I just tried it really quick just to confirm nls for myself. I did 1-2, 2-3 no problems whatsoever. Boost seems to stay more constant throughout the rpm range and throttle is a bit more touchy. I noted when nls'ing I backfired a bit louder/sharper but it still pulled forward and it felt more constant sort of speak.

I need to test against someone lol.

 

I'd test with you but your alllllllllllll the way in Miami lol

 

Lol for sure. I will try to squeeze a dyno day to test this and get a baseline on my car.

 

Some friends and I through a party a few weeks back themed "look real miami".

Best party of the year. haha

and if we decide to sticky this, I don't care to add pictures and a quick how to. Seriously, it took 5 minutes.

 

You guys do realize the purpose of the tank was stated on a GM TSB right? One reason is it's suppose to reduce compressor surge, which in itself is the best reason to keep the vacuum tank connected.

And to the person that keeps saying it was put there to reduce torque steer for magazine reviews is a moron, i'm sorry but that is dumb.

 

Thats why I made mine adjustable. When I open up the ball valve = no surge. When I go to the track ball valve closed = 26 PSI

 

I simply made an observation, ass.

annnd, once again, why don't the solstice and sky lnf's have this too? Do they not have compressor surge? If they can get by without it, I think the cobalt will be just fine.

 

Well here is the difference between the SS and the sky/sol, the SS was actually designed around track use which would involve a lot of throttle manipulation from WOT to partial throttle thus introducing a ton more compressor surge to the system so they had to compensate for this (I.E. The vacuum res.) The Sky/Sol wasn't designed for weekend track use, their just roadsters.

If your not autoxing or tracking the car then by all means, this mod isn't gonna hurt for 1/4 mile passes.

 

Well as of now, I don't track or drag my car. Your argument makes some sense (even though billing the lnf sky/solstice as just roadsters isn't the entire truth), but I'm going to keep the mod because I enjoy the way it makes the car drive. Possibly once I get my tune this summer i will forego the bypass.

This mod would definitely help track times though. The absence of turbo lag would really make a difference.

 

I agree. ^

 

Here are my results.

Lost 2 whp up top but gained around 12 wtq uncorrected and about 6 wtq corrected.

Worth it.

http://www.youtube.com/watch?v=qUjGVz6WCnM

 

thus getting it off the line requires good throttle control as well..

 

I think it is a good mod if you have good tires. The extra torque will really get your stockers going. Have been driving with it for a few days, don't notice anything other than a touchier** throttle. As of right now, I will put it back to stock due to my tires hating me and my dyno said 2 whp loss but quite a bit of torque gained.

 

Worth it. I finally did it to my car. I can deff feel a difference even when it's tuned. It will be great for roll races. Power faster.

 

i changed it back due to my idle ******* up long term... it was really bad till i plugged it back in

 

It effected your idle? I have yet to notice this issue. I will monitor the mod and keep everyone posted. We have two dynos that prove this provides more power. I hope it doesnt effect the long term. I dont NLS so i'm not so worried about this feature.

 

well i dont nls either but i had it done for a few months and it started rapid idling until i plugged it back in

 

Ya but they gain NLS with the GMS1, and I don't think they change the valve setup..

 

I've tested this delete with a K&N drop in and the stock filter and can tell you that it messes up my fuel trims . Also at low rpm throttle let off......occasionally the bypass valve flutters .... it seems to open an close very fast 2-3 times before all the air is out of the pipes.

stock filter
-4/-5 LTFT with the tank bypassed
+/-0 /1 with the tank

K&N
-9 LTFT with tank bypassed
-4 LTFT with the tank

These are what I'm seeing in my car with a mod's in sig. It would be interesting to see if some of you guys could watch your fuel trims and see how they react and post it here . Thanks

 

I logged my files and sent a few to Vince. He said the car is running perfect and didn't need to adjust the tune at all. I do have a SRI from CIA though. I have not seen any idel issues and deff feel better spool times. I'm going to keep it until i feel otherwise.

 

just wait like a month itll change trust me mine ran like a dream until a month later

 

I will unplug my batery and reset the computer

 

Yours might be fine , thats the reason i posted my little test here ...... so maybe people with the ability to log LTFT's could get together here and figure out where this mod stands when it comes to trim's.

My car could have 10-20 different reasons to run the trims it is, compared to yours. Could be my superchicken tune and my downpipe don't like each other combined with the K&N and tank delete . It's just weird how they even out when i plug the tank back in and put the stock air filter back on .


Another thing i'd like to know is what the power difference is between a car running -10 LTFT and 0 LTFT .

 

I have an 08 HHR SS Auto approaching 70,000 miles. It has the BSR (Hahn) tune, have had it almost from the beginning, and a K&N drop in filter, along with the Dejon spring. My SS used to hit 24 to 26 PSI no problem. It will now only go up to 23 PSI. I have also had codes P2261, P1101, and just the other day combo of P2261 & P0234. I have noticed that after a hard WOT from a dead stop, the engine would lose all boost, and that I would have to stop to shut down the engine and restart, and then my boost would return. Also there would be times on the highway, where I would lose boost just driving normally, and that if I pulled over to the side and let it sit for a minute or restart the engine, the boost would return. So I am thinking that my tank is leaking or the BPV does stick close, or a combination of the two.
So I am thinking about doing the tank and solenoid bypass, any opinions or other suggestions are welcomed. I enjoy the SS, but don't fully understand turbo's and how everything operates with them, so your thoughts will be well taken.
BTW, just to let you know about the improvement of the BSR tune, with my Dashhawk at the time, I went from a 7.1 sec 0-60 to a best of 5.6 sec 0-60 after the install. I know that this tune is limited, and probably not quite as good as what is out there now, but when everything is working properly, it runs great.
again, thanks for any info.............................................. .........Tom

 

I had the same problem. One of the vacuum lines was bad. Replaced it and all was good