STM 10% Under-Driven Alternator Pulley w/ Raised Guides | Mitsubishi Evo 8/9 (STM-EVO8/9-ALTP)


Give us a call to get the best prices and parts for your build. Or, just call us with a cool racing story...either way we're here.

Email -

Phone 1-888-627-3736

Fits Your:
Expected Delivery by , when ordered within hrs and mins
Phone  Contact us for availability!

Earn  $1.98 In MAP Rewards!

STM 10% Under-Driven Alternator Pulley with Raised Guides - Evo 4-9

The STM 10% Under-Driven Alternator Pulley with Raised Guides was originally designed to help stop the belt from jumping off at high RPM. With the amount of requests we've had for this product from the racing community, we are very pleased to announce the release! This new revision makes the pulley 10% under-driven and lighter than stock- lightening the load on your alternator. Fits all the Evolution IV-IX models and works with OEM and stock replacement belts.


  • Billet Aluminum
  • Hard Anodized to help resist corrosion
  • Lighter than OEM
  • 10% under-driven
  • 10% less wear on your alternator
  • Works with stock belts
  • Raised belt guides
  • USA Made


  • 1996-2006 Mitsubishi Evolution 4-9

What's in the box?

  • 1 Alternator Pulley


  • Lifetime Warranty on STM Parts to the original purchaser against manufacturing defects

Customer Reviews

Based on 4 reviews
Chris M.
Clean n Simple

Can't get any easier then one 24mm nut! Beautiful pulley and simple mod to help reduce engine draw. Easy decision/upgrade to make when installing a new alternator.

Great pulley

Was having issues with high rpm and alternator not handling. This pulley does its job and is highly recommended for high rpm applications. Thanks MAP.

Jeff Armstrong
Looks nice, works great

Had this installed with a new alternator right before a tune. Does actually weigh less, even though it’s larger than stock. Be sure to use some lock-tight or equivalent as the pulley is not keyed and relies on the nut torque to ensure it turns the alternator.
Charging voltage still looks great at idle (no amplifiers in my sound system). A little piece of mind when at the track consistently running to red line.

Ross Thurston
Under driven alternator pulley

Appears well made and quality