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1988starter
07-26-2003, 07:29 PM
Here are some methods used by members to FIX / MODIFY / DISABLE the EFI Secondary.



If you've done the basic I/H/E to your A20, you might want it to breathe just a wee bit better then it did when it came off the assembly line.

Our secondaries open up at 5,000 RPM. Now with the stock setup, I guess that was just enough to push it that much further down the road. If you want full control and the ability to fine tune your curves out more, this might be a good idea.



Parts Required:
RPM Window switch (MSD (http://www.msdignition.com/rpm_7.htm), Summit Racing (http://store.summitracing.com/default.asp?Ntt=RPM+Switch&x=0&y=0&Ntk=KeywordSearch&DDS=1&searchinresults=false&N=0&target=egnsearch.asp), et cetera.)
Wire screwcap, electrical tape, solder, or whatever you want to use to junction your wires. (It's up to you.)
Spare length of wire with a clip on the end.

======
Note:
Personally, I think the Summit Racing switch is the best value for the buck.
For $20 less then the MSD switch, and the ability to fine tune whatever RPM you want, it's the pick of the litter. No "pills" to deal with, no wire cutting/selecting BS.
======
First, open your magical black box. Take the four screws out of the rubber float section, flip the thing over. Check out where #13 and #12 run. That's the solenoid we're going to deal with.

Since I'm not sure if wiring changed from year to year, do this. Put the keys in, set her on "ON." Take out the test length of wire. Pull off one connector to the solenoid. Connect the test wire to the exposed pole, and repeatingly tap the other end to a ground point. If the secondary diaphram opens and closes, you found the ground.
If it wasn't that pole, then it has to be the other one. Leave the connector off once you found it, and take the keys out. Disconnect negative off the battery.

Wiring directions for the MSD and Summit units:

Connect the red wire to your coil's positive terminal.
Connect the white wire to your coil's negative terminal, or if you have an ignition box, the tachometer output.
Connect the black wire to a nice and solid ground.

Since it's a closed circuit, we want to hook up the Grey wire to the solenoid. Either reuse the connector from the stock wire or just solder it directly on.

Mount the switch somewhere nice, dry, and safe. Maybe you can find a spot for it in the black box.

Put negative back on the battery, put your car back into the "ON" position.
If you hooked either example switch up right, you should get a status LED on.

Now with the Summit unit, it will be set up to toggle on at 5,000 RPM by default. Set the dip switches at whatever RPM you want. If it needs calibration, check out their PDF. It's pretty simple.

With the MSD unit, put in whatever RPM pill you want.

Fire up the car. After it warms up a little, bring the throttle up a little bit at a time until you hit/exceed your target RPM. Hopefully if you wired it up right ( :uh: ) it should open them right up, and the status LED should change color.

Now go play with a dyno, use your butt dyno, G-Tech, or whatever method you want to go find the perfect open time for your setup.

Using the BD, I found that my sweet spot is at 4,100.

Depending on whether or not you have a decent cam, your mileage may vary.

Should make things a little more interesting and fun. =)




OK Yesterday I embarked on a quest to fix my secondary butterflys. The end result was an assload more low end torque BTW this only applies to 88,89.

OK first off the most common problem they are not working is the fact that the silinoid has died you can get a new one from a junkyard and efi accord 86-89 will have one and I have an extra and I will let it go for 15 (plus shipping if it is a mad amount but I don't expect I will even care uless I send it to canada or some place like that) any way here is a picture of the inside of the box

http://www.3geez.com/attachment.php?attachmentid=4507

you want to replace the bypas controll piece. Well after I replaced mine still nothing then I noticed that there was no suction from any of the 2 hoses going to it I think their was a jam in the vacume canaster (below) so I removed it and just used the check valve to hold them together. The check valve was one way on my car so blow through it to make sure it flows in the right direction (green arrow) now they should work hazzaa and enjoy your recovered power.
http://www.3geez.com/attachment.php?attachmentid=4506

shepherd79
07-27-2003, 03:46 AM
nicely done.

