Twinturbo.
Tech Contributor
Joined: Jun 2004
Posts: 20,860
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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
Your stock MAP sensor will go stupid above one atmosphere. You've got to modify or rescale your system so the ECM will know you're in boost. There's several things to consider when going boosted, not just your extra fueling. Spark timing adjustments are important, too. Be sure to think the electonics and software calibrations through thoroughly before you dump the money for the turbo. The engine and plumbing are quite often the easiest part of the upgrade. Getting the ECM, sensors, and software correct can be tedious.
Le Mans Master
Joined: Oct 2006
Posts: 7,484
Likes: 2
From: Dayton, OH HAWG: "this is Off Topic...it can get a bit north of care bears and strawberry shortcake in here"
St. Jude Donor '08-'09-'10-'11
Your stock MAP sensor will go stupid above one atmosphere. You've got to modify or rescale your system so the ECM will know you're in boost. There's several things to consider when going boosted, not just your extra fueling. Spark timing adjustments are important, too. Be sure to think the electonics and software calibrations through thoroughly before you dump the money for the turbo. The engine and plumbing are quite often the easiest part of the upgrade. Getting the ECM, sensors, and software correct can be tedious.
Thread Starter
Instructor
Joined: Aug 2005
Posts: 108
Likes: 0
I have this APU1 usb from Craig Moates so I can make my own ecu chips. So timing and fuel is fixed.
Than it´s maybe just the Map that has to be modified?
Can I change the map to one that handle boost? Or how do I rebuilt it?
/Andreas
Than it´s maybe just the Map that has to be modified?
Can I change the map to one that handle boost? Or how do I rebuilt it?
/Andreas
Safety Car
Joined: May 2003
Posts: 4,283
Likes: 0
From: Houston Texas
Depending on how much boost you are planning to make, you will have to go to atleast a 2bar or 3 bar map sensor. If you are planning on staying with stock computer, plan on burning a lot of chips. I went with the FAST system with wideband to save some time. You have alot of work cut out for you building a tt setup.
Le Mans Master
Joined: Apr 2000
Posts: 5,713
Likes: 105
From: Manassas VA
My knowledge is very limited on this subject, but I will share what I know. The stock map sensor is 1 bar, which is good for vacuum only. A 2 bar sensor will work up to 14.7 psig boost. A 3 bar sensor will work up to 29.5 psig. The GM part no. for a 3 bar sensor is 12223861
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Thread Starter
Instructor
Joined: Aug 2005
Posts: 108
Likes: 0
Depending on how much boost you are planning to make, you will have to go to atleast a 2bar or 3 bar map sensor. If you are planning on staying with stock computer, plan on burning a lot of chips. I went with the FAST system with wideband to save some time. You have alot of work cut out for you building a tt setup.
Also it´s working agains the LM-1 widebroad sensor.
/Andreas
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
Here's the deal....you can do it with a stock ECM, however, it is going to be very difficult. It isn't so much just playing with the tables, other people have tried and it has taken the a LONG time to get it correct.
I have a '93 turbo vette and I had to go to an aftermarket ecm. I chose the Accel DFI Gen 7.
You will for sure have to change out the MAP sensor. If you are planning on running under 15psi then go with a 2bar sensor. Depending on your boost levels you will probably want to change to a bigger fuel pump and larger injectors.
So have you purchased the turbos already? Where are you planning on mounting them? I thought about a twin system and decided it was much easier to do a single. And that was still a pain in the **** to do.
Come to think of it though, you could do a low mount system with an STS oil return on it. I've got Hot piping for a low mount T4 turbo if you're interested. I just never could figure out the oiling system, but if you can buy an STS oil system it would work great.
I have a '93 turbo vette and I had to go to an aftermarket ecm. I chose the Accel DFI Gen 7.
You will for sure have to change out the MAP sensor. If you are planning on running under 15psi then go with a 2bar sensor. Depending on your boost levels you will probably want to change to a bigger fuel pump and larger injectors.
So have you purchased the turbos already? Where are you planning on mounting them? I thought about a twin system and decided it was much easier to do a single. And that was still a pain in the **** to do.
Come to think of it though, you could do a low mount system with an STS oil return on it. I've got Hot piping for a low mount T4 turbo if you're interested. I just never could figure out the oiling system, but if you can buy an STS oil system it would work great.
Pro
Joined: Dec 2002
Posts: 704
Likes: 16
From: Dallas Texas
Here's the deal....you can do it with a stock ECM, however, it is going to be very difficult. It isn't so much just playing with the tables, other people have tried and it has taken the a LONG time to get it correct.
I have a '93 turbo vette and I had to go to an aftermarket ecm. I chose the Accel DFI Gen 7.
You will for sure have to change out the MAP sensor. If you are planning on running under 15psi then go with a 2bar sensor. Depending on your boost levels you will probably want to change to a bigger fuel pump and larger injectors.
So have you purchased the turbos already? Where are you planning on mounting them? I thought about a twin system and decided it was much easier to do a single. And that was still a pain in the **** to do.
Come to think of it though, you could do a low mount system with an STS oil return on it. I've got Hot piping for a low mount T4 turbo if you're interested. I just never could figure out the oiling system, but if you can buy an STS oil system it would work great.
I have a '93 turbo vette and I had to go to an aftermarket ecm. I chose the Accel DFI Gen 7.
