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Discussion Starter #1
Ok, this is what i'm thinking, give me some feedback.

Parts:
Boost Bleeder Valve (Designed to Restrict Airflow so PSI is decreased 2-4 psi)

Theory:
Install Boost Bleeder Valve upstream of the MAP sensor (boost sensor)...Map sensor now reads 2-4 psi less than what actual boost is. In theory isn't the MAP sensor the only sensor that reads the boost generated by the turbo?? If so a bleeder valve should hack or trick the ECU from thinking the amount of boost allowing for the increase from 2-4 psi max?? I'm thinking of doing this tommorow just thought i'd see if anyone has some input, or if someone on this forum has done this before.
 

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When it starts to read everything going on inside of the engine it will reduce throttle automatically; or the more likely event of throwing limp mode.
 

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Frosty288 said:
When it starts to read everything going on inside of the engine it will reduce throttle automatically; or the more likely event of throwing limp mode.
x2

As I understand it, trionic constantly moniters conditions in many different stages of the system. When it sees something that just doesn't add up, such as a request for boost that simply isn't being matched by delivery, it would probably just give you a CEL or limp mode.
 

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I don't think it'll work; the whole system is controlled based on mass air flow. If the mass of air being consumed by the engine is too great to be controlled by the throttle alone, the turbo is bumped back a notch via the wastegate. This means that if, for a particular load request based on accelerator position, the mass air flow is greater than required/desired, the wastegate will be opened to allow exhaust gasses to bypass the turbine, effectively reducing boost.

Also, the MAP sensor readings are used to correct mass air flow readings when calculating fuel quantities during quick load changes (between gears etc.). So if you're fooling the MAP sensor into thinking the pressure is less than it actually is, the correction factor used on the MAF readings will be out, pushing out fuel quantity calculations and eventually causing a C*L (it's almost a swear word).

Lastly, if the MAF ever dies, the ECU will use MAP readings instead until it is fixed. I wouldn't want my fuel calculations to be based on a dodgy pressure reading!

Basically: Engine control is based on MAF readings. If the air mass/combustion does not match the requested, the throttle will be regulated. If the MAF is too great to be regulated by throttle alone, the turbo control kicks in. If the MAP sensor readings don't correspond with the air mass/combustion readings, you get a CEL...

When you think about it, you have a given volume of air (2.0L) at a particular pressure. The mass of the 2.0L of air can be calculated given the temperature and pressure of both the charge air and atmospheric air. If the mass of air entering the engine based on the MAF reading doesn't match that based on the MAP and temperature sensors' readings, it's CEL time.

I've basically said the same thing 3 times, but they're all slightly different ways of looking at the problem.

That's my take on it anyway.
 

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Wow...you're like a senior engineer at a Saab engine and trionic guru~

Dan, you've got a sense of a good humor...you had me at "it's CEL time"
:D


VectorDan said:
I don't think it'll work; the whole system is controlled based on mass air flow. If the mass of air being consumed by the engine is too great to be controlled by the throttle alone, the turbo is bumped back a notch via the wastegate. This means that if, for a particular load request based on accelerator position, the mass air flow is greater than required/desired, the wastegate will be opened to allow exhaust gasses to bypass the turbine, effectively reducing boost.

Also, the MAP sensor readings are used to correct mass air flow readings when calculating fuel quantities during quick load changes (between gears etc.). So if you're fooling the MAP sensor into thinking the pressure is less than it actually is, the correction factor used on the MAF readings will be out, pushing out fuel quantity calculations and eventually causing a C*L (it's almost a swear word).

Lastly, if the MAF ever dies, the ECU will use MAP readings instead until it is fixed. I wouldn't want my fuel calculations to be based on a dodgy pressure reading!

Basically: Engine control is based on MAF readings. If the air mass/combustion does not match the requested, the throttle will be regulated. If the MAF is too great to be regulated by throttle alone, the turbo control kicks in. If the MAP sensor readings don't correspond with the air mass/combustion readings, you get a CEL...

When you think about it, you have a given volume of air (2.0L) at a particular pressure. The mass of the 2.0L of air can be calculated given the temperature and pressure of both the charge air and atmospheric air. If the mass of air entering the engine based on the MAF reading doesn't match that based on the MAP and temperature sensors' readings, it's CEL time.

I've basically said the same thing 3 times, but they're all slightly different ways of looking at the problem.

That's my take on it anyway.
 

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hjl113 said:
Wow...you're like a senior engineer at a Saab engine and trionic guru~

Dan, you've got a sense of a good humor...you had me at "it's CEL time"
:D
Haha, glad you like the humour. I had to add some in there or it would just be a bunch of boring, repetative babble.

Well that's probably the biggest compliment anyone could get around here - I'm flattered! Although I'm sure someone will chime in to put a gaping hole in my theory!
 

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VectorDan said:
Basically: Engine control is based on MAF readings. If the air mass/combustion does not match the requested, the throttle will be regulated. If the MAF is too great to be regulated by throttle alone, the turbo control kicks in.
This system is surprisingly complicated. I was reading the WIS to learn about fuel pump issues last night and came across some MAF stuff.

The ECM actually keeps track of the air mass used per cylinder per combustion. It knows for each full engine revolution that 2 cylinders have fired, either the 1-4 pair or the 2-3. The MAF readings for that revolution are stored and divided by 2 to get air mass/cylinder. The CDM (combustion detection module) reports the completeness of combustion for each cylinder. If a cylinder is overrich (incomplete combustion), it logs a misfire. Air mass is adjusted accordingly.

In a MAF-metered car MASS RULES, and is of supreme importance in all ECM calculations. Anything that screws up the MAF tends to screw up the whole car. There is some flexibility to compensate for an aging sensor, but mainly the checks are in place to tell you when the sensor is bad.

Saw this show on the Speed Channel the other night where some guy added Nitrous to a G35. Did a clean install then showed off the upsized cold air intake which had been previously installed, explaining how that would boost performance. They proceeded to track test the car without ever using any tools to get a lambda or exhaust temp reading. No need to say who sponsors these shows or runs ads on the network. Read the G35 forums; G35's hate intakes as much as our cars.
 

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last summer i tried a little "fix" with my wastegate and it ran hard for one pass, then all of a sudden the computer shut me down
 
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