Topic: Who has pics of velocity stacks

[Whaleman]

http://www.jntperformance.com.au/index_c269035_0.html

I found a place that sells one at a time as I only needed one for my lamp project. Dan

[davesprinkle]

Nice work Dave and it's obvious you know your stuff, but I gotta ask, have you done any dialing in on a dyno to see if that length is optimal for a performance increase?

Thanks for the kind words, BW.  Nope, didn't iterate on stack length.

nice indeed Dave, cost involved?

I went through some heavy pain due to the effect of untried velocity stacks, but those were put on 26VM which originally hava a big step in the bore.

whoever wants is invited into this stacks thread in the perf forum

http://forums.sohc4.net/index.php?topic=58658.0

to the rest of you guys, I have to wnder about the shapes and sharp edges in some of the stacks you posted. Gordon Blair claims that this is the single most important factor, taper is only secondary ....

http://www.profblairandassociates.com/pdfs/RET_Bellmouth_Sept.pdf

I modeled the stock plastic stacks in Solidworks.  Handed the model off to an extremely talented machinist at work.  Couple months, some beer, I get my ally copies.  Nice, huh?  

Out of curiousity, I sent the prints out for quote.  1200 bucks each.  Glad I didn't have to pay that...

I could have gotten exactly the same performance with the plastic versions, but I felt that the bike's aesthetics REQUIRED ally stacks.

BTW, it isn't easy making billet replacements for a modern CR carb.  Trumpets for the early CR carbs could be screwed into place (meaning only a lathe is required for their manufacture), but the later versions have some off-center mounting details, which forces both turning and mill ops.

[davesprinkle]

http://www.jntperformance.com.au/index_c269035_0.html

I found a place that sells one at a time as I only needed one for my lamp project. Dan

Dude, that is a sweet lamp!  Your best girl let you bring that into the house?

The first fight of my young marriage was when I tried to put my Indycar wheel coffee table in the living room...

[Whaleman]

Wife loves it. Dan

[754]

Davesprinkle, if someone came to me to get those made (providing they are like most stacks, ie no offset), I would charge less than 100 each, & do it on a manual lathe..


 Some CNC shops are waaaaaayyyy outa hand.. when was it?..bet they are more realistic in price, this year..

 The offcenter part, could be done in a 4 jaw, or fixture on a lathe maybe..

[turboguzzi]

Davesprinkle, if someone came to me to get those made (providing they are like most stacks, ie no offset), I would charge less than 100 each, & do it on a manual lathe..


 Some CNC shops are waaaaaayyyy outa hand.. when was it?..bet they are more realistic in price, this year..

 The offcenter part, could be done in a 4 jaw, or fixture on a lathe maybe..

indeed, just as I was going to say that the stock plastic ones are expensive enough at what? 60 bucks each?

nice friends at work you have dave!

[davesprinkle]

Davesprinkle, if someone came to me to get those made (providing they are like most stacks, ie no offset), I would charge less than 100 each, & do it on a manual lathe..


 Some CNC shops are waaaaaayyyy outa hand.. when was it?..bet they are more realistic in price, this year..

 The offcenter part, could be done in a 4 jaw, or fixture on a lathe maybe..

Yeah, good analysis.  I had these parts quoted a couple of years ago.  Probably cheaper now...  My guy would have done it all on the lathe, but there are 4 keyed holes in the flange, so he punched those holes on the mill in the same setup as the off-center flange.  So.  First op was on the lathe, cutting OD and ID, leaving enough stock at the base for the flange detail.  Second op was to clamp the trumpet flare on the mill-table.  (Careful not to mark the sweet finish.)  Cut the offset flange and air jet holes, along with relief slots for the mounting clamp.

[davesprinkle]

Davesprinkle, if someone came to me to get those made (providing they are like most stacks, ie no offset), I would charge less than 100 each, & do it on a manual lathe..


 Some CNC shops are waaaaaayyyy outa hand.. when was it?..bet they are more realistic in price, this year..

 The offcenter part, could be done in a 4 jaw, or fixture on a lathe maybe..

indeed, just as I was going to say that the stock plastic ones are expensive enough at what? 60 bucks each?

nice friends at work you have dave!

Yes, I think that's about the right price for the plastic trumpets.  But the US distributor, Sudco, ships the rack with a full set of trumpets, so I didn't need to purchase them separately.

And yes, I'm fortunate to have talented and generous friends.  No doubt.