: P-valve Question



musclesbmf
07-13-09, 02:56 PM
In another thread, kencav mentioned "capping" the p-valve as per Jesse's (W4M) suggestion. I understand that kencav does not want to give away any secrets that are not his own, and I'm good with that. I was hoping Jesse would chime in here and let us know what to do and what the benefit is.

Jesse?

Thanks,
Mark

kencav
07-13-09, 03:40 PM
actually i am going to my shop in a few hours and would be happy to share- i really just don't know how it is done!

musclesbmf
07-13-09, 04:15 PM
sweet... look forward to the info.

thanks,
Mark

stealthjr
07-13-09, 07:52 PM
actually i am going to my shop in a few hours and would be happy to share- i really just don't know how it is done!


Looking forward to pictures and a detailed write up on when and why you should do this. :cool2:

Thanks,

Robert

Nutz
07-13-09, 08:51 PM
:pop2:

CadV
07-18-09, 06:55 AM
I got some pictures but I need help with this as well.

Here is a picture of the sensor (with the green x and o). x other end goes into the blower lid and would this be where the boost gauge gets its reading? o is the opposite end of the p port and I put foam on it after I capped the p port. I used foam because that's how GM had the unused port next to o.

http://i31.tinypic.com/xlh75k.jpg

What about the other two ports (except x) on the sensor? Do we use foam allowing them to breathe or do we cap them?

This is the p port with a vacuum cap (Thanks Robert for the vacuum cap) on it, is this right?

http://i27.tinypic.com/1zee785.jpg

Brent mentioned something about backing a screw out and will give ya a half pound of boost. Is the below picture the screw he is referring too?

http://i31.tinypic.com/2rz9ev6.jpg

qictrk
07-18-09, 09:13 PM
Maybe Jesse could tune in here and give some answers. I too would like to know what to do with the P valve to get an extra pound or so of boost. I don't want to guess which one to plug or not plug. Cecil........

CadV
07-19-09, 02:44 AM
Well I have some accurate information just by trial and error.

The above pictures showing the p port capped and using foam on the opposite end is correct.

Lastly you need to back the screw out or cut the bottom off. I cut mine because I couldn't back it out. Here is a picture...

http://i31.tinypic.com/2liwtib.jpg

With the above mods my gauge hits 15 the shoots down to zero. It is crazy and I will make a video of it.

Does anyone know what that means. I do not lose power it keeps pulling really hard. Maybe I am getting over 15 :confused:

stealthjr
07-19-09, 08:26 PM
It would be nice to hear what Jess has to say about this...

Thanks,

Robert

P.S. What do you mean it shoots down to zero? With your foot at WOT it goes to zero but keeps pulling?

CadV
07-19-09, 09:58 PM
P.S. What do you mean it shoots down to zero? With your foot at WOT it goes to zero but keeps pulling?

Yep at WOT gauge will hit 14.5 at the beginning and then keep climbing where it pegs 15 then it shoots down to zero without any power loss. Blower is still whistling away. Prolly maxing the gauge out.

stealthjr
07-19-09, 10:01 PM
Yep at WOT gauge will hit 14.5 at the beginning and then keep climbing where it pegs 15 then it shoots down to zero without any power loss. Blower is still whistling away. Prolly maxing the gauge out.

Better get that thing to a dyno to make sure the A/F ratio is still on the safe side. If you go...let me know!
I wonder if the gauge is not hooked up correctly now with all of the changes you have made around the P-valve??? What does the gauge do if you just roll into the throttle and keep it around 6 PSI or so?

Robert

CadV
07-19-09, 11:27 PM
The tune I am using is rich and gonna dyno it Saturday with a shop that has AC.

Gauge will hold anything under 15. I just went out and tried to do it again but it held right under 15. It was pretty cool out the night it went to 0 something like 82 degrees.

I am still working through some issues so I have no idea what kind of power my car is making. After I left your house I did some work on the car and figured out some stuff.

qictrk
07-20-09, 07:03 PM
bump :shhh:

stealthjr
07-20-09, 07:11 PM
Does nobody find it strange that Jesse has replied to many other topics and seems to be avoiding this one? Come out come out wherever you are Jesse! :hide:

See ya!

Robert

backup
07-22-09, 09:29 PM
I am really curious about this mod. I smell cheap HP! Here is what I found:

1. Disconnected O line. Found boost seemed slower to build and didn't quite reach 9psi
2. Disconnected X line with O still disconnected. Seemed very similar to step 1 - slower to build boost and barely reached 9psi.
3. Re-connected O, left X disconnected. Seemed to build boost VERY fast, and quickly pegged 9psi. Seat of the pants meter felt this was more responsive and more power, perhaps from faster boost build (more power sooner).

