GSX1300r Hayabusa, 99-07
patented design
Factory Pro Velocity Stacks installation hints

  We'll start with the assumption that you already can competently remove the fuel tank and airbox. If you aren't confident that you can do that, stop right now and get an experienced friend or pay a good shop...........

After you have the airbox removed, (ok, one hint is that the throttle body clamps clamp the airbox rubbers to the throttle bodies). - look at the stock rubbers from the bottom side  - they are "offset" in the hole.

Remove the stock rubber velocity stacks. They are semi glued in with what looks like a light latex glue, so you'll have to kinda push the outer edge inwards till they collapse in on themselves - then push them on out.
Push into the airbox or out of the airbox - either way is fine.
(why do we write "in to" as "into", but, "out of" is two words and not "outof"?

Look at the Factory Pro adapter rubbers. You'll see that our rubber adapter rubbers are "offset" to one side, just like the stock ones.

Flip the airbox upside down.

Usually, there will be a dab of paint on the new adapter rubbers that you'll line up to the 2 index marks cast into the bottom of the airbox.

If there's not  a paint dab, just remember, the "skinny side" of the adapter rubber lines up to the 2 airbox indexing marks.

To glue or not to glue the new adapters?

I don't glue them. They seal relatively perfectly at the airbox and then they clamp onto the throttle bodies. What more could you want? They can't rotate in the hole if they are clamped to the throttle bodies.....

Feed the new rubber adapter into the airbox.

Note! The patented stack's"Throttle Body Stuffer" tongue goes into the stock throttle bodies, retaining more laminar air flow and conserving refracting wave potential. So.... make sure the stuffer tongue is on the outside of the airbox.

If the paint dab wanders away from the index marks on the airbox, no worries (as they say down there) - Once you get the inside and outside lips "happy" above and below the airbox hole, we left just a slight amount of "wiggle room" and you can just rotate the rubbers back into alignment.

This is what it should look like.

Skinny side next to the airbox index marks and thick side of the adapter rubbers - away from the airbox marks - towards the front of the airbox / bike.

Stuffer tongue ready to insert into the throttle bodies.

This is the inside of the airbox view.

You can see the retaining female groove on the Factory Pro stack and if you were playing with the adapter rubbers and the stacks before you put them in, you'll have seen how the patented clampless retaining system works.

Finally, a real use for "Liplock".


You can either install the airbox onto the bike now and put the aluminum stacks on later - that makes putting the stacks into the rubbers easier by keeping the rubber from rotating in the airbox hole - OR - you can install the stacks into the rubbers and reorient the rubbers again before you reinstall the airbox.
Either way is OK.

The early bikes have a 2 piece airbox and the later ones have a glued together airbox. The one piece airbox is a bit more difficult to install the alloy stacks, especially if you've got large hands - but, still relatively easy to do. Especially considering the hp gain........


Anyhow..... inserting the stacks into the rubbers.....

If you are feeling the need for some lubrication, use a temporary water based lube, not oil based.

Almost in........

Wiggle, wobble, twist, and or manipulate the alloy stacks till they look like this.


Once again, if the rubbers rotated in the airbox hole, just rotate them back to reindex them.

This is what your 2 piece Hayabusa airbox looks like with a BMC RACE filter and patented Factory Pro Billet Velocity Stacks installed.

The one piece airbox looks the same except you can't see the inside.

So - the hard part, installing the stacks, is done.

Now - if the airbox isn't already installed, just reassemble the airbox, put the stock throttle body clamps back onto the new adapter rubbers and put it back on the bike - along with the other parts that you took off.

Yes - we always suggest that you use a Genuine Suzuki Service Manual. It's the LAST WORD.

With new Superflare stacks -
Is fuel injection retuning needed?

We did the gsx1300r Superflaretm R&D with a properly tuned stock Hayabusa with a pipe on it. We did no additional fuel injection mapping during stack R&D - beyond originally tuning the "stock stacked" bike to Best Power settings in the first place.

The 6 to 8 True HP that we got in the upper mid was due to the stacks alone - as the mixture really didn't change much with the stacks.

Factory Pro Velocity Stacks work primarily by increasing the engine's dynamic compression - kind of like milling the cylinder head or slightly higher compression pistons over a range of desired rpm ranges. Increasing compression doesn't require big fuel changes. Dynamic compression is different from cranking compression. Dynamic compression is essentially cranking compression + extra air that gets trapped in the combustion chamber as a result of proper intake tract (velocity stack) length, intake cam closing and also the effects of the exhaust systems in a RUNNING engine.
Dynamic compression effects are also related to rpm ranges - as intake ram charging; commonly occurs strongest over a 3000 to 3500 rpm range. (usually....)

Can you get less dynamic compression than cranking compression under running conditions? 
Yes. If the resonant frequencies of the intake or exhaust systems are wrong, the systems can yank air back out of the combustion chamber before the intake valve closes (and you'd call that a "flat spot". and a tuner would call that "reversion").

Our 'Busa stacks make it right. Higher air velocity for stronger "RAM".

Could you get better performance if custom mapping for the stacks?
Well, yes and maybe no.
If you tune your Hayabusa "to an air fuel ratio" on a dealership level dyno, you are virtually guaranteed to miss potential power in the real world.

To put it another way, drop them on a stock engined bike and woohoo!
Tune it to an "af ratio" on a dealership level dyno and less woohoo.

Proper tuning requires that the engine be tuned to Best Power and Engine Smoothness. There is potentially a difference of 6-7 True HP s compared to "af ratio".