![]() Much like small waves lapping up against the edge of a pool and then heading back toward their origin, these resonance pulses will rebound and travel back and forth along the intake tract. A well designed velocity stack with full taper will accomplish its primary and secondary purposes with little left over for you to worry about and so we will focus the remainder of this document on the resonance effect (also called pulse tuning or ram induction). This resonance creates pulses or waves of higher pressures within the intake and the object is to time one of these pulses to hit the intake valve just before it closes. This allows you to create an intake length that will resonate at a certain frequency (RPM). Finally, the tertiatary purpose of a velocity stack is to change the length of your intakes. What this means is that if the intake charge is moving too slowing, it won't have enough interia to overcome the increasing pressure in the cylinder caused by the rising compressing piston and the fuel/air mixture will be forced back out of the intake, costing us power due to poorer cylinder filling. This is a good thing because the intake valve is still open when the piston begins its compression stroke (this is especially true for high duration cams). The secondary reason to use a velocity stack is to increase the (you guessed it) velocity of the intake charge. More air and more fuel means more power!Īdditionally, in reference to our CV carbs, smooth air means we can tune them more reliably and not be forced to a switch to VMs. Because the air molecules are all heading in the same direction and not fighting among themselves, you can make more air and more fuel into your cylinders. First and foremost, it smooths air flow entering into the intake. A velocity stack serves a number of purposes. For those whose minds are set on a solution that will provide better airflow while still allowing the use of their stock CV carbs (as opposed to a switch to Mikuni VMs or the like) a velocity stack offers itself as a good option. The solutions to this problem are numerous and include construction of air boxes to provide "still" air, introduction of air correction systems within the intake itself, and even sticking with the stock air box and making no intake changes whatsoever. Turbulance, mostly, is due to pod filters and other "high flowing" intake systems. I wrote this document a while ago and I've learned a bit since then, but this is the basic gist:Īs many of you may already know, CV carbs don't respond well to changes in the intake system that introduce turbulance. The secondary consideration with stacks is that they usually come in different available lengths and this allows you to "tune" your intake in order to operate best at certain RPM ranges. All things considered, velocity stacks will offer slightly more horsepower than other intake options. Air that is smooth and all traveling in the same direction is more dense than air that is flowing every which way (such as it is after passing through filters and such). Not only does this provide a stronger signal to the carbs, it also allows the air to form a uniform pattern while traveling through the intake tract. Obviously running without any intake will remove all the restriction and so the stacks do something very special and it all has to do with the way they're shaped.īecause of the bellmouth design, stacks smooth the air as is passes through the intake. That's not all there is to the story, though. ![]() ![]() Without filters of any sort, there are less restrictions on getting air through the engine and anyone serious about building for power knows that air is what you're after. Stacks offer several advantages over other intake types.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |