The combination of a lighter weight pulley with reduced engine load generally yields results of 10-12 whp. Just as with a lightweight flywheel, a lightweight or lightweight underdriven set of STILLEN Performance Pulleys will make the car generally feel more lively and responsive and quicker to both gain or drop revs.
Is a lightweight crank pulley bad?
On a well maintained engine with bolt-ons or low amounts of boost like what most owners probably run, a lightweight aluminum crank pulley will not have any life threatening consequences. The engineering reasons are that most modern engines have a short (increasingly strong) crankshaft operating under 8,000 RPM.
What does a smaller crank pulley do?
An “underdrive” crank pulley is a pulley with a smaller diameter. The result is that it drives the accessories more slowly, and with greater mechanical leverage. It’s like pedaling a bicycle up a hill with the smallest sprocket engaged on the crank.
What does a lighter harmonic balancer do?
The function of the harmonic balancer is to reduce the amplitude of the torsional vibration peaks to an acceptable level. Most OEM harmonic dampers are not designed to cope with the rpm and BHP levels experienced in competition. That is why racers must consider a high-performance damper that is fit for purpose.
Do pulleys add horsepower?
Horsepower gains from underdrive pulleys can vary by vehicle, engine, number of accessories and the amount of underdrive (improvements of up to 5–15 HP at the wheels have been seen). Additional and significant performance improvements can be seen by reducing the weight of the pulley versus the original pulley.
What is the lightest SBC crankshaft?
Crower Ultra-Light crankshaft
The Crower Ultra-Light crankshaft is our lightest crankshaft. The Crower Ultra-light crankshaft’s rotating mass is reduces utilizing Pendulum undercutting, lightweight profiling, gun drilled mains, lightening holes in all rod journals and a profiled rear flange for the lightest rotating weight.
What does a aftermarket crank pulley do?
An aftermarket crank pulley can be used to increase the horsepower of a vehicle. These pulleys are designed to weigh considerably less than the pulleys that come standard out of the factory, largely because they do not have harmonic dampeners installed.
What does an under pulley do?
Underdrive pulleys increase engine output by reducing the draw of the engine’s accessories by slowing them down and reducing the horsepower (HP) they use. Additional and significant performance improvements can be seen by reducing the weight of the pulley versus the original pulley.
How big of a pulley do I need?
There are complicated formulas for determining pulley ratios but in generic, layman terms, simply divide the driven component (pump) by RPM, the driver component (motor or engine) rated by RPM to get the required ratio. In the example below, the pump RPM is 1070, for full output, while the motor is 1750 RPM.
Are smaller pulleys better?
A smaller crank pulley ensures that the accessories will spin slower, which results in less parasitic power loss than the stock-sized pulley can offer. On top of these benefits, underdrive pulleys can also increase fuel economy by 2 to 3 mpg since the engine is not working as hard to spin the accessory drive.
Can you run an engine without harmonic balancer?
And because the belts that go around the crankshaft pulley run all of the car’s accessories, without the harmonic balancer you’d have no air conditioning, no power steering, no alternator and no water pump. And without it, you can do damage to the crankshaft and the engine bearings.