AccordEpicenter
07-27-2003, 09:14 AM
yeah... i had the same problem, my solenoid wasnt dead but it would work intermittantly... Also you can use one from any 86-89 accord emissions box, just make sure it works and it does what you want it to do.

Justin86
07-27-2003, 09:45 PM
I might want to invest in a 88-89 intake manifold. Maybe I can pull one out of the junkyard in the middle of the night. or something like that. :D
How about a how to on this.

1988starter
07-28-2003, 06:56 AM
Last time I went to the junk yard I noticed the 88 and 86 were quite different different TB set up along with a bunch of other things including idle controll it may be a project but it could work.

1988starter
07-29-2003, 09:54 AM
Originally posted by Justin86
I might want to invest in a 88-89 intake manifold. Maybe I can pull one out of the junkyard in the middle of the night. or something like that. :D
How about a how to on this.

I was just looking at the parts online I bet you could do this conversion just compair the parts in the JY

BITESIZE
09-21-2003, 07:40 PM
The conversion involves at least 15 horespower, considering the hp difference between a 86/87 versus a 88/89. Those secondary butterflies suck a lot of air!

Justin86
09-22-2003, 06:35 AM
Well hopefuly I will be getting some Se-i parts here soon. I will grab the intake manifold and rear brakes.

Swan
09-22-2003, 09:33 AM
ok, its time to admit that I know nothing about this! I was looking at my box thing the other day, and I noticed that the two little things that look kinda like some kind of filter (which I just found out is the ignition control and bypass control)... anyway, my bypass control looks like a dirty filter, more of a brown instead of yellow.... is that my problem? or is that the part to replace? also, if you get one of these from junk yard, how do you know it will work? could you get a new one from a parts store or the dealership? I know dealership is a buttload of money, but I'd rather pay more for something that is guaranteed to work than pay a little for something, find out it doesn't work, then have to go back and buy another one which may not work....

1988starter
09-22-2003, 02:17 PM
Originally posted by Swan
ok, its time to admit that I know nothing about this! I was looking at my box thing the other day, and I noticed that the two little things that look kinda like some kind of filter (which I just found out is the ignition control and bypass control)... anyway, my bypass control looks like a dirty filter, more of a brown instead of yellow.... is that my problem? or is that the part to replace? also, if you get one of these from junk yard, how do you know it will work? could you get a new one from a parts store or the dealership? I know dealership is a buttload of money, but I'd rather pay more for something that is guaranteed to work than pay a little for something, find out it doesn't work, then have to go back and buy another one which may not work....

Most junkyards let you return defective parts I grabbed 2 just in case from an 86 accord (same sensor different controll) and they both worked. I think it was about 70 bucks at the dealer.15 at the junk ard.

BITESIZE
09-22-2003, 02:22 PM
I took those stupid little filters off (the ones under the Box).

Versanick
09-22-2003, 07:34 PM
Okay so these things do or do not apply to my 86 LX-i intake? That intake's probably slowing down my b20, huh. Would a butterfly conversion help me out a lot?

Or am I an idiot?

BITESIZE
09-22-2003, 07:59 PM
Yes it would. The 86/87 lxi on has single butterflies. I'd say your increase would be at least 20 hp, considering the 86/87 came with 100 hp? and the 88/89 came with 120 hp?

1988starter
09-23-2003, 07:18 AM
The 86 and 87 came with 110 and the 88 and 89 had 122 the butterflys help a lot but are not the whoole reason for power there was a large compression increase and anew exhaust manifold used along with some removed vacume lines.

1988starter
09-24-2003, 04:24 PM
Originally posted by BITESIZE
I took those stupid little filters off (the ones under the Box).

why

1988starter
12-06-2003, 08:07 AM
bump

Justin86
12-07-2003, 07:04 PM
Well I complete my 89 intake swap. Everthing runs great. Once I get my tranny fixed I will do more fine tunning.
So what solenoid do I need to plug to fix the valve. I'm a little lost on what to do????

1988starter
12-07-2003, 08:01 PM
Originally posted by Justin86
Well I complete my 89 intake swap. Everthing runs great. Once I get my tranny fixed I will do more fine tunning.
So what solenoid do I need to plug to fix the valve. I'm a little lost on what to do????

