Just thought I would make a thread showing the progress on my custom manifold setup. As the builder sends me pics I will update the thread.

As many know the intake manifold on the rotary doesn't offer much when it comes to high horsepower numbers. Don't get me wrong, many have made impressive numbers on the stock manifolds, but there is much left on the table... the runners are too long and too narrow, there are unwanted bends and kinks, uneven runner lengths, little to no plenum volume (20B isn't as bad as the 13B, but its still sad).

Plenum volume is increased dramatically, shorter runners for high rpm gain, larger primaries (stock manifold uses the same diameter runner for both primary and secondaries...), removed the kinks, and dropped the overall manifold height by over 3". No need to cut and re-weld the lowers.
The alternator will be relocated to the side of the motor, as the TB now occupies that space. The throttle body of choice is a Q45.

This is shown in the "parts" state... the weld seams and transitions have not been added yet. The primary runners will be cut down to where they enter the flange at the correct angle of the intake port. Secondary runners will also be added, along with new injector bosses and rail.


http://www.flickr.com/photos/20669521@N08/5597189400/

http://www.flickr.com/photos/20669521@N08/5597189452/

http://www.flickr.com/photos/20669521@N08/5597189490/

http://www.flickr.com/photos/20669521@N08/5597189552/

http://www.flickr.com/photos/20669521@N08/5597189620/

 

Considering the 20B was engineered to directly compete with the DOHC V8's of the era, the manifolds are definitely optimized for low-end torque.

That solid model looks good so far.

 

Turbo is a Garrett 45R

I will have my manifold builder measure the volume

 

8.652 liters

I assume the stock plenum is around 3.

 

Looks awesome. Who are you getting to make it...someone local?

 

http://www.flickr.com/photos/20669521@N08/5618360082/

http://www.flickr.com/photos/20669521@N08/5618360012/

http://www.flickr.com/photos/20669521@N08/5617774783/

 

Hey Gordon, here's a shot of both manifolds for comparison. The runners on this manifold don't tuck in as they do on the stocker, which puts the centerline of the front and back runners 2.5" further outside, for an added 3" to each of the plenum. The rest of the added volume comes from the taper towards the throttle body, as the front (not including the mouth) is 9.59" wide.

The nice thing about using solidworks is that every detail is known, and nothing is a guessing game. Volume, weight, every dimension... any information that you'd need is all right there.

 

Thanks Gordon, and you are correct, 20.00" at the base! Once you have an accurately modeled part, say and eblow for example, you set the material and it will give you all of the information. It does the same for assemblies.

 

looks awesome!

There's always been a thought in my mind every time I see a custom intake or single throttle setup. Anyone ever thought of adding independent throttles to the secondaries somewhere along the runners or at the entrance from the plenum to keep them closed at lower rpms to keep intake velocity high and promote better low end? They can be opened electronically or with a boost actuator.

The only one I've seen doing something in this line of thought is Defined NA semi peri 20B with ITB at the peri ports. Mazda uses a single throttle on the RX-8 with secondary valves controlled by the pcm. How come no one pays attention to this and just run all the ports open at the same time all the time?

 

A few pics of the progress... the design has evolved over the course of the build, and although a bit more complex than originally planned, it should fit much nicer in the bay.
Injector bosses will be located at the base of the top eblows, and then she'll be polished to a mirror.

 

A few more.

 

Love the integration of SolidWorks into this!

 

Fancy shmancy...can't wait to install it

 

looks great

 

And the finished manifold:

http://www.flickr.com/photos/20669521@N08/5880332842/http://www.flickr.com/photos/20669521@N08/5880332842/ by http://www.flickr.com/people/20669521@N08/, on Flickr

http://www.flickr.com/photos/20669521@N08/5879769293/http://www.flickr.com/photos/20669521@N08/5879769293/ by http://www.flickr.com/people/20669521@N08/, on Flickr

http://www.flickr.com/photos/20669521@N08/5879766497/http://www.flickr.com/photos/20669521@N08/5879766497/ by http://www.flickr.com/people/20669521@N08/, on Flickr

http://www.flickr.com/photos/20669521@N08/5880328156/http://www.flickr.com/photos/20669521@N08/5880328156/ by http://www.flickr.com/people/20669521@N08/, on Flickr

http://www.flickr.com/photos/20669521@N08/5880326254/http://www.flickr.com/photos/20669521@N08/5880326254/ by http://www.flickr.com/people/20669521@N08/, on Flickr

http://www.flickr.com/photos/20669521@N08/5879762961/http://www.flickr.com/photos/20669521@N08/5879762961/ by http://www.flickr.com/people/20669521@N08/, on Flickr

http://www.flickr.com/photos/20669521@N08/5880323192/http://www.flickr.com/photos/20669521@N08/5880323192/ by http://www.flickr.com/people/20669521@N08/, on Flickr

http://www.flickr.com/photos/20669521@N08/5880320634/http://www.flickr.com/photos/20669521@N08/5880320634/ by http://www.flickr.com/people/20669521@N08/, on Flickr

http://www.flickr.com/photos/20669521@N08/5880319196/http://www.flickr.com/photos/20669521@N08/5880319196/ by http://www.flickr.com/people/20669521@N08/, on Flickr

http://www.flickr.com/photos/20669521@N08/5879755825/http://www.flickr.com/photos/20669521@N08/5879755825/ by http://www.flickr.com/people/20669521@N08/, on Flickr

http://www.flickr.com/photos/20669521@N08/5879751645/http://www.flickr.com/photos/20669521@N08/5879751645/ by http://www.flickr.com/people/20669521@N08/, on Flickr

 

Wow man... thats some clean work

 

Wow, very nice craftsmanship. That thing is pure porno.

 

should make some good powah!

 

that nice

 

 

Beautiful. Post up before-and-after dyno results please and thank you.

 

 

Yes, please keep posting build progress. Very interested. AutoArt on that intake. Incredible work so far.

 

Very nice work!

 

Some nice manifolds within this thread. I should post up my finished N/A manifold. It came out pretty nice