ZPI or NST crank pully?

[ChinoCharles]

Sorry, I skipped right over that post.

Taken straight from the NST GB thread...

1. Regarding Light Weight pulleys vs Underdrive pulleys.

There is a ton of info about these concepts on our website and I will share just a tad with you here, you can look on our site or ask me on AIM and I can explain more. Also a lot of this info has been posted elsewhere on the internet by many of our customers and friends...

There are two benefits to NST pulleys. One is weight reduction, the other underdrive. Weight reduction leads to extra throttle response and a bit of HP and TQ being freed up and sent to the wheels. Underdriving from the crank pulley means sending less power to run the accessories, thus sending even more HP and TQ to the wheels.

The pulley we are offering you guys is of the first variety, it is an OEM diameter, lightweight crank pulley. We call this CR-Lite.

I will share some pics with you in the near future, but know this for now... The design of your crank case and your OEM crank pulley make it very difficult to design an underdrive crank pulley small enough to actually do any underdriving! If we could do more for you, we probably would, believe me.

Also, an underdrive crank pulley would slow your A/C and alternator by a tad, and many of you complain about your A/Cs being weak as they are. Most of you do not seem to want them any weaker.

90% of the time I am actually in favor of an underdrive crank pulley... but after doing some research I have come to the conclusion that for your Yaris a CR-Lite may actually be the best fit and best option.