You don't have to plug anything start by checking to see if your butterlflies open at 5K and then close right after it drops below. If it is not working open the controll box and find the silonoid replace it. and remove the vacume tank circled in the picture and connect the two hoses together.

Justin86
12-07-2003, 08:52 PM
Ok :)

BITESIZE
04-30-2004, 01:28 PM
why
because they were dirty....:)

Rendon LX-i
04-30-2004, 01:41 PM
Okay Does anyone have pics. They aint much of 88s around here. I mean a pic of a 88-89 Intake manifold and a 86-89 Intake manifold to see the difference. Damn i might have to do this

BITESIZE
04-30-2004, 01:44 PM
Basically the 86/87 intake doesn't have a set of butterflies like the 88/89 efi...they open at higher rpms to let more air in, thus more power. I don't have a picture though.

Rendon LX-i
04-30-2004, 06:36 PM
So i can just put a 88-89 intake manifold and bolt on my 86 with no probs

AccordEpicenter
05-01-2004, 11:32 AM
well you could do that but youd have to figure out how to switch the air door to open. The stock system uses a vaccum tank with an electric solenoid to close them, triggered by the ecu. I bet you could get an rpm switch from summit for like $40 and use that.

dillirk
05-02-2004, 12:07 PM
Has anyone tried changing the RPM that these butterflies open and close... maybe an easy power mod?

1988starter
05-02-2004, 04:47 PM
With my cam I get a lot more power with them open at 4K and beyond but I need them closed for tq. I have thought of changing it but I have too much else on my plate

A20A1
05-02-2004, 05:01 PM
They are run off a solenoid? hmm...
I can see the solenoid keeping the butterflies closed by holding vacuum.
This function is like the thermovavle on the carb which bleeds vacuum to keep the secodnary closed when the car is cold.

In either case direct vacuum would still allow the secondaries to operate, and in mostcases increase the vacuum signal strength/responsiveness slightly. You will only be losing the ecu / rpm control functionality.

A20A1
05-02-2004, 05:11 PM
Has anyone tried changing the RPM that these butterflies open and close... maybe an easy power mod?

easy... remove the solenoid from the box or get a spare one and then hook it up to a mechanical throttle tirgger switch... I'm not sure if power on or power off causes it to function... but as long as you can get the vacuum canister to hold vacuum for you untill you feel like opening the secondaries then it should work.

only trouble is opening the secondaries earlier then the drop in manifold vacuum occurs... this would casue the butterflies to remain closed till the vacuum dropped enough to open the secondaries.

You could always have a dual solenoid I guess that cuts off the supply of manifold vacuum and just bleeds of the vaccum before the secondary diaphragm allowing it to open prior to the drop in manifold vacuum.

A20A1
05-02-2004, 05:15 PM
You can also do it the old fasion way and change the spring rates on the diaphragm... a weaker spring would open the diaphragm in the higher throttle where manifold vacuum is at its lowest... and a stronger spring would open the secondaries earlier overcoming the effects of higer manifold vacuum at lower throttle.

Busted_Blue
05-02-2004, 05:52 PM
intersting. I was bored yesterday and a left my intake filterness. It was for just around the block since i was cleaning my throttle body. Anyways, i took it to 6 and at around 5k my car's deep tone from the open throttle body turned into a higher pitchs vroom. Sure sounded like i have something big under the hood but not going anywhere. I guess mine works then :). will this more torque fix aid me?

AccordEpicenter
05-02-2004, 06:28 PM
unless you have considerable mods, you wont gain anything from messing with the pretec point

Busted_Blue
05-03-2004, 04:11 PM
unless you have considerable mods, you wont gain anything from messing with the pretec point


gotcha! I'm stock, and bored but broke so nothing in the works :(

87-Lx-i-3Dr
05-03-2004, 07:12 PM
can i do this to my 87 Lxi ?

