engifineer

lightweight pulleys will never slow down throttle response. Now, I would never put a set on my car due to the potential issues it can create for your engine, but that is all I will say about that part, since a big argument will ensue.

More rotational mass means the flywheel (any spinning disc, so the pulleys as well in this case) resists changes in momentum more (this also means they shed speed slower, which is why you gain no "power" when you reduce rotational mass.. they store energy, not dissipate it). So less rotational mass means you can rev faster and that the engine will shed speed faster. If you want a real change and no risk of issue, go with a lightweight flywheel. You still have the same amount of tq and power, but the engine will rev and rev match quicker. You will have to launch at a higher rpm though, since you are reducing rotational inertia.

jiggadomino

yea i dont think lightweight pulleys are for my tc, and all i am trying to do is better throttle response.

so there is nothing else you can really do but just the lightweight flywheel.

engifineer

The rate at which the engine revs up is restricted by rotational mass. This is great for making a car easier to launch for new manual drivers and to make it smoother running, but not so great for throttle response. So that really is your best bet at a noticeable change in this area.

Thndr13

Not to threadjack or anything, but I've been reading up on headers and the 4-2-1 design. From what I gathered, it basically uses the exhaust pulse of one cylinder to help the next on it's intake stoke, right? So wouldn't that help with the entire powerband if done correctly or would it just help out the low end?

engifineer

That is the purpose behind all header design, to align the pulses to provide power when you need it. You can liken it to an antenna. The signal reception of an antenna is directly related to its length, so shorter antennas for shorter wavelenths and vice versa. Your radio antenna cant possibly be perfect at all frequencies, so it is optimized in the middle of the fm band so you get the best possible overall design.

A header is the same way. Obviously the exhaust pulses will line up differently at different rpms because the frequency changes with rpm. A header is designed to best use the pulses to aid in scavenging. Since its lengths cant change with rpm, a designer will build one that works in the range most often used for the car. A different header can move that power around for you.

Thndr13

That puts it all in perspective. Thanks!

Zebman

I was surprised when I got my Weapon R intake on. I actually did notice a difference! The low-end torque is not quite there anymore, but 3000+ pulls so f*cking hard!