Why is it on headers that all runners lead to a common nice collector...even so on the turbo manifolds to promote the pulsing.

Now why isnt the same applied to intake manifolds.....have all the runners connect to a common collector ....instead of a plenum.....and have a throttle body on the end of the collector????

 

It's been done before; although it doesn't have quite a merge collector like the one you're showing. This is a BBC 472 cubic inch quad turbo motor. Notice how the twin intake manifolds are designed:



Bad picture, but here's something I was working on 2 years ago. The manifold is from a Toyota Corolla, but the distance between the runners are close enough to weld to a B-series head flange. I was building a turbo B-series motor, I never completed the project. I believe this setup would work better than a conventional intake manifold; the air distribution would be more even. If a single plenum manifold is not designed properly, you can starve the last cylinder that's feeding off of the plenum.

 

if your not running a plenum i would think, that at partial throttle 2 of the runners would get less airflow that the other two because of the angle on the butterfly valve, same if you used a giliotine style tb.

 

There was alot of research on this on i forget the car board but like stated at part throtle two of the runners near one side of the TB would get more air then the others. Unless you had a long collector then this would solve that problem. Also the toyota corolls and some ford FWD use this too

 

nice quad turbo set and all, but why do I see shitty wastegate set up? like 2 inch primary on header I guess and everything else and like like half inch or something small tube is coming to wastegate. how V8 with 4 turbo regulating boost on with that.. amazing
I guess 60+psi dont really need bigger wastegate. I guess

 

The pleneum acts as a spring for the resonant waves bouncing back from the intake valves. Unlike the exhaust side were you are trying to evenly space the pulses and they aren't reflected, the intake side of the motor reflects these pulses to create a sort of constructivness to achieve positive pressure in the manifold at a specific rpm. A collector on the intake side, which would essentally be a very small pleneum would have amazing throttle response but no high rpm support capability. This is why you see it on some oem applications. A collectored intake manifold would probably create some impressive top end #'s but would not be a good all around setup, just stick with a plenum type. If you want to learn more on this resonance, look up Helmholtz Resonance Calculations, also team-integra.net has a good article on this.

Edit:
And on that V8 above it does have a plenum, albeit a small one. And the very small wastgate tubes are probablly really good at fine boost control unlike an inconsistent huge tube that would cause a psi drop upon opening.


Modified by savestheday at 8:07 AM 4/26/2007

 

I've been planning on building an intake manifold this way for quite some time now, except I am going to put a plenum on it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by savestheday &raquo;</TD></TR><TR><TD CLASS="quote">The pleneum acts as a spring for the resonant waves bouncing back from the intake valves. Unlike the exhaust side were you are trying to evenly space the pulses and they aren't reflected, the intake side of the motor reflects these pulses to create a sort of constructivness to achieve positive pressure in the manifold at a specific rpm. A collector on the intake side, which would essentally be a very small pleneum would have amazing throttle response but no high rpm support capability. This is why you see it on some oem applications. A collectored intake manifold would probably create some impressive top end #'s but would not be a good all around setup, just stick with a plenum type. If you want to learn more on this resonance, look up Helmholtz Resonance Calculations, also team-integra.net has a good article on this.

Edit:
And on that V8 above it does have a plenum, albeit a small one. And the very small wastgate tubes are probablly really good at fine boost control unlike an inconsistent huge tube that would cause a psi drop upon opening.


Modified by savestheday at 8:07 AM 4/26/2007</TD></TR></TABLE>


That sounnds like a very good answer, but until there are some dyno sheets or some hard data written in stone, I will back off from buying into it....
and also ...doesnt your answer only apply to normally aspirated motors????? (the resonance???)
for forced induction: the "collector design intake" would evenly distribute forced inducted air

 

Anyone else notice how horribly small those two tubes going to the WG are?

leaves me to beleive this motor never actually ran.

But there is a purpose to a properlly designed plenum. It equalizes the intake pressure and volume that each cylinder receives. I'm sure Geoff or someone else could describe why a plenum is benefical.

I remember Cody actually tried this once, and ended up not using it.

 

The wastegate tubes probably don't matter much as they probably aren't really used, the turbines are sized properly to the engine/manifolds/headflow etc. I've done this with my diesels, absolutely no wastegate, obviously the turbine needs to be sized very well to pull this off.

