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-   -   22psi stock tune. (https://www.chevyhhr.net/forums/2-0l-performance-tech-46/22psi-stock-tune-51931/)

bmx racer 10-05-2014 08:23 PM

22psi stock tune.
 
I had the plastic fittings on my stock intercooler break and ran without boast for a week and now have the zzp intercooler on. For about 2 weeks after the install it was holding at 22.5 psi not just spiking and spooling a lot faster. It is now back to normal at 19 psi. Has anyone else had something like this happen and is there any way to get the 22.5 psi back or do I just need to turn it.

firemangeorge 10-05-2014 08:55 PM

Sorry, but 22psi, where you live at, is not a stock tune. If you bought the car new and can verify it's stock, then you either have a faulty gauge or a BV problem. If it is stock, then it would(should) trigger an overboost CEL with boost numbers that high.

If you bought it used, then the previous owner probably had a tune done.

Fwiw. Around 19 is what I get with the GMTU. I'm pretty close to sea level like you are. Your's sounds like those are GMTU numbers.

gamma-wes 10-06-2014 08:45 AM

Quick way to verify; look at the top of the MAP sensors and see if the sensor is marked with a sticker. Blue and white sticker means 3 bar MAP sensor and GMTU.

firemangeorge 10-06-2014 09:11 AM

1 Attachment(s)

Originally Posted by gamma-wes (Post 760682)
Quick way to verify; look at the top of the MAP sensors and see if the sensor is marked with a sticker. Blue and white sticker means 3 bar MAP sensor and GMTU.

This:

Attachment 16634

XtremeSS 10-06-2014 02:54 PM


Originally Posted by firemangeorge (Post 760663)
Sorry, but 22psi, where you live at, is not a stock tune. If you bought the car new and can verify it's stock, then you either have a faulty gauge or a BV problem. If it is stock, then it would(should) trigger an overboost CEL with boost numbers that high.

If you bought it used, then the previous owner probably had a tune done.

Fwiw. Around 19 is what I get with the GMTU. I'm pretty close to sea level like you are. Your's sounds like those are GMTU numbers.

Sounds like your car has learned down the boost quite a bit. For the hell of it, go under the hood and pull fuse #41 ( ECM fuse) which will reset the learn down. Put the fuse back in place and Go for a drive and floor it. I bet you will see 22-24 psi

firemangeorge 10-06-2014 03:25 PM

Nope. Mine has pulled 19 since day 1 of the GMTU install. It has nothing to do with any of that learn down theory.

I have had several back and forth talks with some engineers at GM regarding this. In a nutshell, if it's making the power with 19 lbs, then that's all I'll get according to them.
The RPD does show my output to be right at the GMTU's 290hp, 315tq.

XtremeSS 10-06-2014 05:52 PM


Originally Posted by firemangeorge (Post 760731)
Nope. Mine has pulled 19 since day 1 of the GMTU install. It has nothing to do with any of that learn down theory.

I have had several back and forth talks with some engineers at GM regarding this. In a nutshell, if it's making the power with 19 lbs, then that's all I'll get according to them.
The RPD does show my output to be right at the GMTU's 290hp, 315tq.

Well it worked with mine several times but maybe that's because I had a bunch of intake and exhaust mods. With GMTU I would max at 22 psi. Pulled the fuse and the first wot pull I see 24 psi. Then the next pull was back at 22 psi max. It "learns down" very quickly it seems. I know people say GMTU disable the "learn down" or whatever but I've seen it with my own eyes. Once the computer collects all the data it needs, it makes it's corrections wherever needed(boost timing, wgdc, idc, ect) my .02

2005HHRauto 10-07-2014 08:27 PM

There's no 'learn down"
Our ECMs are "torque-based".
Whatever the "torque-curve" is, in the "tune", is what the ECM is
going to do it's best, to follow.

The GMTU, + all aftermarket "tunes", of course, have better "torque-curves",than stock.
The ECM "learns" quickly, after being reset , to settle into it's programmed
"torque-curve".
That's why, with even a bone stock HHR SS, the 1st few minutes after an
ECM reset, your buggy will fly.
If you reset your ECM at the track, your next run down the track will
probaby be your best run of the day...:twothumbs:

bmx racer 10-07-2014 10:53 PM

The car is back to 22.5 psi and has been there for 2 days now. I'm guessing it is actually already tuned because I noticed the cruise control button got bumped off and that was the first time it was off since I got the car and I know some tunes us it to turn on. I bought the car used by the way.

XtremeSS 10-08-2014 01:58 AM


Originally Posted by 2005HHRauto (Post 760845)
There's no 'learn down"
Our ECMs are "torque-based".
Whatever the "torque-curve" is, in the "tune", is what the ECM is
going to do it's best, to follow.

