redrocket

Hey guys, I was turned on to a little trick by ToMeGun you may want to try.
I was not going to share this because it was his idea but since Ive read several threads related to this issue I wiil. He gets the credit though!!

Disconnect the upper vacuum hose, leave the bottom hose alone. Cap the opening if you wish.
NOW, go for a test drive!!! What does you butt dyno tell you? What changed on the boost gauge?

I was leary of this until he told me he has been running like this for months, no CEL.
Ive been running like this for a couple weeks now and no CEL. Try it, you won't be disappointed.

Yo ToMeGun!! Looking forward to seeing you at the track again

VaMP

Hmm... might have to try that. Pictures would be helpful to avoid confusion.

JapEatr

iTrader: (9)

all it does it create a lean condition
when i dynoed mine it was like super rich so it probaly evens out the mix better if not too much
but if CEL then i wouldnt sweat it
ask MAVEN he would probaly know a lil more of the CPU side of the issue

PaulSS

im at work right now.. but as soon as i get out im plugin that tube... lets say you were to be rock solid on shifitin.. how many tenths faster do you think would result in a 1/4 mile?

zinner

None. The boost bypass value doesn't even kick in with the stock pulley as far as I could tell.

It only kicks in when the PCM ask for it. Also by disabling the system, your messing with the value that opens when there is no load on the supercharger as well.

PaulSS

so is what redrocket feeling all mental?.. this seems fishy

redrocket

Hey Guys, Im not crazy, maybe a little
Anyway, thats why I said to go for a test drive. Give it a try, it won't hurt anything.
I knew some would dought this so thats why I wrote the post the way I did. Also, the results will differ depending on where you live.

Zinner! Are you not doing the same thing by grounding the switch? The differance being that you disabled the valve electronicly at a certain throttle position, I disabled it completely.
The only time I believe that the switch would open and suck air (lean) is at WOT, according to your statement. However, I think it bleeds boost at other throttle positions also. Correct me if Im wrong as I believe you have a service manual for these cars.
However, if the valve only is active at WOT, why do I have more boost a 2K RPM? And My max boost went from 10 to 11.5, according to the gauge.

AS far as leaning out, thats exactly what this engine needs. These cars run rather rich and so rich that leaning out a bit should increase power. So the switch opening at WOT may actualy up the power a little. If it worrys you, cap the switch.

Also remember that I run Sunoco 94 Octane, always. You may actualy hurt perfomance doing this on a lesser grade of fuel as the ECU will retard timing if it senses knock.

BOTTOM LINE - Try it! See what happens.

clownhair

Ive done it before, eventually it throws the car into limp mode. Its very random when it will happen but eventually it shuts down. I now reserve this for track events only.

99_civic_si

Ok, I'm not trying to but into this forum but I'm trying to help my buddy who just picked one of these cars up. I'm a Honda guy, have been, will continue to be (sorry, just my thing) However, I've had a jackson racing (aka eaton) blower on my motor for about 5 years now. Now after reading a bunch of posts, I wanna stab myself in the eye with a pencil. For the record, you guys on ss.net are much more intelligent than the ppl on ss.com. They are a bunch of morons who have no grasp of mechanics at all.

Now anyhow, why am I posting. I'm searching and trying to dig up if the stupid PCM that controls boost can be bypassed completely. I've seen that it can without throwing a CEL. Now what you guys all seem to be missing is that the bypass vavle (same thing on my setup) works off of vac. It's that F'n simple. if the hose that runs to the bypass valve is getting vac, it's open, which recirculates the air for better economy. When you put the pedal to the floor, ur motor has 0 vac, therefore the bypass valve has no more vac and it closes, allowing your system to build boost. You have no worries of overboosting because it'll only create as much boost as the pulleys you have on it, which seems to be 12.5 in stock form. To the people who said "you'll run lean" You are F'n retarded. Your ECU is just like a giant Excel database, like a grid. One side has vac/boost, the other is RPM. At full throttle your ECU will take those two parameters, and use the set fuel values in that matching cell to feed the car with the proper fuel (which is still probably wayyyyy too rich because all manufacturers set up the cars usually in the high 10 A/F range, where as you can probably safely be at 11.5-12.0 A/F with no worries of detonation with proper timing). Anyway, back to my helpful part of this post. So long as the ECU does not certain values coming from the controller that controls the boost, you can simply bypass it, and not have the above mentioned problems that others posted about by doing one simple thing. Connect the bypass hose somewhere before the blower and the maifold if there is a vac nipple present. On my car, it's connected to the throttle body. Now the bypass valve will open when I'm in vac (aka, cruising), and will shut to create boost when I mash my foot to the floor. I will do this to my buddys cobalt and let you all know of the great results with no worries. I know A LOT about this setup and have worked with it for years, I'm sure I'll post up a few ways to get some free HP for you guys.

