IJSTBRNDU

thats how my manifold is different...i can't say much without giving it all away, but it does not have a "traditoinal plenum" and each cylinder should get almost dead-on equal airflow.

and yes...i'm getting it tested

Caj Darkmoon

Well I at least wish you good luck man wink1.gif

tanc

I wish you good luck as well, and I would like to see some flow charts when your all finished as well smile.gif

Heres a bit of what I know....Intakes and exhaust systems are voodoo black magic throw the chicken bones pieces of an engine and need to be designed as such. You could do Helmholtz http://www.phys.unsw.edu.au/~jw/Helmholtz.html calculations to match the runner length to your desired operating band but in the end without a dyno to test various runner lengths you're just shooting in the dark at a target even the automakers can't theoretically hit.

For a force-fed application, runner design is less of a factor than for a N/A design. Plenum volume is the key---the rule of thumb is plenum volume >= engine volume when force-fed. A large plenum has a few draw backs though so it is not the magic bullit either. A large plenum breathing through a single butterfly will have a lag between throttle opening and engine response.

Basically...... there is no easy recipe for intake design. There are some rules of thumb---long thin runners=low end torque, short fat runners=high RPM power plenum volume=engine volume for superchared applications but there is no perfect solution nor is ther an easy formula (helmholtz calculations can get pretty scary when one takes valve timing exhaust pulse velocities, intake pulse velocities exhaust length and desired operating conditions into consideration....even then there are 12937492137 factors not even accounted for so you are nowhere near optimal indifferent.gif

Anyhow, I hopefully my experiance going through this proccess will help you out.

daoust

<div class='quotetop'>QUOTE (tanc @ Apr 5 2007, 12:38 AM) <{POST_SNAPBACK}></div><div class='quotemain'>We'll it's very similar to a magnus manifold. Look it up.

Btw, it's not as simple as you think. You have to calculate your runner lengths, volume, plenum volume, how much room to leave on the side of the plenum, etc. It all has to do with the air waves bouncing through your whole set up down into your valves. All your ports also have to receive the same amount of air at the same time.

That is why I have got mine flow tested a cpl times.</div>


don't waiste your time on a flow bench , some intake flow less and give you more power . don t forget , there is also the velocity , too much flow kill the velocity .

''the runner length , go with the duration of the intake cam and induction waves '' 1 or 2 or 3 ''
the runner size , go with the size of the valves
and the plenum size , for the size of the engine ''

tanc

I wasn't using the flow bench to see HOW much the intake flows, but to see how it flows, where it flows, and the rate each runner flows. I used a wet flow bench.

"go with duration of the intake cam and induction waves for runner lengths" ...so your telling me 1" , 2" or 3" runners?

Show me some proof to your theory.

demon_fox

no quoting post above yours

tanc

Good eye, but I hit the wrong reply button.


Warning a mod is a 25% warning increase... lmao.gif JK. Good thing you pointed it out, I wouldn't want to set a bad example for the young guns.

'treezy

<div class='quotetop'>QUOTE </div><div class='quotemain'>We'll see if ERAU's engineering courses are any good...lol</div>

Who was your Aerodynamics Instructor? Prescott Campus?

I'm building a 9hp shopping cart with Art Draut (flew F104's/test pilot) for our club. LOL, he's getting a kick out of it.

DTN

is there any advantage to having an intake like the Eclipse with no plenum and 4 runners right on the TB?

tanc

Are you referring to individual tb's with the velocity stacks?

It's a big gain for N/A engines, but I haven't seen a tib run with stacks. It's an expensive fab. I'm not sure the gains on a beta.