MODIFICATION , EFI Electronic Secondary Stage Controller

[Vanilla Sky]

well, one of my reasons to go electronic is to get rid of as many vacuum switches and lines as possible while keeping stock functionality... while a switch controlling the solenoid works, i'd rather have a solenoid controlling the butterflies directly... all in all, i'm not that big on everything being vacuum controlled

[POS carb]

shit I have vacuum solenoids... I can rig something up
who wants to be a guinea pig

[Vanilla Sky]

lol... i'd rather do it with electronic solenoids, though... push/pull type... like i said, i wanna do this, but mostly to get rid of some of the vacuum lines

[POS carb]

it's basically a vacuum "switch" that will feed the secondary constant vacuum from the manifold/canister and keep them shut. It would come with a WOT switch that would vent the diaphragm to the atmosphere when you punch it and siultaneously lock the vacuum inside the tank so that it'll close the flaps when you ease off the gas again. 2 parts, 1 wire, 1 extra vacuum line is all you need.

[Vanilla Sky]

but i wanna get rid of vacuum lines not add :p

[POS carb]

then just run a direct tap from the diaphragm to the intake manifold and get rid of the control system, it'll work just fine like that.

[Vanilla Sky]

because then it wouldn't have a set RPM to kick in, just would open during certain vacuum conditions

[Vanilla Sky]

that's the site i was going through when i thought of it...

i jsut don't know if that thing sweeps enough...

[Vanilla Sky]

i was thinking a continuous duty solenoid that would normally hold the butterflies closed... could go the other way, though... could even scrap the spring return and have the solenoid the only thing keeping the butterflies in place

[A20A1]

I wonder if one of my RC servos would work... too bad I took apart my secondary plates.

[Vanilla Sky]

it should... probably better than the solenoid... good call...

[pookypal15]

I was cleanin my intakes and I thought about removing the secondary throttle, that I belive opens up at like 3k+ rpm, I searched the forum for as much info as possible becuase I also wanted to get rid of all those vac hoses on the box connecting to the intake and found out I couldn't really do that without an ECU swap right? So my reason for removing that secondary throttle is alow more air in lower rpm = more power, but is this gonna disturb the ecu, since I noticed the throttle thing is eventually also linked to the box? The Haynes book doesn't say much other than I remember something like it helps keep proper RPMs during gear changes, or something like that, and should be serviced by dealer? What do you guys think... good idea/bad idea?

Anyway, BTY, I've also bypassed alot of things. For instance the heater doesn't get any coolent from the main supply, it's just rerouted back to itself, and the pipe that came from the main coolant line just runs back to the coolant. I also noticed some more stuff off the coolant line that feeds into the intake, and the Haynes doesn't say much about it, anyone know what it is? I was stabbing at it being enginemangement that keeps engine from overheating in excessive RPMs by spraying tiny amounts of coolant since I noticed my intake was all gunky - but it doesn't make sense since coolant is hot when the engine is overheating... Anyway, I took those off the intake and I need to put gaskets and plates on them to make them airtight, but I already bypassed whatever two mechanisms were feeding the intake and just used a longer hose so it plugs back into itself in the main line. I wish I could show pics, but can't sorry - digicam is outta service, let me know your opinions or anything I didn't explain :smilie:

[A20A1]

Well the box controls the opening of the secondary butterflies. You could hook the secondary diaphragm directly to a port on the intake manifold and bypass the box, but then it would be simply based on vacuum with no intervention from the control box, but you would still have operable secondaries.

As for your coolant mods... Sounds like you bypassed the TB heater perhaps and the cold start valves? Someone with more EFI expreience could probably point things out better.

BTW coolant is not sprayed into the motor at all... most coolant things are there to heat parts up... or to control temperature sensative valves that close or open depending on the coolant temp.

as for the intake becoming gunky, I'm not entirely sure but I think your PCV feeds into the intake prior to the TB... if that is the case your manifold and TB will become gunky cause it's injesting blow-by gasses mixed with oil.

[pookypal15]

hhmmm... that's a better explanation about the coolant mechanisms... it's been runin fine without them, but I'm not actually positive because I haven't driven it on the streets. My theory though is it should help maintain power while the engine stays on for long period since there won't be hot coolant surging around the intake housing - and it doesn't get cold here so I'm not too worried about that, plus with the shortened overall distance the coolant travels - that can't be bad.

