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Discussion Starter · #1 ·
Hey folks. I redid the velocity stacks on my ITBs this weekend.

There was an ugly plastic coupler holding the old stacks to the TBs. I cut them out and used a dremell and a lot of sanding to get them to fit nicely inside the stack. It's all port matched, epoxied and bolted together. Everything fits real nice now. The intake tract is a smooth 13.5 inches long.

Before

After


All the pics
http://mrichard.org/images/ITBs
 

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Damn, those stacks are long! Have you ran it yet? How does it work and what rpm? BTW for what carbs/TBs those are meant for? Looks bigger(dia.) than my DHLA45 ones, 48mm maybe?.
How are those secured into ITBs, other than one screw and that plastic coupler inside?
 

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Those are seriously long. Do they fit in your bay?? IMO that is a little too long for me. Cool though. +1 for doing things different
 

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Discussion Starter · #6 ·
Haven't installed them yet, this is for an upcomming build - I know I've been saying that for like 3 months now but seriously it'll be done before autox season... hopefully < 6 weeks...

So, I don't know if they fit in an EK or not. This car is track only and I'm prepared to bang the firewall back to fit them in. I've read that 16 inches from valve to horn is a good number to shoot for so here they are... we'll see what kind of power it'll make. I'm still saving up to get the head ported and reconditioned with the crower stuff in my living room.

IIRC the ITBs were from a Suzuki 600, they're 42mm. I bought the setup from a board member. It came with the plastic coupler. The stacks are from ebay. http://preview.tinyurl.com/2ayrkc

Rushi, you've got a keen eye. I need to fab something to bolt the other side of the stacks down. There's a bolt hole nearby, so a bracket of some sort there should work. Proly hit Home Depot after work. ;)

 
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Ok, interested and waiting results how they work. Velocity stacks looks like they're 48mm, but yours are much longer than those in ebay link. Stange, 42mm in 600.. Are you sure? AFAIK all 600 bikes have 38mm butterflies, did you measure the butterfly or intake before the butterfly? It tapers down into butterfly, my 42mm CBR954RR (and friend's 42mm GSX-R750/1000) measure 45mm at intake side. And 38mm is too small IMO for these engines, I would like to have 45 or 46mm for my engine.. 42mm should be enough for about 50...55hp/cyl.

About securing those stacks, I think you could make a triangular piece of e.g. thick (10mm or so) aluminum or other metal, that has one screwhole and that secures into one thread in middle of TBs, and clamps those flanges tight into TBs.
 

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The only ones I seem to find for my R-1 carbs only work with the factory airbox. I need to find some that work without the big airbox. I can gain more torque and hp if I had them...
 

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My GSXR750/1000s(2002 IIRC) measure about 50mm at the inlet and 42mm at the outlet. They can be bored to 44 or 45mm IIRC.

TL1000Rs on the left, GSXR1000s on the right(inlet):
 

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Discussion Starter · #11 ·
Ok, interested and waiting results how they work. Velocity stacks looks like they're 48mm, but yours are much longer than those in ebay link. Stange, 42mm in 600.. Are you sure? AFAIK all 600 bikes have 38mm butterflies, did you measure the butterfly or intake before the butterfly? It tapers down into butterfly, my 42mm CBR954RR (and friend's 42mm GSX-R750/1000) measure 45mm at intake side. And 38mm is too small IMO for these engines, I would like to have 45 or 46mm for my engine.. 42mm should be enough for about 50...55hp/cyl.

About securing those stacks, I think you could make a triangular piece of e.g. thick (10mm or so) aluminum or other metal, that has one screwhole and that secures into one thread in middle of TBs, and clamps those flanges tight into TBs.
triangle clamp... :TU:

I may be wrong about the motorcycle, pretty sure he said Suzuki but 600 may be wrong... maybe 900, dunno. They measure 42mm here, not sure if they taper down further towards the plate but it doesn't look like it. The stacks are 48 at the top and 42 at the bottom.

 

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12.5 inches sits about .5 inch away from the firewall in an EG. I'm not sure if the EK has that much more room, but keep us updated. You will definetly hit 2nd harmonic with those, so as long as they fit, you should be doing pretty good with 3 harmonics, and not terribly high of a redline.
 

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Discussion Starter · #13 ·
12.5 inches sits about .5 inch away from the firewall in an EG. I'm not sure if the EK has that much more room, but keep us updated. You will definetly hit 2nd harmonic with those, so as long as they fit, you should be doing pretty good with 3 harmonics, and not terribly high of a redline.
cool, thx for the info... firewall will be modified if need be

I was happy to see rushi making 170hp at 7000, that'd be great... if I'm anywhere over 160 I'll be happy. I really just want as much torque as possible as flat as possible.
 

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I was happy to see rushi making 170hp at 7000, that'd be great... if I'm anywhere over 160 I'll be happy. I really just want as much torque as possible as flat as possible.
Heh. High compression, Crower 3 and ITBs are great for that flat torque curve. Crower 3 really is not very wild cam, great for street and torque IMO 8) Dunno how much my merged anti-reversion header has to do with it, but atleast throttle response is great. Torque I'm making is pretty much ~max. that can be achieved from 1.6 NA, bmep is very high (~230psi) and very difficult to get higher, according to A.Graham Bell's books and formulas.
 

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I went after tq a bit too. I used flat top pistons (PM6) a y8 head, and overbore of .040 to help tq. I also think crower tries to pull a bit more tq from its cams. 122 wtq for my build is quite high, and its because of things I;ve done to try and acheive it. Rushi makes 10 more with a more aggressive cam, ITB, headowrk, better header etc. I hope to see 130-136 pd tq at the wheels after my ITB's and crower 3 are installed, along with headwork.
 

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since cai's are benefitted because of length... has anyone ever thought of bending them "down" as in towards the cat converter? (ofcourse not taht close :hammer:) for "length" tuning as well?

like... first it goes horizontal back - then down. or... "equal length" to the side like a regular intake... but yeah.
 

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I wonder how these compare to my Edelbrock IM. I think the manifold is at limit of what can be put into my car without any problems.
Seems they are not much different, so I think it would be possible.

I would imagine having such sharp bends on the stacks would be bad for air velocity.
I'm not an expert by far, but I would think there's a reason it's not done often (if ever, I have never seen it).
 

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then if that's the case... i would like to see some ITB's that went back and curved up... through the hood... and pointed forward... "ram-air-itbs..."
 
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