got the 300Z injectors whats the Base FP set at? 30PSI, 29, 20PSI
Thread Starter
Joined: Dec 2000
Posts: 6,451
From: Near Archer High School, Ga
got the 300Z injectors whats the Base FP set at? 30PSI, 29, 20PSI
I am about to install the vortech SFMU. I got the 300Z injectors.
I need to set my base FP to what?
I seen all types of numbers floating around. Can someone please post the correct FP so I dont drown my replacement motor w/fuel.
I need to set my base FP to what?
I seen all types of numbers floating around. Can someone please post the correct FP so I dont drown my replacement motor w/fuel.
i have mine set to factory spec...
with the vacuum line off of the regulator its set at 43.5psi. which when you put the vaccum back on it goes to 32-33ish at idle.
since you are running a different fuel setup then i am, i am not sure this same logic applies to you. but i hope that helps anyway.
--Paul
with the vacuum line off of the regulator its set at 43.5psi. which when you put the vaccum back on it goes to 32-33ish at idle.
since you are running a different fuel setup then i am, i am not sure this same logic applies to you. but i hope that helps anyway.
--Paul
Senior Member
Joined: Mar 2002
Posts: 602
From: Williamstown, NJ
When I asked Mardi if 34psi was right awhile back, he didn't tell me I was wrong. I am also gettin ready to put Z 370's in, well actually Silvia injectors from Japan but same thing. I am going to be using a 3:1 disk in my FMU along with a FPR for base adjustment. This is one thing I am a little confused on as well though.
There are three operating scenarios that must be addressed when converting to the larger injectors.
1. The first scenario is open loop operation and in NA mode (not boosting). In this case the ecu is relying on predetermined fuel mapping referenced to maf voltage (i.e. air flow) and throttle position (i.e. engine load) and is ignoring O2 sensor information. Examples of this operating regime are when the engine is cold right after startup, or when going WOT in an unboosted car.
Now, a 370 cc/min injector delivers 54% more fuel per pulse width than a 240 cc/min injector, for a given fuel pressure. Fuel delivery for a steady, imcompressible, lossless flow is proportional to the square root of the change in fuel pressure, so to bring fuel delivery down to something close to what the 240's give at a particular injector pulse width, you need to reduce fuel pressure from 34 psi down to about 27 psi. I believe Mardigrasmax mentioned adjusting down to 26 psi in one of his posts.
2. The second scenario is partial throttle operation where you are in a closed loop NA mode with the afr controlled by the ecu based on O2 sensor information. The ecu is capable of learning the 370 cc/min injectors and adjusting afr based on O2 sensor information with the help of the lowered base fuel pressure.
3. The third scenario is open loop, boosted operation. In this case, up to a certain power level (350 bhp), the ecu could adequately control the afr with fuel maps referenced to air flow measurement from the maf and based on a 1:1 increase in fuel pressure provided by the oem fpr, BUT with the caveat that the afr will be too high for safe boosted operation.
If you are below the 350 bph limit that the A32 maf can handle, then the afr can be lowered by raising the fuel pressure an appropriate amount by means of an fmu with more than a 1:1 rise rate, or by increasing the injector pulse width (i.e. duty cycle) with an air flow converter (safc). If you are above 350 bhp, then you have maxed out the maf and the injectors are already at maximum duty cycle and the only means to adjust afr downward is to increase fuel flow by increasing fuel pressure with the fmu.
1. The first scenario is open loop operation and in NA mode (not boosting). In this case the ecu is relying on predetermined fuel mapping referenced to maf voltage (i.e. air flow) and throttle position (i.e. engine load) and is ignoring O2 sensor information. Examples of this operating regime are when the engine is cold right after startup, or when going WOT in an unboosted car.
Now, a 370 cc/min injector delivers 54% more fuel per pulse width than a 240 cc/min injector, for a given fuel pressure. Fuel delivery for a steady, imcompressible, lossless flow is proportional to the square root of the change in fuel pressure, so to bring fuel delivery down to something close to what the 240's give at a particular injector pulse width, you need to reduce fuel pressure from 34 psi down to about 27 psi. I believe Mardigrasmax mentioned adjusting down to 26 psi in one of his posts.
2. The second scenario is partial throttle operation where you are in a closed loop NA mode with the afr controlled by the ecu based on O2 sensor information. The ecu is capable of learning the 370 cc/min injectors and adjusting afr based on O2 sensor information with the help of the lowered base fuel pressure.
