but the belt that the greddy comes with isnt 30"

 

Off of what year and model Honda or are they all the same size?

 

This is someting I enver understood. Why would on want to underdrive the alt?

 

Because the mean old voltage regulator deserves that sort of punishment.

 

It frees up some horsepower.

 

SR motorsports carries individual pulleys and most size belts.
Not cheap but convenient.

http://www.srmotorsports.com/sr93plly.html

 

How can it free up horsepower? The magnetic field of the alternator's rotor is strengthened or weakened to supply a constant voltage to car's electrical system. Basically, if you underdrive the pulley, then the voltage regulator is going to increase the strength of the magnetic field and thus create more resistance on the drive belt.

On the other hand, the water pump may be under-driven for extra power. Seeing as how this car doesn't need modifications to create cooling problems, its best to leave this alone as well.



Under-driving the A/C compressor, P/S pump, and air pump I can understand.

 

I'd like to remove the air pump (going midpipe). I have an underdrive MAIN pulley. What size belt would I need? Do you plug the secondary injection inlet pipe that goes into the LIM? How's your idle?

 

Dont knwo what size you need but u can jsut wrap a string around the pulleys, measure it and go to a parts store and tell them you need a 5 rib belt thats however long you measure, or a 4 rib if a 5 is not available.

 

If you remove your airpump, you will need to Cap the hole on the airbox (if you still have it) that the airpump feeds from.
You should also block off the ACV, since it does not work without an airpump.