I have a stock ecu with a piggy back SAFC & LC-1 Wideband.
Can I use a GM 3Bar map sensor to overcome boost cut?
If yes explain / If no explain
Can I use a GM 3Bar map sensor to overcome boost cut?
If yes explain / If no explain
GM 3bar Map Sensor Question
- Thread starter OneJArpus
- Start date
i don't think you can, i remember reading some where that the gm 3 bars don't work right with our ecus or something like that because the map is either linear or non linear, can't remember which one. i would just get a boost cut controller, that is the easiest route to go by... if you have more mods and tune your car correctly that will also bump up your boost cut... i've ran the stock map up to 22 psi without boost cut
ok just wondering i've got a 3bar map for cheap so i figured i'd pick it up n see if it would work or just sell it if not.
I'm getting mixed reviews, some say yes some say no.
I'm getting mixed reviews, some say yes some say no.
you can use it but it won't work correctly, i also had one and was going to do the samething but when i did research thats what i read so i just sold it
well then i can't use it as it won't work correctly, was wondering if it would work as in correctly.
hks makes a 3 bar map sensor right? im sure that would be better than a boost cut controller, ive never liked the those.
The whole problem with just swapping out a map sensor is that most all of them operate on the same 0-5v output scale. It doesn't matter what 3 bar sensor you try to run, the scale will be wrong compared to the stock one. A 2 bar map at 18psi might output 5v while a 3bar map might only put out 4v. The ecu reads this value and thinks your running less boost than you are.
If you want to run a larger map sensor, you need something that can translate it to the correct voltage for the ecu, as well as provide a fuel map for beyond its limits.
If you want to run a larger map sensor, you need something that can translate it to the correct voltage for the ecu, as well as provide a fuel map for beyond its limits.
GM(3bar map sensor) wired into ecu with no afc = a yield of crash and burn
Oem(2bar map sensor) + afc = a yield of a tuneable car up to 14psi so why bother upgrading the injectors if you want more boost and power that the factory injectors and map could have handled anyway?
GM(3bar map sensor) + AFC = a yeild of a tunable car up to 30psi of boost so all you will do is tune your maximum boost say 19psi? to be around fuel cut 4.7volts because with say like 550s will deliver enough fuel for the air pushed in at 19 psi to be around 500-550whp at nearly 100% duty cycle assuming your afrs on target by wideband under load and no knock with octane and everything. the curve or linearness of the map makes no difference because you are tunning the 3bar map with the afc to be an emulation of the oem map sensor and your 550 injectors similate the 380s but deliver more fuel at that given moment for the same dutycycle.
Oem(2bar map sensor) + afc = a yield of a tuneable car up to 14psi so why bother upgrading the injectors if you want more boost and power that the factory injectors and map could have handled anyway?
GM(3bar map sensor) + AFC = a yeild of a tunable car up to 30psi of boost so all you will do is tune your maximum boost say 19psi? to be around fuel cut 4.7volts because with say like 550s will deliver enough fuel for the air pushed in at 19 psi to be around 500-550whp at nearly 100% duty cycle assuming your afrs on target by wideband under load and no knock with octane and everything. the curve or linearness of the map makes no difference because you are tunning the 3bar map with the afc to be an emulation of the oem map sensor and your 550 injectors similate the 380s but deliver more fuel at that given moment for the same dutycycle.
Evilempire1.3JZ-GTE;1592503 said:
I wired a GM 3 bar into my neo to try this the other day and could just barely get it to idle. I have a walbro and 440's. Am I missing something here?
Gm 3 bar map works the same as a 1,2jz except instead of reading 5volts at 14.7psi it reads 5 volts at 29 psi
At roughly 14psi gm will read a couple volts lower then the 1jz map at the same readings
so a gm 3 bar will read 0volts at -14 just like the 1jz one
what you will end up doing with the afc is tunning up the voltage slightly especialy under boost if all you do is change the map sensors if you go just as proportionaly higher in ijectors size as you do in boost/map sensors the less you will trim.