3. The third scenario is open loop, boosted operation. In this case, up to a certain power level (350 bhp), the ecu could adequately control the afr with fuel maps referenced to air flow measurement from the maf and based on a 1:1 increase in fuel pressure provided by the oem fpr, BUT with the caveat that the afr will be too high for safe boosted operation.
If you are below the 350 bph limit that the A32 maf can handle, then the afr can be lowered by raising the fuel pressure an appropriate amount by means of an fmu with more than a 1:1 rise rate, or by increasing the injector pulse width (i.e. duty cycle) with an air flow converter (safc). If you are above 350 bhp, then you have maxed out the maf and the injectors are already at maximum duty cycle and the only means to adjust afr downward is to increase fuel flow by increasing fuel pressure with the fmu.
Thread Starter
Joined: Dec 2000
Posts: 6,451
From: Near Archer High School, Ga
Originally Posted by Stephen Max
There are three operating scenarios that must be addressed when converting to the larger injectors.
1. The first scenario is open loop operation and in NA mode (not boosting). In this case the ecu is relying on predetermined fuel mapping referenced to maf voltage (i.e. air flow) and throttle position (i.e. engine load) and is ignoring O2 sensor information. Examples of this operating regime are when the engine is cold right after startup, or when going WOT in an unboosted car.
Now, a 370 cc/min injector delivers 54% more fuel per pulse width than a 240 cc/min injector, for a given fuel pressure. Fuel delivery for a steady, imcompressible, lossless flow is proportional to the square root of the change in fuel pressure, so to bring fuel delivery down to something close to what the 240's give at a particular injector pulse width, you need to reduce fuel pressure from 34 psi down to about 27 psi. I believe Mardigrasmax mentioned adjusting down to 26 psi in one of his posts.
2. The second scenario is partial throttle operation where you are in a closed loop NA mode with the afr controlled by the ecu based on O2 sensor information. The ecu is capable of learning the 370 cc/min injectors and adjusting afr based on O2 sensor information with the help of the lowered base fuel pressure.
3. The third scenario is open loop, boosted operation. In this case, up to a certain power level (350 bhp), the ecu could adequately control the afr with fuel maps referenced to air flow measurement from the maf and based on a 1:1 increase in fuel pressure provided by the oem fpr, BUT with the caveat that the afr will be too high for safe boosted operation.
If you are below the 350 bph limit that the A32 maf can handle, then the afr can be lowered by raising the fuel pressure an appropriate amount by means of an fmu with more than a 1:1 rise rate, or by increasing the injector pulse width (i.e. duty cycle) with an air flow converter (safc). If you are above 350 bhp, then you have maxed out the maf and the injectors are already at maximum duty cycle and the only means to adjust afr downward is to increase fuel flow by increasing fuel pressure with the fmu.
1. The first scenario is open loop operation and in NA mode (not boosting). In this case the ecu is relying on predetermined fuel mapping referenced to maf voltage (i.e. air flow) and throttle position (i.e. engine load) and is ignoring O2 sensor information. Examples of this operating regime are when the engine is cold right after startup, or when going WOT in an unboosted car.
Now, a 370 cc/min injector delivers 54% more fuel per pulse width than a 240 cc/min injector, for a given fuel pressure. Fuel delivery for a steady, imcompressible, lossless flow is proportional to the square root of the change in fuel pressure, so to bring fuel delivery down to something close to what the 240's give at a particular injector pulse width, you need to reduce fuel pressure from 34 psi down to about 27 psi. I believe Mardigrasmax mentioned adjusting down to 26 psi in one of his posts.
2. The second scenario is partial throttle operation where you are in a closed loop NA mode with the afr controlled by the ecu based on O2 sensor information. The ecu is capable of learning the 370 cc/min injectors and adjusting afr based on O2 sensor information with the help of the lowered base fuel pressure.
3. The third scenario is open loop, boosted operation. In this case, up to a certain power level (350 bhp), the ecu could adequately control the afr with fuel maps referenced to air flow measurement from the maf and based on a 1:1 increase in fuel pressure provided by the oem fpr, BUT with the caveat that the afr will be too high for safe boosted operation.
If you are below the 350 bph limit that the A32 maf can handle, then the afr can be lowered by raising the fuel pressure an appropriate amount by means of an fmu with more than a 1:1 rise rate, or by increasing the injector pulse width (i.e. duty cycle) with an air flow converter (safc). If you are above 350 bhp, then you have maxed out the maf and the injectors are already at maximum duty cycle and the only means to adjust afr downward is to increase fuel flow by increasing fuel pressure with the fmu.
