Tags Posts tagged with "370z pulley"

370z pulley

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Pulleys – physics happen and you go faster.

For decades, racers and tuners have always sought ways to extract as much power from an engine as possible. Most of the time adding power is a matter of getting more air and fuel into the engine, but what if there was power there that you could “free up”. Well, there is – and you can reclaim that power with a set of STILLEN Performance Pulleys. If you’ve read our piece on lightweight flywheels, this analogy might sound familiar, because the same physics are at work here.

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Imagine you’re trying to run, but you’re wearing heavy work boots. You probably can’t run very fast, and it takes effort to start moving or slow down. Your stock crank pulley is kind of like that. It is a heavy pulley designed to drive the accessories, and it’s often weighted for the same reason as your flywheel – it makes operation slightly smoother, but just as often, the pulleys are heavier than they have to be simply because it’s much cheaper to use a heavier material.

Since the OEM pulleys are heavier than they have to be, lightweight pulleys offer an easy way to free up horsepower that’s otherwise lost. A lightweight pulley accomplishes this simply by reducing rotational mass – or in leymans terms, because it weighs less, it takes less horsepower to spin the pulley, so more horsepower gets to the wheels.

 

STILLEN 370Z Pulley 400370-01 AFTER DYNO OVERLAY

Consider that stock crank pulleys typically weight 4-10 lbs… this varies depending on manufacturer and engine size. As we mentioned earlier, most manufacturers typically make their pulleys in cast iron, which while it is cheap and strong, it’s also heavy, which is why there is some benefit to be had in a lighter weight set of pulleys.

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Manufactured completely in house at STILLEN HQ in Costa Mesa, STILLEN Lightweight pulleys are machined from Aerospace grade 6061 billet aluminum and have been engineered to remove all unnecessary mass while still creating a stronger, lighter part than the OEM unit they replace.

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For Example:

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G37 Stock Crank Pulley = 4.75 lbs

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STILLEN Crank Pulley = 1.30 lbs

That weight savings of around 3.5 lbs makes a noticeable difference on the motor. Some might say 3.5 lbs isn’t much, but you have to remember that since it is spinning, the physics acting on it make it behave as if it’s many times heavier when it’s in motion.

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Stock Crank Pulley – Heavy, Cast Iron Construction

The engine has to spin that extra weight over 1000 times per minute (RPM) at idle alone, which explains why, after upgrading from an OEM pulley to a lightweight pulley, we typically see gains of 5-8 whp. Mind you, these aren’t nonsense numbers like that can be accounted for by dyno variance – there’s no snake oil here, there’s less drag on the engine, thus, more horsepower gets to the wheels.

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STILLEN Underdrive pulleys have all the same benefits of a lightweight pulley and further decrease the workload of your engine. By decreasing the diameter of the crank pulley by a small percentage, we are able to slow the accessories (power steering pumps, alternator, and/or AC compressor), reducing the load on the engine even further. Underdrive pulleys still operate the accessories within their required operating parameters, but use 10-20% less engine power to turn compared to the stock diameter pulley. 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.

As a result of the reduced load on the engine, a set of lightweight pulleys has the additional benefit of being more efficient as well, meaning that you might even see an increase in MPG (if you keep your foot out of it.)

In closing, the TL:DR is that if you are looking for an upgrade that increases power and efficiency (better gas mileage), pulleys might be a great option for you.

If you have any additional questions please feel free to give a call (866-250-5542) or shoot us an email (sales@stillen.com).

For decades, racers and tuners have always sought ways to extract as much power from an engine as possible. Most of the time adding power is a matter of getting more air and fuel into the engine, but what if Here at STILLEN, we’ve been developing high performance products for a variety of makes and models since the early 80’s.

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After a few years of frustrations with outside vendors and outside machine shops, STILLEN invested in an in-house CNC machine shop to “do it ourselves”, and we’ve never looked back.

