Ok so i went to the track and did awesome compared to previous, 13.3 at 26mph lol. Anyways i blew out my MAP sensor on my intake manifold. No biggie now that im boosting over 22lbs for more than 5seconds. When i took the sensor out about 15mins ago to see if it was just dirty or i could clean it i looked inside the manifold and saw what looked like a lil oil pool where the tube drips down. So i was thinking maybe they put this on our cars to be like a catch can?? not sure but im not %100 percent i want to leave it off for the long run.

 

^^Damn, I was about to ask a quick question on this but after what he said I might better hold off.

 

If it caught oil we would have trouble with the solenoid thats in between the tank and the bypass maybe?

Here is what GM says its purpose is ....towards the bottom . One thing that makes me comforatable about deleting the tanks is ....... The GXP solstice and Redline Sky don't have one, and what we are doing to our cars is exactly what their's look like stock .

Service Information 2009 Chevrolet Cobalt | Cobalt, G5 (VIN A) Service Manual | Document ID: 2324723
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#PIP4669A: Intermittent DTC P2261 Setting - (Aug 10, 2009)


Subject: Intermittent DTC P2261 Setting


Models: 2008-2010 Chevrolet Cobalt SS

2008-2010 Chevrolet HHR SS




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This PI was superseded to update model years. Please discard PIP4669.


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The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
A technician may find DTC P2261: Turbocharger Bypass Valve Stuck Closed set with no problem found. It may be intermittent in nature or they may find the dtc will set after a hard acceleration, usually in third gear. DTC P2261 is a type B dtc and will not set on the first drive cycle the dtc sets, therefore multiple test drives should be performed to confirm repair.

Recommendation/Instructions:
SI diagnostics for this DTC states that the ECM compares the measured MAF reading to the modeled MAF and has detected a series of pulsations in the induction system that exceed a calibrated threshold. A snapshot of "Induction Data" will show the fault, however the tech may need to compare the snapshot data to another vehicle if they are unfamiliar with the readings. They should note a fluctuation and or a difference in the desired versus requested boost level. When diagnosing this dtc pay close attention to Circuit/System testing step #1. This step has you inspecting for any vacuum leaks, damage, restrictions, improper routing or connecting of the vacuum hoses on the charge air bypass valve solenoid, the charge air bypass valve, and the charge air bypass valve vacuum tank.

We have found leaking vacuum tanks causing this dtc. When testing the vacuum tank, care must be used or the results may not be valid. The vacuum tank has an integral check valve not noted in SI. To check the Vacuum Tank operation, disconnect the hose that runs from the tank to the Bypass Valve Solenoid at the solenoid and apply vacuum to the tank. The tank should be able to maintain vacuum with no decay. Note: If you remove the vacuum hose from the intake manifold and plug it and the decay stops the check valve is leaking, if the decay continues the tank itself is leaking.

Note: Front wheel drive platforms using the 2.0 Liter RPO (LNF) incorporate a charge air bypass valve supplemental vacuum tank.

The purpose of the tank is to provide an instant source of vacuum to the bypass valve via the bypass solenoid (when it is commanded open by the ECM). This results in less pressure buildup under closed throttle conditions, thereby reducing compressor noise, surge and spool time.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION


Š 2009 General Motors Corporation. All rights reserved.

 

prolly going to keep mine

 

my car surge a little bit when the car was cold. and i was only going like 20mph around 1500 rpm. like when i shift from 2nd to 3rd, it made the surge noise.

 

Funny how it's actually helped surge and spool time with some people... I wonder if it was the placebo effect.

To keep or not to keep...

 

I could see it being beneficial for tuned people just by the nature of how the BPV works. Just a theory.. but Cause when you let off, it's not JUST vacuum pulling it open but also the pressure on the other side wanting to escape.
If you are tuned, there's just that much more pressure to push it open plus the vacuum.
I for one like what the mod did.

The only time I've EVER experienced surge is high boost, low rpm... in 5th gear when I should just be down shifting anyway.

That's normal. If you look at your boost gauge when you first start the car (no matter the weather outside)... well mine always reads 10 inHg when normal idle is 20. So the turbo is "boosting" just slightly as part of the warm up. If you take off it's going to jerk around and stuff. Turbo Diesels do it too I believe.

I always wait for the boost gauge to drop before I take off... even in the heat of summer.

 

Yeah even though it is oil and water cooled it will always be best to let your car warm up and idle before taking off

And no heavy boosting until completely warm.

I haven't noticed a significant change in AFR or LTFT/STFTs with this mod either.