AccordEpicenter
05-04-2004, 07:57 AM
86-87 intake manifolds dont have the dual runners, so no, only 88-89 lxi/sei

cahil_1
05-14-2004, 11:08 AM
Out of curiosity what if you rigged the little control arm that is attached to the diaphram to wide open all the time. i'm just wondering if my torque would be higher at the lowend and throughout the rev cycle or would if just dog out because the air to fuel ratio would be to high early in the rev cycle. i might have to try this.

cahil_1
05-15-2004, 12:19 PM
this is directed towards Starter88 were your butterflies staying wipe open? I took a look at mine and i think that they are already staying wide open no change. are they supposed to be down before 5000 rpms then open. i guess i will try and get the solenoid this week. let me know what you think.

smufguy
05-16-2004, 09:10 AM
Yes it would. The 86/87 lxi on has single butterflies. I'd say your increase would be at least 20 hp, considering the 86/87 came with 100 hp? and the 88/89 came with 120 hp?

i doubt it, cause first off u got 8.8:1 on the 86-87 and 9.3:1 on the 88-89. Second u got different cams. third, u got a 4-1 header on the 86-87 and 4-2-1 on the 88-89. So i would say possibly half the power or even much less from it in stock form. U might get about 115hp or somethinglike that. Thats about it, and this is comparing to the stock form ;)

1988starter
05-17-2004, 07:54 AM
this is directed towards Starter88 were your butterflies staying wipe open? I took a look at mine and i think that they are already staying wide open no change. are they supposed to be down before 5000 rpms then open. i guess i will try and get the solenoid this week. let me know what you think.


Mine were alaways wide open. If you set yours to be wide open you will gain a little after 4K but the low end will suffer.

with the engine off they are open and below 5k they are closed

cahil_1
05-17-2004, 07:11 PM
OK today i really got in there and verified that they are staying in the wide open position. so i am pretty sure that the solenoid is shot and maybe even the diaphram. gonna test the diaphram with vaccum pump. thanks for the help.

Vanilla Sky
02-24-2005, 09:14 PM
ok, as you guys know, a lot of you guys are disabling the vacuum secondary butterflies on your EFI cars... do you guys think there would be any benifit of having it open at a set RPM as opposed to at a certain engine vacuum condion? i'll be upgrading to EFI soon enough and i think this might be something worth looking at, especially since solenoids can be had for cheap, and the wiring wouldn't be too hard to do... would be especially easy with an aftermarket ignition... so what do you guys think? whould i just take the secondary butterflies out? hook them up as stock? what do you guys think?

AccordEpicenter
02-24-2005, 09:25 PM
you have anything even resembling a stock motor youll get way better power under 5k rpm if you leave them setup the stock way. Removing them or leaving them open all the time makes you lose a bit of power

Vanilla Sky
02-24-2005, 09:31 PM
well, i want to keep them operational, but i think there are ways better than vacuum to control them...

i just want to run a minimalist vacuum setup, but keep as much of the reliability, drivability, and fuel mileage as possible... i just figured changing when it engaged might be better

AccordEpicenter
02-24-2005, 09:34 PM
unless you have a significant amt of mods (intake/header/exhaust/cam or somthing comparable, changing the pretec point wont help much

Vanilla Sky
02-24-2005, 09:40 PM
so, are you saying it would be of a bit of help but not on a stock car? that's pretty much what i figured it would come to...

AccordEpicenter
02-24-2005, 11:06 PM
pretty much. I was running like high 15s when i was na, on the stock crossover point

A20A1
02-25-2005, 03:44 AM
If you want to change when the secondaries engage then buy an adjustable secondary diaphragm like the ones use on carbs... or find a way to add a screw and washer to adjust spring tension on the diaphragm... this will adjust how much of a drop in vacuum you'll need before you get WOT on the secondaries.

POS carb
02-25-2005, 03:47 PM
they are in fact RPM operated, the ecu triggers at a preset RPM; it just uses stored vacuum for the force, not direct engine vacuum.
Hack the ecu to think it's at a different rpm is what you are looking for. hell you can get a drag tach shift light and hook it up to that, some are even adjustable

A20A1
02-26-2005, 01:00 AM
But you could hook it to direct manifold vacuum... and then adjust the diaphragm... it's much easie then modding ecu's

AccordEpicenter
02-26-2005, 11:58 PM
id say if you dropped it a little bit itd help, maybe 500rpm or so... you should use an rpm activated switch to adjust the changeover, just wire it up to the solenoid in the mystery box instead of using the ecu signal. There is actually a vaccuum tank to supply the vaccuum to this solenoid to keep the butterflies closed, remember they are open until they have vaccuum to them, then they close.

