Are velocity stacks SS legal?

[CBR929RE]

I've done some searching on google and can't seem to find a clear answer. some say yes its legal others say no. and most of the talk about it was from around 2005. please no one tell me its only cheating if you get caught. if I was gonna go that way I wouldn't even ask. I bought some HRC stacks and they are already installed and are at the dyno being tuned now so they're staying unless I find the power curve horrible. I know I'm gonna lose some midrange but I hope its still good enough where I don't have to shift a billion times like on an R6.

[Degsy]

Wirelessly posted

They are legal if you shut the fuck up about having them.

I mean, whose going to challenge you? Jim? Arguing over who came 22nd and who came 23rd?

[CBR929RE]

lol ass

[union]

Wirelessly posted

They are legal if you shut the fuck up about having them.

I mean, whose going to challenge you? Jim? Arguing over who came 22nd and who came 23rd?

Jim isnt allowed to argue until he can consistently go faster around the track on his 600 then I can on my dirtbike

[Kurlon]

Jim isnt allowed to argue until he can consistently go faster around the track on his 600 then I can on my dirtbike

That's cheating, this is NHMS we're talking about!

[RocketPunch]

My interpretation of the rule book leads me to believe they are legal for SS, as long as the addition of the stacks does not require "alteration" of the OEM "air box" itself, and retains the number and size of the inlet openings. Since the rulebook did not define what "air box" means, it is really up for interpretation. If you define the "air box" as the shell of the OEM "air box" only, then as long as no alteration is made to the "air box" itself, then it is legal.

However, if the LRRS defines "air box" as the OEM "air cleaner assembly" (see item#1 in image), then I would say 95% of the SS riders running sv650's will have a technically illegal bike, as any part (except for the air filter) of that assembly is being replaced with non-OEM part, altered, modified and or removed (such as removing the snorkel in sv650's) will be deemed non "original equipment air box as produced".

20.1.2.4 Original equipment air box must
remain as produced. Air filters must
be used but may be Aftermarket units.
Aftermarket air filters are restricted to
units available via normal commercial
channels and designed to mount in the
stock location for that specific model
machine. Aftermarket air filter units
that replace part of the OEM. Air box
are required to maintain the original
size and number of air inlet openings
as the stock unit.

[CBR929RE]

My interpretation of the rule book leads me to believe they are legal for SS, as long as the addition of the stacks does not require "alteration" of the OEM "air box" itself, and retains the number and size of the inlet openings. Since the rulebook did not define what "air box" means, it is really up for interpretation. If you define the "air box" as the shell of the OEM "air box" only, then as long as no alteration is made to the "air box" itself, then it is legal.

However, if the LRRS defines "air box" as the OEM "air cleaner assembly" (see item#1 in image), then I would say 95% of the SS riders will have a technically illegal bike, as any part (except for the air filter) of that assembly is being replaced with non-OEM part, altered, modified and or removed (such as removing the snorkel) will be deemed non "original equipment air box as produced".

20.1.2.4 Original equipment air box must
remain as produced. Air filters must
be used but may be Aftermarket units.
Aftermarket air filters are restricted to
units available via normal commercial
channels and designed to mount in the
stock location for that specific model
machine. Aftermarket air filter units
that replace part of the OEM. Air box
are required to maintain the original
size and number of air inlet openings
as the stock unit.

that's exactly what I'm thinking. the stacks are in the airbox but are they counted as part of it? I could also see someone saying they are part of the throttle bodies and there's a later section the rulebook that says you can't modify them. to me they are separate parts. but I know it was asked before about some flap thing on the R6 that's attached to the stock air filter but most aftermarket ones don't come with it. I think it was SG that said you have to cut it off the stock one and put it back in to be SS legal. the way I read it is its legal but not sure if anyone else reads it that way (especially the powers in charge)

[RocketPunch]

Personally, I think the "Spirit" of this air box rule for SS class is so the bike retains the amount of air (allowed/restricted by the OEM "air box") going into the throttle body; and not specifically to limit how smooth the air flows into the them.

2 cents.

[Jim]

i always thought they are not SS legal, but who cares really.
do they actually add any HP ?

[CBR929RE]

i always thought they are not SS legal, but who cares really.
do they actually add any HP ?

I thought they were too but the rulebook isn't clear. so you're saying you won't protest me

apparently on my bike they do add a bit. my friend who got them for me talked to the guy who used to build bikes for the top Canadians (I think former champion Jordan Szoke when he was on a honda a few years ago) and he gave me the shorter of the 2 HRC kits cause its better. never heard any numbers from them. and really not sure how much they'll add since I also did the exhaust and air filter at the same time.