 

 

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With in-house CNC lathes and CNC mills, STILLEN is able to control every aspect of their products. From the material selections and quality, to the machining accuracy and consistency all the way down to the plating and finishing processes STILLEN controls each detail so we can be 100% confident in the quality of our product from start to finish.

For many years STILLEN carried other manufacturers pulleys and were able to learn what to do and most importantly, what not to do.

The line of STILLEN lightweight pulleys and complete pulley sets is the combination of decades of that experience combined with STILLEN’s expertise in CNC machining.

 

 

What Is A Lightweight Pulley or Underdrive Pulley?

The simplest answer to this is that they are exactly what their name implies. From the factory your vehicle comes with a cast-iron pulley or steel crank pulley. There is nothing wrong with this other than the fact that it is not optimized for vehicle performance. Anything that spins takes power to spin it. This means that a heavy cast iron or steel pulley is going to take more power to spin than a lighter weight pulley constructed out of billet aluminum and machined to reduce as much rotating mass as possible.

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Underdrive pulleys are designed to slow down the rotation of the surrounding accessory pulleys such as alternator, air conditioning etc. By slowing down the rotation of these pulleys it further reduces the amount of work the engine is having to perform. The less accessory work you make the engine do the more power can be transferred to the rest of the drivetrain, thus ultimately reaching the tires. We like to say that lightweight or underdrive pulleys do not actually “make” horsepower. They recover power that was lost due to the excess power the engine had to put out simply to rotate those pulleys.

Why Are They Important?

Lightweight and/or underdrive pulleys are a great way to make your engine run more efficiently and with less resistance. Whether developing a performance vehicle for the street or for the track one of the most important things to keep in mind is efficiency. How can you make the vehicle run as efficiently as possible? One of the best ways to improve the performance of a vehicle is to reduce the weight of any rotating mass. Whether you’re reducing the weight of wheels and tires, rotors, flywheels, or crank pulleys you are effectively transferring more of that regained power to the tires and therefore to the road.

Aside from the increase in rear wheel horsepower we’ve had, customers tell us they’ve noticed that the engine revs quicker, feels like it’s been freed up and is less restrained. Some customers also report an increase in fuel economy as the engine is running more efficiently and does not have as much weight to spin.

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How Are STILLEN Pulleys Different?

As we mentioned earlier, before embarking on the STILLEN line of high performance pulleys the engineers at STILLEN sat down and discussed all of the things we’ve learned from our decades of experience and what we wanted our pulleys to be.

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We have seen where other manufacturers pulleys were improperly machined and/or improperly balanced or the factory timing marks were not machined correctly in relation to the crankshaft keyway. All of these things and more are huge factors in the performance of a crank pulley and need to be taken into consideration when developing the crank pulleys and associated accessory pulleys.

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To start with all STILLEN pulleys are designed in our 3D CAD software. Once the initial design is completed the parts are rendered in our FEA (finite element analysis) software. This software will simulate loading the parts with forces higher than what they will see in real world situations. By doing this we are able to see the weak points of the design and at what forces the part will fail. Once we know that our design exceeds the real world forces this part will see it will be approved for production.

Some pulleys, primarily crank pulleys, also need to be finished with precise timing marks that need to be correctly machined in relation to the crank keyway. It is extremely important to do this process accurately as this will make the car run improperly if these timing marks are not accurately machined.

Finally, the crank pulleys are finished with a 304 stainless steel sleeve used for main seal contact points just like the factory pulleys.

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To speak with an expert and find out more about our full line of STILLEN lightweight aluminum pulleys, give us a call at (866) 250-5542. You can also visit STILLEN and check out the entire range of performance pulleys we offer.

Up to 80% lighter weight than stock steel and up to 10% lighter than other aftermarket pulleys, we’ve seen power gains of up to 10+ HP at the wheels.

Both underdrive and stock diameter applications available for most popular Nissan / Infiniti vehicles. – See more at: http://www.stillen.com/product/pulleys/stillen-standard-performance-lightweight-crank-pulley-400340-8117.html#sthash.4xvNEuhb.dpuf