I then reconnected all vaccuum/pressure lines and disconnected the electrical connector to the O/X valve device. Noticed it would still move the boost gauge while reving in neutral, haven't had a chance to drive it like that yet.

I want to know what the X, O, P and V lines do, and how the valve and pressure regulator work to control boost. I don't understand how this functions. I got a hunch doing some tricks here will yield power. I want to know if the measured boost pressure as shown on the gauge is used to control the boost level, or whether it is governed by a separate mechanism such as this XOPV vaccuum/pressure valve assembly. It makes me think the 15psi shown above is real, although I don't know why the gauge would drop to zero - if the gauge information is indepependent from the boost control mechanism (the computer reading 9.0psi is not used to govern that boost).

I do know the X/O valve is NOT the boost gauge as I was getting readings with the thing disconnected, both electrically and vaccuum lines.

CadV
07-22-09, 10:07 PM
I am really curious about this mod. I smell cheap HP! Here is what I found:

1. Disconnected O line. Found boost seemed slower to build and didn't quite reach 9psi
2. Disconnected X line with O still disconnected. Seemed very similar to step 1 - slower to build boost and barely reached 9psi.
3. Re-connected O, left X disconnected. Seemed to build boost VERY fast, and quickly pegged 9psi. Seat of the pants meter felt this was more responsive and more power, perhaps from faster boost build (more power sooner).

I then reconnected all vaccuum/pressure lines and disconnected the electrical connector to the O/X valve device. Noticed it would still move the boost gauge while reving in neutral, haven't had a chance to drive it like that yet.

I want to know what the X, O, P and V lines do, and how the valve and pressure regulator work to control boost. I don't understand how this functions. I got a hunch doing some tricks here will yield power. I want to know if the measured boost pressure as shown on the gauge is used to control the boost level, or whether it is governed by a separate mechanism such as this XOPV vaccuum/pressure valve assembly. It makes me think the 15psi shown above is real, although I don't know why the gauge would drop to zero - if the gauge information is indepependent from the boost control mechanism (the computer reading 9.0psi is not used to govern that boost).

I do know the X/O valve is NOT the boost gauge as I was getting readings with the thing disconnected, both electrically and vaccuum lines.

Cool post and I will play along. I will have time this weekend to mess around with it. Let me know what you find out and I will try it and see if we get the same results. I will also talk to my GM buddy and see if I can find out what POXV do.

If you take the unit out you can grab the silver bar in this post:
http://www.cadillacforums.com/forums/cadillac-cts-v-series-forum-2009/174460-p-valve-question.html#post1943911

and push it in and out. Once you cap p it is much harder to do so I assume boost is preserved.

The Tony Show
07-22-09, 10:31 PM
You guys are ballsy, I'll give you that.

CadV
07-22-09, 11:39 PM
Here is a diagram

http://i30.tinypic.com/2942v4l.jpg

Nutz
07-22-09, 11:50 PM
Well, somebody's gotta ask. Curiosity tugs. Which one is the "X" line? Or are they marked?

Not that I would unhook it without seeing substantial evidence here to support or deny any imminent dangers.

CadV
07-22-09, 11:52 PM
Well, somebody's gotta ask. Curiosity tugs. Which one is the "X" line? Or are they marked?

Not that I would unhook it without seeing substantial evidence here to support or deny any imminent dangers.

Check the first picture in post 6. See the x and o in green? x is cable 2 in the diagram. o and p is cable 4. cable 3 is v and other end is not labeled on mine.

Nutz
07-22-09, 11:56 PM
Wow, small. Thanks.;)

backup
07-23-09, 12:09 AM
Great diagram! thanks. Got a legend to go with that? Knowing the official nomenclature for these parts would help understand what they do.
CadV, did you cap the port in the supercharger housing that X connect to?

Thinking this through a bit, here is what I have. The X line port is under vaccuum at idle, and presure at boost. This pressure feeds the X port on the XO valve. The O line feeds the P port on the pressure regulator device. The other port on the pressure regulator device is the V line that connects to something under the supercharger. I was thinking the V line transferred intake manifold vaccuum to the regulator device, to be balanced by the pressure from the P port, but that doesn't make sense because under boost there is no manifold vaccuum. So what the hell does the V line connect to?

If pressure on the P port offsets vaccuum on the V line, and the two work together for some equilibrium to regulate boost, then I can see how capping the P port would allow the V line to maximize its variable. Assuming the V line is the positive feedback signal (increasing boost) then we would not want to cap that, but would want to cap the negative feedback signal (the P port). Capping the O port on the supercahrger housing might preserve some amount of manifold pressure just from eliminating the release that would occur if uncapped. Disconnecting the electrical connection on the XO valve should have no effect as long as the P port is capped. This is what I will test next.