Strugglebucket
02-27-2005, 12:17 AM
id say if you dropped it a little bit itd help, maybe 500rpm or so... you should use an rpm activated switch to adjust the changeover, just wire it up to the solenoid in the mystery box instead of using the ecu signal. There is actually a vaccuum tank to supply the vaccuum to this solenoid to keep the butterflies closed, remember they are open until they have vaccuum to them, then they close.
that's exactly what i did. i have a rev switch from summit wired to the solenoid so that it switches at 4,000rpm instead of 5,000. it's very easy to do. i could probably make a how-to if anyone's interested.

it helps in my situation because i've got a bored t/b, polished/port matched intake, and head work done.

Vanilla Sky
02-27-2005, 12:36 AM
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
03-03-2005, 12:35 PM
shit I have vacuum solenoids... I can rig something up
who wants to be a guinea pig

Vanilla Sky
03-03-2005, 12:36 PM
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
03-03-2005, 12:50 PM
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
03-03-2005, 12:55 PM
but i wanna get rid of vacuum lines not add :p

POS carb
03-03-2005, 12:56 PM
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
03-03-2005, 12:59 PM
because then it wouldn't have a set RPM to kick in, just would open during certain vacuum conditions

Vanilla Sky
03-03-2005, 10:45 PM
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
03-03-2005, 11:42 PM
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
03-05-2005, 06:52 PM
I wonder if one of my RC servos would work... too bad I took apart my secondary plates.

Vanilla Sky
03-06-2005, 01:54 AM
it should... probably better than the solenoid... good call...

pookypal15
06-08-2005, 07:37 PM
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
06-08-2005, 07:49 PM
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
06-08-2005, 08:08 PM
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
06-08-2005, 08:23 PM
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
06-08-2005, 08:49 PM
well thanx guys, I have alot more to work with now

pookypal15
06-10-2005, 08:08 AM
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 :D 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
06-10-2005, 12:00 PM
? 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
06-10-2005, 01:57 PM
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
06-10-2005, 02:13 PM
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
06-10-2005, 02:20 PM
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
06-11-2005, 02:00 AM
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
08-29-2005, 09:54 PM
cool to see one of my ideas come to fruition. good work, man.

A20A1
08-30-2005, 12:13 AM
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http://www.3geez.com/showpost.php?p=396504&postcount=28

I was talking about that last year, cept in place of the Mechanical trigger (http://store.summitracing.com/default.asp?target=partdetail.asp&autofilter=1&Ntt=throttle+switch&view=4095&N=0&part=NOS%2D15641NOS) (Adjustable, based on throttle linkage position) you use the RPM trigger (http://store.summitracing.com/partdetail.asp?autofilter=1&Ntt=RPM+Switch&view=4095&N=0&part=SUM%2D830449) (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
08-30-2005, 12:26 AM
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.

A20A1
08-30-2005, 01:43 AM
I wonder about ignition Vacuum Advance
Both carb and EFI have two ports. One for Cold and one for warm.

The cold one I think doesn't advance as much as the regular one.

I figure you could hold onto the advance for as long as you want using;
Vacuum Holding Cannister
Vacuum Check Valve
Vacuum Solenoid
RPM Switch

Hook it up to either the cold or regular advance port.
You'll probably have to bypass any stock ECU/Thermovalve interventions into the Vacuum Advance or at the least make the new system independent while sharing the same port.

You'll want to dump the advance before 3,600 RPM

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Strugglebucket
08-30-2005, 03:49 AM
the stock system on the efi engine has a vacuum holding canister and a check valve (hose #13) already.

one thing to note with the summit rev switch is that it is specified for 8 cylinder engines only, so if you use it with a 4 cylinder engine whatever rpms you set it at are actually half of what it will "see"(8 sparks=1 rotation to the circuit, 4 spark per rotation engine means 2 rotations=1 rotation registered to the circuit). for example, if you set it to 2,000 rpm (the lowest setting), it will switch when our engine reaches 4,000 rpm.