The only condition a GM3bar wont works is if its.
deffective
not wired in properly
not tuned
kink or leak in the vacume hose?
At roughly 14psi gm will read a couple volts lower then the 1jz map at the same readings
so a gm 3 bar will read 0volts at -14 just like the 1jz one
what you will end up doing with the afc is tunning up the voltage slightly especialy under boost if all you do is change the map sensors if you go just as proportionaly higher in ijectors size as you do in boost/map sensors the less you will trim.
The only condition a GM3bar wont works is if its.
deffective
not wired in properly
not tuned
kink or leak in the vacume hose?
im gonna give it a try but i'm still not sure how i'm going to tune the map sensor with the SAFC. I thought i was just pulling and adding fuel with the safc
Thats what your doing indirectly. Your Safc modifies the Map signal going into the computer in order to do the adding or trimming of the fuel.
anybody have an idea what each wire is.
mine has a brown black,which i believe to be the ground.blue black=maybe 5volt.green black =signal.any of this sound right.
i have the gm 3bar also,but it has a generic plug on it with black wire's.i need to find some kind of referance for it also.
mine has a brown black,which i believe to be the ground.blue black=maybe 5volt.green black =signal.any of this sound right.
i have the gm 3bar also,but it has a generic plug on it with black wire's.i need to find some kind of referance for it also.
Its easy to figure out with a meter.
You will check the resistance of the map sensor 3 wires 2 wires at a time between each of the three.
2 wires will always read the same and will have the highest resistance!
1 of those 2 wires is VCC the other is ground! ill tell you how to figure that out just read on!
The 1 wire that reads the lowest resisatnce between either of the 2 wires is the sensor output wire and if you vary the pressure into the sensor the resistance in the meter reading will change! this is your pressure sensor signal output.
Now which wire is Vcc which wire is ground easy connect the meter lead to the sensor signal wire then connect the meter lead to either of the power wires.
If you increase the map pressure into the sensor and the resistance increase then that leg where the other lead is hooked up to is the ground wire. If you get a decrease in resistance as you increase map pressure that leg wire on the sensor output is Vcc.
Now if you add slight vacume onto the map sensor and the resistance on the other wire dereases that is the ground wire if you create a vacume and the resistance increases as you add vacume it is the Vcc +5vdc wire. your done label connect call it a day.
You will check the resistance of the map sensor 3 wires 2 wires at a time between each of the three.
2 wires will always read the same and will have the highest resistance!
1 of those 2 wires is VCC the other is ground! ill tell you how to figure that out just read on!
The 1 wire that reads the lowest resisatnce between either of the 2 wires is the sensor output wire and if you vary the pressure into the sensor the resistance in the meter reading will change! this is your pressure sensor signal output.
Now which wire is Vcc which wire is ground easy connect the meter lead to the sensor signal wire then connect the meter lead to either of the power wires.
If you increase the map pressure into the sensor and the resistance increase then that leg where the other lead is hooked up to is the ground wire. If you get a decrease in resistance as you increase map pressure that leg wire on the sensor output is Vcc.
Now if you add slight vacume onto the map sensor and the resistance on the other wire dereases that is the ground wire if you create a vacume and the resistance increases as you add vacume it is the Vcc +5vdc wire. your done label connect call it a day.
http://hhscott.com/93tmv/3-bar_map.htm
Here ya go the voltage curve mapped out and yes it is linear.
By using that map you can calculate the % of fuel you need to pull or add to compensate.
Here ya go the voltage curve mapped out and yes it is linear.
By using that map you can calculate the % of fuel you need to pull or add to compensate.
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One pin in 5v, one pin is ground, and one pin is signal.
Sensor Ground A
Sensor Signal B
+5v Sensor Power C
Sensor Ground A
Sensor Signal B
+5v Sensor Power C