Is there such a thing as a wastegate on a supercharger? How is excess boost bled off? Or is it all controlled with a throttle or pressure plate (which would explain the pressure regulator adjusting a butterfly valve of some sort)? Experts we need your help!

Nutz
07-23-09, 12:28 AM
Just what us men need, another difficult to understand little p valve that can make more blower pressure and increase whining AND can be quite volatile and very expensive to maintain if not delicately handled by an experienced professional.
O.k, o.k, Sorry guys the door was open. :alchi:

Back to the regularly scheduled technical discussion.:thumbsup:

CadV
07-23-09, 12:34 AM
Got a legend to go with that?

I will try to get it tomorrow.


CadV, did you cap the port in the supercharger housing that X connect to?

No I did not. I did not cap the other end of P either.


So what the hell does the V line connect to?

See the bolt holes on the blower snout? Go down you you will see a port pointing passenger side. V goes into that.

backup
07-23-09, 12:45 AM
See the bolt holes on the blower snout? Go down you you will see the a port sticking out. V goes into that.

Yeah but what is that? What does the V port connect to, inside the engine? If that is intake manifold, then the pressure should be the same as the supercharger housing. If the V port offsets pressure from the P port then I would assume it is pressure, not vaccuum, and the net presssure sets the regulator position. I am at the edge of my understanding of engine design, so somebody help me here. Maybe there is a difference between the pressures at the supercharger core (X port) and the intake manifold (V port)? And this difference regulates the boost??

I just capped my P port line with a heavy dose of electrical tape. If my theory is right then I should see increased boost. Might need to cap the X port on the supercharger housing also. This also jives with what I saw by disconnecting the X line and the increased boost response (the V port was left unbalanced or unrestrained). But at atmospheric pressure the P port may have still offset the V line impact, so capping it might let the V line vaccuum (or pressure) maximize its effect. I will find out!

CadV
07-23-09, 12:48 AM
Yeah but what is that? What does the V port connect to, inside the engine? If that is intake manifold, then the pressure should be the same as the supercharger housing. If the V port offsets pressure from the P port then I would assume it is pressure, not vaccuum, and the net presssure sets the regulator position. I am at the edge of my understanding of engine design, so somebody help me here. Maybe there is a difference between the pressures at the supercharger core (X port) and the intake manifold (V port)? And this difference regulates the boost??

I just capped my P port line with a heavy dose of electrical tape. If my theory is right then I should see increased boost. Might need to cap the X port on the supercharger housing also. This also jives with what I saw by disconnecting the X line and the increased boost response (the V port was left unbalanced or unrestrained). But at atmospheric pressure the P port may have still offset the V line impact, so capping it might let the V line vaccuum (or pressure) maximize its effect. I will find out!

You lost me at regulator position haha. If you find anything let me know and I will test it too.

CadV
07-23-09, 06:42 PM
Here is the legend...

http://i32.tinypic.com/2h3wvuq.jpg

wait4me
07-24-09, 02:15 PM
The p port is basically for overboost situations. The P or "Protection" port will bleed off boost by opening the boost bypass valve when it reaches levels over stock. It is that way so even if you remove the limits inside the computer to still allow boost past 10psi, the valve will try to bleed off boost on its own. So by capping the line and venting the p valve will make it apply full boost without reventing the boost into the manifold to be recirculated.

stealthjr
07-24-09, 02:21 PM
The p port is basically for overboost situations. The P or "Protection" port will bleed off boost by opening the boost bypass valve when it reaches levels over stock. It is that way so even if you remove the limits inside the computer to still allow boost past 10psi, the valve will try to bleed off boost on its own. So by capping the line and venting the p valve will make it apply full boost without reventing the boost into the manifold to be recirculated.


Thanks for the clarification Jesse. So, I assume there is ZERO benefit to messing with this UNLESS one has a pulley to increase boost over stock levels right???

Also, to avoid some confusion...you are saying to "CAP or plug" the P-Port LINE and vent or leave the "nipple" that the P-Port line was attached to...open? It looks like CADV capped the "nipple" on the valve and not the "line" as you stated. Just making sure I understood you correctly so folks on here dont mess something upo or do something backwards because of a misunderstanding of words.

Thanks,

Robert

wait4me
07-24-09, 02:26 PM
Correct, Even though you get about .5 lbs of boost extra by tweeking the bypass valve on the stock one to make it fully closed. Even a slight gap will cause a pressure loss, so make sure it is fully closed.

stealthjr
07-24-09, 02:30 PM
Correct, Even though you get about .5 lbs of boost extra by tweeking the bypass valve on the stock one to make it fully closed. Even a slight gap will cause a pressure loss, so make sure it is fully closed.