A20A1
08-30-2005, 02:05 PM
the stock system on the efi engine has a vacuum holding canister and a check valve (hose #13) already.


I was refering to duplicating the secondary system for ignition advance... that is why I listed an extra holding cannister, check valve, and solenoid. I assume #15 is the cold advance. Odd how #5 & #15 are hooked up within the black box... I'd think they'd use seperate solenoids.

Rendon LX-i
08-30-2005, 05:01 PM
So this is only for 88-89 for the fact beening that 86-87 only have the single.....No Secordenderys LOL like 88-89s right? looks intresting thou

Vanilla Sky
08-30-2005, 05:54 PM
honestly the 86/87 manifold is a better piece.

lostforawhile
08-30-2005, 06:56 PM
the stock system on the efi engine has a vacuum holding canister and a check valve (hose #13) already.

one thing to note with the summit rev switch is that it is specified for 8 cylinder engines only, so if you use it with a 4 cylinder engine whatever rpms you set it at are actually half of what it will "see"(8 sparks=1 rotation to the circuit, 4 spark per rotation engine means 2 rotations=1 rotation registered to the circuit). for example, if you set it to 2,000 rpm (the lowest setting), it will switch when our engine reaches 4,000 rpm.they make rpm switches that work on 4 cylns. thats a reference. you just set the dip switches depending on what engine you have. just like a tach :stupid:

lostforawhile
08-30-2005, 07:05 PM
here are some examples msd. 8950 rpm activated switch,uses msd modules,59.88$ if you want you can plug in the msd 8670, 47.69$ it lets you choose 12 rpm limits with a knob. that one is 3000 to 5200 rpm.

lostforawhile
08-30-2005, 08:20 PM
you don't have to use the switch i thought it might be nice to set the point where secondaries come on. why not just hook it up with a t fitting at the secondary then you could have the secondary operate normal or have it come on sooner if you want.

lostforawhile
08-30-2005, 08:27 PM
honestly the 86/87 manifold is a better piece.yea,why does everyone think the manifold is so terrible? i think it a well designed manifold, the bottleneck is whats on the top of it. this manifold can flow a lot more then the stock carb can. this really is a performance manifold it's the carb that sucks. no pun intended. from studying automotive design for years as a hobby i think it's a great manifold.

Strugglebucket
08-30-2005, 08:44 PM
they make rpm switches that work on 4 cylns. thats a reference. you just set the dip switches depending on what engine you have. just like a tach :stupid:
hey man, don't gimme that smiley :lol: summit only makes one rev switch and it's a good deal but there are no dip switches for #of cylinder selection. so the lowest you can set it with a 4 cylinder is 4k, that's all i was sayin'.

lostforawhile
08-30-2005, 08:58 PM
hey man, don't gimme that smiley :lol: summit only makes one rev switch and it's a good deal but there are no dip switches for #of cylinder selection. so the lowest you can set it with a 4 cylinder is 4k, that's all i was sayin'.just cutting up with you,i know they make rpm switches for 4 cyls a lot of ricers use them for NOS switches. oh heres a picture of the manifold without all the crap on it,it really is automotive art. the japanese like to make beautiful parts,it the culture. http://memimage.cardomain.net/member_images/10/web/2050000-2050999/2050019_204_full.jpg http://memimage.cardomain.net/member_images/10/web/2050000-2050999/2050019_207_full.jpg

A20A1
09-05-2005, 12:21 PM
there was no room in the box for the switch?

Oldblueaccord
09-05-2005, 09:16 PM
Is it just me or do our cars sound way different with them fully open? ;)


It does to me. Very differant sound when they open up.


wp

A20A1
09-07-2005, 09:58 PM
The Carb Model secondary is throttle + slightly shorter runner length

Your EFI throttle is independent of the Secondary air passage.

It's simply too dangerous to have throttle not based on the throttle linkage / cable / return spring. You may end up with run-away engine speeds if the system fails.

