Smaller plenum = more power?? It can!(sidewinder test too)

Markz · Post by **Markz** » Sun Aug 27, 2006 4:46 pm

Plastermaster wrote:[/url]merged intake header?[url]

Here is another thread on the subject.
Ron

Edit-- I cant get it to turn up as a link.

It should look like this [url*=http://www.something.com]merged intake header[/url*] note/asteriicks inserted to break the code

Post by **Piledriver** » Fri Sep 15, 2006 2:18 pm

Scored a late 2.1 Wasser plenum/TB today (actually whole intake w/injectors) for $40.
(Also located 110K mile 2.1 core for $200, got a free set of KYB shocks and free late front Wolfie/carat spoiler...)

For the record, the 2.1 WBX runners are (visually--havnt stuck the calipers on it) exact diameter to the 2.0 Porsche runners...

Bigger TB, I think.

Bigger plenum vs the T4 2.0, same layout. The 2.0 bus plenum outlets are ~3mm smaller.

Mounting needs modified for T4 case, NBD.

raygreenwood · Post by **raygreenwood** » Fri Sep 15, 2006 3:21 pm

Nice info! Thank you! Ray

Steve Arndt · Post by **Steve Arndt** » Fri Sep 15, 2006 7:15 pm

2.1 wasser TBs I have are 50mm. Haven't measured the runners yet but they are huge compared to the btlemex mexican beetle runners that I am going to use on my 2275 engine!!

Post by **Piledriver** » Fri Sep 15, 2006 9:47 pm

OK...
runners are ~1mm larger.
(still no caliper measurements, but the small gradient it the right direction, MUCH closer vs the 2.0 Bus plenum)
Plenum itself APPEARS to be only a tad bigger than the 2.0.

(I'll fill it up with water for you, Ray

)

runner offset pretty severe with 2.0 Porsche runners, but the bus one is essentially identical. something must be tweaked... Usually the long skinny things. Not going to attempt that until it's mounted.

TB has ~same mounting, OD(intake) and plenum side, but dwarfs the 2.0 internally... it's not necked down much, if at all.(TBs LOOK physically interchangable, haven't actually tried it, no spare seal gasket, and I'm chicken)

throttle is same on top... plus a switch driver extension on the bottom, could drive whatever.

throttle plate isn't flat, wedge shaped on the "in" side, (for better progression?)

The 2.0 Porsche runners are ~30mm too short to reach properly... Considering (but resisting so far) hacking off ~25mm of tube off the wasser runners and welding on.

tomtom · Post by **tomtom** » Sat Sep 16, 2006 1:52 am

This works great too!

This way you got a much better atomization and a great response from 0 to 30% Trottle position!

raygreenwood · Post by **raygreenwood** » Sat Sep 16, 2006 6:30 am

That drawing makes for nice INITIAL atomization...but actually has all the problems of carburettors. That would be the problem that fuel begins to immediately seperate from the the air and will cause the loss of most of the benefits of fuel injection on the way down the runners.
This is also why the factories have all abandoned throttle body style injection in favor of port injection. It just was not a grand result.

It is true that as far as atomization is concerned....that the venturi of a carburettor does a much better job of initial atomization of fuel and air...as compared to the injector...which produces micro-droplets. But...by the time the fuel and air from a carburettor winds its way through the plenum and runner system...it is actually much worse than what is delivered by an injector....right at the port.

An interesting cross over might be.....a port injector with a small venturi configuration installed right at the tip to take advantage of teh high velocity sweeping off of teh runner bend. I have been playing withsomething like this for a whil. I have not tested it on a running engine yet...or in the turbulence that will be in that area. Ray

Post by **Piledriver** » Sat Sep 16, 2006 9:32 am

OK, figured out another possible reason for the "wedge" shaped butterfly...

In the low throttle range, the only "active" side during the reigon of vacuum advance is the side the vac advance port is on. Better signal, and "smaller" TB effective at small throttle openings.

Post by **Piledriver** » Sun Sep 17, 2006 11:13 am

The 1,9 and 2,1 plenums appear to be identical.

(Not 100%, basing comparison on a plenum I got with a DH 1.9 junk motor, wasn't attached)

Mueller · Post by **Mueller** » Thu Sep 21, 2006 12:17 am

Ray or Jake

Has anyone seen an "iris" type throttle body??

I bought a couple of these for playing with...25mm when fully opened.

Post by **Piledriver** » Thu Sep 21, 2006 10:49 am

Those optical spatial filters are neat, but won't tolerate dirt...

VERY cool idea though.

raygreenwood · Post by **raygreenwood** » Thu Sep 21, 2006 3:46 pm

The affect an "iris" style TB would have is exactly what we were speculating about with a plateless "bullet" style. That being that it is much more encrementally adjustable.....and has no ugly plume of turbulence. But...The iris type would have just a bit more turbulence than a "bullet/plug" type one.....because when the air is being compressed/sucked through a small to mid-size orifice in the center of the iris...it will expand into the negative spaces behind teh iris plate...and begin to roll a bit. But...it has the large advantage over a plate type TB of being symmetrical at that point.

I just have been out of time lately. I am on vacation next week and will be in Vegas doing an industry trade show. I "might" have some time next weekend to finish teh series of sizing correlation drawings.....bullet vs each degree of plate type TB...to send to Jake. I knpow I promised them last month but it has been ugly. Ray

arlo · Post by **arlo** » Fri Sep 22, 2006 11:25 am

Reading through this thread I dont see the point of this quest for a less turbulent throttle valve. What am I missing here?!

The way it looks to me, at WOT the butterfly presents a pretty smooth profile to the air flow. It could easily be made smoother by contouring the shaft and adding filler. It could be made very smooth by changing it to an air foil shape and perhaps changing the throttle body to a rectangular openiing so that a foil with a uniform cord could be used. This is much simpler and more rugged than any of the ideas suggested here....but I dont believe the gains would be significant in any case for WOT. If the butterfly was producing a great deal of turbulence in this position I don't think you would see such high volumetric efficiencies (sometimes greater than 100%) at WOT in a well designed combo.

At less than WOT the turbulence IS certainly MUCH greater. Even a foil shapped butterfly would be turbulent due to separation of the flow from the foil surface at large "angles of attack" to use an airplane wing analogy. But so what? The result of turbulence would be a reduced flow into the cylinders compared to a non turbulent solution. Reducing flow at partial throttle is the only purpose of the throttle...thats why its called a throttle! Are there negative effects resulting from turbulence at partial throttle? All I can think of is uneven filling from one cylinder to the next but I think this is delt with adequately in the design of the plenum and runners. Actually, I think that turbulence is benificial in aiding fuel/air mixing for a more uniform mixture within a cylinder's volume.

These are just my thoughts, what do you guys think?

Wally · Post by **Wally** » Fri Sep 22, 2006 12:11 pm

I don't know what its called, but these 'roller' butterflies are 'IT':

Other pics of them in this photo album:
http://www.keversite.nl/fotoalbum/my_photos.php?id=1651

Enjoy!

Post by **Piledriver** » Fri Sep 22, 2006 3:33 pm

arlo wrote:Reading through this thread I dont see the point of this quest for a less turbulent throttle valve. What am I missing here?!...

I believe the issue is turbulence induced airflow distribution variations (and thus cylinder-to-cylinder mixture ), induced by the TB.

With enough distance from butterfly to plenum, or if you used an air straightener honeycomb, the problem is solved.

It is ALSO probably solved by the proposed 1>4 "HeadersByEd" collector//plenum setup.

IR setups, no issue. Additional turbulence might even be a feature, as long as it's consistent.