Makes sense, thanks.

Also, I added to my last post when you were typing this response...could you clarify for us and answer my edited question please?

Robert

backup
07-24-09, 02:35 PM
Thanks for the legend! post edited after reading Jesse's response!

CadV
07-24-09, 03:27 PM
I am confused

1-2-N-V
07-24-09, 03:38 PM
You Know, There was a pdf download from Hennesse site a while back describing a module that will control the boost on a SC. I thought this was on a Vette, I do not recall. As i am thinking what vette besides the ZR1 has a SC? Anyway I know i saw it but i can't seem to find it now. I should have saved it. Well if it works like a Waste gate it may have a higher preset than stock and will bleed of the excess psi when necessary. Just plugging that off seems dangerous to me unless you have a way of purging that extra boost. On my GN i had a manual waste gate adjustment though a dial controller valve which when the boost got up to about 18 PSI at WOT i could dial it down on second and third gear and open the waste gate before i would get any over boost or lean condition. Worked great.

Anyway maybe someone can find it. Maybe do a search on the web about it. According to Jesse i thought this mod would only get you a .5 lb of boost probably not much to worry about an over boost condition. Now if this is blowing past 15 lbs i would say that there may be a need for a controller and this indeed is a way of a few extra ponies. Just my 2 pennies worth

wait4me
07-24-09, 03:43 PM
The boost bypass still works just fine with this mod. you are only changing / removing the overboost protection.

1-2-N-V
07-24-09, 03:51 PM
Jess,I am not following that. Plugging the P port i think they said will yield more boost but there is no fear of an over boost as this bypass is still working? I have to really have things broken down to me in the progression of how something works in order to really understand this completely. I could understand the simple waste gate theory for my GN but this may be a bit more sophisticated. When you guys get through with your testing this weekend can you let us know what the result was? thanks guys.

jwa999
07-24-09, 04:08 PM
^^^^^^^^^^^^^^^^^
I think the bypass is the process of not generating boost.

Your supercharger is always spinning. However it's not always generating boost.

You can be running at 6000rpms, it can generate 9lbs of boost, but unless the engine is under load, the supercharger is instructed *not* to boost or only to boost a certain amount.

I think that was what backup was playing with. Mess with the bypass control (the X connection), so the supercharger would generate the maximum boost for what ever rpms it's running.

The overflow valve is there to leak any excess boost. Sounds like the overflow valve is normally leaking .5lbs of boost.

Question is, what can cause an overboost situation that the engine needs protection from?

Hans.

Nutz
07-24-09, 05:27 PM
My assumption:

Safe to assume we make 9 lbs. stock.

There are everyday things that can lead to 1-2 lbs. of slight increases in boost such as barometric pressure, increased octane, and significant air temperature drop which can lead to an unexpected lean condition. I assume the P Valve seems to protect/prevent such conditions.

Soooo, it sounds like you need to perform this procedure only when significantly increasing boost with such as a pulley kit. (over 10 lbs.)

It also sounds to me as if those that are experiencing seat of the pants increase are one of the three above ambient effects resulting in slight boost increase.

IF my guess work above is correct than I have questions (Jesse):

1. Does the stock PCM adjust fuel for such changes?

2. Does your (W4M) PCM adjust?

3. The obvious one. Will this hurt the car by offering a dangerous lean condition?


Don't flame me guys. Just my thoughts. Plus, I think these are valid questions.

backup
07-24-09, 06:06 PM
The boost bypass still works just fine with this mod. you are only changing / removing the overboost protection.

Guys I think Jesse has the key here. In my experimentation, I could not get the boost much over 9psi. The best thing I could get was perceived faster boost build, which felt stronger, and maybe a little extra on the boost gauge (.5lb?). This was by capping the P port or removing the X-line (both do the same thing - removes the pressure feed to the P port). I got a hunch this little mod might be worth a few HP, or at least a few HP earlier. The car certainly felt more responsive.

I don't think the supercharger can make more than about 9 to 10psi in stock form anyway. You need pully swap to increase rpm to get beyond that. Jesse, is that right?

CadV
07-24-09, 09:09 PM
So if you cap X you could cap everything right?

qictrk
07-24-09, 10:22 PM
The way i understand it, is if you cap O and leave the line open that connects to it, your set. Cecil...............

backup
07-24-09, 10:39 PM
So if you cap X you could cap everything right?

Yes, capping X is the same as capping P, it removes the boost pressure from the P port. I have simply pulled the O line off the port on the OX valve which does the same thing. From what I have seen, the car builds boost fast and maybe .5-1.0 extra boost. The car certainly feels more responsive, and the boost gauge is clearly a little higher this way. I think it is more than placebo.