The GMTU, + all aftermarket "tunes", of course, have better "torque-curves",than stock.
The ECM "learns" quickly, after being reset , to settle into it's programmed
"torque-curve".
That's why, with even a bone stock HHR SS, the 1st few minutes after an
ECM reset, your buggy will fly.
If you reset your ECM at the track, your next run down the track will
probaby be your best run of the day...:twothumbs:

"Torque based parameters adjustment"s , "learn down"- same same lol

firemangeorge 10-08-2014 05:25 AM


Originally Posted by bmx racer (Post 760855)
The car is back to 22.5 psi and has been there for 2 days now. I'm guessing it is actually already tuned because I noticed the cruise control button got bumped off and that was the first time it was off since I got the car and I know some tunes us it to turn on. I bought the car used by the way.

Well. That makes sense. From the numbers, it sounds like you have the GMTU with a select-a-tune on top of it.
Did you look to see if you have the Bosch sensor like in the picture I posted ?

2005HHRauto 10-08-2014 08:36 AM


Originally Posted by XtremeSS (Post 760860)
"Torque based parameters adjustment"s , "learn down"- same same lol

No
Think of the ECM as being "wide-open", in an "out-of-control" state,
in the neutral zone, with all the tables frantically, trying to get in sync
with each other, to deliver the desired "torque-curve", that the ECM
was programmed for.
The ECM will quickly, achieve control.
If we had a NA engine, you wouldn't notice this taking place.

Put your E47 program into a bone stock HHR SS , with a few parameters
reset for gasoline, & the ECM will try it's best to deliver the same
"torque-curve", that you have now, on E47, & you'll never feel it's trying to
reset to a lower "torque-curve', as it will be constantly tring to reset to a much higher "torque-curve", that it will never achieve.

I've done this, & it's really awesome.
When driving my E47 "tune", on gasoline, it feels exactly the same as when on E47, up to at least half throttle.
With just cruising around town, or going to work, it's the same..:twothumbs:
The ECM is easily doing this, by smoothly increasing the boost.
I tryed this, incase of a scenario, in which I didn't have access to Ethanol.

It really makes sense, as it's the Ethanol that's giving us the awesome power
& torque increase.

XtremeSS 10-08-2014 11:55 AM


Originally Posted by 2005HHRauto (Post 760876)
No
Think of the ECM as being "wide-open", in an "out-of-control" state,
in the neutral zone, with all the tables frantically, trying to get in sync
with each other, to deliver the desired "torque-curve", that the ECM
was programmed for.
The ECM will quickly, achieve control.
If we had a NA engine, you wouldn't notice this taking place.

Put your E47 program into a bone stock HHR SS , with a few parameters
reset for gasoline, & the ECM will try it's best to deliver the same
"torque-curve", that you have now, on E47, & you'll never feel it's trying to
reset to a lower "torque-curve', as it will be constantly tring to reset to a much higher "torque-curve", that it will never achieve.

I've done this, & it's really awesome.
When driving my E47 "tune", on gasoline, it feels exactly the same as when on E47, up to at least half throttle.
With just cruising around town, or going to work, it's the same..:twothumbs:
The ECM is easily doing this, by smoothly increasing the boost.
I tryed this, incase of a scenario, in which I didn't have access to Ethanol.

It really makes sense, as it's the Ethanol that's giving us the awesome power
& torque increase.

If the engine is making more power right after resetting the ECM then it takes the power away to achieve it torque goal then you can call it what ever you want. The point is that you can gain a little bit of power after resetting the ECM with GMTU until the parameters come in sync with each other to achieve torque goals as you say. "Learn down" is just what I call it since it is effectively pulling power while configuring the parameters.

2005HHRauto 10-08-2014 02:10 PM

Then with the example that I gave, it will be a "learn-up", & will never
reach the higher programmed, "torque-curve".
Learn up or down, the ECM is just syncing it's tables, to best follow the
programmed "torque-curve"...:twothumbs:

If you do feel a nice increase in power with an ECM reset, it just means that
your "tune", not as strong as it could be, there's room for improvement.

XtremeSS 10-08-2014 02:47 PM


Originally Posted by 2005HHRauto (Post 760926)
Then with the example that I gave, it will be a "learn-up", & will never
reach the higher programmed, "torque-curve".
Learn up or down, the ECM is just syncing it's tables, to best follow the
programmed "torque-curve"...:twothumbs:

If you do feel a nice increase in power with an ECM reset, it just means that
your "tune", not as strong as it could be, there's room for improvement.

Yea exactly, I was referring to when I had the GMTU tune only.


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