Cobb AP Street tuner / Pro tuner and PE 850's

04stiguy · 08-28-2005, 09:14 PM

Looking for some AP street tuner assistance. I am putting PE850's in my 05 STI. Need to know what injector latency values and injector scalar to use from those who have done this already.

RacerXS · 08-28-2005, 09:23 PM

Do you have the turbo on yet?

04stiguy · 08-28-2005, 10:20 PM

Not yet. Getting base injector stuff in the ballpark first. One step at a time

Christian. · 08-29-2005, 01:50 PM

You should not have to adjust latency for the PE 850s. Start with 3034 for the scaler value and the vehicle should start right up. The vehicle will tell you how you should adjust the Intake calibration to properly tune the vehicle, just look at your A/F Trim Immed. & A/F Trim Learned, if they are both positive, then simply add more grams/sec of airflow for that corresponding MAF voltage. If your dashboard is up, observe MAF Voltage, A/F Trim Immed. & A/F Trim Learned...you will see that your trims go down while you add grams/sec of air flow for that corresponding MAF voltage. If their sum is negative then remove value from the Intake Calibration table for that MAF voltage. At WOT, if your actual A/F datalog is leaner than the dictated A/F for that particular load and RPM point, then add grams/sec for the MAF voltage datalogged at that particular load and RPM point. Make sense? DO NOT try to make the A/F output of the vehicle match exactly what you have dictated in your Primary Fuel table...as soon as you fill up with different gas, the atmospheric pressure changes, temperature changes, etc. the A/F output will slightly change. You will spend too much time and money chasing your tail trying to get it perfect.

Christian.
AccessECU Trainer

RacerXS · 08-29-2005, 10:35 PM

This is great, I have some injectors going in next week. Should I start with 3034 scaler value with 816's?

04stiguy · 08-30-2005, 07:12 AM

Quote:

Originally Posted by surfa2527

This is great, I have some injectors going in next week. Should I start with 3034 scaler value with 816's?

I noticed in your signature that you have PE850's. Why are you switching to the 816's? Do you have problems with the 850's?

Thanks

Christian. · 08-30-2005, 08:20 AM

Quote:

Originally Posted by surfa2527

This is great, I have some injectors going in next week. Should I start with 3034 scaler value with 816's?

I need to know what vehicle you have to be able to assist you. What intake/MAF housing will you be using?

RacerXS · 08-30-2005, 10:43 AM

I actually had the 850's on order, I found some Perrin modded 816's on E-bay for way cheaper so I went for them instead, never changed my sig.

Quote:

Originally Posted by 04stiguy

I noticed in your signature that you have PE850's. Why are you switching to the 816's? Do you have problems with the 850's?

Thanks

RacerXS · 08-30-2005, 10:47 AM

Quote:

Originally Posted by Christian.

I need to know what vehicle you have to be able to assist you. What intake/MAF housing will you be using?

05' STi, probably going to be either the Cobb intake or the TXS short ram. I have the TXS front mount intercooler so a CAI is out of the question.

Christian. · 08-30-2005, 12:36 PM

Start with 3160 for the scaler value. You can always make small adjustments to that value to assist your closed-loop fuel trims. You can do that or just adjust the Intake Calibration table for the MAF voltages that are off if you have an aftermarket intake.

Start your vehicle, let it idle, and come to temperature...it may not be perfect, but just deal with it until it comes to temperature, 180-190. Use the dashboard to pull up your A/F Trim Immed., A/F Trim Learned, MAF Voltage, Coolant Temp. After the vehicle has come to temperature, re-set the ECU (you will be prompted to turn the vehicle off then back on). Start up the car again, then watch your MAF voltage and A/F trims. You want the combination of your A/F trims to be as close to 0 as possible. EX = If your A/F Trim Immed. is +5% and A/F Trim Learned is 0, then simply look up the MAF voltage, which should be close to 1.2-1.28 volts at idle, on the Intake Calibration table and adjust the grams/sec value for that voltage up (+) until your total fuel trims are 0 or close to. I would shoot for a A/F Trim Learned value of +/- 5% max. You may have to re-set your ECU throughout this process. Make sense?

Do this along the Intake Calibration table up to 2.3 volts or so ON A DYNO at part-throttle. Datalog your actual A/F and dictated A/F in your Primary Fuel table @ WOT, then you can make your adjustments from there. If you have a properly designed intake system the Intake Calibrations should look very similar to your stock Intake Calibration graph under the table data.

Your trim values will always adjust back and forth (+/-), let them, that is what they are supposed to do. Do not beat yourself up trying to get them at exactly 0...it is impossible (temperature, weather, gasonline, etc. changes will not keep anything constant while you are tuning).

