fangyooo
New Member
anyone tried the Graves Velocity Stack Kit?
does it work?
does it enhance the performance?
does it work?
does it enhance the performance?
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thanks scout,I have these. But I installed them last winter when I did a bunch of stuff, so can't report how much butt dyno improvement with just these alone. However, my bike runs excellent and Ivan pointed out that the multi sized stacks work better over all that those of the same length.
Graves is mostly a racing company.
I have these. But I installed them last winter when I did a bunch of stuff, so can't report how much butt dyno improvement with just these alone. However, my bike runs excellent and Ivan pointed out that the multi sized stacks work better over all that those of the same length.
Graves is mostly a racing company.
Really? Ivan's been telling me they're kind of a waste of money...:eyebrow:
I'm just surprised because I'm thinking of getting them myself, but if they really don't do much, then I won't...hmmmm...
I have these. But I installed them last winter when I did a bunch of stuff, so can't report how much butt dyno improvement with just these alone. However, my bike runs excellent and Ivan pointed out that the multi sized stacks work better over all that those of the same length.
Graves is mostly a racing company.
This reminds me of when I used to work on carburetors. Velocity stacks work, period.
The longer the intake tract, the more velocity achieved earlier, the more power at lower RPM. The shorter the intake tract, the more velocity achieved later, the more power at higher RPM. This is true when compared to a gun (or garden hose for you greenies), the longer the muzzle the higher the velocity the higher the exit speed.
Many manufacturers have used electronically controlled variable length intake tract for years. On race bikes the intake tract is lengthened with velocity stacks connected to a solenoid that moves them up or down depending on RPM. Yamaha could not do this on the FZ1 and still keep it within the cost guidelines.
An alternative would be to have a different length velocity stack on each sequential cylinder. This way you have two cylinders tuned for low RPM and two tuned for high RPM. This broadens the powerband.
If you look at Graves dyno figures, there is a power gain to behold in the meat of the RPM range that we enjoy on the street.
Let’s look at this economically. $149.95 divided by 5.5hp (average) equals 30 percent gain per dollar spent. Not bad. This puts that $500 you spent on an exhaust to shame!
This is my 2 sense on the subject.
Steve
:fencers:
This reminds me of when I used to work on carburetors. Velocity stacks work, period.
The longer the intake tract, the more velocity achieved earlier, the more power at lower RPM. The shorter the intake tract, the more velocity achieved later, the more power at higher RPM. This is true when compared to a gun (or garden hose for you greenies), the longer the muzzle the higher the velocity the higher the exit speed.
Many manufacturers have used electronically controlled variable length intake tract for years. On race bikes the intake tract is lengthened with velocity stacks connected to a solenoid that moves them up or down depending on RPM. Yamaha could not do this on the FZ1 and still keep it within the cost guidelines.
An alternative would be to have a different length velocity stack on each sequential cylinder. This way you have two cylinders tuned for low RPM and two tuned for high RPM. This broadens the powerband.
If you look at Graves dyno figures, there is a power gain to behold in the meat of the RPM range that we enjoy on the street.
Let’s look at this economically. $149.95 divided by 5.5hp (average) equals 30 percent gain per dollar spent. Not bad. This puts that $500 you spent on an exhaust to shame!
This is my 2 sense on the subject.
Steve
:fencers: