FAQ

Are Velo Staks difficult to install?

No. They simply bolt onto the intake face of the carburettor or throttle body. All gaskets and stainless steel mounting hardware are included. No adjustment or special fitting is required. Typically a 4 Stak installation will take well less than an hour.

Why do they have dimples?

Velo Staks have dimples because a dimpled surface creates a thin turbulent layer of air that allows the air above it to flow more smoothly, thereby reducing drag by about 50%. Golf balls have been using this design for decades—and with good reason!

Are Velo Staks adjustable for length?

When you purchase Velo Staks, we include a cutting jig that easily fits over the Stak column to guide the hacksaw blade. The material is robust yet quite easy to cut. The jig is very easy to use and a diagram is included on the Technical page for reference.

Why would I want shorter Velo Staks?

There are two reasons why you may want to cut the Staks. The first is that you may need to shorten them to fit into your engine compartment. Not all cars have commodious engine bays!      The second reason is that longer Staks provide more torque at higher RPMs. This is important for a race car but if you want to put Velo Staks on a car for street use, you may want to shorten the Staks to lower the torque output to a more useable RPM range. If you have access to a ‘rolling road’ dyno, the Staks can be tuned to your requirements quite easily. However, as most of us don’t have this option, we recommend that you begin by leaving the Staks as long as possible and to use the car. If you find that the acceleration (torque) improvement is at an RPM range that is above what you typically use, then you can shorten the Staks a bit at a time (say 12mm or 1/2”) until you begin to feel the difference. This may take some time but the performance improvement will be worth the effort. Don’t forget that all stacks should be the same length.

What is the Velo Stak tuning kit?

The tuning kit consists of a standard Velo Stak package (1, 2 or 4 Staks) plus an extra set of barrels. Intended for professional builders with access to a dynamometer, the standard stacks are progressively shortened until the maximum performance (based on pre-determined requirements) is reached. Once that data is determined, the extra set of barrels can then be cut to length and installed in the Velo Stak mounts.

What kind of power increase can I expect?

The application of Velo Staks to your engine will typically yield at least a 2-3 % increase in power. Depending on your engine’s state of tune, cams, porting, valves, jet sizes and a multitude of other factors, the gain may be greater.

Are Velo Staks available in colours?

Velo Staks are available in red, yellow, blue, green orange violet, black and grey.

I don’t see Velo Staks to fit my car. Will you be offering more choices?

We are constantly working on designs and tooling for other makes and sizes of carburettors as well as for fuel injected engines. If you have a specific request, please send us a note and we’ll do our best to supply your needs.

What is the anti-reverberation device?

The anti-reverberation device is a small fixture designed to partially combat the return shock wave that happens in the intake tract when in-rushing air strikes the closed intake valve and is forced back through the intake tract. Normally this (understandably) causes a great deal of turbulence which upsets the intake flow. On an engine operating at 6000 RPM, this event happens 100 times every second! Modern, electronically controlled engines have ‘variable valve’ timing to help with this problem but it is impossible with traditional engine designs to affect this effect, until now. The Velo Stak anti-reverberation device acts as a partial barrier to the returning shock wave, lessening its disruptive effects and thereby increasing air flow into the cylinder. No other manufacturer of velocity stacks includes this device.

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