stock pulleys are a certain weight from the factory... for example.. underdrive pullies sometimes are in the 5-6 pound range.. they are also a certain radius, say 4 inches radius.. with these new pulleys. not only do they free up energy wasted to turn a heavy and larger pulley, they spin faster (weighing in at ~2 pounds, and only 2 inches in radius..), thus revving the engine faster, and getting a bettter throttle response...

Evil350z brought up a good point with the harmonics... the car was built with the stock pullies in mind and these new pullies sometimes are made with bad weight distribution so when they spin it wears the engine down by vibration... but UR are REALLY REALLY good quality pullies.. i've had them on my car before and i think they're a good product...

the only compromise is some people notice that the power draw from the alternator is slightly less and the A/C is sometimes affected because those pullies are the ones often changed.... i only noticed a minute difference with my A/C on the maxima.. but i've heard stories of people with big audio systems having problems..

 

Yeah, i don't think that you need new belts. The UR Underdrive pulleys only have a larger crank pulley to underdriver EVERYTHING. THe other pulleys are just lighter and "prettier". YOu might just have a really tight belt on the car then...

 

Then again, if you have that big a stereo, maybe pulleys, or any other go fast stuff may not be for you.

 

Yeah, I was going to do the entire set myself, but I decided that I didn't need the other pullies at this time.

 

I'll be sure to do a fair an honest review with pics.

The Balanced question came up before about a month ago and it sounded like it was going to be a non issue. I need to run some old forum searches about the harmonic balancer issue and do some reading on what was said in the past but if I was that worried back then I wouldn't have ordered them now, That's how I recall it anywayZ.

I trust UR, as Chesbo said they are top notch and have a reputation to uphold and they spent months on these babies before releasing them so I am hoping they did it right. They were even delayed 2 months.

I have 2 farads for my audio and our Alt is 110 amps so my biggest concern is the water pump not so much the juice.

That is why I mentioned the stat change.

I have hopes for a good mod, but I will be honest after install.

I was skeptical about the Eibach's and that turned out great so I can only hope at this point.

 

All I've read on the balance issue with a VQ engine has said the engine is internally balanced.

Here is one article about putting the UR pulley on an Altima.

 

From the great article just posted

That is how I recall the thread going too.

Thanks for the link, good enough for me!

 

So if I were to do it, I'd only need the one pulley rather than the whole set? Please explain the difference, thank you!

M.

 

I had the whole set. They look nice and are of the highest quality. I had a 6 speed MKIV Single Supra and did notice quicker revs. However, I also had a dual-electric fan kit and notcied the shudder/vibration mentioned earlier. Maybe the dual fan kit will be your next mod? Then cam gears and the list goes on?

I have not researched this kit for the 350Z but I assume a new belt will be needed. On the supra it was like 3 sizes smaller because the crank was that much smaller. On the supraforums there is still mixed thoughts on this subject. Everything from crank walk, harmonic balancing and even lack of charge for the battery. If I recall correctly it was not reccomended for automatics. I can't remember why but I am glad MAX that you are setting the path for others to follow. I also have an auto and would like to hear your review.

It will be nice to see an automatic hit 12's!

 

Smaller! Hence lower weight and slower RPMs on the belts.

 

The crank pully underdrive all the accesorys, but you still have the rotating mass of the stock pullys, lowering their weight free up some torque as well, rotaing inertia is weird, a lil wieght on a pully goes along way.

Ben

 

If the VQ is indeed internally balanced, this could be the shizzle....i have a UR underdrive crank pulley on my MR2, which btw now has 240K on it....it's quality stuff

Max......be VERY careful doing the install.....the pulleys are solid aluminum......if they get dropped, even a short distance, it could throw their balance off

Good luck, and keep us posted!

 

Whoops, I stand corrected....I wasn't really thinking when I did that!!! In order to underdrive the accessories, they would have to be larger....but the crank needs to be smaller....

 

Wanna help?

Did you use the stock bolt and belt?

 

why sure!!!!!!.......when you doing the install?

Stock bolt: yes.....Stock belt: no

Check the Unorthodox Racing Website for your pulley set, they will have all the belt sizes listed that you will need to acquire.....if it's still too new to be listed, then it will be in the instructions.....who knows, maybe they will throw some in......won't know til it arrives i guess

 

I'm sure the quality is there, but the fact that you are putting an unnecessary strain on the crank without a harmonic balancer for such little horsepower is not worth it.

.02

 

actually it's less strain, as long as the pullies don't have any density irregularities and have less mass than the original pullies it should actually be the opposite

 

Maybe from this one pulley, but there isn't just one pulley on the car combined with the other forces coming from the other side of the pulley why bother with it. Cheap hp yes. Wait for better mod's yes.

 

Did you miss the part where we said the VQ is internally balanced? It does not come from the factory with a harmonic balancer so you are not putting a pulley on the car and losing anything. Of course this is only what I have read on this site and not what I know for certain. However, I believe it.

 

My old Honda motor came balanced. I still had it blueprinted and balanced and still retained harmonic balancer. Not to say you aren't correct. I can't find a picture of the the pulley. I'll know soon enough.