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Why not just make another post to this thread with the pics at the new hosting service? :)
 

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This post describes the installation process. Note that each image FOLLOWS its description.

Image #1: Before Installation
The image below shows my GXP in unmodified condition. Note the stock air intake and cooling pipes.




Image #2: Remove Engine Cover
Pretty self-explanatory.




Image #3: Full Engine View with Cover Removed, Before Mod
A full engine image with the cover removed, so you can see where everything is located. The exposed valve is in the center of this image.

You can see the "incoming" rubber tube coming around the front side of the engine block into the front side of the surge valve (this is the one we'll unplug). (We'll call this Hose #1.) (See this post for more information about where this hose comes from.)

Another rubber tube comes out of the side of the surge valve facing away from camera (the right side of the car when viewed from the driver's seat) and circles over the top of Hose #1 over to enter the intercooler pipe (bottom-left area of the image below). (We'll call this Hose #2.) (This hose will not be touched in this mod.)

A third rubber tube comes out of the side of the surge valve facing the camera, then takes an immediate 90-degree turn and drops down into the engine block (this is the one we'll slice in half and insert the T connector into). (We'll call this Hose #3.)




Image #4: Close-up of Charge Air Bypass Valve (Solenoid) Before Mod
This image shows a close-up of the valve before the mod takes place. You may want to read the description for image #3 above again while looking at this image closely. Note that the plastic-covered wiring that comes up from the bottom of this image (just above the dip-stick) and enters the surge valve is not going to be touched during this mod. Be careful not to slice it when you cut Hose #3.



Image #5: One Last "Before" Shot
This image shows the "before" from one more angle, just to give a better view of where some of these rubber tubes are coming from and going to.




Image #6: The T-Connector
Close-up of the T-connector that you're going to insert into the sliced rubber tubing.




Image #7: Unplugging the "Incoming" Tube
This image shows the removal of the tube that's plugged into the left (front-of-car) side of the surge valve. Here we see Hector loosening the green metal tie piece that holds the tube firmly clamped. DO NOT CLAMP THE TUBE WITH THE PLIERS! Just loosen the tie piece and then you should be able to pull the tube loose with your fingers.




Image #8: Capping the Inlet Hole
Once you've removed the rubber tubing that leaves an open nozzle on the valve that has to be closed. Simply place the cap onto the nozzle. (It doesn't need to be tied off.)




Image #9: Slice the Rubber Tubing
Now we need to slice the rubber tubing. It's a bit hard to see which tubing is being sliced here, but it's the shortest of the three tubes that we've been talking about, and it runs from the surge valve into the engine block just a couple of inches aft of the surge valve. This is "Hose #3" described above. Slice this hose all the way through, and then insert the T-connector into the gap you've just created.




Image #10: T-Connector Inserted
This image shows the T-connector after it has been inserted into the sliced rubber hose. You can just see the white "T" portion of the connector sticking out from the black hose. If you look closely you can also see Hose #1 hanging loose, with its disconnected end dangling just to the left of the dip stick handle.



(Continued in next post.)
I can't see any of the pictures can someone send some to me so I can do this mod.. Thanks a lot guys.
[email protected] or send it through my inbox here. :grouphug:
 

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I can't see any of the pictures can someone send some to me so I can do this mod.. Thanks a lot guys.
[email protected] or send it through my inbox here. :grouphug:
read through the thread before you do the mod, after noticing degradation in performance or no performance gains at all plenty of people put it back the way it was designed

it seems it's an electronically controlled, "either on or off" (as solenoids are) waste gate facilitator and I guess some people thought the only reason for something like that would be for nany control, wiki tells us the purpose of the redundant control and it's pretty impressive;

Advantages
Since less positive pressure can be present at the wastegate actuator as desired boost is approached the wastegate remains closer to a completely closed state. This keeps exhaust gas routed through the turbine and increases energy transferred to the wheels of the turbocharger. Once desired boost is reached, closed loop based systems react by allowing more air pressure to reach the wastegate actuator to stop the further increase in air pressure so desired boost levels are maintained. This reduces turbocharger lag and lowers boost threshold. Boost pressure builds faster when the throttle is depressed quickly and allows boost pressure to build at lower engine RPM than without such a system.
if this is the type of solenoid we have, (and according to the part description small dealer posted it is), I really don't think you want to dis-engage this device

summarized, for the waste gate to work properly it can't be as granular (precise) at low pressure, this added control simply adds to the efficiency of the waste gate that it couldn't have without it

wiki goes on to say that because of this device the spring actuating the waste gate can be softer so if you do perform this mod you'll probably need a stiffer spring to make up for the control the engine loses

as I stated earlier in the thread, you might notice an increase in some instances but there will be a performance hit at other times that you won't notice, for instance you might get lag and attribute it to your turbo when it's not your turbo it's your mod

or, because of a tighter spring you might be in boost when cruising, wearing everything, your engine, your turbo, your mileage

wiki goes on to tell what the disadvantages are for the device, all have to do with device failure and I have never seen this device mentioned as a failed part on this board

I say this "mod" is counter productive and should have been removed from sticky status a long long time ago, at the very least a serious disclaimer placed at the top of the original post
 

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Mods, you may want to move this to the w/g mod section / posts. I didn't realize EDAL didn't include the W.G. Mod... Shows how much I've read up on it :) My post below is much more applicable to this sticky.