The Tony Show
07-27-09, 04:35 PM
If there was no risk to doing this and the car performs better this way, GM would have done it from the factory. I sincerely doubt that they'd intentionally handicap their flagship performance car in this manner unless it somehow provided better performance, longevity or protection.

musclesbmf
07-27-09, 04:43 PM
If there was no risk to doing this and the car performs better this way, GM would have done it from the factory. I sincerely doubt that they'd intentionally handicap their flagship performance car in this manner unless it somehow provided better performance, longevity or protection.

Two words: Warranty Claims.

So when we decide to up the boost, they still had protection to bleed off the boost. That's like saying GM/Cadillac will tune the ECM for max performance. No they won't. Or that their intake will perform better than aftermarket, etc. Can be applied to anything. I guess aftermarket headers and exhaust don't perform better either....

The Tony Show
07-27-09, 05:09 PM
You must have missed the part where I said "provided better longevity or protection". I have no doubt that putting a bigger crank pulley, upping the boost and defeating the boost limitations and bleed off make the car more powerful. Anyone who thinks they aren't taking a huge risk though, is kidding themselves.

I never said that they tune it for max performance- every carmaker sets the car up in the "sweet spot" between max performance and realistic durability. I've been modding cars for years, and the reality is simple: Every time you add power, you remove some of the margin for error in how bad things break if something goes wrong. Top Fuel engines sure make awesome power, but then they get torn down and rebuilt after one quarter mile pass.

Things like overboost protection are there to keep you from shattering a piston if something causes a boost spike. Does defeating it make more power? Sure it does- just like headers and tunes. But just like headers and tunes, it becomes a lot easier for something to get damaged if something happens.

I'm not trying to rain on anyone's parade, but based on a lot of the comments I'm reading here I think a lot of the posters on this forum are new to modding (not all, but some). They need to be aware of what exactly they're doing when they tinker with overboost protection.

Gotham CTS-V
07-27-09, 05:20 PM
http://i31.tinypic.com/xlh75k.jpg


Ok, so to make things simple....for us guys with pulley kits which will make more boost...all we have to do is disconnect the X line and put something to cover where the X line would be? And what should we use to "cap" this X opening? I'd be scared to just put a piece of foam in there, although if that is what's recommended and is "safe" then cool.

Thanks.

jwa999
07-27-09, 06:03 PM
Ok, so to make things simple....for us guys with pulley kits which will make more boost...all we have to do is disconnect the X line and put something to cover where the X line would be? And what should we use to "cap" this X opening? I'd be scared to just put a piece of foam in there, although if that is what's recommended and is "safe" then cool.

Thanks.

Actually, the O line goes to the P valve. I pulled out the O line. It just a rubber hose that is pushed on a plastic tube. I used some electric tape to close both ends. Might need to find some foam, the tape might not last.
If you look closely, there is already a piece of foam on the unused tube left of the O.

No adverse effects, did't see any boost gains, but my airbox is still limited.
Perhaps the boost comes on a little quicker, it's hard to say.

Hans.

musclesbmf
07-27-09, 06:07 PM
Personally, I capped the "P" and left the "O" open and did not like the results. I thought boost was lower, so I put it all back to normal. There are 2 contradictory posts in this thread. One says to cap the "P" (the foam dosn't cap anything, it keeps debris out of the "O"), and the other post says cap the "X".

So once again, does anyone know what they are talking about?

Mark

musclesbmf
07-27-09, 06:12 PM
You must have missed the part where I said "provided better longevity or protection". I have no doubt that putting a bigger crank pulley, upping the boost and defeating the boost limitations and bleed off make the car more powerful. Anyone who thinks they aren't taking a huge risk though, is kidding themselves.

I never said that they tune it for max performance- every carmaker sets the car up in the "sweet spot" between max performance and realistic durability. I've been modding cars for years, and the reality is simple: Every time you add power, you remove some of the margin for error in how bad things break if something goes wrong. Top Fuel engines sure make awesome power, but then they get torn down and rebuilt after one quarter mile pass.

Things like overboost protection are there to keep you from shattering a piston if something causes a boost spike. Does defeating it make more power? Sure it does- just like headers and tunes. But just like headers and tunes, it becomes a lot easier for something to get damaged if something happens.

I'm not trying to rain on anyone's parade, but based on a lot of the comments I'm reading here I think a lot of the posters on this forum are new to modding (not all, but some). They need to be aware of what exactly they're doing when they tinker with overboost protection.

