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Yoshi Style Velocity Stacks


Mohawk

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Mohawk can you confirm you complete bike setup? Exhaust, Cams, Intake?

What is the best setup for the dual velocity stacks?

4 stock "short" stacks mounted to the airbox?

4 stock "short" stacks mounted ?mm below the tops of the 1st units

Air box cut as per "big airbox mod" thread

Very impressive power gains and weight losses!!

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Bigger is not always better... my story...

My friend Stephen called long distance from England because he just
installed a $900.00 HRC air box on his RC45 and saw 120HP on the
dyno... mmmmm... together we wondered if the stock box be modified???

gallery_3131_51_178065.jpg


We found that stock RC45 throttle bodies are 46mm but the air box was
restricted to 40mm... no problem... I'll bore the air box out to 47mm
on the milling machine...
gallery_3131_51_12643.jpg


I drew up plans for 47mm bell mouth based on the stock 40mm bell
mouths and purchased a block of black Delrin...
gallery_3131_51_61101.jpg


I'm not happy doing repetitious work but I labored long hours to
machine 4 each bell mouths with my best accuracy...
gallery_3131_51_60103.jpg


Don't you love when a plan comes together especially if it turns out
perfect???
gallery_3131_51_73307.jpg


Now I had an unrestricted air box with my own 47mm bell mouths... it
was the best I could do to replicate HRC $900.00 air box... not to
mention I wanted to keep my home made K&N filter...
gallery_3131_51_44329.jpg


Time to put the Mod to the test... this is Dave at Chandelle
Motorsports...
gallery_3131_51_181600.jpg


No joy... I lost 1.8HP on the dyno... so bigger is not better in this
case... a whole week worth of work shot down in flames... it seems
Honda got the intake velocity right for a stock pipe after all... air
boxes are like tuned instruments... alter the holes and the tune
suffers...

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Mohawk can you confirm you complete bike setup? Exhaust, Cams, Intake?

What is the best setup for the dual velocity stacks?

4 stock "short" stacks mounted to the airbox?

4 stock "short" stacks mounted ?mm below the tops of the 1st units

Air box cut as per "big airbox mod" thread

Very impressive power gains and weight losses!!

Engine is stock, apart from the following;-

My own spec cams

CoIl on Plug, from cbr1000rr 2007 model

Matched throttle body to head rubbers

TBR full exhaust, with Delkevic mid length Ti silencer

Big airbox mod with ramair intake

Velocity stack tops (the round lips) mounted straight on to airbox base, for 10mm stack height. Plus secondary stacks, base flush at 10mm from airbox.

Rapid Bike Racing fuel controller with one MTB O2 sensor.

What did you do to compensate for the necessary fueling changes?

Still running the single MTB, bottom & top end are fine, mid range from 5500-7500 still being tuned, but winter interrupted play :(

Hey Larry, you should try my dual stack idea with those big intakes I think it would help your fuelling !

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Hey Larry, you should try my dual stack idea with those big intakes I think it would help your fuelling !

Mr.RC45 fueling is not the problem... my air box will remain stock

because our air box works like a finely tuned instrument... any wild

ass guess mod disrupts this highly engineered resonant to where to

you're producing nothing but sour notes... The airbox inlet tubes, or

“horns”, are specifically designed to provide a resonance that can

increase the total airflow by up to 10-15%. Second guessing these can

cause the engine to loose power and increase the intake noise as in my

case...

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No not you mohawk, I was asking busy little shop. I know you are running Rapid Bike, so you have the ability to make air flow changes/mods and then see if the AFR is going richer or leaner. That way you can tell if the corresponding mod is pulling in more air/demanding more fuel or not. I know you put a lot of thought and calculations into the design of the velocity stacks and they are not "wild ass guess mods". On the other hand, I don't know why busy little shop was opening his air inlets from a conservative 40mm to a gigantic 47mm with out any ability to make the necessary fueling changes. I am not surprised the rc45 ran sour after doing that, but I am surprised that he feels the need to compare his untuned wild ass guess mods to your highly thought out and tunable mods.

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Hmmm, I can't helper wonder what I might see with my 5th gen. I got some great dyno numbers, and now see I need a full exhaust system to make it even better, but this stack thing sort makes sense.. ;) what goes in, gota come out though.

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Hmmm, I can't helper wonder what I might see with my 5th gen. I got some great dyno numbers, and now see I need a full exhaust system to make it even better, but this stack thing sort makes sense.. ;) what goes in, gota come out though.

Unless you are on the confirmed buyer list for the Tyga headers, good luck finding a real full system.

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LOL yea yea yea... we'll see when TYGA gets it together what comes of it. I'm praying it works out, but???

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Just thinking out loud but can the dual-stack setup not be replicated by just "floating" the OEM velocity stacks off the bottom of the airbox with spacers? 

 

OK, there will be no bell mouth on the bottom stack (there is no bottom stack at all) but it does create a dual setup with a gap. It also lengthens each stack by the size of its gap. 

 

Just curious...

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On 9/26/2017 at 5:54 PM, Stray said:

Just thinking out loud but can the dual-stack setup not be replicated by just "floating" the OEM velocity stacks off the bottom of the airbox with spacers? 

 

OK, there will be no bell mouth on the bottom stack (there is no bottom stack at all) but it does create a dual setup with a gap. It also lengthens each stack by the size of its gap. 

 

Just curious...

 

You are definitely going to want a "bell mouth" at both of the air entrances.

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On 9/30/2017 at 4:24 AM, jerritt said:

Has anyone tried this with r6 stacks. I was thinking r6 on the bottom and vfr on top or would that open up the bottom too Much? 

 

I am running pain r6 stacks on the bottom, it definitely does not "open up the bottom too much".

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