Measured my boost via MAP reading
01-23-2009, 12:03 AM
#1
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2003 W211 E55, 2003 W220 S600
Measured my boost via MAP reading
Finally I got my hands on a obdii scanner with CAN Bus feature so I could get live telemetry. The reading you need to look for from the scanner is the MAP or manifold air pressure.
Now in order to get the boost you have to do some calculations. Which I will describe below.
You will need to know the atmosphere pressure in your area, which you can get from weather . com
BAP - atmosphere pressure
MAP - manifold air pressure
Vaccum - boost
Now the map and bap numeric values were in nhg ( inch mercury) so to convert them into psi you have to multiply by .491
I did 2 pulls one in 3rd and one in 4th. I got the map reading at 6000 rpms.
Formula (bap in stafford texas was 30.01 nhg)
Bap - map = vaccum
3 gear at 6000 rpms
30.01 - 56 = 25.99 X .491 = 12.7psi
4 gear at 6000 rpms
30.01 - 58 = 27.99 X .491 = 13.74psi
I am happy with the boost level. I have the vrp550 package and the numbers are dead on the benchmark ones vadim gave me.
Hope this help. It is a easy way to measure boost without drilling or tapping, but if you want to measure boost regularly this may not be practicle.
Now in order to get the boost you have to do some calculations. Which I will describe below.
You will need to know the atmosphere pressure in your area, which you can get from weather . com
BAP - atmosphere pressure
MAP - manifold air pressure
Vaccum - boost
Now the map and bap numeric values were in nhg ( inch mercury) so to convert them into psi you have to multiply by .491
I did 2 pulls one in 3rd and one in 4th. I got the map reading at 6000 rpms.
Formula (bap in stafford texas was 30.01 nhg)
Bap - map = vaccum
3 gear at 6000 rpms
30.01 - 56 = 25.99 X .491 = 12.7psi
4 gear at 6000 rpms
30.01 - 58 = 27.99 X .491 = 13.74psi
I am happy with the boost level. I have the vrp550 package and the numbers are dead on the benchmark ones vadim gave me.
Hope this help. It is a easy way to measure boost without drilling or tapping, but if you want to measure boost regularly this may not be practicle.
01-23-2009, 10:26 AM
#2
Member
great info!!
....13.7psi @6000rpm should be 500whp according to the flowchart I have. Do you have a 3rd/4th gear dyno??
Im trying to perfect my flowcharts---Did you manage to get AIT's for those runs??
Because if you are seeing 13.74psi at the MAP sensor(after the intercooler which probably eats 3-4psi) --that means the supercharger outlet temp must be 266*F!!!!!!!!!!!!!!!!!
that makes the intercooler alot more effieciant than I thought.
....13.7psi @6000rpm should be 500whp according to the flowchart I have. Do you have a 3rd/4th gear dyno??
Im trying to perfect my flowcharts---Did you manage to get AIT's for those runs??
Because if you are seeing 13.74psi at the MAP sensor(after the intercooler which probably eats 3-4psi) --that means the supercharger outlet temp must be 266*F!!!!!!!!!!!!!!!!!
that makes the intercooler alot more effieciant than I thought.
01-23-2009, 10:42 AM
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2015 S212
Great information!!
I also have a VRP pulley and am planning a dyno run as soon as I get it back from VRP. I could datalog, too. I want the data to figure out ideal pulley size / weight.
What info can you feed into your setup? A/F I will get from the dyno folks but what else do I need? Is there a sensor to monitor the pop off valve?
I also have a VRP pulley and am planning a dyno run as soon as I get it back from VRP. I could datalog, too. I want the data to figure out ideal pulley size / weight.
What info can you feed into your setup? A/F I will get from the dyno folks but what else do I need? Is there a sensor to monitor the pop off valve?
01-23-2009, 11:28 AM
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great info!!
....13.7psi @6000rpm should be 500whp according to the flowchart I have. Do you have a 3rd/4th gear dyno??
Im trying to perfect my flowcharts---Did you manage to get AIT's for those runs??
Because if you are seeing 13.74psi at the MAP sensor(after the intercooler which probably eats 3-4psi) --that means the supercharger outlet temp must be 266*F!!!!!!!!!!!!!!!!!
that makes the intercooler alot more effieciant than I thought.
....13.7psi @6000rpm should be 500whp according to the flowchart I have. Do you have a 3rd/4th gear dyno??
Im trying to perfect my flowcharts---Did you manage to get AIT's for those runs??
Because if you are seeing 13.74psi at the MAP sensor(after the intercooler which probably eats 3-4psi) --that means the supercharger outlet temp must be 266*F!!!!!!!!!!!!!!!!!
that makes the intercooler alot more effieciant than I thought.
**** i forgot there were IAT reading also but i didnot look at them closely will do it again to see those reading.
01-23-2009, 11:31 AM
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2003 W211 E55, 2003 W220 S600
Great information!!
I also have a VRP pulley and am planning a dyno run as soon as I get it back from VRP. I could datalog, too. I want the data to figure out ideal pulley size / weight.
What info can you feed into your setup? A/F I will get from the dyno folks but what else do I need? Is there a sensor to monitor the pop off valve?
I also have a VRP pulley and am planning a dyno run as soon as I get it back from VRP. I could datalog, too. I want the data to figure out ideal pulley size / weight.
What info can you feed into your setup? A/F I will get from the dyno folks but what else do I need? Is there a sensor to monitor the pop off valve?
let me know what you are looking for i can check on saturday when i do it again.
01-23-2009, 12:27 PM
#6
great info!!
....13.7psi @6000rpm should be 500whp according to the flowchart I have. Do you have a 3rd/4th gear dyno??
Im trying to perfect my flowcharts---Did you manage to get AIT's for those runs??
Because if you are seeing 13.74psi at the MAP sensor(after the intercooler which probably eats 3-4psi) --that means the supercharger outlet temp must be 266*F!!!!!!!!!!!!!!!!!
that makes the intercooler alot more effieciant than I thought.
....13.7psi @6000rpm should be 500whp according to the flowchart I have. Do you have a 3rd/4th gear dyno??
Im trying to perfect my flowcharts---Did you manage to get AIT's for those runs??
Because if you are seeing 13.74psi at the MAP sensor(after the intercooler which probably eats 3-4psi) --that means the supercharger outlet temp must be 266*F!!!!!!!!!!!!!!!!!
that makes the intercooler alot more effieciant than I thought.
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01-30-2009, 03:48 PM
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2005 E55
01-30-2009, 03:53 PM
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2003 W211 E55, 2003 W220 S600
How much is your boost dropping to. Give us some more info like is the sc belt slipping etc. According to sunil@motorwerks he has seen boost dropping when some of the sc teeth are chipped or broken.
