Hi Chris.

The LSJ Map sensor is a 2,5 Bar sensor because it max out at 22 PSI of boost in the manifold, logged with a scan tool on the PCM.

(22 PSI + 14.7) / 14.7 = 2,5 Bar.

Will we be able to scale the Map table up to 22 PSI of boost (2,5 Bar), thus fine tuning the injectors pulse width ?

Because as the GM 2005 Cobalt SS LSJ service manual stays, injectors pulse width is based on the MAP sensor and fuel pressure is constant.

LOL I experimented it, my supercharger pulley is so small, thus throwing A LOT too much of fuel and removing a LOT too much of timing advance. I need the VCM suite !

If we are limited to 2 bar, maybe we will have to use an adjustable fuel pressure regulator ... for the fuel. But what about the timing advance settings ?

Thanks !

Hi Chris.

The LSJ Map sensor is a 2,5 Bar sensor because it max out at 22 PSI of boost in the manifold, logged with a scan tool on the PCM.

(22 PSI + 14.7) / 14.7 = 2,5 Bar.

Will we be able to scale the Map table up to 22 PSI of boost (2,5 Bar), thus fine tuning the injectors pulse width ?

Because as the GM 2005 Cobalt SS LSJ service manual stays, injectors pulse width is based on the MAP sensor and fuel pressure is constant.

LOL I experimented it, my supercharger pulley is so small, thus throwing A LOT too much of fuel and removing a LOT too much of timing advance. I need the VCM suite !

If we are limited to 2 bar, maybe we will have to use an adjustable fuel pressure regulator ... for the fuel. But what about the timing advance settings ?

Thanks !

Thats not how you do it by tuning a map value. You will scale the IFR table. 100 KPA is WOT, 0 KPA is idle

The MAFF is the crtical component from which all tables are based on. You'll see;)

Yeah we will adjust the IFR on each 5 increment MAP value, but what if the software ends at 100 KPA if I'm boosting up to 150 KPA ??? How will the PCM controll the injectors pulse width with a 50% more pressure in the manifold ?

Like this ;)

Note negative vacuum is boost. The maximum injector size supported by the PCM is around 65 lb/hr.

Chris...

http://www.hptuners.com/pub/chris/LSJ_IFR.jpg

OK thanks.

So How Much Psi?
( Hp?)

Notice the table is 200 KPA span....

Is that the LSJ table?

Is that the LSJ table?

yes.

yes.

Chris,
Is this specific to the LSJ or to the new software version. The SC 3800 is 0-100KPA with 0 being idle and 100 being WOT. Totally opposite of the data you just showed. Yea, more learning:lol:

Chris,
Is this specific to the LSJ or to the new software version. The SC 3800 is 0-100KPA with 0 being idle and 100 being WOT. Totally opposite of the data you just showed. Yea, more learning:lol:

totally different PCM and code to the older V6 PCM's.

eg. here an example of the supercharger boost control parameters you never had in the V6's ;)

http://www.hptuners.com/pub/chris/LSJ_boost.jpg

Nice!! Looks like a long learning session is in order! I see 5 areas already in that folder alone that i need to change.:lol:


To all the newbies out there, BABY STEPS!!!!! Ask questions and DON'T change something you don't understand.

There is a curious peak at -70Kpa, what is that mean ?

There is a curious peak at -70Kpa, what is that mean ?

it probably means the calibration engineer used the injector flow rates to tune something out. I doubt the injectors actually follow that weird flow curve.

Holden have done did things this way on the Aussie LS1's and the GTO as well. Most US cars have a straight line for the flow rate, which is what you would expect since flow should vary linearly with pressure difference. I don't know any injectors that flow more at 6psi boost than under high vacuum... but then maybe the fuel system on these vehicles has some impact. I honestly don't know why GM does things they way they do sometimes...

Tuning potential with HPTuners software is simply and totally AWESOME ! You guys rocks ! :twothumbs :twothumbs :twothumbs

Seeing that we have a returnless fuel system on a boosted car, you will have some weird graphs and charts no doubt! Returnless SUCKS!!!

Why not use the little valve on the fuel rail to do a custom fuel return system, along with a good adjustable fuel pressure regulator wit 1:1 rising rate ...