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Discussion Starter #1
I've had my GXP for a whole day and a half now and the last time I drove one was back in February which was a loaner car the dealer gave me to drive while my 06 was being delivered. from what I remember, which gave me turbo fever and made me hate my 06 ever since I drove it off the lot, the GXP had great pick up pretty much the second you step on the gas. well, mine does not seem to have the acceleration the other one did. with the loaner, I remember cruising at real low speed in 1st or 2nd and I could give it some gas and it would put you back in your seat right away. mone does not. it seems it accelerates slowley for a second or two and then takes off like a bat out of hell. I saw that the charge tube before the intake wasn't flush with the pipe so I loosened the clamp, pushed it in and tightened it good and I want to say it's a bit better but still no way near the low end torque I remember. I think the loaner was an 07 and it had 60k miles and was beat up a bit. could it possibly have had a tune and that's my problem? I'm not looking to race this thing but the acceleration was very impressive and that's what I was hoping for. any help would be appreciated. oh, and while it's not taking off, the boost gauge stays on 0 and doesn't seem to increase until about 3k rpm.
 

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Definetly look into a tune. 1st gear on the stock tune (and GMPP) is set to limit boost to only 5psi. Thus the reason your probably not feeling that kick in the pants right away. I've seen mine as high as 17psi in 1st gear, then I ran out of gear and had to shift. Mine also does still take a 1/2 second or so to spool though. Your turbo bearings could be "caked" too. Although this isn't supposed to happen with synthetic oil unless the car was completely abused. If I know that I have to take off in a hurry, I start revving the engine about 2 seconds before to get the turbo spooling. At that point I can literally smoke the tires off the car in 1st and 2nd. From a dead full throttle start, my boost will start to show about 2200rpms.
 

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Not sure where Ghost got his info on the GMPP tune, but his comments about 1st gear are not correct.

The GMPP tune does not limit boost in first gear to 5 PSI. I have been running the GMPP tune since 2008. At my altitude (5000 above sea level): 1st gear will pull upwards of 19-23 PSI (depending upon ambient air pressure at the time); this would be equivalent to 17ish to 21ish at sea level.

Check all clamps on the charge system, especially the Throttle Body Clamp. If it still has the OEM worm gear clamp; replace it with a good quality T-Clamp.

An aftermarket tune can change the command table to allow even more boost, across all gears. But be aware that the efficiency curve on the stock turbo runs out at 23 PSI (at sea level), which is about 27ish at my altitude.
 

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Some turbo lag is normal. The GMPP tune or Westers will give you a bit more bottom end along with a lot more top end.

My GMPP tuned car pulled hard from about 2k RPM up. Boost as GS stated is a function of ambient conditions and varies from day to day with temperature and humidity changes as well as altitude changes. 18 PSI at sea level equates to 23 PSI at altitude. Read Flashe's Owner s threads on the impact of air density on boost levels. Its in the 2008 time frame

Check all the clamps. The factory ones are prone to failure if over tightned or if they are cycled several times. Replace them with T clamps if possible.

Check the intercooler for cracking or damage. Its possible that the previous owner damaged it without knowing it.

Pull the drain plug just to be sure that there is not a lot of oil or water inside the IC.

Pull the hose on the front of the turbo and check for oil. Read the threads on the oil catch can.

Enjoy the fun.
 

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Discussion Starter #5
didn't I read something about the stock tune having a granny feature or something like that which limits the amount of boost under a certain RPM? When I adjusted the fitting and tightened it back down, I felt a gritty / crushing feel and figured it was something in the clamp. I will remove that boot and get better clamps. it does have the worm clamp but not like the one that TS posted a while back. these are pretty stout and the groves are actually raised rather than being cut into the band. weird that it has the tough ones on the other side though. Thanks. And if i do get a tune, should I go GMPP or get one of the others. I have 43k miles but bought the GM extended warranty.
 

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Not sure where Ghost got his info on the GMPP tune, but his comments about 1st gear are not correct.
Hmmmm.....I'll have to find the video. There were 2 tuners that were tuning off of the GMPP tune for the Solstice and they both said the GMPP limited boost to 5psi in 1st gear.... I'll look for it. But aparently its wrong anyway....
 

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A couple things I would suggest would be
1) Get yourself a good tune. I would very highly recommend going with a good tuner through HPTuners software or possibly Westers
2) Buy yourself some charge tubes. They really made a difference in the feel of the boost in my car. It's kind of hard to explain, but the boost felt like it came on much more smoothly as a little earlier.
3) Buy yourself some t-clamps! (Or if you buy charge tubes, some places will include the t-clamps with them). You may not be having any issues with your stock clamps at the moment but chances are you will.
4) HAVE FUN with that sexy new car of yours!!!
 

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didn't I read something about the stock tune having a granny feature or something like that which limits the amount of boost under a certain RPM? When I adjusted the fitting and tightened it back down, I felt a gritty / crushing feel and figured it was something in the clamp. I will remove that boot and get better clamps. it does have the worm clamp but not like the one that TS posted a while back. these are pretty stout and the groves are actually raised rather than being cut into the band. weird that it has the tough ones on the other side though. Thanks. And if i do get a tune, should I go GMPP or get one of the others. I have 43k miles but bought the GM extended warranty.
If you have the GM warranty then I would stay with the GMPP tune.

Pull a log from the GM data base for your car so you know that all the recalls have been applied, the inservice date and any maintenance activities that have been applied.
 

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Discussion Starter #9
yeah, I have the stock tune and I glanced down at the display and ran it up to 17psi in 1st so yes, that it incorrect. doesn't seem to start boost till about 3k and then it jumps up to 17 in a hurry and the thing is flying by then. it's quite impressive like it is. I let the wife drive it and she got mad. she took it for a spin and came back and told me you're gonna kill yourself in that thing. needless to say, that made my day.
 

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Hmmmm.....I'll have to find the video. There were 2 tuners that were tuning off of the GMPP tune for the Solstice and they both said the GMPP limited boost to 5psi in 1st gear.... I'll look for it. But aparently its wrong anyway....
My guess would be that those were tuners that where inexperienced with the new ECM tech at the time. Maybe they were working on cars that were stuck in "Limp Mode Lite" and didn't know that. Limp Mode Lite shuts down electronic boost command, but leaves all other engine functions normal. In this mode, you will only have mechanical boost command available; which peaks out at about 4-5PSI.

Even the stock tune, does not limit first gear to 5PSI. The OEM ECM tune does limit max torque to 260 lbs, and will adjust A/F, boost command and spark advance to keep the engine from exceeding the 260 lbs of torque max. However, I have never seen a stock tuned Kappa pull less than 15ish (sea level) peak boost. Again, peak boost commanded varies greatly upon many environmental factors; as well as how efficient any particular turbo is.

The GMPP tune does still retain some torque management in the lower gears (part of the 100,000 mile power train warranty, I am sure), and additional gains can be had with an aftermarket tune; as Rob mentioned. The GMPP tune also retains a couple other engine protection protocols: Turbo max RPM and Max Manifold Pressure. The aftermarket tunes disable or raise these thresholds, so that they can obtain higher peak boost commands. All of which, is still a moot point when you exceed the efficiency curve of the stock turbo anyway, thereby creating more heat than additional boost.
 
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