If you are seeing plateaus or peaks in the graph for the Intake Calibration table then you know something is wrong...replace the intake system with a properly designed one.

Christian.

04stiguy · 08-30-2005, 01:36 PM

Christian

You have been quite helpful. I have a few more questions for you.

Is the max. MAF voltage 4.6 or 5.0? (I have been told two different values)

Does the factory ECU monitor barometric pressure?

Does the factory ECU monitor manifold air temp (post-charge cooler), or just air inlet (@MAF) temp?

What is the max. boost the factory MAP sensor will function to? What happens when this pressure is exceeded with the ST?

Thanks

Christian. · 08-30-2005, 02:00 PM

Is the max. MAF voltage 4.6 or 5.0? (I have been told two different values)
The Intake Calibration goes all the way to 4.92 volts for your vehicle.

Does the factory ECU monitor barometric pressure?
Yes.

Does the factory ECU monitor manifold air temp (post-charge cooler), or just air inlet (@MAF) temp?
Just at the MAF inlet.

What is the max. boost the factory MAP sensor will function to?
I am not sure...I cannot recall right now.

What happens when this pressure is exceeded with the ST?
The pressure is exceeded. I am not trying to be a smart ass...the factory ECU will only read up to a certain pressure, which I cannot remember right now, then the reading will flat line. You will see it in the datalogs.

What gas will you be tuning on?

04stiguy · 08-30-2005, 02:15 PM

Initially 91 octane will be used. Eventually C16 will be used for weekend dragstrip use. I read about guys making 25-30 psi with the STI. Wondering if the OEM MAP senser needs replacement etc. to properlay map at this level.

RacerXS · 09-01-2005, 07:50 AM

Thanks for your help Christian. I hope you continue on with the great info, this should help ST sales and the community to grow.

Christian. · 09-01-2005, 07:36 PM

Thanks for the kind words and I am glad I can be of assistance. Our goal is to step up the level of tuning in the U.S. through constant education and exposure to different tuning styles and techniques. These forums are a great way to communicate with end users.

08-28-2005, 09:14 PM	#1
04stiguy Senior STI Driver Car: '05 STi Fav Mod: Cusco Zero 2R's Posts: 336 Join Date: Jun 2004 Trader Rating: (0)	Cobb AP Street tuner / Pro tuner and PE 850's Looking for some AP street tuner assistance. I am putting PE850's in my 05 STI. Need to know what injector latency values and injector scalar to use from those who have done this already. This ad is not endorsed by this member. Please register or login to hide this ad.

09-01-2005, 07:50 AM	#14
RacerXS S204 Racer Car: 05' Sti Black Fav Mod: Dyslexia Location: Central, NJ Posts: 3,362 Join Date: Oct 2004 Trader Rating: (13)	Thanks for your help Christian. I hope you continue on with the great info, this should help ST sales and the community to grow. Last edited by RacerXS : 09-01-2005 at 07:58 AM.

09-01-2005, 07:36 PM	#15
Christian. STI Driver Car: 01 Subaru WRX STi Sp Fav Mod: Coming Soon Posts: 262 Join Date: Aug 2005 Trader Rating: (0)	Thanks for the kind words and I am glad I can be of assistance. Our goal is to step up the level of tuning in the U.S. through constant education and exposure to different tuning styles and techniques. These forums are a great way to communicate with end users. This ad is not endorsed by this member. Please register or login to hide this ad.

08-28-2005, 09:23 PM	#2
RacerXS S204 Racer Car: 05' Sti Black Fav Mod: Dyslexia Location: Central, NJ Posts: 3,362 Join Date: Oct 2004 Trader Rating: (13)	Do you have the turbo on yet?

08-28-2005, 10:20 PM	#3
04stiguy Senior STI Driver Car: '05 STi Fav Mod: Cusco Zero 2R's Posts: 336 Join Date: Jun 2004 Trader Rating: (0)	Not yet. Getting base injector stuff in the ballpark first. One step at a time

08-29-2005, 01:50 PM	#4
Christian. STI Driver Car: 01 Subaru WRX STi Sp Fav Mod: Coming Soon Posts: 262 Join Date: Aug 2005 Trader Rating: (0)	You should not have to adjust latency for the PE 850s. Start with 3034 for the scaler value and the vehicle should start right up. The vehicle will tell you how you should adjust the Intake calibration to properly tune the vehicle, just look at your A/F Trim Immed. & A/F Trim Learned, if they are both positive, then simply add more grams/sec of airflow for that corresponding MAF voltage. If your dashboard is up, observe MAF Voltage, A/F Trim Immed. & A/F Trim Learned...you will see that your trims go down while you add grams/sec of air flow for that corresponding MAF voltage. If their sum is negative then remove value from the Intake Calibration table for that MAF voltage. At WOT, if your actual A/F datalog is leaner than the dictated A/F for that particular load and RPM point, then add grams/sec for the MAF voltage datalogged at that particular load and RPM point. Make sense? DO NOT try to make the A/F output of the vehicle match exactly what you have dictated in your Primary Fuel table...as soon as you fill up with different gas, the atmospheric pressure changes, temperature changes, etc. the A/F output will slightly change. You will spend too much time and money chasing your tail trying to get it perfect. Christian. AccessECU Trainer

