bout to order velocity stacks for my new zx14r what size do i go with? 25mm or the 15 mm i wil be running full brocks?

I like the punch in the face you get with 4-short OEM stacks. Match air flow velocity to cam profile and Padow. Right in the yes yes.

* Last updated by: Cblast on 4/5/2014 @ 10:24 PM *

6000 and up ya betta be pointed in the right direction. :) lol

well its a stock motor and when i do the job it will have about 600+ miles on the bike...so im not sure what ya mean by matching it to the cam profile...do i need it with my application? or am i wasting money?

No, not a waste, better with an exhaust and a flash overall. Like anything else, the mods should compliment each other. The cams in the bike come on strong around 6000 or so, short stacks mimics that by creating more air flow up high in the rpm range. Intake air velocity increase adds to that top end rush. Longer stacks accent the mid-low end grunt. Kind of a personality change is all. If you are not spending a lot of ur time in the upper reaches of the rpm range, the long and short combo is overall probably better for street manners.

* Last updated by: Cblast on 4/5/2014 @ 9:05 PM *

Are you a die hard drag racer who will notice .025 (most likely less) difference in your ET? If your answer is yes then sure go ahead and do it, but do yourself a favor and order the OEM shorts. The aftermarket velocity stacks are one of the best kept gimmicks in the business.

Ya.......they look cool and I am just enough of a bike geek to appreciate pretty stuff that is inside the bike wher only I will see it. I love those velocity stacks but I WILL NOT pay full price because I hear as many people say they do nothing at all for performance as I hear people who say they are a worth while mod.

Most say short stacks for top end, tall stacks for the street where you will have some chance of feeling the performance enhancement in the midrange. Pleas let us know if you think they do anything.

The 2012 & up bikes have two different sized stacks in the airbox. That is if you have the second gen model. Save your self some cash and buy the stock OEM shorties. Just because aftermarket is made of stainless does not mean it will add extra power. Even if your running a first gen buy second gen stock short stacks. They will fit. I don't know what is inside the first gen but the second gen machines run two different sided stacks in the box. Seriously if you are considering shorties go with the stock rubber shorties.

The aftermarket velocity stacks are one of the best kept gimmicks in the business.

Bikes running faster with or without stacks?

I've seen the OEM look like this:

Don't ask me which big4, but short stacks on the outside. Why? Curve the the plastic air box in tighter is one theory. Neuter it is another or put some grunt behind it some.

I better not guess this one, but here are 4 even stacks on a linkage. Just think of a row of ice cream wooden sticks shrunk down to size, pivot on a rivet as they hold the 4 stacks all at one time, and at one level across the board. Key off, these stacks are raised off the throttle bodies and you can push the whole mechanism back down on the throttle body, which then springs back up when let go. So at one section of rpm the stepper motor (actuator) lays the stacks on the bodies. Take it to another rpm level, they are sitting off the bodies as if the key was turned off and they are now way off the bodies full tilt. Why?

Speed of entry. Watch a molecule sit next to a v-stack and has to rise up the stack to get in. This linkage sent the stacks up in the air. Molecule did not rise, but rolled right into the throttle body. See that speed event? Time it takes to fill a void? Why the stack rise?

The crank is turning faster so you want less friction having that guy run up the stack to get in. This would be the short side of the stack length. Faster entry for faster rpm speed. For the stationary kind of stack, place the other 2 length stacks inside or out, these 2 cause a drag to the top end. Low rpm may cause an effect with the 2 different lengths, but in a different way. 2 enter faster when low rpm is present.

Go to the track, run a base stock run. Install either size stacks with either firing order, meaning, 1-4 is a stack and 2-3 are a stack. Take a run and now switch stacks. Who made the best pass out of 3 variables?

do yourself a favor and order the OEM shorts. The aftermarket velocity stacks are one of the best kept gimmicks in the business.

Mav I have played the stack game. Can you tell me more about your thoughts Why OEM ???? I may have missed something ?

Shown 15MM Race Stacks

Shown stock soft rubber stack

* Last updated by: Romans on 4/6/2014 @ 8:21 AM *

Hub has it. The R1 uses a variable velocity stack setup for "optimum" performance across the powerband. The short stacks are indeed more suited to top end performance, and after the launch I spend the rest of my run between 10,200 and 11,500. Romes I'm not poking fun at anyone who has purchased them. I just couldn't justify that kind of transaction when I replicated the effect for $40. Kawasaki has access to near unlimited funds when it comes to R&D on these bikes. Do you really think they left a pile of horsepower on the table due to inefficient velocity stack designs? Use the OEM shorties if you want the maximum top end. Also unify your cylinder fueling maps if you want to gain the very tiny benefit from doing so. Each cylinder has its own unique map. I had #1 copied and pasted into #2 and #4 copied and pasted into #3. Food for thought guys. Spend your money on maximum return. What are your performance goals Matt?

I don't know what is inside the first gen but the second gen machines run two different sided stacks in the box. Seriously if you are considering shorties go with the stock rubber shorties.

The R1 uses a variable velocity stack setup for "optimum" performance across the powerband.

Yes, Hayabusas also have the tall/short combo. shorts on the sides, talls in middle.

Just because aftermarket is made of stainless does not mean it will add extra power.

Rook I think you misunderstood what I said about the variable stack heights. Each of the stacks has the ability to change it's height. They are all at their tallest setting at lower rpms and then shorten as the engine gets into the top side of the powerband. Each stack can slide up and down.

