PetersRedYaris
04-10-2007, 06:32 PM
Well here it is; the ZPI lightened crank pulley write-up. First off, I decided to weigh the new billet aluminum pulley from ZPI. I posted the stock crank pulley as well.
ZPI Pulley- 13.9 oz or 393 grams
Stock Pulley- 50 oz. or 1422 grams
The ZPI pulley is fully machined billet aluminum. I inspected the pulley very closely and it seems well made although not as pretty as the NST. Installation is a snap.
Tools/parts required-
Air wrench with 19mm socket
12mm and 14mm sockets/wrench
14mm wrench
Torque wrench
Blue loc-tite
Grease
Permanent marker
Installation Steps-
1. Turn your steering nearly all the way to the right. (optional)
2. Remove the front right wheel.
3. Remove the plastic shield covering the engine by removing the six 12mm bolts holding it in place. (take note that two of the six are fine thread and must go back to their correct locations)
4. Relieve the belt tension by loosening all three bolts holding the alternator in place. A 12mm socket and wrench will work for the top two but a 14mm regular wrench is need for the third bolt under the alternator. Don’t fully remove them, just loosen them. The alternator can then be pivoted toward the engine which releases the belt tension. Also, don’t forget to mark where the belt tension adjustment bolt was with a permanent marker.
5. With the belt out of the way, remove the factory pulley using an air wrench to remove the 19mm bolt. (Don’t lose the little dowel pin)
6. Put a light coating of grease on the dowel pin and a small amount of blue thread-lock on the crank bolt threads before reinstalling.
7. Install new pulley and torque bolt to 128 Ft. Lbs.
8. Reinstall belt and tension to factory specs., or realign with the mark you made using the permanent marker.
9. Install plastic shield and wheel.
10. Done
http://img3.freeimagehosting.net/uploads/6fde1639d6.jpg (http://www.freeimagehosting.net/)
http://img2.freeimagehosting.net/uploads/120a0a1d0e.jpg (http://www.freeimagehosting.net/)
http://img2.freeimagehosting.net/uploads/30eeb373cc.jpg (http://www.freeimagehosting.net/)
http://img2.freeimagehosting.net/uploads/a3faa1e8bf.jpg (http://www.freeimagehosting.net/)
http://img3.freeimagehosting.net/uploads/c7968c1f75.jpg (http://www.freeimagehosting.net/)
http://img3.freeimagehosting.net/uploads/ae706fd687.jpg (http://www.freeimagehosting.net/)
http://img3.freeimagehosting.net/uploads/5b22445966.jpg (http://www.freeimagehosting.net/)
With the new pulley installed throttle response is improved generously, even with an automatic transmission. The biggest gains are felt in the lower gears at low to mid RPM’s, but the top gears seem relatively unaffected. Even if my transmission downshifts on the interstate I can’t really tell the difference. It’s fun in town however as it’s much more zippy. Off the line starts and up to 50MPH seems much improved but I don’t have any numbers. This mod seems to be the best mod for everyday driving as an air intake isn’t felt until higher RPM and exhaust isn’t felt at all. Overall, I would recommend a lightened pulley as they are cheap compared to other modifications (exhaust, air intake) and seem to be the best bang for your buck.
ZPI Pulley- 13.9 oz or 393 grams
Stock Pulley- 50 oz. or 1422 grams
The ZPI pulley is fully machined billet aluminum. I inspected the pulley very closely and it seems well made although not as pretty as the NST. Installation is a snap.
Tools/parts required-
Air wrench with 19mm socket
12mm and 14mm sockets/wrench
14mm wrench
Torque wrench
Blue loc-tite
Grease
Permanent marker
Installation Steps-
1. Turn your steering nearly all the way to the right. (optional)
2. Remove the front right wheel.
3. Remove the plastic shield covering the engine by removing the six 12mm bolts holding it in place. (take note that two of the six are fine thread and must go back to their correct locations)
4. Relieve the belt tension by loosening all three bolts holding the alternator in place. A 12mm socket and wrench will work for the top two but a 14mm regular wrench is need for the third bolt under the alternator. Don’t fully remove them, just loosen them. The alternator can then be pivoted toward the engine which releases the belt tension. Also, don’t forget to mark where the belt tension adjustment bolt was with a permanent marker.
5. With the belt out of the way, remove the factory pulley using an air wrench to remove the 19mm bolt. (Don’t lose the little dowel pin)
6. Put a light coating of grease on the dowel pin and a small amount of blue thread-lock on the crank bolt threads before reinstalling.
7. Install new pulley and torque bolt to 128 Ft. Lbs.
8. Reinstall belt and tension to factory specs., or realign with the mark you made using the permanent marker.
9. Install plastic shield and wheel.
10. Done
http://img3.freeimagehosting.net/uploads/6fde1639d6.jpg (http://www.freeimagehosting.net/)
http://img2.freeimagehosting.net/uploads/120a0a1d0e.jpg (http://www.freeimagehosting.net/)
http://img2.freeimagehosting.net/uploads/30eeb373cc.jpg (http://www.freeimagehosting.net/)
http://img2.freeimagehosting.net/uploads/a3faa1e8bf.jpg (http://www.freeimagehosting.net/)
http://img3.freeimagehosting.net/uploads/c7968c1f75.jpg (http://www.freeimagehosting.net/)
http://img3.freeimagehosting.net/uploads/ae706fd687.jpg (http://www.freeimagehosting.net/)
http://img3.freeimagehosting.net/uploads/5b22445966.jpg (http://www.freeimagehosting.net/)
With the new pulley installed throttle response is improved generously, even with an automatic transmission. The biggest gains are felt in the lower gears at low to mid RPM’s, but the top gears seem relatively unaffected. Even if my transmission downshifts on the interstate I can’t really tell the difference. It’s fun in town however as it’s much more zippy. Off the line starts and up to 50MPH seems much improved but I don’t have any numbers. This mod seems to be the best mod for everyday driving as an air intake isn’t felt until higher RPM and exhaust isn’t felt at all. Overall, I would recommend a lightened pulley as they are cheap compared to other modifications (exhaust, air intake) and seem to be the best bang for your buck.