 

I would advise against this mod. Because. Stay with me on this metaphor: A condom has a little bit extra at the end to prevent the eruption of the condom itself when you blow your load. It desperses the pressure. This is the same with this tank. The reason your BOV is louder is because it is working harder than it is intended to work. The tank slows down the air escaping essentially to a specific speed for the above benefits. The engineers designed the weight of the spring according to this force as well. SOOO if you get rid of this speed bump , your spring is working harder and there is a potenially determintal amount of air that usually is metered and accounted for that needs to evacuate. It is more of a safety measure than anything, and I will take anything that helps prevent compressor surge. $0.02

 

I've screwed around with a few hoses from the bypass and the solenoid when connection my blow off valve and I've gained some impressive response,maybe it was the aftermarket hot pipe that I also installed. Oh well the restrictive pancake one wasnt all that great anyways.

I've screwed around with a few hoses from the bypass and the solenoid when connecting my blow off valve and I've gained some impressive response,maybe it was the aftermarket hot pipe that I also installed. Oh well the restrictive pancake one wasnt all that great anyways.

 

i re-routed the lines
disconnected the ones from the vaccum tank i also managed to connect it to my HKS bov
and my car runs great
no CEL's yet i do feel a difference though

 

so then why do the solstice guys not have one? same motor.

 

i think this mod is better for the turbo swaps. no bypass just bov

 

There are many differences, one of them and being the most important is the induction system.

 

You know, I started thinking while on the farm more about the solenoid+tank. I bet the reason it and the tank exists has a lot to do with the ETC. If you have the ability to log your car, you know that often the throttle plate lags the peddle quite a bit on opening and closing. Could kinda make operation of the bpv kinda goofy at times.

Just a thought.

 

That could be true as well. I am sure that they did not install something on the car that they could do without. LOL

 

Somebody from the Solstice/Sky world needs to show us the BPV spring they have and we can compare it to ours. That'll tell us something right off the bat. If it's the same, I call this theory at least partially debunked.

I'm not saying there isn't anything to it at all. At least you're reasoning it out... something many on here don't bother doing usually.

Perhaps that Dejon BPV spring is a stronger spring in part because they may start with a stronger BPV spring. Technically I think it's called a Solstice BPV spring to begin with if I remember right. Perhaps the Dejon spring has a place after all if you do the vacuum tank delete.

"Hey guys, I just discovered that you get better acceleration off the line and better gas mileage when you do a rear passenger side wheel delete! It even makes cool sounds now!"

 

I like all the input on this. Your idea on the spring from the sky does make a lot of sense aswell. Your getting pressure to your bpv quicker and possible a little more. So the heavy duty spring may be needed. Some one said a ways back that the extra pressure on the bpv would hurt it.... that cant be true. Just think about the other people that are tuned at 22+PSI?? they have alot more pressure just from the tune.I have been running it since i posted it up with no problems. IT is just a simple little piece as well, a spring, rubber garmet, and little piece of metal to work as a plunger. After taking this thing apart a couple times i have also found another trick to the bypass valve... Im still playing with it so il let yall know if its a fail or not.

 

Dejon actually sells the same spring "upgrade" for the Kappa cars, so I think that throws that theory out. I guess anything possible, but...

Anyone here ever prove at what point the stock BPV even leaks? Would be pretty easy to verify with an air compressor and a boost leak checker. Someone whos not in a place where its 30F outside go find out

 

Clarification: I was stating before that the one we use is actually one originally for the Solstice and got passed off as a Cobalt one too. There's only one kind that I know of.

That being said, since it was originally made for the Solstice/Sky, that may explain why some of us have been having issues with it and why it's designed so much stronger. It may be because their version is missing a tank. We need to see what the stock Kappa LNF BPV spring is like compared to ours to be able to tell if we're onto something.

 

I did it, and I have the dejon spring. just saying.

 

I did this about mod 45 min ago on my 09 HHR SS and took the car for a ride through town and on the interstate. I do have the GM upgrade kit, I also have the DEJON SPRING. Boost felt like it built a little faster but the main thing I noticed in my case is how rock steady max boost stayed in every gear, no fluctuation what so ever and boost drop off betweens shifts seemed less.

Before this mod with the Dejon spring, the boost came on a little slower and then it hit hard, but I had slight fluctuations in boost 1-3 psi top end, now it goes straight to max boost and stays there till I take my foot out of it. I'm going to keep the mod for awhile and see how the long term effects turn out.

 

I've seen the same thing . I have a superchips tune and it would spike to 21-22 then fall to 17-18 and go back to 21 psi. Now it's solid all the way threw the power band.

 

Maybe I'll get out the car tonight and do a before/after 3rd pull and post the logs. Although getting the cover off/on is a PITA blah.

 

C'mon... take one for the team...