Ha! I don't remember posting on this thread last night. I was pretty pissed up on whiskey.

my performance goals? not really sure yet. this is my 1st sport bike, ive owned an M109r and a 2010 Concours but got real bored as i maxed em out. I dont want a bike a can redline at will. I like to be scared and have my butthole puckered LOL well traded in the Connie for its faster and meaner cousin...after reading a bunch of reviews i decided not to order the stacks...saved myself $360. my full Brocks exhaust will be installed thursday. SO i will have plenty of power for now. Once i get used to this bike i can alwasy go turbo :) so in the mean time ill try and figure out how to keep the front wheel down in 1st lol

Velocity stacks work the same way as an exhaust system, only in reverse. The length of the stack corresponds to the timing of a positive pressure wave that bounces back down the intake at the speed of sound and, if timed right, helps stuff more air/fuel mixture into the combustion chamber. This is why a shorter stack is more beneficial at higher rpm; it takes less time for individual positive pressure pulses to reach the intake valves. And a shorter time frame corresponds with a higher frequency of valve opening events.

People bolt stuff to their bikes with no idea how it works, or even IF it works, mostly on the word of someone who tells them it works, or more often, wants to sell them something. Make sure you understand the basic principles before you spend your money so you're not surprised or disappointed at the results or lack thereof.

* Last updated by: Danno on 4/6/2014 @ 4:07 PM *

Romes I'm not poking fun at anyone who has purchased them. I just couldn't justify that kind of transaction when I replicated the effect for $40.

Mav I was curious to see if you found a issue with After market Stacks. U know, why OEM ? "but do yourself a favor and order the OEM shorts" These words.

The OEMs gotta be cheaper. If it isn't going to make a big dif, why spend a lot of $$$? Now if they would anodize those Factory Pro stacks, that would be more enticing.

Rook I think you misunderstood what I said about the variable stack heights. Each of the stacks has the ability to change it's height.

Na Romes I never had an issue with aftermarket stacks because I replicated what they were advertising for an 1/8th of the cost. $360 will buy a new Hook-Up and an entire OEM clutch pack. Priorities for me. If you have that money to just throw into the wind and hope some sticks then by all means... Do so. Prove to me they work on the track and I'll listen. (Not holding my breath)

Na Romes I never had an issue with aftermarket stacks because I replicated what they were advertising for an 1/8th of the cost. $360 will buy a new Hook-Up and an entire OEM clutch pack. Priorities for me.

Makes sense.

Mav, the after market stacks have a much better seal than OEM and do not leak. This was my priority. I know playing with stacks provides very little gains. More of a power relocate if anything. Still I needed them so i do not regret the purchase.

Turbo applications are not my forte and I respect your input on the matter. Plugging all those boost leaks can lead to hair loss!

can lead to hair loss!

I knew it, So What leads to making hair stay glued in the skull ? Quickly becoming a issue, UGH !

When I was finished chasing every little hp bolt on I could find back in 2007 I went for the stacks. You know, 2 more hp as advertised with proper fueling.

Was I played ? Maybe but for me I was running 45, 46, 47 tooth rear. For my application I wanted to lose some bottom end hp and move more power to top where I could use it. So I went for it.

I firmly believe they did what they said they would do, and that was relocate some hp from the bottom to up top, win win. My marked mile showed positive results. The masses all say stacks do almost next to Nothing. But, I know what they did for my set up and that's really what counts. Worth the money,,, well,,, ? Perfect for Boooossst. Chris Jones kit comes with them but most others don't so I kept them. Glad I did.

Untill I read your post I never gave any thought to making my own. Where were you 7 years ago,,,l Don't say combing your hair lol Good read guys, cheers

7 years ago I didn't have a bike. I have been riding 6 years and racing about 5 1/2. If all you wanted to do was move power around you should have had someone tell you about adjustable cam gears. Our Kawi gears are slotted from the factory for a bit of adjustment, but you have unlimited options with the aftermarket units.

If all you wanted to do was move power around you should have had someone tell you about adjustable cam gears.

I did look into this. I know you were not around awhile back but we had Slowninja light weight $ 1bad 300 plus pounds with boost(who were our resident drag racers around here)in a little drag racing time slip war. It was great to learn from. U know what works in the real world not internet BS.

Slowninja went for the adjustable gears and thin head gasket and picked up almost 6hp from what I can remember. Which Sounded great at first and I almost went for it.

What I took away from it was he spent allot of time on the dyno setting it up. Plus Mechanic's time. That being said huge money for what he received $$$$$$$$$$$$$. I quickly lost interest after the math was done.

I don't remember exactly where his times ended up. 8's anyway, Smookin FASSSSSStttttt.

With today's set up on the 14R allot of guys with flashed ECU's, so how are going to tune for it ? Now must add PCV into the cost or pay for Dyno time and play with the software. Either way allot of money for what you get. IMO labor and dyno time for this set up just not worth it.

Very curious to your thoughts on this Mav, have you done it ?

No I'm still stock. I know that the guys who are getting further down into the 8s at stock wheelbase were using a SB6 box and developing a timing curve that would allow throttle lock right out of the gate. They would also degree the cams to perform up top to further exaggerate this effect. Pull the power from down low and make it a monster up top. Being 50 pounds lighter than most riders helps too. I'm not sure what is possible with my setup but I think that I can get into the 8.80s this season WITHOUT all the expensive goodies and possibly WITHOUT a custom tune. I will stick with pump gas until I absolutely believe that it is holding me back from reaching my goal. I will keep you guys updated. Mr. Lee graciously offered an awesome deal on a drag shock that I KNOW would peel some ET off, but I just can't afford it at the moment.