Revisiting the underdrive pully topic for fresh info.

[pothole]

I'd also quite like to ditch the aircon kit in my car - do any of the UDP makers offer a no-aircon belt?

[AndyA6]

Originally Posted by pothole

I'd also quite like to ditch the aircon kit in my car - do any of the UDP makers offer a no-aircon belt?

Do a search here, I posted a link with the different belt lengths.....!!

[jaykay]

Originally Posted by pothole

I'd also quite like to ditch the aircon kit in my car - do any of the UDP makers offer a no-aircon belt?

Go with dummy pulleys from BGB

[Steve Tinker]

Mike, what you probably read was that if you fit the smaller UDP, there is no hole in the pulley that lines up with the hole in the crankcase boss to lock the cams.

After saying that, you are not completely cutting off the boss, only trimming it about 5mm to clear the new pulley.

[Ghostrider 310]

FYI to all doing this mod the piece to trim cuts like butter, the access isn't wonderful but it cuts so easily it's one of the easiest mods I ever did. Regarding the use of the old bolt, I used mine and see no reason for concern in reuse unless the item is in poor condition.

[AndyA6]

HELPFUL HINT: What size serpentine belt to run when using an under drive pulley? - GSR Autosport Community

Here you go!

[Meir]

is anyone familiar with the Mantis UdP?
how is it compered to the RSS or the BBI?

[jaykay]

It was one if the first things I did to my car. A lot of Cayman guys have the Mantis. Check out Planet nine. It was one of the first available. Apparently it was tested and gave 7-8 rwhp.

Mine was solid, black anodized. Looked very high quality; it's solid and heavy. The BBI is light and spoked. I am unsure of the relative polar moment of inertia. If it is significant then the bbi would give you more of a light flywheel effect where as the Mantis more flywheel momentum smoothness. I doubt this effect would be noticeable

At the time I did notice a feeling of more power. I desnorked at the same time so I might have been up 10 hp