Last week I ordered the Injen intakes from forum vendor THMotorsports. Nick at THMotorspots offered great pricing and his free 3-day air shipping special is awesome. I ordered early Thursday afternoon and the intakes were delivered Friday morning. Sweet!
The kit comes in a bright red Injen box. It's neatly and safely packaged. All of parts are quality pieces, and the instructions are pretty detailed. There are 85 images in all. Some can be a little bit confusing, but if you take your time and think them through it's pretty simple.
Installation requires removal of the front fascia and the factory washer fluid tank (located on the passenger side). The intake kit includes a smaller volume tank with mounting brackets to make room for the air filter. The only downside to this is that the factory washer fluid filler neck needs to be cut so the included rubber hose can be fitted to the new tank and freshly cut filler neck. This is the only cutting required.
I know a lot of people are intimidated by removing the front fascia. It's really not that difficult at all. Simply remove two bolts and two clips inside the fender wells, unbolt the bottom of the bumper, and remove the clips at the top of the fascia and gently pop it out. It will probably take you 15 minutes your first time. Reinstalling is easy as well.
I'd say the most difficult part of the entire install is dealing with replacing the washer fluid tank, but all-in-all it's really easy.
Anyways, on to the good stuff.
After everything was put back together it was time to fire up the car. It sounds the same as stock on startup, but when you rev it you hear the "woosh" from the intakes sucking in a ****-ton of air. When you're on the road it's a deep growl that's most noticeable from around 3k-5k.
As far as the butt-dyno is concerned... it's hard to tell. I haven't really been able to go all-out with the car yet... low and mid-range power feels unchanged. If there are gains up top I haven't really driven the car in such a manner to feel them yet. This is what I expected, though, as it seems like the intake systems make their gains at the very peak of the RPM range whereas the exhaust mods seem to provide solid gains all throughout.
I did disconnect the battery during the install and I will be giving the car the rest of the week to adjust to the new intakes. Earlier in the day I took a trip out to Function Tuned in Dulles, VA where I had baseline dynos performed on their Dyno Dynamics machine. The stock result is 258.1 whp which is in line with stock 370s on this type of dyno. Be advised that different dynos measure whp differently. Dyno Dynamics tend to read quite a bit lower than DynoJet, for example. I'm sure I'd be somewhere between 275-280whp on a DynoJet.
I will be going back to Function Tuned next Saturday for another dyno. I'm hoping the weather conditions are similar to today (87*F at the time of the dyno, will have to check for the humidity) and hopefully we'll see some gains. I'm going to take the car out again in the morning and find some places to stretch it's legs and report back.
For now, here's a short video of startup/revving and some light acceleration.
Results 8/22/09:
I took the car in for a dyno this morning and saw a +7.3whp gain for a total of 265.4whp. Based on the conditions and type of dyno, I think this is more or less in line with Injen's +15whp claim (on a DynoJet). I will post the comparative dyno graph when the shop e-mails it to me on Monday (printer ran out of color ink), but I can say that it looks very much the same as the Injen and Stillen G3 manufacturer supplied charts. Minimal or no gains until around 7,000 rpm when the stock intakes become a restriction.
My thoughts? I think the only intakes worth buying are long-tube designs... whether you choose the Stillen G3 or Injen's is up to you. I think both systems, tested in identical conditions, would yield very similar results.
I believe that the stock intake system functions very well on a stock n/a car. It is
not a restriction until the very top end of the RPM range, where only the long tube intakes provide any gains. I don't think short-tubes are a worthwhile investment.