new itb turbo setup build pics
...........great job
05-12-2005, 08:29 AM
#36
0.5 BAR
Join Date: Jan 2005
Posts: 114
Re: new itb turbo setup build pics
Originally Posted by AbaZ
hmm, not really digging the plenum, You'd think you would want the velocity stacks directly at the bottom of the plenum, so the transition would be smooth?
IIRC this question came up in the Endyne forums talkin about manifold design. Larry's answer was that older intake designs raised the stacks away from the plenum wall to keep turbulent boundary layer flow out of the ports. He also said that proper radiusing of the plenum to runner smoothes the transition enough to prevent turblent flow in the runners. He also posted a formula for determining the correct radius diameter for the best flow but, alas, I have forgotten it.
FYI The belly scoop on the P-51 Mustang was raised away from the fuselage for the same reason.
05-13-2005, 11:50 AM
#39
1.0 BAR
Join Date: May 2003
Posts: 326
Re: new itb turbo setup build pics
Originally Posted by projekteg
Originally Posted by davebrul
Actually, having the stacks sticking out into the plenum is a good thing. It allows the stacks to suck in air from a greater surrounding volume area (rather than just from the front). For best results full radius donut shaped stacks are required, but half radius stacks benefit from the same.
Air flows because of pressure differences, always from high to low. The larger the pressure difference the greater the volume you flow for the same setup. Also the higher the pressure the more dense the air (PV=nRT for the nerds).
As your piston moves down the stroke it creates a lower pressure because the volume is increasing (Think of your lungs filling with air, ribs and diaphragm expand, increase volume, air from high outside pressure (14.7 psia) to low (lung pressure)). On the manifold side, in NA (WOT) the pressure is equal to the atmospheric pressure (~14.7psia (14.7psi above full vacuum)). Under boost its 14.7psia+boost pressure (so 10psi boost = 24.7psia)
Air flows from the intake manifold in NA and boost not because its being forced or sucked but because it is flowing from the high pressure manifold side to the low pressure cylinder side. All the same rules of flow are the same for FI and NA. The only difference is under FI the density of the air is higher (PV=nRT again) and the pressure difference is higher.
NA==> 14.7psia Manifold--> 0psi* Cylinder (*The cylinder pressure starts at 0 and equalizes as it fills to its equal to manifold)
FI++> 14.7+Boost Manifold --> 0psi* Cylinder
Oh and the Europie is right about the trumpets in the manifold. It allows air that is even behind the stack to be drawn around and flow into the stack. Slight increase in flow.
05-15-2005, 06:52 PM
#40
1.0 BAR
Join Date: Oct 2004
Posts: 273
Re: new itb turbo setup build pics
Originally Posted by Paperchaser013
i belive some nissan bluebirds came like that...ITB w/ turbo.
