I was trying to track down a belt squeak and noticed the rubber insulator on my crank pulley is all dry rotten. Going to order an OBX underdrive pulley next week. Anyone running one? you like? notice anything on the butt dyno?

 

95-01 junk yard will work also......

 

I have the UR on my 99, also had it on my 95. Worked flawlessly, not sure about quality of the OBX, but you should be fine. I know the UR requires a slightly smaller (length) belt for a nice fit.

 

I Dont think ill be able to remove it from the donor car in the junk yard without air tools...sounds like to much work. The OBX underdrive is actually cheaper than new oem at only $80 too..

 

I wondered about belt sizes, thanks for clearing that up. Did you notice any power increase?

 

I just had the same prob with my car except the pully over took the power steering pully, and snapped my belts. Idk anything about the obx pully but i kno its a b**** to take the nut of wen replacing, the way i did it was with a braker bar and i had it braced with a 2x4. Then i CARFULLY turned the engine over, it worked quite well and from wat i understand alot of ppl do it, hope this helps

 

The only thing I really noticed was top end revolutions. I based it off of distance vs speed at WOT. I used a specific stretch of interstate where I had a certain starting point, and the end point was going under a bridge. Before the pulley, I hit the starting point at 70, would be at ~105 by the time I passed the bridge. After the pulley, I would be at ~120. So around a 15mph difference, alls I could see as a difference.

 

Umm
There's no way that could happen. The hp increase for you to gain 15 mph in that little time would be huge.
Thats not what a udp does.

 

yes i am familiar with this method...i had to use this on a Volvo before, but my civic crank zipped right off with air tools...hope its not a *itch

 

tell me how it works then...i understand the pulley is a smaller diameter. Is it just about less rotating mass?

 

It's smaller and way lighter than the OEM and you will need smaller belts too.They gave me two sizes and both needed to be changed because there wasn't enough to tighten.I had to go 3 different belt sizes smaller than the OEM until the belt stop squealing.

 

Straight from Wikipedia.... Underdrive pulleys usually are marketed as a performance enhancing item that increases the torque and horsepower output of an engine by reducing parasitic drag caused by belt-driven accessories, but more importantly by reducing the moment of inertia.


According to websites... a V8 LS1 gains 15 hp from this mod. Our cars get way less I speculate. Not many people feel a difference from what I hear.

 

It's not a perfect situation or exact numbers, hence the "~". It's around about. When I had my Maxima dyno'd it had 168 fwhp, and 207 ft lbs torque, but I guess that's impossible too.

Let me re do it:

without = 104.7 mph, 87 degrees outside, clear day
With = 116.3 mph, 75 degrees outside, partly cloudy

See, weather played a part in it as well. My bad.

 

Zoomin...

 

Chordless impact.....

 

I looked into Ud pulleys. Then I realize on the vq30 engine you might see 5hp? for the few hr install if thats worth it to you then go for it. Not for me esp bc I am more interested in audio than the minimal HP gain. Better bet is to go with a lighter stock diameter pulley. my 2c

 

Underdrive pulleys are a waste of time and money. Very little gain and possibly negative effects. (that rubber ring on the factory pulley does help damp vibration slightly)

I bought a Dorman crank pulley on Amazon last month for ~$87. Works fine for me.

 

Buy a battery operated impact I just replaced mine got it from the junk yard but make sure u charge the bsttery my pops forgot so a 30 min job turned into a 2 hr job and hey u get an excuse to get new tools ^_^