What is the "underspeed pulley" mod?

[Flavor 987S]

Is the Flat 6 part a Porsche part? Can any of you guys really "feel" at 5 HP gain? Is this a "while your in there mod" when doing the Serpt. Belt? Thanks.

[Topless]

Originally Posted by Flavor 987S

Is the Flat 6 part a Porsche part? Can any of you guys really "feel" at 5 HP gain? Is this a "while your in there mod" when doing the Serpt. Belt? Thanks.

No, it's a custom 4" pulley. I did the pulley as a reliability mod to prep my car for track use. My original P/S pump is still intact at 100k miles and 70+ track days... Yay! I cannot say I feel a difference but my car has some weight removed also. Others have ridden in my car and thought it was faster than their 2.5L but it's all subjective until you measure it.

If your car is mostly a street car and you love your stereo, don't bother with this.

[thstone]

Originally Posted by Flavor 987S

Can any of you guys really "feel" at 5 HP gain?

No and yes.

No, you can't really (truthfully) feel the slight increase in power.

But yes, it does make a difference because my car does not have this mod and when I am chasing someone on the track who does have the mod, I can see that they have a bit more acceleration out of turns. Not a lot, just a little bit more. It might only be a few tenths of a second per lap, but in 5 laps they can be a full second ahead of me and then I have to drive the dang wheels off the car to keep up.

Of course, there are many, many variables involved, but when someone with an identical car on identical tires can pull away just a litle bit out of every corner, my man-pride forces me to conclude that something else HAS to going on!

The only other conclusion is that my driving sucks so I really prefer to believe that the underpulley helps.

[Jerkstore]

Originally Posted by Flavor 987S

Is the Flat 6 part a Porsche part? Can any of you guys really "feel" at 5 HP gain? Is this a "while your in there mod" when doing the Serpt. Belt? Thanks.

I just did this mod yesterday and it was 103* outside. You can definitely feel the extra HP. Went out with the wife and she said "your car seems faster" which was great being out in insane heat.

I was concerned about getting the 24mm bolt out that everyone talks about. If you use the proper tools (an extra long 24mm wrench) the bolt will come out easily. I reused the bolt but others say to buy a new one.

I couldn't find the Flat6 pulley on their site so I purchased the RSS kit that comes with the new pulley, serpt belt, and special wrench. The hardest/longest part was cutting the boss down IMO. I just took a hacksaw blade off the saw and sawed through with the blade in my hand. Rest of the install was a breeze.