 

something like this? Toyota corolla.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by savestheday &raquo;</TD></TR><TR><TD CLASS="quote">The pleneum acts as a spring for the resonant waves bouncing back from the intake valves. Unlike the exhaust side were you are trying to evenly space the pulses and they aren't reflected, the intake side of the motor reflects these pulses to create a sort of constructivness to achieve positive pressure in the manifold at a specific rpm. A collector on the intake side, which would essentally be a very small pleneum would have amazing throttle response but no high rpm support capability. This is why you see it on some oem applications. A collectored intake manifold would probably create some impressive top end #'s but would not be a good all around setup, just stick with a plenum type. If you want to learn more on this resonance, look up Helmholtz Resonance Calculations, also team-integra.net has a good article on this.

Edit:
And on that V8 above it does have a plenum, albeit a small one. And the very small wastgate tubes are probablly really good at fine boost control unlike an inconsistent huge tube that would cause a psi drop upon opening.

</TD></TR></TABLE>


I want my 15 seconds or so back for reading this.


A common single throttle body plenum doesnt work well for distribution imo its like running at full speed and then trying to make a right turn into an intake runner.

All cylinders dont make the same horsepower, one cylinder will be colder one cylinder will be hotter. Distrubution matters a great deal.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boostwerks.com &raquo;</TD></TR><TR><TD CLASS="quote">Anyone else notice how horribly small those two tubes going to the WG are?

leaves me to beleive this motor never actually ran.

</TD></TR></TABLE>

There's also two turbos it feeds off of and I would debate the need for a bigger wastegate. Would you want to run low boost on that engine?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote &raquo;</TD></TR><TR><TD CLASS="quote">
But there is a purpose to a properlly designed plenum. It equalizes the intake pressure and volume that each cylinder receives. I'm sure Geoff or someone else could describe why a plenum is benefical.

</TD></TR></TABLE>

A plenum is to meet ( and exceed) the capacity of the cylinders its feeding if you want to meet the needs ( you got one big bitch of a plenum)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by hmongboyLS &raquo;</TD></TR><TR><TD CLASS="quote">something like this? Toyota corolla.

</TD></TR></TABLE>

Yup, that's the engine my manifold came from. I still have it, with the flange and plenum cut off. Let me know if anybody wants it!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MidShipCivic &raquo;</TD></TR><TR><TD CLASS="quote">

There's also two turbos it feeds off of and I would debate the need for a bigger wastegate. Would you want to run low boost on that engine?

</TD></TR></TABLE>

? that honestly makes no logical sense as an argument to what I said.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Boostwerks.com &raquo;</TD></TR><TR><TD CLASS="quote">

? that honestly makes no logical sense as an argument to what I said.
</TD></TR></TABLE>

BullShit .. If I ran a small wastegate on a large turbo setup I have no intention of running low boost because it wouldnt be capable of doing so.

 

All that piping looks to be aluminum, interesting. Should disepate heat but will they last.

Who's motor is that? I saw that Mike Moran on his Camaro "Casper" was trying to run the quad set up.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MidShipCivic &raquo;</TD></TR><TR><TD CLASS="quote">

BullShit .. If I ran a small wastegate on a large turbo setup I have no intention of running low boost because it wouldnt be capable of doing so. </TD></TR></TABLE>


Exactly. Most people have no clue the reason why a large capacity WG is needed.

They are used for low boost on large turbos. The reason is that you need to bypass so much of the exhaust to keep the turbine wheel under control. If you are running them to the max, most of the exhuast flow goes through the turbine, not the WG.

 

the pontiac quad 4 had a same style of intake mani i kinda tried to make it fit my old saturn but had no luck

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by MidShipCivic &raquo;</TD></TR><TR><TD CLASS="quote">I want my 15 seconds or so back for reading this.


A common single throttle body plenum doesnt work well for distribution imo its like running at full speed and then trying to make a right turn into an intake runner.

All cylinders dont make the same horsepower, one cylinder will be colder one cylinder will be hotter. Distrubution matters a great deal.
</TD></TR></TABLE>

I can't give you any hard data to show against what you're saying, but in reality the air coming into a plenum style manifold is not a constant flow sort of thing that needs to be directed evenly into each cylinder. The valves opening and closing are sort of an on/off switch for needed air supply. In a full throttle environment (no vacuum) no cylinder will be starved for air, unless the engine is at a considerably high rpm, the far wall of the plenum is poorly designed, and the cylinders are fighting for the available volume of air.

I would assume this is why most forced induction manifold have large plenums, to support the needed volume of air. Engine displacment X Boost = Plenum size, sort of thing.

Don't take any of this as fact, i'm just speculating. A plenum manifold might work well, but i think it would create a good bit of surging on throttle input and not make as much power as a well designed harmonic manifold.

- Geoff