My Stillen Stage 4 Supercharger Mods Review :)

[PerformanceTony]

Well, it's finally done... We installed Stillen's stage 4 supercharger upgrades to my car about a week ago, and I just have to say I'm very happy with the results.
First off, We installed the stage 3 supercharger kit nearly a month and a half ago. The car ran well with the stage 3, the power was on tap right away, which was very nice. But it flattened out in the top end, the common symptom of this style of supercharger vs a vortech style unit.
Stage 4 on the other hand offers a much more linier power curve, and seems to pull very hard all the way into the 6000rpm area.
Stage 4 upgrades involve changing the stock fuel pump out to a walbro 255, replacing the 7th injector that comes with the supercharger to a RC 750cc, a new pulley for more boost (7.5psi on my boost gauge), and new fuel/timing controller for the added injector.
The car really pulls strong, and reading air-fuel, runs a bit on the rich side, which is safe to say, better than being lean...

Also, I still get 25 miles a gallon on my way to work under normal cruising conditions, without really getting too heavy of a foot to and from work. Although it is a lot of highway miles...

A few things i noticed about this install:
1)you have to modifiy the fuel pump cage that the OEM pump sits in, because the walbro is bigger.
2)You may want to look into getting a smaller or shorter belt, because the stage 4 doesn't offer one. When installing the new pulley, you'll have to tighten up that tensioner a bit more, and it will push the belt close to itself. I have no issues, just a concern really
3)There is an adapter block, made from machined aluminum, that spaces the fuel rail that the 7th injector sits in, and it needed to be shaved down nearly 1/4 of an inch. This is something Stillen says was a one-time mistake, and is corrected now.

All-in-all, a few hour job, and excellent results! I'm very happy... http://forums.freshalloy.com/images/graemlins/wink.gif
I highly recomend this to anyone with a stillen SC kit. It really makes the car drive like a FI car, and I would say really makes the whole setup comparible to a greddy TT on nominal boost. IMO

[asad]

Are you planning on dynoing any time soon?

Asad

[PerformanceTony]

With my work schedule it's hard for me to get out to dyno, but when I get a chance i'll set one up.

[rickdogg]

I'd really be interested in the dyno numbers as well http://forums.freshalloy.com/images/graemlins/smile.gif

[Deathmage]

so I'm assuming that the power gain is about similar to a stage 4 (maybe a slight gain?) and most of the difference is in the power curve/distribution?

[PerformanceTony]

The stage 4 kit really does seem to tie the whole power band together. On my car, I'm not sure if its the same with you guys, but I noticed that with stage 3, that the car really pulled hard until about 5k, then it started to fall flat. And that if you were in higher gears on the fwy, that it didn't seem to pull as hard as the lower gears. Maybe just perception and all. But with the stage 4 kit installed on my car, the car feels like it just pulls all the way to redline. I'm sure that If i dyno it, that i'll see the power still flatten out, simply because of the supercharger design itself, but it is much better now. The car also has a much stronger pull down low, which is perfect for you drag racers with this kit. The difference between stage 3 and 4 is significant, at least in my eyes, and those who have driven my car before and after.
Even on the fwy, at cruising speeds, it's much easier to get power where and when you want, and it really feels like it pulls harder in the higher gears than before.