You will for sure have to change out the MAP sensor. If you are planning on running under 15psi then go with a 2bar sensor. Depending on your boost levels you will probably want to change to a bigger fuel pump and larger injectors.
So have you purchased the turbos already? Where are you planning on mounting them? I thought about a twin system and decided it was much easier to do a single. And that was still a pain in the **** to do.
Come to think of it though, you could do a low mount system with an STS oil return on it. I've got Hot piping for a low mount T4 turbo if you're interested. I just never could figure out the oiling system, but if you can buy an STS oil system it would work great.
I'm interested...what are you asking for the hot parts?
Thread Starter
Instructor
Joined: Aug 2005
Posts: 108
Likes: 0
Well, I don´t have the turbos yet.
Looks like underhood mounted. and not low. Wanna soulve what I need around to do this.
I will remove/move everything that I don´t need to fit in the turbos.
/Andreas
Looks like underhood mounted. and not low. Wanna soulve what I need around to do this.
I will remove/move everything that I don´t need to fit in the turbos.
/Andreas
Thread Starter
Instructor
Joined: Aug 2005
Posts: 108
Likes: 0
Hehe, sorry WIDEBAND.. Don´t have time to check if everything is right, but...
I lern the language in school, din´t do my homework. And never use it in life exept here and when I see movies without subtitles.
I´m from sweden u see.
/Andreas
I lern the language in school, din´t do my homework. And never use it in life exept here and when I see movies without subtitles.
I´m from sweden u see.
/Andreas
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
Here's the deal....you can do it with a stock ECM, however, it is going to be very difficult. It isn't so much just playing with the tables, other people have tried and it has taken the a LONG time to get it correct.
I have a '93 turbo vette and I had to go to an aftermarket ecm. I chose the Accel DFI Gen 7.
You will for sure have to change out the MAP sensor. If you are planning on running under 15psi then go with a 2bar sensor. Depending on your boost levels you will probably want to change to a bigger fuel pump and larger injectors.
I have a '93 turbo vette and I had to go to an aftermarket ecm. I chose the Accel DFI Gen 7.
You will for sure have to change out the MAP sensor. If you are planning on running under 15psi then go with a 2bar sensor. Depending on your boost levels you will probably want to change to a bigger fuel pump and larger injectors.
Any of the tables that use MAP KPa only go to 100 KPa, which is generally about atmospheric pressure.
What happens when the MAP is telling the PCM there is more than 100 KPa? Does the PCM have any calibration ubove 100 KPa when a 2 bar MAP is connected or does the maximum output of the 2 bar MAP come up in the PCM as the same or simular signal as the maximum for the 1 bar MAP?
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
So just a quick question i have for you about a 94, it has a MAF and a 1 bar MAP, but if i was to put on a 2 bar MAP, how would i tune above 100 KPa?
Any of the tables that use MAP KPa only go to 100 KPa, which is generally about atmospheric pressure.
What happens when the MAP is telling the PCM there is more than 100 KPa? Does the PCM have any calibration ubove 100 KPa when a 2 bar MAP is connected or does the maximum output of the 2 bar MAP come up in the PCM as the same or simular signal as the maximum for the 1 bar MAP?
Any of the tables that use MAP KPa only go to 100 KPa, which is generally about atmospheric pressure.
What happens when the MAP is telling the PCM there is more than 100 KPa? Does the PCM have any calibration ubove 100 KPa when a 2 bar MAP is connected or does the maximum output of the 2 bar MAP come up in the PCM as the same or simular signal as the maximum for the 1 bar MAP?
You need to look at it from a different point of view. The output of a map sensor is 0-5V (roughly I think, but its not important for this).
1-Bar 0V=High vaccume(0kpa) 5V=Atmosphereic(100kpa WOT)
2-Bar 0V=High Vaccume(0kpa) 2.5V=Atmospheric(100kpa) 5V=14.5psi(200kpa)
3-Bar 0V=High Vaccume(0kpa) 1.67V=Atmospheric(100kpa) 3.33V=14.5psi(200kpa) 5V= 29psi(300kpa)
So as you can read more boost, you loose resolution in the reading of the map sensor since you still have the same number of boxes in your MAP table
The ECM then takes that 0-5V signal and turns that into a MAP table.
ECM 0V=0kpa 5V=100kpa
If you were to put a 2-bar map sensor in place you would basically divide the actual kpa in half and get the table value that it corresponds to.
You are basically tricking the computer into thinking it is a 1-bar map sensor and adjusting the fuel/timing curves accordingly. So with a 2 bar sensor if you see 100kpa on the MAP table it is actually 200kpa going into the engine.
I'm not exactly sure how the MAF sensor plays into everything though. You may have to recalibrate how it reads things as well.
Le Mans Master
Joined: May 2005
Posts: 5,214
Likes: 65
From: Queensland, AUSTRALIA
Thanks mate, youve done well 
That is about how i thought it would work, although the way you typed it out was abit more straight forward and confirms what i thought may be the case.
Not too concerned about the MAF tables, they are pretty straight forward really. The tables can be adjusted for up to about 520 AFGS give or take abit.
mate, i appreciate that help 
That is about how i thought it would work, although the way you typed it out was abit more straight forward and confirms what i thought may be the case. Not too concerned about the MAF tables, they are pretty straight forward really. The tables can be adjusted for up to about 520 AFGS give or take abit.
mate, i appreciate that help