You are correct sir... I did miss your point, and I do agree that many posts lead me to believe this is the first car some have modded.
Best rule of thumb: "You play, you pay."

Mark

qictrk
07-27-09, 06:13 PM
I don't believe tape is going to work. Go to an auto parts store and they usually sell rubber end caps that come in a box of assorted sizes. I was told by Jesse to pull the line marked P at the valve and close off the nipple the line came off of. I believe you can also do it by closeing the O instead. The line goes to both O and P. Leave the line open. Cecil.........

backup
07-27-09, 06:28 PM
The X port feeds pressure from the supercharger to the XO valve. O feeds from the valve to the P port on the actuator.

X-->O-->P

So whether you remove X, O, or P, the pressure signal is broken to the P port. Capping the P port itself might be advantageous as the V (vaccuum) port on the actuator will pull air thru the P port if left uncapped.

I found the best results from removing the X line from the X port, as the O/P line remains connected to the XO valve and acts as a cap or seal on the P port.

As everyone else has said, this seems to have a very minor effect, and it could be placebo. In my seat of the pants testing it feels more responsive, with faster boost build, but it is really hard to say if it is real.

Guys, I have seen people jump on a custom engine and trans tune, pulley swap, headers, intake, etc, without touching internals (some of you here posting in this thread). If you think this extra .5lb of phantom boost might kill your motor, then don't do the mod!! Ask questions and consider all alternatives, but pulling one of these lines will not suddenly give you 15lbs of boost though.

jwa999
07-27-09, 06:33 PM
Personally, I capped the "P" and left the "O" open and did not like the results. I thought boost was lower, so I put it all back to normal. There are 2 contradictory posts in this thread. One says to cap the "P" (the foam dosn't cap anything, it keeps debris out of the "O"), and the other post says cap the "X".

So once again, does anyone know what they are talking about?

Mark

Well, from what it looks like X is an input and O is an output on the valve that they are both connected to.
X comes from the upper supercharger body, most likely outputting pressure that is then switched to O by the valve if needed.
The O goes to P on the bypass controller, and I guess if enough pressure is applied to P, the bypass controller will stop boost.

So if X is disconnected, the supercharger would be blowing air through that hose if it's not blocked resulting is a small amount of air loss. If O is disconnected, then it would only be blowing air if the valve is open.

I don't thing the P input cares if it's blocked or open. Once it's disconnected from the supercharger, it's 1 atmosphere and won't activate the bypass valve.

Caveat: This is pure speculation, I could be completely wrong.....

lol: I see backup got a response too. End result: close everything, just make sure X does not go to P?

Hans.

musclesbmf
07-29-09, 10:59 AM
TTT.
For more clarity. I've checked the ZR1 forum on corvetteforum and could find nothing on this topic over there.

Mark

Gotham CTS-V
07-29-09, 11:54 AM
I wish there was an actual solution. It's crazy how some of us are unplugging certain lines, capping others, leaving everything disconnected, etc. Wish there was a way to find out exactly what the best configuration is.

CadV
07-29-09, 11:55 AM
I tried everything on mine and saw no difference. This is of course when I was hooked up to the dyno and reading the AF.

jwa999
07-29-09, 11:58 AM
I wish there was an actual solution. It's crazy how some of us are unplugging certain lines, capping others, leaving everything disconnected, etc. Wish there was a way to find out exactly what the best configuration is.

Since there's a valve connecting X to O controlled by the ECU, the best solution would be to change the parameters in the ECU when it opens that valve.

musclesbmf
07-30-09, 04:23 PM
Sorry you got banned, seriously.
But shouldn't your beef have been with American Racing Headers because it was their product that was giving you a CEL? It was nothing you installed from Jesse that was giving you the fault code. Unless I have totally forgotten what your original gripe was.

bottom line is this.... high flow cats will trip the CEL. And now that O2 sims are not sold anymore, the only way to get around the CEL is through programming. There are many avenues for programming and Jesse is just one of them. He doesn't want to turn off the rear o2 sensors for fear of EPA lawsuit like caspers electronics had. Can't blame him for that. So take your car to a local dyno and have the local "expert" tune your car with HP Tuners or LSEdit and be done with it. The reason for the quotes is because there are not a lot of GREAT tuners around.

Personally I wish I lived near W4M Performance, Quality Motorsports, or LG, or Lingenfelter, or VetteDoctors, or any of the like. Places like that have great tuners and can get the car spot on. But I still don't believe they have the knowledge of Jesse when it comes to these cars. He has 2 of them and drives them into the ground (quarter mile and track racing).

Anyways, we digress again.... P-valve anyone?

Mark

Domsz06
10-07-10, 09:11 AM
Very interesting thread....

