I thought that it was intuitively obvious to the most casual observer.

 

Well guys, This is getting annoying to me.

Sometimes i will mash it (40, 50, 60mph etc) and it will go and hold a nice 26psi, Then other times it will only go to 16psi which makes NO SENSE if i literally just mashed it and it went to 26psi now it's at 15psi?

When it pushes low boost you can really feel the car being sluggish, then when 26psi comes in it's like night and day. Something is telling me this isn't normal...

Could i need to take it back to the dealer? I always have the auto trans in D also.

 

There are times I see 23 psi at part throttle and other times I see 17-18 with it floored. Most times lots of power and other times it feels as if it is a little less peppy. Ever SS I have driven does this and it used to be worse in past Turbo cars.

If you want take yours back as it could be something but I suspect from what you are seeing it is normal

The gear should not matter. it will kick down no matter what on the boost. It just makes it kick done a little faster if you are in I vs D.

The worst thing GM did is put a Boost gage in these cars. All of us get Boost obsessed one some point. I did nd many others did.

When it comes to boost on this and most other turbo engines there are no absolutes. The computer makes all the adjustments and if the engine is not loaded even with it floored it will not always kit max boost. On the other hand with a load and lower speed and it at part throttle it may hit 21 PSI with out trying.

Most of us here do not have a clear understanding how this system works nor does GM spend a lot of time explaining it anywhere. I have owned and deal with a lot of serious cars with everything from superchargers tri powers and duel quads. and know a lot on some things but this system has been a learning experience for me. I still have a lot to learn on this turbo.

 

Yeah i think it's all in the GM tune, my buddy has the BSR tuner and no matter when he floors it, he gets a constant 25psi so i'm just kinda lost as to why mine isn't as consistent.

 

That's it. He's aftermarket tuned while you have the GM upgrade. Remember that the factory ECU without any aftermarket tune always manages torque output, ESPECIALLY in the auto trannies so we don't grenade them with our leadfeet lol. That's why (among other convoluted reasons like weather, temp, barometer, etc etc, blah blah) in some cases you'll see 25/26psi and others you'll barely see 15psi. I've learned NOT to pay too much attention to the boost gauge anymore, I watch other parameters with the Aeroforces now haha.

Later
Allex

 

I agree that may just be it.

Keep in mind GM kept this under warranty and I ma sure most of the torque managment properties are still there to help keep the Auto healthy. It is just shy of the point where they die.

The Aftermarket tunes do not have to worry about warranties and with some [not pointing out any SS tune but some tunes in general] are not sorted out to the point that they have a handle on everyting. If it ends up breaking something that is your loss.

When I got my GTP in 04 there were only a couple aftermarket tunes for the Series III SC engine. One tune wasted pistons with bad settings and another tune killed the trannys as it removed the torque managment program. It made them faster for a while.

Most tunes are fairly safe but you always have to be wary as some may not be as well sorted.

 

The GMPP tune has a bit higher demanded air load and a bit less torque managment but is set to have the boost tapper off at higher rpms. It also comands a few degress more timming. And I'm sure there are a few other changes that can't be seen usung HP tunners.

If you tune the GMPP tune is it really hard to get it to hold a constant boost all the way trough the rpm it will spike and then taper off. Your friend with the BSR tune is tuned on top of the stock tune and it really is completely different. The stock tune can be tuned to hold more consistant boost by the looks of it. I had my car seeing over 30psi when I tried to set my air loads on my GMPP tune to the same ones used to get 22 to 25 psi on a stock tune.

On a side note when I first got my GMPP tune I had the same thing happening to me I found all of my intercooler pipes clams loose. After I tightened them up the car was much more consistant.

 

How do i tell if they are loose or anything else exactly? This is the last straw and if i can't figure it out i'm trading the car in on something else. I don't owe a thing on it so i have nothing to lose except a car that boosts 15-26psi, you just don't know which and when it wants to.

Out of 5 pulls the car will run "correct" around 26psi then creep to 24 and hold 3 out of the 5 times but the other times it goes to 18 then drops to 15 and man it's like going from wow to a all motor hhr lt

I know this thing isn't a "race car" but it would be nice to be consistent.

 

Selling a car over a varied boost level we all see with this tune is a bit extream.

May be More tourque More HP can chime in as he knows this kit better than anyone here. May even send him a PM.

He can answer question here that no one elese can. Lets just say he has a lot more info on this than anyone on this kit.

The one question I have is if you tape off your boost gauge would you be able to really tell the boost level on each run by feel? Or are basing this all on what you see.

My levels will vary but my performance is always the same. It may not pull as hard at a higher speed as much but the power is always there.

I would learn exactly how this system works before you say it is broke. It is not like the systems of old or aftermarket tunes.

 

I do understand how it works but the feeling is different. It literally feels like the car is stock at times, then at other times it feels like the tune is installed. I've had turbo cars before and never had any problems like this.