7 whp...?

Even if you add a cross member it wouldn't do it's intended job( deflecting the energy of a collision away from the passenger compartment and motor )like its intended with out some eingeneering behind it.

I'm in for the pics also

Sounds like too much work.

likewise!

I appreciate the concern and I am building a structural replacement for the factory bar that will bolt to the same locations for deflection of the crash energy as well as will allow for the foam to be replaced, but that fits with the new filter setup.

Sounds like a lot of work just to squeeze out minimal hp

you could also take out all of the airbags and safety equipment and have much bigger gains than what you'd get from 5-7whp, but that wouldn't be very safe.