I'll present a few thoughts and then you guys can carry on :)

First a few notes about the mechanics of the control system:
- The wastegate is a valve that bleeds off exhaust gas to control the turbine energy, the control of this energy controls the boost pressure generated by the compressor on the other side of the shaft.
- Why have a wastegate? Because there are a variety of situations where the engine is capable of making too much boost. Rather than simply close the throttle and resist the boost pressure, we simply stop the turbo from generating it in the first place.
- - This "too much boost" concept may be difficult for you performance guys to understand :)

The wastegate valve position is controlled by a spring inside the wastegate canister and air pressure, supplied by the boost control (or wastegate) solenoid from the compressor outlet.
- This is very important to understand.

- The force of the spring is controlled by adjusting the pre-load... meaning the length of the rod relative to the wastegates closed position
- This means that the more pre-load you add to the spring, the more boost pressure it takes to open the wastegate.
- - This is called "basic pressure", or the pressure at which you can start controlling the turbo.

Modifying the length of this rod, by adjusting the jam nut location, changes the pre load changing the basic pressure of the engine / turbo setup.

What this means:
- The engine controller controls boost in a variety of ways. lets start with the failsafe:
- If all else fails, the engine closes the throttle to prevent the turbo from over boosting the engine @ high load. This means, that even though you press the accelerator pedal all the way, and have cranked down your wastegate spring, the ECU is simply closing the throttle to control boost pressure because it KNOWS something is wrong. These conditions occur when we set a check engine light for boost control (P0234, overboost)

- Normally the engine takes the accelerator pedal position and converts it to a desired torque. The engine knows about how much boost pressure it needs to achieve that torque and sets the wastegate position ahead of time (feed forward control).
- If the feed forward position is significantly off (doesn't deliver the desired boost pressure) then we have PID controller that integrates the signal sent to the wastegate solenoid accordingly, either up or down, to adjust boost pressure to a desired level.

The controller LEARNS THIS OFFSET! This means, that if you adjust the wastegate rod position, the feed forward position will be wrong, but the ECU will correct it, eventually. We have certain conditions that must be satisfied over time for the ECU to learn this offset. If the offset is too large, we'll set a code saying that something is wrong, and you will take your car to the dealership, and they'll fix your wastegate rod for you :)

The reason for this is again, the controller knows how much torque it wants, meaning it knows how much boost pressure it wants.

Furthermore, simply increasing the pre-load doesn't do anything for turbo lag, because the wastegate is already fully closed until we ask it to open. This means that when you go to wide open throttle the wastegate is closed until we achieve our desired boost pressure (or close to it). When you crank down the wastegate rod what actually happens is the boost pressure over shoots, giving the feeling of better performance. Over time the controller again learns to fix the overshoot and the performance gain goes away.

On the other hand, a certain amount of pre-load is required to actually close the valve @ peak power. Meaning that when we take away all the air pressure from the solenoid we want to the valve to close all the way to give maximum power. This balance is how the basic pressure is determined. If for some reason you wanted to make more power @ a higher airflow / back pressure with the stock turbo, adjusting the wastegate rod may be benficial, if you find that the valve is not closing all the way @ your peak power point. You will over course have to modify the control system to allow you to make more power, but it is possible.

Again, by changing this relationship you are simply requiring the control system to adjust back to stock.

The other thing to consider is that the higher the basic boost pressure the less control you have over the turbo @ part load (boosted). For instance, if you basic boost pressure is 135kPa, and you request a torque level that only takes 125kPa of MAP to make, the throttle is closed to reduce the boost pressure down 10kPa. This means that the turbo is actually fighting the throttle, creating an efficiency loss, costing you fuel economy. The reason for this being that on the exhaust side you are generating all the energy to make 135kPa of boost, but you are only using 125kPa of it. The other 10kPa is just wasted.

For this reason, the balancing act of setting basic boost pressure is quite strenuous, You want the lowest pressure possible for control and fuel economy, but has to be high enough to satisfy the peak power requirements of the engine. By upsetting this you are essentially undoing what is otherwise an optimal balance.

That is all.. carry on.
 

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Interesting post, Sodaminsane! Thanks for sharing!

Can you comment on the function of the Charge Air Bypass Solenoid and give your opinion on bypassing this solenoid as described earlier in this thread?

Thanks! :thumbs:

Yogi
 

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Technically speaking the bypass valve is only there to prevent compressor damage in situations where the wastegate is not fast enough to control boost pressure, such as @ WOT lift off where the throttle closes quickly... For instance, if you are @ a WOT accel, and then lift off the pedal, the throttle will close quickly, and all the air that the turbo is pump will have no where to go. This produces a rapid spike in boost pressure that can damage the compressor, so we open the bypass valve to prevent that damage.

In older systems a bypass spring was set for a specific pressure, now we use a vacuum driven solenoid to actuate the canister when we want.

