First of all my car does 20 psi stock

Im thinking of getting ZZP canned tune, now before you guys go, "go HPT or Trifecta" there's reason behind my decision to go this route.

I'm doing this so I can get a spare PCM and have a little instant gratification in the process.

I'm going to get all my bolt on store them until I get them all.Install them all at once then trifecta tune it.

So my question is, is 22 psi safe for my car, it's 100% safe? Like I said earlier My car stock does 20-21 psi stock due to low atmospheric pressure depending on temp.

So if I set it to 22 psi does that mean I'm going to be at 27 psi and we know how happy 27 psi is.

Thanks

 

I get that your in colorado but....Im skeptical.

Via what device are you confirming that you are hitting 20psi of boost stock?

 

I'm just going off of my stock boost gauge, I'm sure its set for 15 psi, I'll take a video if it'll help you answer my question

 

So let me get this straight, you are going to take a video while driving, trying to hit peak boost?

Can you datalog MAP sensor output voltage? do you have software that can give that to you in terms of pressure?

 

its not so much "boost" as "how much horsepower can my stock engine withstand for years to come." personally, i wouldnt run more than 270 crank horsepower with the stock cast aluminum pistons and head gasket

 

No I don't have any equipment, its not hard for me to record and WOT in second gear, if it does I'll have a friend sit in back and record for me.

 

I run 23 psi on my tune, stock I was hitting maybe 15-17 psi, Some times my custom tune will spike to 25 but it will drop down real quick to 20-23.

 

And, due to altitude and possible leanout issues in the mountians I would recomend a good custom tune rather than a canned tune.

 

Sounds about right. The air density is about 17% less@5000ft (according to air density calc). So if the ECU is compensating for 17% decrease of (17 Lbs max stock), that's almost 3 lb increase>>>20lbs.

 

How do I know if I'm tuned or not? I don't have GMS1 sensors so I'm not GMS1, but I know I've gotten to 20 psi more than once.

Importkiller you're from colorado and you're saying you haven't gotten to 20 stock, so is this 20 I'm getting regularly in second gear a sign of a tune?

 

strange, most cars dont do altitude correction in this manner. they run the same boost at any altitude because the boost control (ie boost solenoid) only knows when to cut boost by measuring manifold pressure. not ATM.

It seems a little risky in the vehicle design department, if you got into some freakishly low atmospheric pressure you it might try to run so much boost it overspins the turbo. Those bearings are only rated for so many rpms....

Or what if the atmospheric pressure sensor broke and read 0volts (0psi), it'd boost to the moon! lol.

 

to answer ur question, no u will not boost to 27 psi if u do 22 psi trifecta tune, reason is, stock has learn down, so it pushes as much psi as it needs to hit 260hp, trifecta doesnt have learn down, so it always stays at 22 psi, u will just not make as much power is u would in a lower altitude.

 

i have a trifecta tune and im hittin 24 psi in my car its fine

 

The stock can run as high as 20LBs according to GM info. The ECU will *do what it takes* to maintain the 260 HP (torque target). You have *learn UP* as well as learn down. That's why you will see higher boost in warmer weather and lower boost on cool weather..opposite of what you would expect with a *normal* turbo set up. So how does the ECU *know* when it's at higher altitude? I'm thinking the:1) The MAP sensors are reading too *low* for the specified inputs (RPM/throttle..etc) 2) wide band O2 reads RICHER A/Fs given the MAF reading ???....or 3) maybe it's just that torque isn't at *target*. In any event, the ECU can increase boost pressure..this runs CLOSED LOOP system to control boost. We have a boost control solenoid that can leave the waste closed more than normal, resulting in increased boost if needed. It will not overboost (as you suggested)..there's a built in fail safe shut down to limp mode if max *targeted* boost is exceeded..which is in the ECU program.
If anyone here differs chime in..this is just my take.

 

Boost pressure is based upon desired air load. Thinner air at higher altitudes (or warmer air) requires more boost to reach the DAL. More dense (or cooler) air would require less boost pressure to achieve the DAL.

When tuning the LNF to increase boost we raise the DAL setpoint. If you raise it extremely high you can never reach the setpoint so learndown is effectively eliminated.

 

Thanks for this response. The only other thing I want to say is I am considering a ZZP tune for the spare PCM. Do you think this same theory applies for the ZZP canned tune?

I understand what another user said about mountains and getting a custom tune via trifecta is ideal but what and why exactly is it not advised to get a canned tune? GMS1 is a canned tune and this tune has no bias in altitude.

So I'm just bit sure why, I know the general consensus here on CSS.net is trifecta or HPT but ZZP is offering a spare PCM that makes it hard for me to ignore them. Warranty protection with a tunable PCM.

 

im pretty sure all aftermarket tunes are like that, otherwise u could never take advantage of ur boltons.

 

i also live in colorado, and due to the altitude i do not think you will get the boost readings you clame to get on a stock engine.
remember one thing,when the boost is raised to a certain point,you will get blow by
and pressureise the crankcase. the rings are not designed for pressures above 20 pounds.
you better start thinking about total seal rings

 

I understand, but what happens to the boost control when you do that? You still have DALS to regulate boost right? Also, why doesn't it spin HIGHER than say 23lbs with the limit set to *the moon*?

 

The rings are not designed for pressures above 20

?? You can run 23 lbs with NO problems. The GM1 (yes FACTORY!!) tune allows this!

 

Okay so there's some skepticism going on here. I bought my car with 1000 miles on it and as far as I know it is 100% stock. Also I know I'm at least hitting (spiking, don't even know what that means exactly just assuming) 20 PSI. On my way to work in the morning I will attempt a video of me hitting 20 PSI

 

I see your sig says *stock 20lbs*

That's NOT correct if you're truly stock. Most people use SEA LEVEL as the bench mark.
If you're stock at sea level..it's 17 lbs max. To verify this..either 1) test there 2) get a tuner to read your state of tune. I thought I was *stock* after buying a used TC and it was holding 20 lbs solid to redline with spike to 23 (Highest point reached very briefly). Took it to an HPT tuner and they verified it had already been tuned.
Here's another *test*..floor it in 3rd gear from 60-90MPH. If you're tuned, you should get around 5.3 or sec or less. I cut you some slack for altitude.

 

I know I'm stock, I just ran a test run this morning and only got 17 psi in 53 degree weather. I recorded it and I'm going to wait for this afternoon to record another video when its warmer.

Also my signature is way incorrect, I know I'm not set for 20 psi, I only did that because in another thread I asked how do I know if I'm GMS1 and LSD, another user stated if I get 20psi in second gear than I'm GMS1 I went out and tested this and sure enough I was getting to 20 psi. It was a hot and rainy day that day.

That's when I decided to throw that on my signature.

I will uploaded all four videos of my psi readings tonight and this will help. I'm starting to wonder if the moist air caused me to get 20psi and this learn down someone else spoke of.

Regardless, this morning I got 17-18psi in 53 degree weather.

 

Because there are other tables than DAL that control the boost. Trifecta has control of a few more than HPT, but the turbo is also flow/pressure limited (as are all turbos) in it's design parameters.

I can boost 27 lbs in the midrange if I choose to. Keep in mind that any flow increases such as going catless are going to make it harder for the turbo to hold a given pressure. My VE airflow is over 30 lb/min at 5k at roughly 23 psi depending on conditions.