[Kurlon]

CCS has traditionally counted the airbox to include the filter and internal plus external snorkels, etc. So you can replace the air filter for example, but if the airfilter includes an opening to allow air (GS500E uses a round filter with an opening at one end for example) the opening must match OEM. I can't see how different snorkels would be SS legal, especially if there is a perf boost associated with them.

[Jim]

Jim isnt allowed to argue until he can consistently go faster around the track on his 600 then I can on my dirtbike

Attachment 34059 Attachment 34060

[union]

Thats not my fastest on the tard but you would still win

[Jim]

brett, how much are they? like $600

[CBR929RE]

brett, how much are they? like $600

well normally they are sold as a kit with 2 sets of stacks and the air filter. the place I just got the overflow bottle from has the whole kit listed for $2734.46. I've also seen them on an Australian site and their price translates to USD as over $4300. I only got one set of stacks and the hold down brackets for $470

[Tunertype]

well normally they are sold as a kit with 2 sets of stacks and the air filter. the place I just got the overflow bottle from has the whole kit listed for $2734.46. I've also seen them on an Australian site and their price translates to USD as over $4300. I only got one set of stacks and the hold down brackets for $470

$4,300 for a few tubes? holy crap!!!! I could probably build some decent velocity stacks out of PVC from home depot for $20!!!

for those that don't know how it works, it basically shifts your air flow around a little, by playing with volume flow rate, and inertia. A longer thinner stack will give you more torque at lower RPM because the velocity of the incoming air will help pack it in more due to inertia. At higher RPM the same stack will cause a flow restriction. So you will sacrifice peak HP for torque and must balance this.

what year yamaha do you have? I thought they had variable stacks that give you the best of both worlds??

[Slowpoke387]

He's on a Honda

[CBR929RE]

He's on a Honda

yup. and its the R1 that has variable height stacks, I don't think the R6 does.


got the dyno sheet last night, midrange looks good still. I was worried I'd have a dip there and would have to start shifting all over the place like you R6 guys

[csmutty]

yup. and its the R1 that has variable height stacks, I don't think the R6 does.


got the dyno sheet last night, midrange looks good still. I was worried I'd have a dip there and would have to start shifting all over the place like you R6 guys

08 and up R6 has variable stacks.

[Tunertype]

He's on a Honda

Oh miss read the post. THought he had an R6, but he was just saying how much they suck... my mistake...

[Tunertype]

yup. and its the R1 that has variable height stacks, I don't think the R6 does.


got the dyno sheet last night, midrange looks good still. I was worried I'd have a dip there and would have to start shifting all over the place like you R6 guys

That's a pretty nice bump there. Looks like a good mod.

[RocketPunch]

got the dyno sheet last night, midrange looks good still. I was worried I'd have a dip there and would have to start shifting all over the place like you R6 guys

The gain is from stacks alone??

[CBR929RE]

Oh miss read the post. THought he had an R6, but he was just saying how much they suck... my mistake...

I wasn't saying they suck, just their midrange sucks so they require more shifting. the R6 is actually my second choice right behind my CBR.

new graph after a few more pulls. need .04 more noticed these numbers are uncorrected and the dyno sheet I have from the previous owner where it said 109hp was SAE corrected. not completely sure what that means.

[Tunertype]

I wasn't saying they suck, just their midrange sucks so they require more shifting. the R6 is actually my second choice right behind my CBR.

new graph after a few more pulls. need .04 more noticed these numbers are uncorrected and the dyno sheet I have from the previous owner where it said 109hp was SAE corrected. not completely sure what that means.

You can't compare dyno numbers from different times and different dynos. It's not that accurate. You can only compare before and after on the same dyno in the same day. If there is an improvement it's good. but the actual numbers are sorta meaningless..

SAE corrected means they've factored in air temp and elevation as an attempt to kind of even out the ability to compare different dyno numbers to eachother.

[CBR929RE]

You can't compare dyno numbers from different times and different dynos. It's not that accurate. You can only compare before and after on the same dyno in the same day. If there is an improvement it's good. but the actual numbers are sorta meaningless..

SAE corrected means they've factored in air temp and elevation as an attempt to kind of even out the ability to compare different dyno numbers to eachother.

I know they're all different. final evaluation is the butt dyno. I'll be able to tell then how much better it is.

that's what I thought the correction was. thanks. what I like is that the stacks don't seem to cause any dip in the low/mid range. and its nice and smooth all the way up.