So if the secondaries are based on vacuum, the more vacuum they get the more likey they are to open? Of course I can try to test it out, but I won't be able to visually see what's happening, but if I can get the butterflies to open up much lower, at like 2k rpm, that would be awesome. I don't know really how those systems work, I'm guessing, so correct me please

[A20A1]

So if the secondaries are based on vacuum, the more vacuum they get the more likey they are to open? Of course I can try to test it out, but I won't be able to visually see what's happening, but if I can get the butterflies to open up much lower, at like 2k rpm, that would be awesome. I don't know really how those systems work, I'm guessing, so correct me please

No they open when there is no vacuum supplied to the diaphragm that controls the throttle plates. If you simply disconnect the vacuum line from the diaphragm and plug it to stop any vacuum leaks you'll see the effects of the secondary throttle open all the time.

Vacuum drops naturally as you open the throttle... at wide open throttle ( WOT ) vaccum should drop to "0"

I'm thiniking about what cke said... I assumed the solenoid held onto vaccum to keep the throttle plates from opening even as vacuum dropped in the manifold. The once the time was right the solenoid bleeds the vacuum and the secondaries open.

[pookypal15]

well thanx guys, I have alot more to work with now

[pookypal15]

Well here's how it went, but it's a shame I can't show pictures..

I cleaned entire intake man with toothbrush and TP and I noticed that all those vacuum lines are numbered, but doesn't necessarily matter what order they connect to intake - as long as they get vacuum (except for the one that connects to the thing that opens the secondaries). My intake was pretty disgusting, but after it being fresh I connected everything and fired'er up and she ran real smooth for 2 seconds and then started revvin up and down. Realized that pipe from crankshaft to intake to recirculate gases wasn't hooked - but it gave me the idea that that was part of what was makin my intake dirty/gunky (Which A20A1 said, dunno why I was think coolant spraying in the engine) and robbing a little power from the heat. So I simply bypassed the intake and routed it right back to the PCV on the top on the engine. But now I had to get my intake airtight to keep it from doing that idling thing, and what I really want to do was keep my secondaries open at lower rpm...

I figured routing a pipe from where crankshaft gases used to enter down to the mechanism that opens the secondaries would work, but I had to use two pipes of different diameter and make sure they were air-tight, otherwise it wouldn't idle right. It ended up working a little different then I thought, a little too good - there's so much suction that the secondaries stay wide open all the time and I can't control them - I was hoping I could maybe get it set to where they start opening alow in the 2k's RPMs. And since the line to the box now isn't feeding the thing, for now I've just plugged it but I will try between feeding directly from a free vacuum line or one that is somewhat regulated to fool it into thinking nothing's changed (but I haven't thought of anything yet or know much of how it works)

I gotta go around and drive and see the penalties of wide open secondaries all the way through the RPM range, until I figure out how to control the vacuum to the mecahnism without doing anything to complicate - but thanx cke and A20A1

[A20A1]

? the secondaries close with vacuum. If you disconnect the secondary vacuum source the spring tension causes them to open on their own.

I'm a little comfused what you did with the PCV... as long as it gets manifold vacuum you're okay. Cause you need to vent blow-by gasses.

[pookypal15]

If I understand correctly the blow by is sucked into the intake and burned off again as an emissions measure? and the PCV does the same? So I connected those two, which would in my theory just mean the oil collects it instead of making a combustion filled with blow by gases or alternately venting it into the atmosphere - which for the PCV is popular, but I haven't seen/heard about venting the one down from the crankshaft (it's hard to word because I can't come up with specific names of the components). And that's probably not popular cause it'll mess up the idle unless the intake manifold is completely airtight (PCV just connect to intake tube, right?).

So I'm not denying anything said about the vacuum about the mechanism that opens the secondaries, but it actually seemed quite simple in practice. The tube that usually goes to the mechanism to the black box can control it, and this is easy to watch... with no vacuum it does nothing, but if you plug it to a spare vacuum line on the intake manifold that hasn't been taken up (there's like only 1 left over that has a stock stopper on it) then the suction, even at idle is enough to fly it open. My problem I believe is using too big of a vacuum line - the one that pickes up blow by, so it'll be permanantly open and there's not a gradual openining as suction increases. I don't know if you can interchange suction and vacuum but hopefully it makes so kind of sense? As for the feed line to the box I drove with it plugged no problems

So as cke mentioned, (but I haven't evaluated to my satisfaction whether to keep it like this) it's probably not the best mod without some mods down under already. There was only a very slight difference in sound, the tone was a bit deaper. When i had cleaned my intakes, the engine was smoother and more responsive - after messing with my scondaries, it lags especially in the low 1 and 2 whenever I'm rolling - for instance, I can't really start in second like I used - it takes alot more gas. But the most noticeable difference is better pull where the power was at originally, and slightly deeper sound where the power is not/slow driving. It acts alot like a turbo car with lots of lag with the way it pulls now

[A20A1]

At idle vacuum is high in the manifold
Vacuum drops as you step of the gas... As vacuum drops the secondaries open assuming the solenoid isn't blocking off the vacuum till it decided to drop it on it's own.

