Intake Interest

Phinx · Post by **Phinx** » Mon Jun 11, 2007 12:15 pm

http://www.nissansilvia.com/forums/inde ... um+install

I'm phoning around lets see how much I can get this done in SA for

The Calibrator · Post by **The Calibrator** » Mon Jun 11, 2007 1:04 pm

Something like this you mean?

Which has stuff like this inside it

That is a general schematic of the plenum chamber which bolts onto the runners hence the Flange with all the holes.

By the way its not for a S anything its for another car but you get the idea

You really expect me to post everything with all the dimensions on a public forum?

Phinx · Post by **Phinx** » Mon Jun 11, 2007 1:14 pm

Help confused.. .

Wheres the inlet and the runners?

Is this a top View? Side view?

More interesting stuff.. I didnt know they still made the SR20VET 206 Kw / 305 Nm Damn

Link: http://www.nissansilvia.com/forums/inde ... pic=237435

Nissan Link:
http://www.nissan.co.jp/X-TRAIL/T30/030 ... main1.html

The Calibrator · Post by **The Calibrator** » Mon Jun 11, 2007 1:24 pm

Maybe this one makes more sense to you. Once again not for a S13 or S14.

Gary57 · Post by **Gary57** » Mon Jun 11, 2007 1:58 pm

Why are the runners 90 degrees to the plumen?? Why dont you angle them which would aid in the flow?? Its alot more work but I am sure the benefits would be good!?

The Calibrator · Post by **The Calibrator** » Mon Jun 11, 2007 2:54 pm

1: Because if you angle them you have one side of the venturi close to the wall. This limits airflow on that side.
2: Bends are a restriction the more bends you have the bigger the restriction.
3: If you angle them all the same way then the 1st one will get plenty of air and the rest will be in the 1st ones "shadow"
4: Space constraints limit the size of what can be fitted in.
5: Machining costs

Gary57 · Post by **Gary57** » Mon Jun 11, 2007 3:14 pm

Posted: Mon Jun 11, 2007 2:54 pm Post subject:

--------------------------------------------------------------------------------

1: Because if you angle them you have one side of the venturi close to the wall. This limits airflow on that side.
2: Bends are a restriction the more bends you have the bigger the restriction.
3: If you angle them all the same way then the 1st one will get plenty of air and the rest will be in the 1st ones "shadow"
4: Space constraints limit the size of what can be fitted in.
5: Machining costs

1. I meant angle them all to face the throttle body.
2. By having the runners at 90 degrees to the plumen the air is already changing direction so you cant loose much more than that.
3. The plumen should be shaped in such a way that the air is evenly distibuted. Look at a F1 air intake, its kinda triangle in shape, because the air will want to flow on the surface of the plumen the back cylinders would get more air than the front ones.
4. -
5. I think this is the biggest factor, if you told someone you can build the best air intake in the world but will cost you R12000 they would laugh at you. Just to design a decent air intake would a week or so and at R285.00/hour (or what ever you charge) is big bucks.

Phinx · Post by **Phinx** » Mon Jun 11, 2007 3:22 pm

Phinx · Post by **Phinx** » Mon Jun 11, 2007 3:24 pm

Phinx wrote:

Its call a velocity stack, The above picture is a 2002 F1 car's intake system.
The Intake that Calibrator suggested is correct and would probably flow the best

Gary57 · Post by **Gary57** » Mon Jun 11, 2007 3:33 pm

But you forgot to add the picture of the air intake cavity, the F1 one is very intricate in design and uses the gas laws to aid in the flow into those cylinders. As I said they are "trianglular in shape to even disperse the air through out all the cylinders. They also have vents, ducts and channels to speed and aim the air going into the cylinders. I read somewhere that a F1 motor can as much as 0.5bar positive pressure at the inlet valve, yip that means boost from a NA motor.

The plumen Duane will make will probably be a hollow cavity so nothing aiding in the filling of the cylinders. But as I said I think cost in the major factor here.

I personal like the shape of the stock one, I think if you could take most of the metal away and seriously flow it you could get some good results. But then again I know nothing of our plumens, never had mine off.

Phinx · Post by **Phinx** » Mon Jun 11, 2007 3:38 pm

But Duane's Will be shaped very similarly to control the path of the air.

It will tapper down to the end on the intake

The Calibrator · Post by **The Calibrator** » Mon Jun 11, 2007 3:48 pm

1. I meant angle them all to face the throttle body.
2. By having the runners at 90 degrees to the plumen the air is already changing direction so you cant loose much more than that.
3. The plumen should be shaped in such a way that the air is evenly distibuted. Look at a F1 air intake, its kinda triangle in shape, because the air will want to flow on the surface of the plumen the back cylinders would get more air than the front ones.
4. -
5. I think this is the biggest factor, if you told someone you can build the best air intake in the world but will cost you R12000 they would laugh at you. Just to design a decent air intake would a week or so and at R285.00/hour (or what ever you charge) is big bucks.

If you angle them all to the throttle body you will get shrouding unless you have a huge plenum and point them all in different directions ala BMW M5 and the only reason the angle them is due to height constraints.

The whole idea of a plenum is to have a reservoir of air that the motor draws from, not to direct the air down each runner. BMW's intake systems are among the best in the world and not one of them does as you suggest.

The reason the plenum is big in front and tapers is to allow the air to slow down immediately after the intake so that you dont get it bypassing the 1st runners.

I think you are referring to the 2nd drawing, the 2 venturis are misleading there are 4 but I have only shown the 2 outer ones.
They are actually welded to a flange which is bolted to ITB's the intake to the right is only a intake not a throttle body.

The plenums above are under construction. The ITb's are bolted onto a 2.2ltr SR20DE with equal length exh manifold and T3/T4 turbo. It also happens to have HKS cams and Greddy cam gears in a flowed head.

Pics on my website ( turbo sabre)

The Calibrator · Post by **The Calibrator** » Mon Jun 11, 2007 3:53 pm

The F1 cars will have positive pressure due to the ram effect of air being forced into the plenum at high speed.

If you give me a F1 budget I will also make you a carbon fibre dream.

OEM intake manifolds are fairly well designed with the cars intended use in mind.
Its only when you start looking for every last hp that you would need to change it.

Vlade · Post by **Vlade** » Mon Jun 11, 2007 3:57 pm

Ummm interesting stuff as the topic siaz...

On the CA18DET I can nearly confirm that the first cylinder doest get more air than the rest, how can I confirm this?

Well on all the import motors I the first intake chamber are always the dirtiest on mine and Ero's I had to manually clean them...

Also our plunems serve a duel purpose, its meant for FWD engines and RWD, on FWD engines the intake actually sits on the opposite end, one can actually swap the front and the back...

So the Nissan boys didn't design ours for performance but rather for re usability and cost saving... would be nice to see what performance increase you can get from just a decent designed plunem its like free power

The Calibrator · Post by **The Calibrator** » Mon Jun 11, 2007 4:01 pm

Well on all the import motors I the first intake chamber are always the dirtiest on mine and Ero's I had to manually clean them...

Dirty intake runner normally means
Little airflow (leass than the others) Dirt settles where the air speed is lowest.
Reversion ie intake valves dont seal properly or cam overlap excessive at low rpm.
Engine breather directed to or near the runner in question.

in any engine the cleanest intake runner assuming a good condition engine will have the highest air flow.

Sorry