08-29-2005, 10:35 PM	#5
RacerXS S204 Racer Car: 05' Sti Black Fav Mod: Dyslexia Location: Central, NJ Posts: 3,362 Join Date: Oct 2004 Trader Rating: (13)	This is great, I have some injectors going in next week. Should I start with 3034 scaler value with 816's?

08-30-2005, 12:36 PM	#10
Christian. STI Driver Car: 01 Subaru WRX STi Sp Fav Mod: Coming Soon Posts: 262 Join Date: Aug 2005 Trader Rating: (0)	Start with 3160 for the scaler value. You can always make small adjustments to that value to assist your closed-loop fuel trims. You can do that or just adjust the Intake Calibration table for the MAF voltages that are off if you have an aftermarket intake. Start your vehicle, let it idle, and come to temperature...it may not be perfect, but just deal with it until it comes to temperature, 180-190. Use the dashboard to pull up your A/F Trim Immed., A/F Trim Learned, MAF Voltage, Coolant Temp. After the vehicle has come to temperature, re-set the ECU (you will be prompted to turn the vehicle off then back on). Start up the car again, then watch your MAF voltage and A/F trims. You want the combination of your A/F trims to be as close to 0 as possible. EX = If your A/F Trim Immed. is +5% and A/F Trim Learned is 0, then simply look up the MAF voltage, which should be close to 1.2-1.28 volts at idle, on the Intake Calibration table and adjust the grams/sec value for that voltage up (+) until your total fuel trims are 0 or close to. I would shoot for a A/F Trim Learned value of +/- 5% max. You may have to re-set your ECU throughout this process. Make sense? Do this along the Intake Calibration table up to 2.3 volts or so ON A DYNO at part-throttle. Datalog your actual A/F and dictated A/F in your Primary Fuel table @ WOT, then you can make your adjustments from there. If you have a properly designed intake system the Intake Calibrations should look very similar to your stock Intake Calibration graph under the table data. Your trim values will always adjust back and forth (+/-), let them, that is what they are supposed to do. Do not beat yourself up trying to get them at exactly 0...it is impossible (temperature, weather, gasonline, etc. changes will not keep anything constant while you are tuning). If you are seeing plateaus or peaks in the graph for the Intake Calibration table then you know something is wrong...replace the intake system with a properly designed one. Christian.

08-30-2005, 01:36 PM	#11
04stiguy Senior STI Driver Car: '05 STi Fav Mod: Cusco Zero 2R's Posts: 336 Join Date: Jun 2004 Trader Rating: (0)	Christian You have been quite helpful. I have a few more questions for you. Is the max. MAF voltage 4.6 or 5.0? (I have been told two different values) Does the factory ECU monitor barometric pressure? Does the factory ECU monitor manifold air temp (post-charge cooler), or just air inlet (@MAF) temp? What is the max. boost the factory MAP sensor will function to? What happens when this pressure is exceeded with the ST? Thanks

08-30-2005, 02:00 PM	#12
Christian. STI Driver Car: 01 Subaru WRX STi Sp Fav Mod: Coming Soon Posts: 262 Join Date: Aug 2005 Trader Rating: (0)	Is the max. MAF voltage 4.6 or 5.0? (I have been told two different values) The Intake Calibration goes all the way to 4.92 volts for your vehicle. Does the factory ECU monitor barometric pressure? Yes. Does the factory ECU monitor manifold air temp (post-charge cooler), or just air inlet (@MAF) temp? Just at the MAF inlet. What is the max. boost the factory MAP sensor will function to? I am not sure...I cannot recall right now. What happens when this pressure is exceeded with the ST? The pressure is exceeded. I am not trying to be a smart ass...the factory ECU will only read up to a certain pressure, which I cannot remember right now, then the reading will flat line. You will see it in the datalogs. What gas will you be tuning on?

08-30-2005, 02:15 PM	#13
04stiguy Senior STI Driver Car: '05 STi Fav Mod: Cusco Zero 2R's Posts: 336 Join Date: Jun 2004 Trader Rating: (0)	Initially 91 octane will be used. Eventually C16 will be used for weekend dragstrip use. I read about guys making 25-30 psi with the STI. Wondering if the OEM MAP senser needs replacement etc. to properlay map at this level.