I think I may have to do it tonight. Why not... the 9.5 is on the way anyway.

Domsz06
10-07-10, 09:13 AM
I got some pictures but I need help with this as well.

Here is a picture of the sensor (with the green x and o). x other end goes into the blower lid and would this be where the boost gauge gets its reading? o is the opposite end of the p port and I put foam on it after I capped the p port. I used foam because that's how GM had the unused port next to o.

http://i31.tinypic.com/xlh75k.jpg

What about the other two ports (except x) on the sensor? Do we use foam allowing them to breathe or do we cap them?

This is the p port with a vacuum cap (Thanks Robert for the vacuum cap) on it, is this right?

http://i27.tinypic.com/1zee785.jpg

Brent mentioned something about backing a screw out and will give ya a half pound of boost. Is the below picture the screw he is referring too?

http://i31.tinypic.com/2rz9ev6.jpg

so is this the screw jesse refers to that keeps the boost from building? he mentioned in my dyno I was bleeding boost and need to make sure the screw is closed. Is it he screw to the right of the upside down l bracket?

6speeder
10-07-10, 11:38 AM
I got some pictures but I need help with this as well.

Here is a picture of the sensor (with the green x and o). x other end goes into the blower lid and would this be where the boost gauge gets its reading? o is the opposite end of the p port and I put foam on it after I capped the p port. I used foam because that's how GM had the unused port next to o.

http://i31.tinypic.com/xlh75k.jpg

What about the other two ports (except x) on the sensor? Do we use foam allowing them to breathe or do we cap them?



This is the p port with a vacuum cap (Thanks Robert for the vacuum cap) on it, is this right?

http://i27.tinypic.com/1zee785.jpg

Brent mentioned something about backing a screw out and will give ya a half pound of boost. Is the below picture the screw he is referring too?

http://i31.tinypic.com/2rz9ev6.jpg

I'm new to this discussion, but it seems to me you are messing with two different boost control systems. The sensor with the x and O ports is for overboost control and could be turned off with the tune. The screw you turn to eliminate boost bleed is the boost bypass system which keeps the supercharger from delivering boost all the time.

Yes? No?

Domsz06
10-07-10, 12:09 PM
I'm new too. On ls1tech Jesse said my car has an issue, he said I'm loosing 30 rwhp, as well as bleeding boost. My car is CURRENTLY stock. So he mentioned there was a screw I needed to make sure it was not keeping the flap or something from allowing full boost.

Back to your over boost, yes there is an overboost turn off in the comp when you tune, however it appears that GM made another fail safe that is a physical device, that needs to be over ridden or else it won't allow full boost WHEN i put my 9.5 pulley in.

Thanks everyone.

http://www.ls1tech.com/forums/13955152-post7.html

here is the post.

GMX322V S/C
10-07-10, 12:49 PM
Here's a simplfied diagram I posted awhile ago that indicates the letter labels:

http://lh3.ggpht.com/_7fp7bZcElbk/TK3o-qO_aiI/AAAAAAAAA5g/G0nvoJDv9Js/s400/LSA%20Boost%20Control.jpg

When the Boost Bypass Valve is closed, the SC can build boost normally. Above about 12 PSI, the ECM kicks in a failsafe and opens the valve to bleed boost. In order to build boost above 12 PSI, you have to override the failsafe by disconnecting the Boost Control Solenoid from the Bypass Valve Actuator.

PhxTriode
10-07-10, 05:15 PM
I find this post interesting. I have hit 13.5psi (on the Dyno) and never have done anything to my P-Valve

Domsz06
10-07-10, 09:52 PM
Phx....

Intersting. Perhaps the computer elimated it still is true... Idk...

I still need to find that screw...

PhxTriode
10-08-10, 01:38 PM
I think it is referring to a set screw that is on the shaft of the bypass butterfly that is adjusted to give a 'Home' or closed position. Kind of like a idle adjustment screw for a carburetor.

Domsz06
10-08-10, 01:46 PM
I think it is referring to a set screw that is on the shaft of the bypass butterfly that is adjusted to give a 'Home' or closed position. Kind of like a idle adjustment screw for a carburetor.

That's what I thought, just wondering where and how to tell......

jft69z
10-29-10, 03:54 AM
delete

HUGN*RDS
04-29-13, 12:11 PM
Hey guys, referring to the picture I attached (from above), I was wondering if anybody has the answers to my questions below:

1. If we disable the boost control solenoid from controlling the bypass valve actuator and remain using the stock pulley, can we see higher boost?

By removiong line P/O we completely remove the control of the actuator from the solenoid, and the same can be done by removing the line X, which is the boost/vacuum source. Either will achieve the same result, but I personally removed the P/O line on mine. I am not seeing much boost above 9psi (digital readout from manifold absolute pressure sensor, MAP, on my interceptor).

