another velocity stack question

[arthur39]

in my quest to build a new turbo system for the busa, i read velocity stacks in the plenum are a good mod. I am building the plenum now, and have a set of 48mm id velocity stacks that are 72mm long appx 2 3/4", the inside of the plenum is 3 inches deep, about 5/8 to 3/4 of an inch will be outside the plenum for the hose clamps wich will leave about 1inch above the stacks for flow.
my question is will this help for driveabiliy for around town? I am looking for a very streetable busa, 80 percent of time will be under 5g's the rest will be for fun I figure since the longer stacks help low and mid torque I should use them for putting around, I will be also loosing bottom end due to .080 spacer, so it should help the low end out a little better? Or.... should I cut the stacks even shorter or just do away with them and stick a 2" tube flush with the bottom? Anything? thank you for your assistance

8lbs boost

 

[Big Red]

The longer the tubes the better the bottom end on a normally aspirated engine. On a turbo that could be a tough call unless you have a tuner to sort it all out. I agree with you on building your engine with streetability.

 

[megawatt]

Turbo = forced induction

I doubt V stacks are going to do anything for you. I never seen a pic of a plenum with velocity stacks on a stage 1 turbo bike.

I went from stock compression to turbo pistons with a spacer, thinking I would lose a lot of the bottom end. It was not even an issue as far as streetability riding. I think your over thinking your project.

But do keep the updates on your progress coming. Good luck

 

[cdhoroho]

A few companies use v stacks in their plenums

 

[arthur39]

here's the updated plenum, it's just about complete, stacks installed, hks bov installed, welded from inside, laying out the up pipe next, will be going through the ram air hole, .125 aluminum with an .030 etch of logo and grooves, I prefit it, fits great, i have tabs for hold downs, with room to change spark plugs it's for a stage one street bike, hopefully next season, turbo is a 16g, with a 20g housing ported out and pipe welded in for external gate, tial 38mm is next welded to housing, just taking my time for this winter, coming along slow and steady

 

[OZBooster]

Plenum looks great

Header looks good too , ...now the friendly critique , the head flange looks thin, maybe its just the angle,lots of weight and heat expansion working at that , bends if its not thick enough,
also how is your installed height of the turbo, enough height to gravity drain ??
on mine i put the merge right at the turbo flange and use studs to get as high as possible .

 

[arthur39]

Thank you, , im on vacation in Maine, no internet at the cabin, so Mickie D's it is, I see what your getting at with the flange, and I will do as you say and place the flange at the merge just to be safe, do you have a picture? The header was purchased over the internet, the tig welds on the piping are excellent, the flange looks like it was added afterword, somebody tried to steel mig it, and it shows rust and burn through in that area, I'm gonna cut it off and have a new flange tig welded to it, i think this flange is 3/8 I will try to find one that is 1/2", anyway welding the header and the housing are my next project ill be working on, since they are disimilar metals i'm gonna have to farm the work out, outside my scope and I don't want to take a chance a

 

[OZBooster]

Check your height, it may be ok, just need to be about an inch above the oil level

here's a 750 header i did a couple of months ago, there more trouble to drain than the busa as everything is shorter , you can relieve the top of the flange so the pipe settles into it and weld to the side otherwise the gap at the sides makes the weld pull bad

 

[arthur39]

ty, probobly going to get new flange anyway, should be able to get a stronger weld, in there as well, post it up when it's done,