Hello everyone,


I am in search for info on the UDP for our 420a motor. Is this pulley referred to as the crankshaft pulley? or am I making a fool of myself? I was wondering because I recently acquired AEM cam gears and was gonna install them when I do my 60k mile service, but I also saw that there is a pulley called the crankshaft pulley that is a part of the timing belt system as well. Maybe I can knock out both things in one time. I was also looking into port matching my 420a, any of you done it? How much better is it? Thanks for the help.

Yup, crankshaft pulley's the same thing for the UDP. Get it at ptuning.com for a 2GNT disc. Dunno the code tho...

No they are not the same, the crank shaft pulley can sometime be confused with the UDP, The UDP is actually a pulley that bolts right infront of the the crank pulley, this has it what the pwr steering belt and altenator belt hook too, this is the heavy pulley you can lighten for more HP

he's right the crank pulley goes with the timing parts and the UDP goes with the alternator and power steering. you can't get an aftermarket crank pulley that i know of but you can get a lighter UnderDrive Pulley to help with HP and a littl Torque.

thanks for the info.....in the case that the underdrive pulley is not the crankshaft pulley will it be something that I can do while doing my timing belt, or will it be something totally apart from that? Also, how effective is it? I know what it does and how it is "supposed" to be effective, but real world street driving: how good is it? Thanks a lot....

You DO replace the crankshaft pulley when installing a UDP. So, you take the crankshaft pulley off, put the UDP on, and don't re-install the crankshaft pulley. The part that is behind the crankshaft pulley that turns the timing belt is the crankshaft sprocket.



Eric Madden

Exactly. The crankshaft pulley, or harmonic balancer on some, or harmonic damper on others, is replaced by an underdrive pulley. Which unnderdrives the accessories, spinning them slower, and in most cases is a significant loss in weight. both of which add power, or more accurately free up power formerly drained by the stock crank pulley.

Una salus victus.
It's not about being invincible, it's about being ready; for anything.



Michael J. Kulaga
e-mail: Michael_97RS@2gntDSM.zzn.com aol IM: MJKulga
http://highlander.dsmpower.com/

Injen CAI, 55mm TB, Hooker 4-1 Stepped Header, GS-T Muffler, AFX UDP, S-AFC, 8.5mm Magnecor Wires, Crane Fireball HI-6DI2, SS Clutch Line, NRG Susp. Motor Mount Ins., FU/RU/RL STBs, TSW Blade 17x7.5, Bridgestone Potenza RE730 215/45ZR-17. Front KVR Cross-Drilled Rotors & Carbon Fiber Pads

To Be Installed: P&P Intake Manifold 1/2, P&P Milled Head, Rear Disc Brakes, Rear KVR Cross Drilled Rotors & Carbon Fiber Kevlar Pads, SS Brake Lines