Circuit Werks lightweight pulley kit?

[Ralph Spoilsport]

Originally Posted by Boofneenee

why didnt the manufacturer of this car just use lighter pulley's to begin with? Everything can be modded but I am curious. Could their possibly be any adverse effects on long term engine stability with these or other brands? Is this safe all around?

There are those that claim that the heavy steel / rubber OEM crank pulley is in fact a torsional vibration damper, the removal of which will lead to shortened life and/or increased risk of failure of a) the crank, b) the timing chains, c) the oil pump and gawd knows what else. There are others who claim to have asked Subaru and gotten the response that "It's only a pulley". In which case one wonders why they put such a heavy piece of crap on a sporty car. Having worked for big manufacturing companies in the past (and a smaller one now) I think the sound engineering reason (i.e. we need it) is probably no more likely than the inertial one (i.e. we've always done that and it doesn't break (much)).

I thought about buying lightweight pulleys (I'd like less flywheel effect during shifts)... but on doing a little math I think I'd be disappointed in the difference these would make. I'll put the cash in the piggy bank for now and maybe put it towards a lightweight flywheel later (which will make a much bigger difference and doesn't come with the downside risk of some internet maven looking under my hood and screaming "Oh Noes! Lightweight Crank Pulley, your crank is half broken!! ".

There's a ton of opinion on the subject, very little actual info.

[350matt]

is this kit undersized pulleys or standard ?

as just lighter/ same size pulleys shouldn't make any difference to steady state horsepower?

unless the dyno pull was done with a transient brake?

[Kodename47]

They are same size

[vgi]

Standard size. I wouldn't pay much attention to the dyno, I got it for throttle response

[350matt]

so who does the best undersized ancillary pullies?

I was thinking about 10% smaller on water pump and the alternator

[Kodename47]

Smaller overdrives the alternator and water pump. You oversize to reduce the drag. Which is therefore better, normal size (lighter) or larger (less drag) who knows?? I'd suggest that both are pretty much close enough, I'd just rather not under drive essential parts.

[350matt]

Whoops thats what I meant

10% slower running is what I was after

the reason for asking is that most water pumps are over capacity and alternators too so while you're there making new pullies, then it makes sense to me to slow these down a little

circuit werks seem to be std size so who does a lightweight overszed pulley?

[JarradLS]

These guys:

http://www.fensport.co.uk/Parts/Mode...ategory_1/4246

[JarradLS]

But after much deliberation, I went Circuit Werks from Mark @ Pride Exhaust.....

........couldn't be happier.

[NYCsubaruBRZ]

Originally Posted by vgi

received my pulleys. it's not state of the art, if to be very anal, there are minor blemishes and light scratches on anodized surface (must have been packaging and shipping), the edges of the holes are not smooth but finished. overall however these are decent well done pulleys.


now the communication and support though from seller is awesome. the guy is always responsive although I have bugged him a lot with bunch of questions. he even offered money back if I'm not happy with the pulleys.

hopefully will install these this saturday

Edit: re-read my post and noticed that i am being VERY picky considering how soft aluminum is.

i got the same exact pulleys but they are made by a company called Ralco

[NYCsubaruBRZ]

Originally Posted by Boofneenee

why didnt the manufacturer of this car just use lighter pulley's to begin with? Everything can be modded but I am curious. Could their possibly be any adverse effects on long term engine stability with these or other brands? Is this safe all around?

thanks

they always try to leave some meat on the bone. they want a reliable car.

[NYCsubaruBRZ]

Originally Posted by vgi

i believe it's all chinese made but branded but different us vendors

still, i'm happy with my purchase decision

thats probably the case. but yea. good stuff

[tennisfreak]

I am happy with mine. Been running them for about 4,000 miles now. Absolutely no wobble.

With the price of the Circuit Werks so cheap I cant see why you would go with another set. Name brand does not mean much to me if it is going to cost double and get me nothing. They are all aluminum pulleys.

[dj petey]

Originally Posted by Boofneenee

why didnt the manufacturer of this car just use lighter pulley's to begin with? Everything can be modded but I am curious. Could their possibly be any adverse effects on long term engine stability with these or other brands? Is this safe all around?

thanks

The quick answer is easier shifting and lower cost.

Here's the long answer if you're curious.

Any weight removed off the drivetrain assembly (crank pulleys, flywheels, drive shafts, wheels, etc) reduces rotating mass and thus improves throttle response, acceleration, and drivetrain efficiency which is why there are slight increases in HP.

The side effect is that rev matching must be more precise because the throttle response is so quick and may be a challenge for some drivers to shift smoothly. More mass makes shifting easier but also creates throttle lag. Manufacturers always try to find a balance between performance and driving comfort for the average consumer. They also have a target production cost. Lightweight components cost more and they have to pick and choose what components are made of aluminum let alone forged billet aluminum. The cost of CNC machining is also a factor. They made the right move on the aluminum hood as this has more impact on the power to weight ratio without any adverse affects to comfort.

Lightweight flywheels and pulleys are a personal choice depending on whether you want smoother and easier shifts or better throttle response. They left these kinds of choices up to the end consumer.

I've had a lightweight flywheel on a previous car and it was one of the best bang for your buck upgrades i ever made. You can feel it most in first and second gear but I had to be more precise with my throttle and clutch technique to keep shifts smooth.