[Guest]

I have been thinking about getting an underdrive pulley for my d16a6. I have researched and read lots of debates on harmonic balancers and screwing up engines and what not. What do you guys think? I am going to have my car for awhile and really don't feel like having a pulley split in half or ruining the bearings after 30k miles........lets hear it.........is it worth the money? and the life of my engine

 

[Guest]

Theres a lot of better way (and in some cases safer) ways to make horsepower....

 

[Guest]

There's no debate a lightened flywheel will give you better results (ie freeing up HP that is lost to acceleration mass attached to the crankshaft) but some people will find that swapping a crank pulley is easier/cheaper than dropping a tranny and installing a $250-400 flywheel. Although, if you don't have a strong impact wrench to remove a crank pulley, then installing a flywheel may actually be easier.

People such as MistaBone who are strong believers in bearing damage from using non-OEM pulleys will tell you the damage can occur much sooner than 30K miles.

Keep in mind that Honda themselves does manufacture a one-piece undamped crank pulley for race use (I think it's an option for a Civic Type R, referred to as a N1 pulley), but it is NOT specced as standard equipment on any car intended for daily driving/long term longevity.

When I put a UR Ultra R (alternator belt only) pulley on my mostly stock D16A6, it DID make a difference - the car pulled stronger in 1st and 2nd gear and it shifted more smoothly too. I even measured a repeatable .2-.3 second drop in 0-60 times by G-tech. But is that worth potential engine damage? If you have easy access to replacement engines or want to do a swap later anyway, maybe. If you're into the car long term, probably not.

But I will say that swapping out the 6 lb. OEM pulley for a .5 lb. UR pulley made a better improvement in seat-of-the-parts HP than intake, exhaust and header by a long shot.

 

[Guest]

Disregarding the safety issues, don't you want to get a lightened overdrive pulley for the crank and then lightened underdrive pulleys for the accessories?

 

[Guest]

Disregarding the safety issues, don't you want to get a lightened overdrive pulley for the crank and then lightened underdrive pulleys for the accessories?

I've never used underdrive accessory pulleys, but it seems that the benefits are pretty negligible (ie you can't feel it at all).

Every UR crank pulley I've installed is also an underdrive, ie it's smaller in diameter than stock and required a new, shorter belt. Your lights will be dimmer at idle b/c the alternator won't be able to create a full 13 volts or higher at that speed.

 

[freeturkeys]

umm i dont have any experience with them but the UR website says that the pulleys are the same size, but that they are lightened

 

[Guest]

I used a complete set of UR pulleys on my accord for around 40k miles. I didn't have any problems. I did bring it to a shop though to get them put on since I don't have an impact gun. They might have balanced it for me since it was a friend of mine who did it. I didn't ask. It was nice having them, but for my mini me I am going to stay away from them since I have learned that they can do damage in the long run.

 

[Guest]

umm i dont have any experience with them but the UR website says that the pulleys are the same size, but that they are lightened

Why do some people feel compelled to post incorrect information?

From UR's website (unorthodoxracing.com/faq_pulleys.html) -

"Underdriving/underdrive is slowing the speed of the accessories, or the driven component, from the original speed they were turned by the OEM crank pulley. Underdriving can be accomplished in two ways. First is by increasing the diameter of the accessory pulley/s. The problem with this method is that it increases the size of the accessory pulley/s which increases their weight. Weight reduction is the most important key to increasing engine performance and response. This method also eliminates the ability to underdrive the a/c, which is a tremendous robber of horsepower.

THE SECOND METHOD, USED BY UNOTHODOX RACING, IS BY REDUCING THE DIAMETER OF THE MAIN DRIVE PULLEY OR CRANK PULLEY. By using this method we can achieve the best ratio of size reduction, underdriving, and most importantly we can maximize the reduction of weight on the crank pulley where most of the weight savings can be seen.

Weight loss is the most critical factor in making, or more accurately, releasing Horsepower! Each pound of weight taken off the engines rotating assembly is worth approximately 2.7HP and the figure increases dramatically with forced induction, nitrous, VTEC and increased RPM's. Only 15-20% of the gains seen from our pulleys comes from the underdriving. THE DIAMETER OF EACH OF OUR CRANK PULLEYS IS REDUCED UP TO 20%. We tailor the exact amount of underdrive to each vehicle based on factory specified accessory performance."