Map Sensor Question

steady slamming · 08-30-2004, 10:10 PM

Does the Map sensor vent any boost from the two small holes on the back.Iam using the TPS to trigger the controller because the Map is not working anymore.TIA,AL

Razor · 08-30-2004, 11:42 PM

No it doesnt vent

ws6formula50 · 09-09-2004, 09:47 PM

why is the 3 bar map needed????

Razor · 09-10-2004, 10:30 AM

If it pertains to my kit,

1 bar = 14.7 PSI
2 bar = 29.4 PSI

On a 2 bar sensor.. one bar is "vacuum" and one bar is boost. A 2 bar sensor reads to 14.7 PSI.

A 3 bar sensor reads one bar vacuum. 2 bar is boost aka 29.4 PSI.. aka 30 PSI.

So I use a 3 bar on the Buick kits so if the car is at 20 PSI and the boost goes to 24... the controller has a way of knowing the boost has increased and adds more alcohol into the motor.

Using a 2 bar.. once the motor hits 14.7 PSI.. controller has no way of knowing to add more. If you ran a supercharger at 8 PSI boost.. a 2 bar would be more than sufficient.

HTH

ws6formula50 · 09-10-2004, 05:12 PM

thanks, I completely understand now, good idea BTW

kuku · 09-13-2004, 11:20 AM

Can you use the 2 bar and 3 bar sensors together? I have the boost sensing harness from turbo-link and Julio's alky kit. I am just wondering if I will be able to use the boost sensing kit with the alky kit?

Razor · 09-13-2004, 08:43 PM

Sure, leave the 2 bar sensor on the fender, and get another plug for the three bar. Obviously "T" off the vacuum signal to supply the 3 bar with boost pressure. You'll need to supply the 3 bar 5v and ground.

Now the question arises whereby does the T-link harness affect the output of the 3 bar sensor? Easy test plug it all in, measure voltage on the center pin of the 3 bar.. it should read 1.6 volts DC. If it reads way higher.. than there may be an issue.

Also make sure the chip your are using is not using the MAT tables for any compensation. Like a thrasher chip for example. Which chips do... which ones dont... only one that can answer that is the chip maker.

You can put as many MAP sensors in your car as you wish.

08-30-2004, 10:10 PM	#1 (permalink)
steady slamming Quarter mile master Join Date: Jul 2003 Location: boca raton Florida Posts: 187	Map Sensor Question Does the Map sensor vent any boost from the two small holes on the back.Iam using the TPS to trigger the controller because the Map is not working anymore.TIA,AL __________________ 87 WHITE TURBO T,TA49,36Lbs Injectors,Duttweiler mod intercooler,Walbro 307 fuelpump,3in THDP with dump pipe,Reds 93 chip,Adjustable fuel pressure regulator,Big mouth cold air kit/w KN filter,volt booster,Progressive alcohol injection,scanmaster,heated o2 sensor,GNX Dash,Adj wastegate,Type II coils&module,Accel 300+ wires,metco upper&lowers,hotchkis trailing arm braces,centerline telstars,nitto drag radials,hooker cat back w/2 1/2 aero chambers,aluminum radiator,auto meter EGT gauge,cc980 valve springs,B&M line lock,metco drive shaft safety loop.Transmission upgrades next.72 Big Block Nova,83 Firebird 468 BBC

09-09-2004, 09:47 PM	#3 (permalink)
ws6formula50 Registered User Join Date: Feb 2004 Location: VA Posts: 890	why is the 3 bar map needed???? __________________ 2005 GTO 6Spd 1987 Regal WE2 New Girdled 109 Shortblock underconstruction short block being built by Eastern Virginia Turbo Buicks EVTB@cox.net

09-10-2004, 05:12 PM	#5 (permalink)
ws6formula50 Registered User Join Date: Feb 2004 Location: VA Posts: 890	thanks, I completely understand now, good idea BTW __________________ 2005 GTO 6Spd 1987 Regal WE2 New Girdled 109 Shortblock underconstruction short block being built by Eastern Virginia Turbo Buicks EVTB@cox.net

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08-30-2004, 11:42 PM	#2 (permalink)
Razor Registered User Join Date: Jul 2003 Location: Tampa, Florida Posts: 882	No it doesnt vent

09-10-2004, 10:30 AM	#4 (permalink)
Razor Registered User Join Date: Jul 2003 Location: Tampa, Florida Posts: 882	If it pertains to my kit, 1 bar = 14.7 PSI 2 bar = 29.4 PSI On a 2 bar sensor.. one bar is "vacuum" and one bar is boost. A 2 bar sensor reads to 14.7 PSI. A 3 bar sensor reads one bar vacuum. 2 bar is boost aka 29.4 PSI.. aka 30 PSI. So I use a 3 bar on the Buick kits so if the car is at 20 PSI and the boost goes to 24... the controller has a way of knowing the boost has increased and adds more alcohol into the motor. Using a 2 bar.. once the motor hits 14.7 PSI.. controller has no way of knowing to add more. If you ran a supercharger at 8 PSI boost.. a 2 bar would be more than sufficient. HTH

09-13-2004, 11:20 AM	#6 (permalink)
kuku Registered User Join Date: Sep 2001 Location: South Dakota Posts: 152	Can you use the 2 bar and 3 bar sensors together? I have the boost sensing harness from turbo-link and Julio's alky kit. I am just wondering if I will be able to use the boost sensing kit with the alky kit?

09-13-2004, 08:43 PM	#7 (permalink)
Razor Registered User Join Date: Jul 2003 Location: Tampa, Florida Posts: 882	Sure, leave the 2 bar sensor on the fender, and get another plug for the three bar. Obviously "T" off the vacuum signal to supply the 3 bar with boost pressure. You'll need to supply the 3 bar 5v and ground. Now the question arises whereby does the T-link harness affect the output of the 3 bar sensor? Easy test plug it all in, measure voltage on the center pin of the 3 bar.. it should read 1.6 volts DC. If it reads way higher.. than there may be an issue. Also make sure the chip your are using is not using the MAT tables for any compensation. Like a thrasher chip for example. Which chips do... which ones dont... only one that can answer that is the chip maker. You can put as many MAP sensors in your car as you wish.