2. There must be different areas of boost throughout the intake manifold, supercharger and heads so which sensor is a better indicator of actual "boost" pressure as defined by a tuner?

3. I would like to boost 10-12psi so can I do this on the stock pulley?

I am trying to avoid removing the upper blower pulley as that is pressed on. The lower pulley looks like a PITA (even with my 18V snap-on electric impact gun) too so I would like to avoid that. I just want a few more PSI and feel it's achievable with just a little work. Thanks for the input guys.

Da V-Man
04-29-13, 04:52 PM
Hey guys, referring to the picture I attached (from above), I was wondering if anybody has the answers to my questions below:

1. If we disable the boost control solenoid from controlling the bypass valve actuator and remain using the stock pulley, can we see higher boost?

By removiong line P/O we completely remove the control of the actuator from the solenoid, and the same can be done by removing the line X, which is the boost/vacuum source. Either will achieve the same result, but I personally removed the P/O line on mine. I am not seeing much boost above 9psi (digital readout from manifold absolute pressure sensor, MAP, on my interceptor).

2. There must be different areas of boost throughout the intake manifold, supercharger and heads so which sensor is a better indicator of actual "boost" pressure as defined by a tuner?

3. I would like to boost 10-12psi so can I do this on the stock pulley?

I am trying to avoid removing the upper blower pulley as that is pressed on. The lower pulley looks like a PITA (even with my 18V snap-on electric impact gun) too so I would like to avoid that. I just want a few more PSI and feel it's achievable with just a little work. Thanks for the input guys.First off, that diagram is wrong. The X line should tie into the intake plenum. The boost control solenoid feeds boost to the bypass valve actuator. There is no boost upstream of the SC rotors.

To answer your questions:
1. No, not unless the bypass valve isn't fully seated.
2. Not really. Just as water seeks its own level, pressurized air will equalize all chamber to which it has access (upstream of the intake valve).
3. Nope, not unless you cause a restriction somewhere. You may be able to tweak it up slightly by opening the intake path, but no where near 11-12 psi.

If you're concerned about the boost control solenoid opening too soon, just increase its actuation value in the tune. I would take that route and leave the plumbing alone.

Stillborn
04-29-13, 06:13 PM
this thread in all honesty is a joke for the V comunity as it neither 'clearly' shows how to do it, as well as arguments of why it should be done.
can anyone who has "successfully" bypassed this over boost subject please make a short you tube video of said mod? 5 pgs of garbage and no
clear solution has been given. i can see the m5 forum guys coming here for a laugh. :suspense:

HUGN*RDS
04-29-13, 09:12 PM
First off, that diagram is wrong. The X line should tie into the intake plenum. The boost control solenoid feeds boost to the bypass valve actuator. There is no boost upstream of the SC rotors.

To answer your questions:
1. No, not unless the bypass valve isn't fully seated.
2. Not really. Just as water seeks its own level, pressurized air will equalize all chamber to which it has access (upstream of the intake valve).
3. Nope, not unless you cause a restriction somewhere. You may be able to tweak it up slightly by opening the intake path, but no where near 11-12 psi.

If you're concerned about the boost control solenoid opening too soon, just increase its actuation value in the tune. I would take that route and leave the plumbing alone.

I am aware of where the x line goes. There are two lines used for vac/boost in that system. I think they are on the manifold correct me if I am wrong. I think if I disabled the bypass valve it would be fully seated. We swap pulleys to gain more boost but is there a few more in the stock one? And I already have a D3 intake and my air duct modded, that should help. I have done this on a similar supercharged vehicle so I figured the same concept of the bypass valve operation at high rpm's would apply because our stock pulley is limited.

Da V-Man
04-29-13, 10:41 PM
The bypass valve is a spring-loaded, normally-closed valve. With the engine off, and if the set screw is adjusted properly, it will be fully seated. With the engine on and in low-load mode (idle, cruising, etc), manifold vacuum is applied to one side of the actuator diaphram, which pulls the bypass valve open. In high-load mode (boost), manifold vacuum goes away and the valve closes. If the boost level exceeds what's programmed in the tune (about +12#), boost is then fed from the boost control solenoid to the other side of the actuator diaphram, which pushes the bypass valve open. The stock pulley is good for about 9# of boost, nowhere near the programmed limit for the boost control solenoid. If the bypass valve is operating correctly, you will not get any more boost from the SC unless you spin it faster. Bottom line: disabling a correctly-functioning bypass valve will not allow you to build more boost. What it may do is build boost a little faster. And you will always be compressing air through the SC, which may require tweaking the tune.