If you've ever built engines you would understand. The rotating assembly (on a proper build) is balanced. The OEM assembly is balanced with the stock harmonic balancer and therefore I cannot justify possibly wrecking my engine by throwing off the balance for ~10whp at the most. Cooler weather can do that for you without harm.

 

Yes, a properly built engine is balanced, and even then the stock pulley provides dampening that is lacking with MOST aftermarket UDPs. There are manufacturers that make UDPs with dampeners, but I don't know if anyone makes one for the G35. For the Z, Fisher makes one, but they're pretty expensive.

I've never used one, but I know plenty of people that do. I feel the same as you - I don't want to take that risk for a mere 10 HP.

 

So what's your take on lightened flywheels? Their mass and diamter make a much bigger influence on the harmonics than a small pulley would.

 

aren't lightened flywheels the same diameter as oem otherwise you would have a starting problem since the starter will not mesh properly if they are not.

 

It's not the dia change. It's the fact that people use light flywheels with no apparent concerns. Also the flywheel dia is alot larger than a pulley so any slight harmonic changes are bigger in a flywheel. On top of it all, light flywheels typically represent 8-15 lbs of mas reduction vs just 3-5 with a pulley. If there's any upset in balancing, I'd think it would be on the flywheel side and not the pulley side.

 

Damn that watermark on the photos is really annoying!! Next time make it lighter.
Anyways, glad to hear you feel a difference! I'm surprised there arent more people with this mod! I must now do research!

 

we need dyno numbers,to see if its worth the time and the effort

 

+1 on the watermark, that crap is super annoying!

 

I did the install today and there is a significant difference between the stock/UD pulley; this thread helped out a lot; 12mm sockets are needed for the long tensioner bolts, 14mm sockets for the pullies and the shorter belts are a must; when I bought the pulley I was told the stock belts would work and they don't.

I broke a 3/8 ratchet and a 1/2 adapter trying to get the crank bolt out...I used a 1/2 breaker bar, cheater bar and the bumping over of the engine to get the crank bolt loose.
I had to bump the engine 2-3 times.

I will see how it feels after driving it the upcoming week.

 

Took mine off a few weeks ago. The lease is running to an end and I'm getting ready to turn the G back in to the dealer. Anybody want my pulley and belts?

I've got a few other things that I'll be posting in the wanted section.

 

What brand is yours and how did it look?

 

Pulley: WRP.
Belts: Dyaco

I installed it last April. This is my installation thread so you can see the pix from the start of this thread.

 

Gotcha..mine was made by OBX..hopefully it holds up!

 

still available?

 

Did you order your wps pulley online? Have a website?