quote Originally posted by Pyrthian: actually looks like a good design. even has EGR - which most wont. center balanceing tube, with all the vacuum ports. yes, it is UGLY tho, eh? and, I do question how well that thing seals to the Lower Plenum

I decided against it for several reasons. It's made of steel and heavy as hell (compared to an alloy), possible clearance problems with the decklid, and the throttle linkage between TBs looked rather suspect.

[This message has been edited by Patrick (edited 03-25-2009).]

Those ports also do not look very good in terms of size. If you use the middle section of the stock intake as runners, you still have to hog them out some IMHO.

Arn

quote Originally posted by Patrick: I decided against it for several reasons. It's made of steel and heavy as hell (compared to an alloy), possible clearance problems with the decklid, and the throttle linkage between TBs looked rather suspect.

yeah - it does look like farm equipment of some kind
but, I expect it is one of the better functioning setups shown in this thread.
large balancer
EGR
all vacuum ports accounted for
tho - I agree with arn on the ports
when I gutted & expanded my stock intake, I belled out openings of the Lower Penum ports, and looks like this one could use the same
and, looks like they sloppily goo'd this thing onto the Lower Plenum
and, yes - a nice jointed linkage between the TB's would have been nice, instead of a welded rod

and, for anyone making one in the future:
you get a little more flow, if the ports have little trumpets, sticking up from the floor of the plenum

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if ya can find a way

quote Originally posted by Pyrthian: large balancer

As has been mentioned before, the balance tube is completely unnecessary.

quote Originally posted by Will: As has been mentioned before, the balance tube is completely unnecessary.

ideally - yes - that is true - the cold start passage will balance vacuum/pressure
but, if you use the EGR, you must then feed it to both sub-plenums

Again, why? Didn't you just say that the cold start passage takes care of balancing the banks?

quote Originally posted by Will: Again, why? Didn't you just say that the cold start passage takes care of balancing the banks?

yes - the pressure/vacuum - but I dont think it will do the job of balancing the EGR gasses
tho, I suppose you could dump the EGR into the cold start passage as well
and, of course - those of us who delete the EGR - non issue

I just see the balance tube as nice spot to hook everything to.

you could fab a piece that combines the EGR and the idle air supply into that one port on the lower plenum. That way you have the EGR divided evenly between the two banks and you dont have an unsightly pipe sticking out of your otherwise very pretty dual plenum. Or is that what you've all been talking about?

[This message has been edited by MordacP (edited 03-25-2009).]

quote Originally posted by MordacP: you could fab a piece that combines the EGR and the idle air supply into that one port on the lower plenum. That way you have the EGR divided evenly between the two banks and you dont have an unsightly pipe sticking out of your otherwise very pretty dual plenum. You're welcome.

yes, that is the cold start passage

quote Originally posted by Pyrthian: and, looks like they sloppily goo'd this thing onto the Lower Plenum

I believe you mean the Middle Plenum.

quote Originally posted by Patrick: I believe you mean the Middle Plenum.

nope
Upper Plenum
Lower Plenum
Intake Manifold

There's no plenum in the *Middle Intake Manifold* (MIM). In the stock setup, the plenum is only a part of the upper intake manifold (UIM). The part that bolts to the heads is the Lower Intake Manifold (LIM).

depends on the manual, eh?
because mine says upper plenum, lower plenum & intake manifold
but, thats the joy of communication - as long as we all know what we mean - its fine
and, most are perfectly happy saying upper intake middle intake & lower intake manifold

Whatever, we're all referring to that chunk in the middle that's one of three hunks of metal which makes up the intake manifold.

I'm glad we got that worked out.

Just to be clear for everyone, the "plenum" is a large collection cavity, or a milk jug if you like.

The rest of it is "runners" or tubes.

The top of the Fiero intake is the plenum if called by any other name, and the middle and lower sections are all part of the runner system.

Hope this helps.

Arn

Ah, it was so much easier in the old days when intake manifolds were just one chunk of metal.

Even that older style intake manifold still has a plenum under the carb area, and runners. :P

quote Originally posted by Will: As has been mentioned before, the balance tube is completely unnecessary.

Only true if you balance both TBs with a pair of matched vacuum gauges or better yet long vertical tubes with water
as you would with a multi-carb motorcycle setup. But then some don't care if one half of the engine is at say 13" while the other is at 14" Also a balance tube provides a good spot for all you vacuum take-offs. I for one, would not want my power brakes only getting vacuum from half my engine.

quote Originally posted by pmbrunelle: Even that older style intake manifold still has a plenum under the carb area, and runners.

Wouldn't work very well if it didn't! x2

quote Originally posted by Francis T: Only true if you balance both TBs with a pair of matched vacuum gauges or better yet long vertical tubes with water as you would with a multi-carb motorcycle setup. But then some don't care if one half of the engine is at say 13" while the other is at 14" Also a balance tube provides a good spot for all you vacuum take-offs. I for one, would not want my power brakes only getting vacuum from half my engine.

the cold start/IAC passage will balance the vacuum/pressure
but, I agree a central balance tube is a good idea, for central vacuum & EGR hookups

quote Originally posted by Francis T: Only true if you balance both TBs with a pair of matched vacuum gauges or better yet long vertical tubes with water as you would with a multi-carb motorcycle setup. But then some don't care if one half of the engine is at say 13" while the other is at 14" Also a balance tube provides a good spot for all you vacuum take-offs. I for one, would not want my power brakes only getting vacuum from half my engine.

A balance tube should very significantly diminish the need to sync throttle bodies with manometers.

As far as the power brakes getting vacuum from only half the engine, look at the location of the vacuum source for the power brakes on a 2.5 car (or a stock 80s 305 4bbl manifold) I don't think the air volume required is very large.

quote Originally posted by Arns85GT: This guy on 60degreev6 did one. I expect you can contact him for info. http://60degreev6.com/forum...enum-part-two-t39024 Arn

That was me......
I dont hae time to reply right now, but Ive got a crap ton of info for dual plenums. mine worked great. except I made it out of fiberglass....

Will's intake > *

quote Originally posted by merlot566jka: That was me...... I dont hae time to reply right now, but Ive got a crap ton of info for dual plenums. mine worked great. except I made it out of fiberglass....

I hope you find time to reply! In fact, you could could just make your own thread with pictures of your build. The fiberglass part is very interesting.

sorry, i have no experience with this intake, but has anyone used any of these intakes on a turbo-charged car? my guess is that you would need to fab a y-pipe from the TB's to the rest of the turbo plumbing?...or would a single, larger TB design something like Truleo's result with more gains/regular driveability?

Shaun has.

EMC209i
pm sent

quote Originally posted by Francis T: Only true if you balance both TBs with a pair of matched vacuum gauges or better yet long vertical tubes with water as you would with a multi-carb motorcycle setup. But then some don't care if one half of the engine is at say 13" while the other is at 14" Also a balance tube provides a good spot for all you vacuum take-offs. I for one, would not want my power brakes only getting vacuum from half my engine.

There's a hole through the lower manifold that connects all 6 runners and eliminates the need for any balance tube.

Consider the volume of flow from the brake booster into the engine. Does that air have to be metered in a MAF controlled engine? No. Why are you worried about it affecting vacuum of one bank over the other?