Is the short/ long stack combination a way of equalizing the intake tracks to make all four port runners the same lenght ? I know some cam manufactures design camshaft profiles to equalize power on engines that have different total intake track lenghts on automotive engines.
sort of a tough question to answer.. it is more of a "yes" "no" answer.. sometimes equal length ports are wanted and other times not..
They do use them to tune runner lengths but there is A LOT of reliance on the parts put into the motor as well. Anything (and I mean anything) that affects air flow (exhaust, intake, cams, port work, cam timing, throttle bodies, air density, humidity) will make a difference when it comes to V-stacks.
It takes gobs of dyno and track time to figure out the best combination on any given setup for a given riding style. As most guys are just buying to make bigger dyno numbers, it gets a little easier..
If you are building a motor that needs to run through a wide band of rpms (say a cosworth on a road course) you could end up with different stacks on each cylinder.. If you are building a strictly drag race motor, it gets a little more simple.
We found that dumping the big 8 hole Enderle injectors in favor of a big tunnel ram with a bug catcher produced around 20hp less on the top end and cut almost 2 tenths off the ET on my hydro in the 1/4 (less power, faster boat)
If you are going to spend the money on them, do your homework (or better find a tuner that has already tried 10 sets and knows what works best) Max hp is not always the best option, sometimes giving up power at top end is better used in the mid range..
Most of this is why I figure it is not worth the expense on most street bikes and the stockers are just fine.. I would buy them for show before I would by them for go on my bike..
