jere

Gti-r ITBs are pretty small for a race car that new manifold should show some nice improvement.

Offtopic - bill@dentsport what is the that Roush composite can coming on the PCV system? Fan?

bill@dentsport

We are actually getting 1000rpm sooner spool with the new setup. There are many variables though. The vtec type VVL helps spool the turbo a bit on the low lobe and the head overall flows 40% more than the old one. We also switched the turbo from a TS GT3076 to a TS GTX3576 which is absolutely awesome. I cannot wait to get the boost up to 30+.

The Roush tank is a catch can mainly for condensation, the alu tank being a air/oil separator.

Cole D

Bill, would you be interested in building me one of these for a B18C?

exgr

very cool. anyone have dyno results to share for changing to dual plenum?

xxbulaxx

The actual calculations for coming up with the second plenum are relatively basic. The harder part is coming up with the design of the intake runners and main plenum, but this is the complicated part of any intake manifold. What's interesting, though, is that the dual plenum designs posted above actually do a great job of naturally "evening out" the air flow in the main plenum across all 4(+) runners...So it can actually make your job easier when it comes time to perfect the main plenum and runners.



The main challenge with the computer simulations(CFD - Computational Fluid Dynamics), is the way in which internal combustion enignes work. You'll see a lot of CFD images that demonstrate how evenly the air is flowing through all four runners...The problem is, these tests are treating the intake runners as if they're wide-open and flowing 100% of the time. This is ok if you just need to get a general idea of how well the design is performing, but it's not very accurate when you're trying to hammer down an awesome design that you want to put into production(or even just spend the money/time cutting a one-off on a CNC, etc).

In order to properly test the design, you need to simulate the rest of the engine(intake valves, cam profile, engine RPM, etc) and the airflow through each individual runner throughtout the 720* cycle of the engine...This is where it gets complicated and time consuming. Here's a youtube video demonstrationg what I mean:
Ahh, the joys of engineering. :D

xxbulaxx

I see them as kind of unnecessary on 'most' drag cars.(edit: Although, they could be beneficial in classes that limit turbo size, engine combinations, etc)

You'll see these manifolds really shine on forced induction cars that are limited to engine size, turbo size, turbo restrictors, etc. I learned about them due to my interest in rally racing. In the Rally America Open class(The one Ken Block, Higgins, Pastrana, etc run), they're limited to no greater than a 3L engine with a 34mm restrictor in front of the turbo. In order for them to go as fast as possible, they need to get the turbo spooled up quickly and make as much use of that limited amount of air as early as they can. The dual-plenum intake is great here because it improves efficiency/consistency between cylinders(allows for them to tune more aggressively), and improves mid-range torque and power. When it all comes together, you have a small turbocharged 4-cylinder that acts like it's a big, torquey V8.

95gsrtt2

its sounds like this could have some application for the drift guys.
this is a great thread keep it going

HellaFab

if it works for rally racing the way you say, it would work for others as a base design if it were allowed by the sanctioning body.

a "drag" manifold would just be a higher flowing version of the same thing tuned for a different powerband.

exgr

Joe Mac's 8.5 backdoor plenum is also dual in design:

Cole D

Is anyone currently building one of these? I would like to try it using the JG/edelbrock race intake manifold