A bigger vacuum line will supply more vacuum but if the ends aren't restricted then the vacuum will drop off a little quicker.

The VENT hose from the valve cover is a part of the PCV system and can vent to the intake pipe... the PCV VALVE needs to have manifold vacuum applied in order to operate the Valve.

Manifold vacuum and Intake pipe vacuum are not the same.

Manifold vacuum is created because the throttle body is closed. Vaccum is measured after the Throttle Body.

Intake vacuum is the air suction created when the throttle body is open.
Vacuum is measured before the throttle body.

[pookypal15]

AH $#@!, so as I'm steppin on it the butterflies are probably closing.... $hit.. that explains why they stay open so good at idel.. You gotta excuse me, lots more to do and learn. But thanks for your help

[Oldblueaccord]

I was cleanin my intakes and I thought about removing the secondary throttle, that I belive opens up at like 3k+ rpm, I searched the forum for as much info as possible becuase I also wanted to get rid of all those vac hoses on the box connecting to the intake and found out I couldn't really do that without an ECU swap right? So my reason for removing that secondary throttle is alow more air in lower rpm = more power, but is this gonna disturb the ecu, since I noticed the throttle thing is eventually also linked to the box? The Haynes book doesn't say much other than I remember something like it helps keep proper RPMs during gear changes, or something like that, and should be serviced by dealer? What do you guys think... good idea/bad idea?

Anyway, BTY, I've also bypassed alot of things. For instance the heater doesn't get any coolent from the main supply, it's just rerouted back to itself, and the pipe that came from the main coolant line just runs back to the coolant. I also noticed some more stuff off the coolant line that feeds into the intake, and the Haynes doesn't say much about it, anyone know what it is? I was stabbing at it being enginemangement that keeps engine from overheating in excessive RPMs by spraying tiny amounts of coolant since I noticed my intake was all gunky - but it doesn't make sense since coolant is hot when the engine is overheating... Anyway, I took those off the intake and I need to put gaskets and plates on them to make them airtight, but I already bypassed whatever two mechanisms were feeding the intake and just used a longer hose so it plugs back into itself in the main line. I wish I could show pics, but can't sorry - digicam is outta service, let me know your opinions or anything I didn't explain :smilie:

well couple tips ill just quote outta the book
page 12-69 the secondary only opens after 5 k rpms its vacuum line #13
there should be manifold vaccuum at idle on #13 none after the 5k rpm set point.

If your tricky I would guess you could manipulate the voltage to the sensor that controls it in the Map sensor box and vary the set point soome how.

Good luck.


wp

[Vanilla Sky]

cool to see one of my ideas come to fruition. good work, man.

[A20A1]

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https://www.3geez.com/showpost.php?p=396504&postcount=28

I was talking about that last year, cept in place of the Mechanical trigger (Adjustable, based on throttle linkage position) you use the RPM trigger (Adjustable, based on RPM). I would agree to the RPM swith being better then a Mechanical one.

Still the same issue is present, not that it matters because no one would open the secondaries very early.
Anyways what I said in the link is there was a limit as to how early the secondaries could open based on how much vacuum is still present in the manifold... though it will drop off rather quickly at WOT.
As a fix to that issue I then suggested the use of Dual solenoids... one would bleed of vacuum from the Vacuum holding cannister while the other would block any Residual vacuum signal from the Intake manifold.


Nice write up.


I'm just throwing this out here in case someone asks.
For carburetors you would need to disengage any mechanical link on the secondary and reverse the pull or direction of the diaphragm to allow manifold vacuum instead of venturi vacuum to control the secondary... only danger is you must be certain your solenoid isn't leaking and that there are no vacuum leak in the system or you'll run into a dangerous threat of the secondary opening when it shouldn't and you not being able to bring down the throttle.
IMO it't not a good idea to do.
Basicly for carbs you're stuck with:
- Pure Venturi vacuum
- Mechanical Secondary
Or the stock - Mechanical / Venturi Vacuum Hybrid.
Any adjustablility would have to be in the spring tension or how you set up the ratio on the mechanical linkage

[Vanilla Sky]

well, one way to get rid of the vacuum problem would be to go fully electric. i don't see it as much more work than this, if any at all.