The "Before" Dyno:
This was an interesting thing, and I was less than pleased with what happened here. After the first 3 pulls, my car - which was dyno'd at 270+ at Uprev before I had my Stillen headers installed - was only putting down 251whp and 234wtq on Humble's Dynojet. Naturally, I was concerned. Either I had lost power back when I put on my headers (which it certainly didn't feel like), it was just a different dyno, or there was something wrong with my car.

As it turns out, and I didn't find out until after I came back for the "after" dyno, the goofball behind the wheel during my first pulls at Humble had the car in 3rd.

Yes, 3rd.

Now before you start shouting into your computer screen how dumb I am for letting them do this, I should stop you - I actually asked them which gear. I knew that 5th was 1:1, but I asked to make sure they were going with 4th because it's easier on the engine. After all, as long as the before and after dynos are in the same gear, the recorded gains should still be accurate.

Either way, they did the pulls in 3rd, and I was upset. But at least it explains the abnormally low numbers. So for the sake of the comparison, please try to focus on the gains, and not the peak numbers. After all, that's the whole point of this dyno comparison. It's still good data.

[video of this dyno will have to wait, as it's on the shop camera right now]

The Installation:

With the ART Pipes directly replacing my Stillen High Flow cats, the installation was very simple, with the only issues encountered being preexisting ones due to my Stillen exhaust and some of its own imperfections (and lack of flex pipes). Chris did a fantastic job once again, and everything fit perfectly. My only concerns are with the location of the ART Pipes' Helmoltz resonators and their proximity to a lingering screw from the stock heat shield. There's about an inch of clearance, but I do worry about jostling or movement of the pipes. It shouldn't be an issue with that much clearance, but if you're worried, you might consider trimming the screws down just in case (something I might go back and do).


Once it was installed, and you can see this in the pictures... it's just gorgeous. The look might not be for everyone, but I think it looks just plain sick. It almost makes me wish they were more visible so that they could be more readily appreciated. Regardless, the ART Pipes presented no fitment issues.


The "After" Dyno:

After taking the car back to Humble... and finding out that we needed to be in 3rd gear ... Chris hopped behind the wheel and I sat in the passenger seat with my laptop and Cipher running so I could get some good datalogs for an eTune.

We put down four runs in 3rd gear. One of them had some abnormalities, but the others were consistent - 260whp and 239wtq with very solid gains throughout the entire range. I gained power at every single point, and the numbers were completely in line with the ones initially presented by Tony at Motordyne.

Here's a video:
http://www.youtube.com/watch?v=CNpMkE6GM7o

Before/After Dyno Chart:



I can sit here and give you some grand explanation of what is clearly visible, but I'll try not to. The dyno charts speak for themselves. However, since I don't have the means to give you a fancy-pants delta gains chart like Tony did in his announcement thread, I'll give you a breakdown like this:

RPM - Gain
2500: +3.5whp, +7wtq
3000: +8whp, +14wtq
3500: +5whp, +8wtq
4000: +4whp, +5wtq
4500: +4whp, +5wtq
5000: +5whp, +5wtq
5500: +8whp, +8wtq
6000: +10whp, +8wtq
6500: +6whp, + 4wtq
7000: +7whp, +5wtq

Again, these numbers are in 3rd gear, and this is for comparative purposes, so it is the gains that matter. As you can see, this was SOLID improvement throughout the entire band of performance. And yes, I can definitely feel it. The most amazing part about this, though, is not even the gains. Those alone are fantastic, especially that low-end torque I picked up (+23 ft-lbs at 2800rpm!). What I am so thoroughly impressed by is that this is a simple bolt-on modification replacing another bolt-on modification. So many companies out there cite huge gains for their test pipes, high flow cats, and what not. Those gains are cited over stock catalytic converters, and are all too often exaggerated. These are solid gains on a car that already had full-bolt ons and a tune. Furthermore, the improvement falls in line with what Tony has shown from his own tests. Now, we have an independent test that confirms them.

Before/After Sound Clips:
As far as difference in the sound, there is a distinct difference, although it isn't too pronounced. On a car with fewer modifications, I would imagine the difference would be more noticeable. As it is, I can say this much. The drone at low RPMS that I incurred after installing my Stillen headers is all but gone. The rasp is transformed into something ... different. It's almost not rasp anymore. At the very least, the car doesn't seem as eager to turn from Jekyll to Hyde at 3300rpm anymore (where the raspiness would kick in). In terms of volume, it almost seems a little quieter with the ART Pipes than it did with my Stillen HFCs. This says a lot, since the transition to straight pipes normally adds rasp, volume, and noise.

Also, a lot of the noise in the exhaust has been mellowed out; it sounds more harmonically refined and less chaotically aggressive. Chris (Failsafe) said that where there was once a distinct rasp to my car, there isn't anymore. My wife also commented on how it sounds 1) deeper and 2) like it has a high harmonic note under full throttle (which she likes).

Also, something really cool that I didn't notice until I made the video below, is that the car has picked up a very new note that you can hear during the last flyby at the very end. Listen between the gear shifts for everything to clear up so you can pick it out, and you can hear this very, very deep note. I had no idea it was even there, but I love it.

As I just installed these yesterday, I am still trying to figure out the differences of the sound, so my descriptions are not going to be perfect. Unfortunately, as well, the video below doesn't entirely capture the difference either. So I'm giving you my best assessment at this moment in time. The sound difference from one exhaust to another is undoubtedly going to vary tremendously, and I'm really, really looking forward to hear how it sounds on other exhaust setups. I doubt it will be anything short of awesome.