STILLEN lightweight crank pulley
 

I saw STILLEN added one of these to there website. What is the consensus on the value of these for non-supercharged applications?

+1 I want to know because I might get a set.

Actually these have nothing to do with supercharged or non-supercharged applications.

Lightweight pulleys work the same way as a lightweight flywheel or lighter wheels and tires, lighter brakes...Any time you can free up some rotating mass you are freeing up horsepower. By reducing the weight of the pulleys you are reducing the energy or horsepower required to spin them. It makes your engine much more efficient.

If you plan on getting a supercharger sometime down the line we do not recommend getting an underdrive pulley. An underdrive pulley will underdrive everything that is powered by your engine...Basically meaning your supercharger will be underdriven. Lightweight pullies are great for superchargers, but we don't recommend installing underdrive pullies for supercharged vehicles.

Turbo vehicle's will benefit from either light weight or underdrive pullies.

^ thank you

Kyle, you guys have any numbers on how much gain these yield?

Kyle, that reminds me about the all-plastic engines they've been working on... Crank, pullies, connecting rods, and flex plate are all supposed to be made out of some super-strong lightweight plastic... I imagine some sort of aluminum/carbon alloy, but I can't really see that as cost effective. Heard anything about this?

eh, I knew all that. I was more interested in how it affects the SRM system. I figure if this doesn't mess with it, nor will the flywheels...

We don't like to say that lightweight pullies "make" horsepower because they really don't. They do FIND lost horsepower though. Typically we've seen gains of around 10-12 HP on an underdrive pulley and a little less on a lightweight pulley.

This is news to me but what you're describing doesn't surprise me. With the new technologies they're constantly developing and the new materials being produced every day I truly believe that anything is possible.

Like you pointed out, I have a hard time imagining that it could be produce in a cost effective way but could you imagine how much higher you could rev an engine with lighter internals. It'd be pretty awesome to learn more about this stuff. Sounds too exotic to be in most production cars for awhile though.

I have to be honest. I am HORRIBLE at figuring out acronym's. What does SRM mean?

do you sell lightweight pulleys also ( those the same size just lighter - so you can use the same belt ) ?

Josh just gave me a little edumacation and informed me that SRM stands for "synchro-rev match." With that in mind. The lightweight pullies won't affect that system at all. The Synchro Rev Match system will basically have a set RPM point that it takes the engine to upon downshift. That won't change it'll just allow the engine to achieve that RPM point faster.

Yes we do.

STILLEN : STILLEN Performance Lightweight Pulleys

Part # 400338

Fifth one down. It doesn't show 370Z yet but that's because we JUST did the test fit the other day and haven't updated the site yet.

Very good, sorry if I keep beating a dead horse. We arrived at the same conclusion in another thread, however you can't be sure until someone comes over and says it is one way or another 100%. Some argued that the SRM system took the mass of the factory driveline into account. That makes very little sense to us from a practical standpoint, however it's better to be safe than sorry. (This was more about light weight flywheels than pulleys, but they have similar effects, so I was seeing if you could shed more light on the subject) Anyhow, thanks again Kyle!

Now the question becomes...will a lighter flywheel AND a lightweight pulley be too much lightening for a daily driver?

^^sorry for my ignorance, but why would a lighter flywheel and/or underdrive pulley make it a worse daily driver?...or any different different driver for that matter. any past experiences would help... thanks

Its all good ssqpolo - The reason that it may become a problem is because of the clutch engagement. The mass of the stock flywheel allows you to engage the clutch at low RPM's and without much jerkiness. The inertia of the spinning mass (flywheel) counteracts the clutch as it tries to clamp down, therefore allowing for smoother, gradual engagement. If you get rid of that mass, then the flywheel will slow down to match shaft speed much faster (jerkier) and you may sometimes stall if you aren't being careful or giving it enough revs. This is a common issue with the Carrera GT, the drivetrain / flywheel is so light that engaging first gear can be a tricky endeavor. Often people don't give it enough revs...or too many.

By lightening the flywheel AND the pulley, you are making it even worst. Some people would advice that you do one or the other. Usually it is better to go with the flywheel because there's more performance to be gained there...However, on some cars, it is OK to do both...Hence my question :)

tks man. good to know.