Another thing I'm thinking about, would be hooking up my wideband to see the A/Fs. If they are insanely rich, perhaps put a valve in the fuel line to drop the pressure a few psi, which should (depending on GMs system) lean out the mixture a touch. That should definately squeeze out some extra HP no problem. But I really don't recommend doing that without at least a wideband and perhaps an EGT gauge.

LTSRAPCON

doesnt this valve only open when there is a vac in the manifold, such as when you are at idle or low rpms? If this is so then disengaging it could cause a rough idle. Older Super Chargers didnt have these and they had problems at low RPMs. Because of the way S.C work when they are not providing boost they are not helping they system. I might be wrong.

06black

i've had this hose blocked for quite some time now...and you will get a cel light at some time even if you disconnect the battery and all that good stuff it'll happen but by blocking this i was geting more than the 11lbs or so you were talking about....accordeing to a auto meter digital gage i was geting around 14.3 or so...wich in turn made around an extra 30hp.....its great for sneeking up on other cobalts and redlines....it wont hurt the moter dont worry aobut that you jsut get a CEL ligth some times...good luck

99_civic_si

Yes the valve only opens when it sees vac. The PCM controls when the bypass sees vac or not. The PCM is honestly just a useless piece of equiptment GM put on the car so it can't be "abused" aka raced as hard.

I'll try to explain this the best I can. Weather the blower is on ur car or not (if you don't believe me, drop ur blower belt) Every car still sees vac, obviously. When you mash the gas, ur car will have 0 vac. Your manifold is going to be the only part of your system that gets any "boost" before the air is pushed into the head. Your throttle body can NEVER see boost, it's before the "boost" system (where as a centrifugal system would differ). So if you run the line from the throttle body to the bypass, it will open and close when it should (cruising, it'll be open for recirculation, WOT it will close allowing for boost). Honestly, ur bypass valve works the SAME EXACT way a BOV does, hell it it a BOV, only it gets recirculated to the manifold and not the intake (like many stock turbo cars). Someone with a thinking mind will chime in on this thread and say holy **** he's right. The PCM that controls boost is ghey. Hope this helps. I'm sooo ready to post pics of my setup to try to make more sense of this.


First off, take that autometer gauge and throw it out the window. You are using the signal from a stock narrowband sensor to get that reading, it's honestly just a light show if you don't have a wideband running to it. Ask any tuner and they'll say the same thing. Now, if you were really running 14.3 A/F and ur motor didn't go boom, drive the GM and pray for thanks on their front lawn for a few days. My only concern with seeing more boost and running lean would be if you are maxing out the duty cycle of the injectors, but I can't imagine GM didn't but in an injector large enough for some more boost, but I could be wrong. How big are your injectors???? I hope for your sake they put in like 440s or something.

edit: by blocking that hose, you are keeping the bypass closed AT ALL TIMES, that is not good for the system, think about it. Where is the extra air gunna go? ur blower is still spinning, probably enough even at idle to create a little boost. Having that valve closed at all times would be very very inefficient to the system, also creating extra heat I would imagine. If you connect the bypass BEFORE the blower and manifold, it would work properly without using the stupid PCM.

codyss

99_civic_si

Here in the states injectors are rated in lbs not cc.

And I belive 06black was speaking boost psi not a/f ratios.

99_civic_si

Yeah, now that I reread it, you are right, I believe he is talking about boost. :bonk: Ahhh well, I still mean what I say about A/F gauges Anyway, I'll probably be bypassing the pcm for him on wednesday because we both work today all day today. I'll keep you guys updated.

CobaltSS422

whats that light green colored cap that u can screw in and screw out by the bypass valve?