StephenNow THAT needs to be stickied somewhere. Very well said!
Originally Posted by Stephen Max
There are three operating scenarios that must be addressed when converting to the larger injectors.
1. The first scenario is open loop operation and in NA mode (not boosting). In this case the ecu is relying on predetermined fuel mapping referenced to maf voltage (i.e. air flow) and throttle position (i.e. engine load) and is ignoring O2 sensor information. Examples of this operating regime are when the engine is cold right after startup, or when going WOT in an unboosted car.
Now, a 370 cc/min injector delivers 54% more fuel per pulse width than a 240 cc/min injector, for a given fuel pressure. Fuel delivery for a steady, imcompressible, lossless flow is proportional to the square root of the change in fuel pressure, so to bring fuel delivery down to something close to what the 240's give at a particular injector pulse width, you need to reduce fuel pressure from 34 psi down to about 27 psi. I believe Mardigrasmax mentioned adjusting down to 26 psi in one of his posts.
2. The second scenario is partial throttle operation where you are in a closed loop NA mode with the afr controlled by the ecu based on O2 sensor information. The ecu is capable of learning the 370 cc/min injectors and adjusting afr based on O2 sensor information with the help of the lowered base fuel pressure.
3. The third scenario is open loop, boosted operation. In this case, up to a certain power level (350 bhp), the ecu could adequately control the afr with fuel maps referenced to air flow measurement from the maf and based on a 1:1 increase in fuel pressure provided by the oem fpr, BUT with the caveat that the afr will be too high for safe boosted operation.
If you are below the 350 bph limit that the A32 maf can handle, then the afr can be lowered by raising the fuel pressure an appropriate amount by means of an fmu with more than a 1:1 rise rate, or by increasing the injector pulse width (i.e. duty cycle) with an air flow converter (safc). If you are above 350 bhp, then you have maxed out the maf and the injectors are already at maximum duty cycle and the only means to adjust afr downward is to increase fuel flow by increasing fuel pressure with the fmu.
1. The first scenario is open loop operation and in NA mode (not boosting). In this case the ecu is relying on predetermined fuel mapping referenced to maf voltage (i.e. air flow) and throttle position (i.e. engine load) and is ignoring O2 sensor information. Examples of this operating regime are when the engine is cold right after startup, or when going WOT in an unboosted car.
Now, a 370 cc/min injector delivers 54% more fuel per pulse width than a 240 cc/min injector, for a given fuel pressure. Fuel delivery for a steady, imcompressible, lossless flow is proportional to the square root of the change in fuel pressure, so to bring fuel delivery down to something close to what the 240's give at a particular injector pulse width, you need to reduce fuel pressure from 34 psi down to about 27 psi. I believe Mardigrasmax mentioned adjusting down to 26 psi in one of his posts.
2. The second scenario is partial throttle operation where you are in a closed loop NA mode with the afr controlled by the ecu based on O2 sensor information. The ecu is capable of learning the 370 cc/min injectors and adjusting afr based on O2 sensor information with the help of the lowered base fuel pressure.
3. The third scenario is open loop, boosted operation. In this case, up to a certain power level (350 bhp), the ecu could adequately control the afr with fuel maps referenced to air flow measurement from the maf and based on a 1:1 increase in fuel pressure provided by the oem fpr, BUT with the caveat that the afr will be too high for safe boosted operation.
If you are below the 350 bph limit that the A32 maf can handle, then the afr can be lowered by raising the fuel pressure an appropriate amount by means of an fmu with more than a 1:1 rise rate, or by increasing the injector pulse width (i.e. duty cycle) with an air flow converter (safc). If you are above 350 bhp, then you have maxed out the maf and the injectors are already at maximum duty cycle and the only means to adjust afr downward is to increase fuel flow by increasing fuel pressure with the fmu.
Originally Posted by JAY25
thanks alot 27PSI it is then
Thread Starter
Joined: Dec 2000
Posts: 6,451
From: Near Archer High School, Ga
Update:
I finally got done today, fired her up and she woke up very fast and no black smoke or anything. If anything I believe the FP might be quiet low. The car did not blow smoke or stutter
I thought it did since the 370s are a bit larger. Today I may install a apexi electronic FP gauge and see what it reads.
I finally got done today, fired her up and she woke up very fast and no black smoke or anything. If anything I believe the FP might be quiet low. The car did not blow smoke or stutter
I thought it did since the 370s are a bit larger. Today I may install a apexi electronic FP gauge and see what it reads.
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