Description Velocity stacks to suit 20V 4age Silvertop throttles – Set of 4 Individually machined from a solid round bar these velocity stacks have been carefully designed and tested resulting in a product that not only works excellent but also has the looks to match. Unlike other cheap alternative offerings there aren’t any low quality compromises to save costs such as mismatched “20V universal” types, thin flanges, using slots for the mounting or using something such as an unreliable join to a separate flange. Lengths available Normally we offer these different velocity stack lengths: – 50mm – 100mm – 100mm Bead blasted (Discontinued): Available only as a limited batch these velocity stacks have been bead blasted giving them a very fine satin textured finish. Note: These may have subtle blemishes in the finish. An example of these can be seen in the product picture. Design features and advantages – Machined out of a single solid billet aluminium bar – Full radius bell-mouth – Long internal taper down before merging straight just before the flange – Internal diameter ideal size for throttle opening: no nasty steps. – Positively located: no adjustment available or needed: no crude slots! – Different Blacktop and Silvertop versions, the shape and taper was optimised for each – Parabolic / Exponential curve inlet transition – Designed and machined in Australia – No nonsense semi-polished finish Development When the new billet velocity stacks where being designed, they where made from the beginning to be the best there is. These shown here are the result of research, prototype works, testing and then finally CNC machining of the final product. The result of this development was used to update the 100mm rolled type. The shape of the bellmouth, inlet transition and taper where all optimised to allow for the highest net airspeed possible. During development multiple prototypes where made and put on the flow bench, even the rough test version was able to outflow HRC, IMEC and by a massive 55% the original rubber OEM stacks. Parts compatibility These velocity stacks have not been compromised in their design to make them a universal design for the different throttle types. So therefore these will only fit up and match internally with those from 20V Silvertop throttle bodies. A way to double check the type of throttles that are fitted to the engine can be done by measuring between the M8 mounting holes on the top throttle body face where the velocity stacks are normally mounted. There are as follows: – Silvertop 20V (Gen1 2): 73mm center to center – Blacktop 20V: 83mm center to center
