Boost curve very wavy, graph inside, opinions welcome
#26
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e55-03 , m3 e36 irs drag car
#29
MBWorld Fanatic!
What Hulk said.
Also, put the front engine cover on (the part with the star logo that falls off) and make some WOT runs. Check the bottom of the cover for a trail of belt dust. Telltale sign the spring is weak.
Also, put the front engine cover on (the part with the star logo that falls off) and make some WOT runs. Check the bottom of the cover for a trail of belt dust. Telltale sign the spring is weak.
#34
Senior Member
I am on stock pulleys and see just over 11psi. I also get a decent amount of dust/oil on my engine cover, and no belt squeal. I am running a BWK though.
#35
MBWorld Fanatic!
If you happen to be reading boost though the OBDII port, the data rate can be slow enough to miss the "dips" in boost. The BWK is not a band-aid for a failing tensioner. For reference, I have the 84mm pulley and zero belt dust on the cover.
#36
Super Member
This is very interesting. So should a normal everything perfect in the motor boost curve should be linear, let's say starting at 5psi and then builds up to 12psi at redline as the motor spins up... My boost definitely is up and down on the way to max. Any one that can share a nice curve of how it should be?
#37
MBWorld Fanatic!
How are you measuring? If its obd then you can not have other parameters at the same time because the refresh rate will be too slow. Also if it's going up and down by 1-2 pounds that's not good but if it's .1 or .2 that's ok
#38
Member
This is very interesting. So should a normal everything perfect in the motor boost curve should be linear, let's say starting at 5psi and then builds up to 12psi at redline as the motor spins up... My boost definitely is up and down on the way to max. Any one that can share a nice curve of how it should be?
On centrifugal superchargers you will see boost rise with RPM. They will start low and go up with RPM. Boost curve goes from low to high in an increasing manor.
#39
MBWorld Fanatic!
Thread Starter
I am not sure how accurate that boost graph is now. I logged boost through my dashdaq with a sensor mounted in the surge tank, and it was straight as an arrow.
#40
Member
It depends on your sampling rate. I would go with the one that has a higher rate. Dyno operator should know how often they are sampling. Where did they get the signal from?
#42
Member
If you can get the Dyno file into excel you can plot your Data against it and see. Plot against rpm.
#46
Senior Member
What you use for obd to meassure boost then?
Torque DashCommand does these work I mean are they trust worthy monitoring boost?
Torque DashCommand does these work I mean are they trust worthy monitoring boost?
#47
MBWorld Fanatic!
I use the boost sensor from zeitronix, real time and no lag
If you must use obd do not use more than 2 parameters or the refresh rate gets bad and lags
If you must use obd do not use more than 2 parameters or the refresh rate gets bad and lags
#48
Senior Member
Thank you will remember that.
The Zeitronix boost sensor sound interesting and thread aswell.
Super thanks will remember that 2 parameters
The Zeitronix boost sensor sound interesting and thread aswell.
Super thanks will remember that 2 parameters
#49
Senior Member
Is that the same?
There is a lot of good stuff boost can be adjusted
https://torque-bhp.com/wiki/Boost_Adjustment
#50
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2002 CLK 55 AMG cabriolet Eurocharged
Hulk is stating, (Do not utilize any extra resolution from the CAN bus of the car).
It will slow down the actual Fr (resonant frequency) degrading bus speed and performance.
I think an AEM Wideband with a piggy back input would be more desirable.
Thoughts, Gator
It will slow down the actual Fr (resonant frequency) degrading bus speed and performance.
I think an AEM Wideband with a piggy back input would be more desirable.
Thoughts, Gator