# how to make a velocity stack



## turbo gli (Apr 14, 2003)

hey i was just wondering if any one out there know how to form a velocity stack . .. or make a tool to form a velocity stack.. i have been on sds site and they show a die type thing that they made to from a velocity stack for the custom intake manifold porject. well i am making a custom manifold and i need to now how to form a velocity stack
dose any one know of something i can use to form this .. or were they might sell a die like this .. i have acces to a leath in metals calls and i plan on making the manifold in the class for my final .. please any help .. thanks


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## turbo gli (Apr 14, 2003)

bump


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## hkk735 (Jul 14, 2001)

*Re: (turbo gli)*

just buy one of my manifolds- you will pass the class no problem









but on to your ?....i had a friend of mine who does all my maching make the die up for my stacks- on the cnc


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## turbo gli (Apr 14, 2003)

can you send pics of your manifold .. also i was going to make one bc i was going to go with a vr6 tb .. is there any way i can get a hold of on of these dies..


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## turbo gli (Apr 14, 2003)

bump


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## RavenGTi (Dec 12, 2000)

*Re: (turbo gli)*

couldnt you make the die on the lathe?


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## speed51133! (Aug 5, 2002)

*Re: (RavenGTi)*

what you need is a CNC lathe. you need to cut in a radius into a piece of round bar stock. the smaller end will fit into the pipe you want to make a stack out off. then you use a hydrolic press, and lube up the die, and press the pipe into the radius.
OR, use a CNC mill, and buy an end mill bit that has a ball shaped cutter. But the ball in whatever size you need for the radius of the stack. program the mill to cut the circumference of the round stock. you can drill a hole through the center of the die to run a bolt through it so you can secure it to the mill's table.
either way you need a cnc.


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## turbo gli (Apr 14, 2003)

any ideas on how to do this on a regular lathe .. thers one in my class but to create the radius would be difficult . is there a bit that could do this .. the machin only has in/out . side/to side ajustbent and a 90 degree bit positioning .. any one who has used a lathe knows what i am talking about. a cnc mill is out of the question . i have to make everything in this class. .. or dose any one know of an object that would have a velocity stack type radius arleady on it .. . thanks for the ideas so far .


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## speed51133! (Aug 5, 2002)

*Re: (turbo gli)*

how to do it on a regular lathe........
well...it depends how nice of a stack you want.
a nice stack has a full radius, like a trumpet horn. the next below that is like the trumpet, but the end of the stack doesnt curve all the way back down. it only goes horizontal, then the radius ends. Lastly, there is the stack that has a cross section of a big "Y". note the lack of a radius. there is a taper though. this type is still better than nothing.
if your cool with the last type, just get some round bar stock that has a diameter of the diameter you want at the end of the stack. chuck it in the lathe, and cut a 45 degree taper. keep cutting the taper until the very tip of the "cone" shape you cut in is the inside diameter of the pipe youll be making the stack out of. go a bit smaller so you can remove the die easier when you make the stack.
anyways, I hope this helps. lets us know what you decide to do.


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## Agtronic (May 14, 2001)

*Re: how to make a velocity stack (turbo gli)*

I think it will depend on the metal you're using.
If you're using steel, you'll be able to stretch it into a horn shape with a die, but if you're using aluminum, you'll have to machine a piece since you can't stretch it.
I've never worked with metal, so don't take my word for it, I don't know anything about this, but I just thought I'd add this to get some flames going.







But seriously, I could be dead wrong.


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## RavenGTi (Dec 12, 2000)

*Re: (speed51133!)*

i think a die made on a regular lathe would be adequate. the die doesnt have to be perfect, just as long as its close. because the metal wont conform entirely to the die, the die is just shaping it.


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## turbo gli (Apr 14, 2003)

wow thanks for all the ideas .. hey speed51133! i was planing on doing your 3rd example cept i was going to use a round stock then taper it \ / then in the middle -\ /- i was going to use some type of file like a bastard to create the radius .. hope the drawings are selfexplanitory. .any ways . .thanks a lot .. any one just tuning in have any ideas. the more the better..


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## 2kjettaguy (Dec 24, 2000)

*Re: (turbo gli)*

See if you can get a cutter for your lathe with a rounded head on it. You can come pretty damn close to immitating a perfect radius if you are patient and have a rounded tool (very forigiving when trying to make an inside radius)


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## speed51133! (Aug 5, 2002)

*Re: (2kjettaguy)*

or use a die grinder with a cabide ball shaped cutter.
turn the part on the lathe at a slow rpm, and manually put in the radius.


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## speed51133! (Aug 5, 2002)

*Re: (RavenGTi)*

who says you cant stretch aluminum??
its all in the lube on the die, and also heat the metal a little bit.
the thicker the wall thickness on the tube your making the stack out of, the better, since the material has to stretch out and become thinner when you press it on the die.
if your cutting the radius, keep in mind then the radius has to start where the taper ends. you cant cut deeper into the material than the taper at the point where you start the radius.
hard to explain, but im sure you know this, or will figure it out.


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## turbo gli (Apr 14, 2003)

bump for some more ideas


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## Vdubin474 (Jun 2, 2003)

*Re: (turbo gli)*

In ur metals class do u have a ball shaped die that goes in an anvel for metal forming? If u do u can take ur aluminum tube heat the end of it and tap the ball into the end of the tube to roll the edges out. If pretty sure thats what u could use to flare the edge out in a velocity stack and be safe. They won't be dead nutts like they would be doing it with CNC, but for amatuer street racers they will probably give u the same power curve or one pretty close to one done with CNC. 
i don't know how critical velocity stacks need to be and i hear they are pretty critical in demensioning, so be carefull http://****************.com/smile/emthup.gif .


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## speed51133! (Aug 5, 2002)

*Re: (Vdubin474)*

a ball will give the opposite shape a velocity stack has.


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## turbo gli (Apr 14, 2003)

yea a ball shape wouldnt do much for smoothing out the incomign air.. i think a velocity stack with a 45 degree radius would achive better results. ther has got to be a type of tool to achinve this ...such a simple die dam what a pita .. i asked sds how they made the one in there web site and they said "it was machined on a lethe" .. anyways i aprreciate all the ideas and info ..


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## turbo gli (Apr 14, 2003)

bump


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