The reason for this is that it allows us to fine tune the bypass valve actuation (read delay it).

For instance, if you have an automatic transmission, you don't want to blow off all your boost pressure during a shift event. The transmission can shift quickly enough that we don't need the bypass valve, and having the excess boost pressure after the shift produces a faster response (no torque sag) because you don't need to spool the compressor again.

For that reason, we tolerate the boost pressure build up, as long as it stays below a critical level, and don't blow the bypass valve. it's a fairly slick process that produces a very nice torque response after the transmission torque limitation is released.

The other "trick" is that because you are using a 2-way solenoid, same as on the wastegate side, you don't need as stiff of a spring. You use compressor out pressure (boost pressure) to keep the valve closed, and then switch it with vacuum (via the solenoid) when you want it to open. This produces a VERY fast response (50ms or less) when you want it.

A couple of other notes specifically related to the discussion previously in this thread...
First, I hope the above has painted a picture of how an electronically controlled bypass valve helps prevent compressor damage, but also allows you to have some more flexibility in the regions of low load operation.

Second, lets address the physics of the bypass valve being open @ part load
- Holding the bypass valve open @ part load is actually a good thing. IT keeps the compressor speed up (as mentioned before) here's how:
- Pressure actuated wastegate compressors generate basic boost. IE, a nominal pressure before you can actuate the wastegate to control the boost pressure... If your pressure request is below this basic boost level, then you just waste the boost pressure you have made by closing the throttle.
- - For instance, @ 90kPa MAP the solstice LNF is actually making about 10 - 15kPa of boost (108 - 115kPa pre throttle pressure). This pressure is wasted because we only want 90MAP, so we close the throttle to reduce the manifold pressure.
- - Instead of generating the boost pressure, you can open the bypass valve and short circuit the compressor loop. This means that instead of building air pressure the exhaust energy from the turbine is instead generating AIRFLOW. Anyone who has looked @ a compressor map knows that for a given pressure ratio, as you increase airflow, you increase speed. This means that you spool up the compressor by recirculating some of the air the engine is consuming through the compressor.

This doesn't cost you any performance because the engine doesn't need all the air anyway, and it reduces the pumping work on the turbine which increases your fuel efficiency. THEN, when you try to boost, you already have a quickly spinning compressor, and as soon as you shut the bypass valve, boom, instant boost pressure.

I suppose as I read this thread I'm a little confused by the phenomena that someone observed that made them think that modifying the bypass valve circuit was a good idea? Anyone have an HP tuners trace of before and after mods? I've got plenty of boost pressure buildup data from my solstice, but I've never tried the mod...

In reality all the described modification has done is short circuit the control to rely only on manifold pressure (either boost or vacuum) to prevent any ECU control? I suppose no one with an automatic has tried it because it would actually make the shift torque lag worse?
 

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I had my doubts about this mod and your explanation of how the CBV solenoid works has reinforced my suspicions that this mod is not a good idea.

Thanks, Sodaminsane, for taking the time to write such a detailed response! :dthumbs:
 

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I had my doubts about this mod and your explanation of how the CBV solenoid works has reinforced my suspicions that this mod is not a good idea.

Thanks, Sodaminsane, for taking the time to write such a detailed response! :dthumbs:
I've always thought this "mod" was counter productive as I've stated a few times

really glad to have the actual purpose for this part,per sodamninsane's post the wiki quote above nailed the funtionality of this part

I think it also needs to me mentioned, so long as this solenoid connected, making the blow off valve spring stiffer is counter productive

sodamninsane said:
I suppose no one with an automatic has tried it because it would actually make the shift torque lag worse?
this is why I ask everyone to read through this thread to see if they really want to perform this "mod", there are a few people on the thread that did notice a decrease in performance, I don't think they were just the automatic

it's funny, I work incomputer I T and I see some of the "tweaks" people advise on some tech sites, just about everyone of them actually slow down a computer yet people seem to think their box is faster when they do the "tweak" till they go for a benchmark and realize it was no "tweak" at all

it's like the butt dyno, sometimes more noise makes you think your car is faster when the reverse could be true
 

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All this is very goodbut.... I am unclear just how I as the driver will feel the difference. Does it really work? Has anyone got a before and after feel that it was all worth it?

CASam
 

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Stay away from this mod.....
 

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Edal and Waste Gate Mod

The past few years this mod has been Ok. My vehicle has only a few mods and nothing substantial. The mods were even returned back a couple of years ago just to confirm how it worked and did not like the delay of the turbo and the speed it spooled after reverting back to the original.

Since then I had the GMPP update done and now I am having an HP Tune. I have revisted the info and have read that several memebers do recommend against these two mods.

Wondering if now is the time I should return back to original and ride the tuned configuration for a while.
 

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Yes, put it back to stock.
 

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I concur with LV. Stick with the stock config. Especially after any tune is done.
 

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Add my name to the "tried it, didn't notice any change" group.

Tried it and the waste gate mod years ago and changed them right back when nothing felt any different.

It's nice to finally read about why it didn't work. :)
 
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