 |
|
|
Wed Oct 21, 2015 9:13 am |
Post subject: Velocity stack design |
nefarious user

Joined: 02 Nov 2008 Posts: 205
|
|
|
|
I'm in the process of designing a simple nitrous system for the Westfield and trying to come up with a clever idea for minimising the flow disturbance from the injector nozzles.
The plan at the moment is to have a sandwich plate made to fit between the TBs and the manifold, and mount the injectors into that. But the nozzles protrude about 5mm into the velocity stack (do you still call it that beyond the butterfly?), and this will negatively impact flow for the majority of the time when the the nitrous system is inactive.
The initial thought was to "hide" the nozzles behind the butterfly spindles, but packaging considerations make this impossible on the centre two bodies.
Next idea was to recess them into a NACA duct-type shape in the inner wall of the sandwich plate.
I know some of you lot are hotter on your aerodynamics than me (Adam?) - anyone got any brighter ideas for an internal design which will allow good atomisation when the injectors are in use, but minimises the degree of obstruction when they're not? _________________ Strong Broo Racing |
|
Back to top |
|
Wed Oct 21, 2015 9:28 am |
Post subject: |
AK Site Admin

Joined: 27 Nov 2006 Posts: 19548 Location: Aberdeen
|
|
|
|
can you not get a different nozzle setup the can fit snug in a hole, and flush with the inner surface?
Or is that not possible due to....
Never really looked at the jets before but are they angled to spray the nitrous where you want it (towards combustion) rather than just a spray out the end of a tip?
Can you 'edit' the inlet manifold and weld in angled bosses like used for injectors _________________ Impreza Race Car - SLS/SMRC
Mini Race Car - SMRC
911 - 1981 Air Cooled 3.0
500 - 1969 Fiat 500 L
Toureg 262 RLine
Track Scotland |
|
Back to top |
|
Wed Oct 21, 2015 9:33 am |
Post subject: |
AK Site Admin

Joined: 27 Nov 2006 Posts: 19548 Location: Aberdeen
|
|
|
|
ultimately I think the restriction would be none existent... maybe even help by making the air turbulent I remember finding these vortex/venturi 'devices' in the inlet of my Impreza when it was imported :S _________________ Impreza Race Car - SLS/SMRC
Mini Race Car - SMRC
911 - 1981 Air Cooled 3.0
500 - 1969 Fiat 500 L
Toureg 262 RLine
Track Scotland |
|
Back to top |
|
Wed Oct 21, 2015 9:38 am |
Post subject: |
AK Site Admin

Joined: 27 Nov 2006 Posts: 19548 Location: Aberdeen
|
|
Back to top |
|
Wed Oct 21, 2015 9:39 am |
Post subject: |
nefarious user

Joined: 02 Nov 2008 Posts: 205
|
|
|
|
The nozzles are straight cylinder shapes with the jets pointing out of the side (i.e. in line with the air flow). I guess they're designed that way because the fuel and nitrous are already mixed prior to injection, and the evaporation of the nitrous handles the fuel atomisation issue (meaning that nozzle design/angle is less critical than a regular injector).
It might work to angle them backwards (so the jet points at c. 30 degrees to the airflow), and at least partially recess the 'cylinders' into the inner walls.
Any clever shapes to think about (e.g. NACA duct type things)? Given I'll be having the sandwich plate CNC'd, I can choose pretty much any design/injector angle I like. _________________ Strong Broo Racing |
|
Back to top |
|
Wed Oct 21, 2015 9:42 am |
Post subject: |
nefarious user

Joined: 02 Nov 2008 Posts: 205
|
|
|
|
Same problem as I'm trying to tackle, just without redesigning the whole system from scratch (project is supposed to just be a cheap bit of fun).
Oh, and I'm calling BS on that "30bhp increase" figure, unless they're talking about a 0.5% improvement on a 6000bhp drag engine. _________________ Strong Broo Racing
Last edited by nefarious on Wed Oct 21, 2015 10:00 am; edited 1 time in total |
|
Back to top |
|
Wed Oct 21, 2015 9:42 am |
Post subject: |
AK Site Admin

Joined: 27 Nov 2006 Posts: 19548 Location: Aberdeen
|
|
|
|
 _________________ Impreza Race Car - SLS/SMRC
Mini Race Car - SMRC
911 - 1981 Air Cooled 3.0
500 - 1969 Fiat 500 L
Toureg 262 RLine
Track Scotland |
|
Back to top |
|
View previous topic
View next topic
|
You cannot post new topics in this forum You cannot reply to topics in this forum You cannot edit your posts in this forum You cannot delete your posts in this forum You cannot vote in polls in this forum
|
Powered by phpBB © 2001, 2005 phpBB Group
TrackScotlandv1.0 Theme created by TrackScotland
|
|