99_civic_si

I have to look at the ones on the cobalt again because mine doesn't have that and I don't recall ever seeing what you are describing, I'll check it out though. Like I said, I'll figure it out over the next 2 days or so and get back here with results.

edit: if I had to guess about that screw it would just be how much it bypasses based on how much vac it sees.

JapEatr

iTrader: (9)

EVAP check valve, it is used to check vacuum pressure to diagnos EGR malfuntions

Maven

iTrader: (1)

The PCM cannot be bypassed.it controls fuel delivery, spark timing, the generator,air conditioning, cooling fans, stop lamps, starter relay,etc...etc...

The green cap is the Evaporative emissions test port, and of no use in these discussions.

While it is true the ECM wont let the engine run lean and hurt itself it does know it has to add more fuel to compensate for the lean condition and will set trouble codes.

zinner

Is the PCM and ECM different names for the same thing (computer that controls the engine/powertrain)?

Maven

iTrader: (1)

The PCM is the Powertrain Control Module in Supercharged coupes.

The ECM is the engine control module in other models, those cars also have a TCM(trans module) if equipped with an auto trans.

99_civic_si

All I'm going to do, is basically have the bypass gets it's "info" from the throttle body or somewhere before the manifold and blower. The damn piece of electronics is still going to be trying to do it's thing, it just won't be hooked up to the bypass that's all. Therefore, it hopefully won't throw a code (because the bypass will still open and close rather that just staying closed all the time using other methods) and it will work the way it should for performance, not for GM to make the car "abuse proof". Anyway, I'm trying to get a hold of my buddy later to see if we can do this.

Maven

iTrader: (1)

It WILL work.....however it will set codes eventually(depending on how hard the car is driven) and the PCM may actually force it into reduced power mode.

Also note that the PCM will not be able to control boost under ANY circumstances with this mod. That includes the parameters under which boost is disabled in favor of engine longevity, including:

• When reverse gear is selected

• When the engine coolant temperature (ECT) is excessively high

• When the vehicle is decelerating

• If an intercooler pump failure is detected

• If the intake air temperature (IAT) sensor 2 becomes excessively high

• Under heavy load in first and second gear at engine speeds above 5,800 RPM


Plus the anti-abuse parameters.

clownhair

I ran mine like this for about a month and then BAM car shut down, reset it and 2 weeks late BLAM! I was so confident I had beaten the car too.

redneck

hi!! when you say upper vaccum hose ,do you mean the one with the white stripe???

99_civic_si

OK, this is done and done. It was quite simple and will not **** up the partial throttle (vac. aka cruising) fuel mixture in any way. Simple as this, the top vac line coming from the bypass works the same way mine does. If it sees vac it opens the bypass. However, your cobalts have something mine doesn't. the bottom nipple. What this does is, when it sees pressure, it will open the bypass, as in just the opposite of the top nipple. Now how your "controlled" system works is like this: There is a vac hose from the manifold (which obviously gets boosted air). This hose runs back to the "control" unit. This "control" unit just allows the boost to get back to that lower nipple of the bypass under certain conditions (aka, the above mentioned parameters that maven stated).

Here's what I did to bypass it. Keep the upper hose on the bypass right where it is. remove the lower one and leave it exposed to open air (put a breather on it if you a paranoid biotch) Now on the hose that's now disconnected from the lower bypass nipple leading back to the "control" unit, take that hose off completely. Now use a vaccum nipple to cover that nipple and zip tie it on there (so when boost tries to pass, it doesn't blow the nipple off)

The way I would have preferred to do it, would be to block the nipple off right at the manifold and completely disconnect all hoses to the "control" unit and let the "control" unit have both nipples open to the exposed air. That way there would be no pressure whatsoever entering that "control" unit at all. that control unit would still open and close it's valve but have absolutely no effect on the boost control at all. I highly doubt this will trip and engine code unless GM has put some special code within the ECU to trip a light if the car is revved through redline and doesn't "see" the boost drops under the above conditions maven mentioned. They also wouldn't have it trip a light if the cars ecu reaches a certain boost point in 1st gear, because then everyone with smaller blower nose pullies would be throwing CELs left and right.

I'll try to post some pics of this so the light thinkers have a simple 3 step DIY w/pictures so they in no way can mess it up.