GFB 3-Piece lightweight aluminum pulley kit

[ripcityFR-S]

Exactly what ive been waiting for. Thank you!

[VSGTS14]

a carbon fiber driveshaft will yield you better results than lightweight pulleys.
the pistons are turning the crankshaft, which turns the transmission, which turns the driveshaft, which is connected to your diff, which turns your wheels.

no where in there are "pulleys". yes, they are lightweight, but those few lbs will not make a difference. would i run them? yea sure, the more lightweight parts the better. it has caused the knock sensor to freak out on certain year wrx/sti's, that's a turbo charged motor though. i don't forsee these doing any damage to our motors. lightweight pulleys have been out since the year 2000. in those 13 years, nothing has ever happened to any car running them.

[so26]

Originally Posted by VSGTS14

a carbon fiber driveshaft will yield you better results than lightweight pulleys....

Depends on what you are defining as "results" for me the Perrin LWP definitely improved my shifts (see my recent post). You could not get this "result" from a light weight driveshaft. That said I know you were talking about making the car ultimately quicker in which case the CF driveshaft would probably produce better results .

[VSGTS14]

Originally Posted by so26

Depends on what you are defining as "results" for me the Perrin LWP definitely improved my shifts (see my recent post). You could not get this "result" from a light weight driveshaft. That said I know you were talking about making the car ultimately quicker in which case the CF driveshaft would probably produce better results .

correct. the dyno may not show a result, it's ultimately weight that is the challenge. lighten everything the motor is trying to turn, in essence, the pulleys too. they just don't have an ultimate effect on the car as the other parts mentioned do (the cf shaft, lighter flywheel, lighter wheels, lighter brake rotors). these are what the motor is really trying to turn. the pulleys just hitch the ride along. it's an ongoing argument. they don't harm anything though. and it's not a bad mod to do. there are tons of sti owners who have them.

[LeeMaster]

Start a groupbuy please. I was waiting for the unorthodox racings 3 piece kit but I am willing to buy these now. Let us know, please start a groupbuy

[Dr. BRZ]

dyno numbers....

[so26]

Originally Posted by Dr. BRZ

dyno numbers....

Unless its the butt dyno it won't really show up... it should show up in lap times though.

[boredom.is.me]

Originally Posted by Dr. BRZ

dyno numbers....

reduction in rotational mass isn't horsepower gain...

However, there is a way, but I doubt it would really be that noticeable. It would be a ~2k to max pull. The time measured from point to point is the only physical measurement you can make. This would also have to be a no load test too which is pretty much impossible without removing the engine.

[nonicname]

Originally Posted by so26

Unless its the butt dyno it won't really show up... it should show up in lap times though.

it should show up, not a power increase but power should come in earlier along the rpm range.

[benster]

there won't be a power increase, but the reduction in drag and inertia will enable more of the horsepower the engine makes to get to the wheels instead of turning the pulleys. whoever says using lightweight pulleys is worthless obviously never used any. I was skeptical when I bought mine and I felt the difference. like the OP said, you feel it mostly during 2nd and 3rd gear but it is there and the revs do go up and down quite a bit faster.

IMO, it's not something you'll be saying wow, there's a huge difference but you'll surely appreciate the gains, I know I do.

[Celica00]

trying to decide if it's worth it to get the water pump and the other one as i already have a aftermarket crankshaft pulley.

[breezy]

Originally Posted by Touge Factory

Here is what Go Fast Bits wrote:

A better name for a harmonic balancer would be "torsional dampener" since its main task is to absorb the rotational pulses inflicted on the crankshaft by the pistons. Most often it is incorporated into the crank pulley by attaching the outer belt drive ring to the inner by means of vulcanized rubber. At the right RPM, it is possible for a resonant frequency to be set up torsionally on the crankshaft. Resonant frequency occurs when the pulses of the engine correspond with the natural frequency of the crankshaft and it ancillary components. However, since factory pulleys are often comparatively heavy (reasons for this are described later) it is actually the large mass (and therefore inertia) of the factory harmonic balancer and flywheel that will help to excite this natural frequency. So by dramatically reducing the weight and inertia of the crank pulley, the natural frequency of the crankshaft is shifted and its ability to self-excite is greatly reduced. ....

Was any work done to find where the natural frequency shifted to? Shifting the natural frequency doesn't allow you to run an engine trouble-free without a harmonic damper. It means you need to to provide damping at a different frequency. Simply, if its still within the operating range of the engine, you still need a damper.

I don't mean to doubt the product, just looking for healthy discussion. I would like to know how you have determined/validated a way to run the engine without a damper with no adverse effects on durability.

[benster]

lots of people have ran lightweight pulleys for over a decade on stock or modified engines that had a stock dampened crank pulley with no ill effects.

I was also skeptical about running one on my car for the same reasons, had it on for 4 years as a daily and have not noticed any difference on the engine, or had the crank pulley bolt loosen due to vibrations.

[breezy]

Originally Posted by benster

lots of people have ran lightweight pulleys for over a decade on stock or modified engines that had a stock dampened crank pulley with no ill effects.

I was also skeptical about running one on my car for the same reasons, had it on for 4 years as a daily and have not noticed any difference on the engine, or had the crank pulley bolt loosen due to vibrations.

Yes, there have been people running lightweight pulleys without ill effects. But I've seen a few instances where crankshafts were snapped in half where a damper was not used, and that's enough for me.

I won't refute real-world results of lightweight pulleys. There's no denying that some have been able to run them without catastrophic failures. But there's also no denying that torsional vibrations exist in the crankshaft. You either give the vibrations a place to go (rubber damper) or you don't. I respect how people decide to modify their own cars, so this is just my 2 cents.