It could fail if there is a vacuum leak
It could fail if there is an electrical issue
It could have a mechanical failure

With the carb secondary how it is now all you have to worry about is a mechanical failure... much safer. The vacuum diaphragm system is backwards so a vacuum failure would actually be to your benifit in a bad situation cause the throttle would close.

I mean it's certainly possible, but it's not somthing I would do.


The safest way would be to use the stock diaphragm and hook it to venturi vacuum, making sure the diaphragm can open the plate all the way... it's on a fairy tight return spring. Anyways, if that works then the EFI solenoid would act as a controller for venturi vacuum supply.

Problem with a venturi vacuum supply is venturi vacuum inscreases with throttle / RPM. This will limit how early the secondary would open since there is only a weak venturi vacuum signal at low rpm/throttle.

You could hook both venturi and manifold vacuum up, with a check valve where needed, and maybe add some lower rpm operation speeds to the secodnary, but then you again run the chance of the solenoid failing and then secondary getting vacuum when it shouldn't.

If you trust the solenoid enough then it may be a very worth while mod, and fun.

:)

A20A1
09-07-2005, 11:30 PM
Nope, vacuum pulls the diaphragm to open the secondary, much like the distributor advance...

If they had it the other way a vacuum leak would cause it to open which would be bad since that would increase the throttle and up the rpms.

Also you'll have to disable the mechanical secondary part of the throttle linkage... since it keeps the diaphragm from opening.


.

logic
09-22-2005, 12:15 PM
The 86 and 87 came with 110 and the 88 and 89 had 122 the butterflys help a lot but are not the whoole reason for power there was a large compression increase and anew exhaust manifold used along with some removed vacume lines.

1988starter, what all is different? I just dropped a new engine when mine died and they gave me an 87 instead of an 88. I swapped both manifolds, but what did I miss?

logic
09-24-2005, 06:51 AM
1988starter, what all is different? I just dropped a new engine when mine died and they gave me an 87 instead of an 88. I swapped both manifolds, but what did I miss?

O.K., Anyone help me out here.... Is there a difference in the head or the crank, or just the cam? Hello....(long echo, then nothing....) :sad2:

logic
09-27-2005, 11:34 AM
O.K., Anyone help me out here.... Is there a difference in the head or the crank, or just the cam? Hello....(long echo, then nothing....) :sad2:

Hello? Does no-one care to answer my question because no-one cares, or did I offend everyone already? :sad2:

A20A1
09-27-2005, 06:14 PM
I dunno what did you miss?

The engine compression can be changed with pistons, head gasket thickness, or the cylinder head clearance.

A compression ratio increase can increase power.

A different cam profile can give more power, but I dunno if there was a difference in 86-87 and 88-89 cams.

The intake manifold it the only real visable difference between the two, You already have the 88-89 ECU and vacuum controls since you had the 88 engine in your car before you swapped to the 87 motor.

Swap_File
10-03-2005, 04:26 PM
I think having the ability to vary the disengagement point would only be helpful if you boost. Go ahead and set the point at when the turbo spools and full boost comes into play. :dunno:

And if you are boosting, why use the stock manifold? An aftermarket unit would be much, much better. Heh.

For turbo applications, a B16 or B18 stock intake manifold would still probably be better than a A20 stock manifold with the secondary control modification, right?

Strugglebucket
10-04-2005, 06:55 PM
(as originally posted by justanothermike):

u can always try removing the iabs and making the 88 up manifold into a single runner manifold. Having a two piece manifold makes it really easy to get a die grinder in it to port it out. It would probably out flow a B16 manifold but maybe over kill for internally stock A20s. With a B16 manifold u can use the newer larger throttlebodies aswell, but we have adapted the top part of an H22 iab manifold onto the A20 manifold but 1 bolt did not matchup and there may have been a slight vacuum leak. This is what the IAB manifold look like with the single runners. The top one is the manifold on our H22 accord and the bottom one is a GSR thats going on my 1.9l LSVTEC

http://openloopmotorsports.com/h22man.jpg
http://openloopmotorsports.com/gsrman.jpg