jb4 map 1 why does it get to 16psi?

bmwhp · 08-06-2013, 02:56 PM

why does jb4 map1 get to 16psi? i thought it only goes up to 13.5

video

Jeff@TopGearSolutions · 08-06-2013, 03:46 PM

Just for the record a proper datalog would be a more accurate method to use. (You should also be measuring boost in a 3rd gear pull from 2000 RPM to redline).

Second, 16 PSI is fine in the mid-range. It's 13.5 PSI at redline. All is normal. Enjoy your tune.

bmwhp · 08-06-2013, 03:53 PM

Quote:

Originally Posted by Jeff@TopGearSolutions

Just for the record a proper datalog would be a more accurate method to use. (You should also be measuring boost in a 3rd gear pull from 2000 RPM to redline).

Second, 16 PSI is fine in the mid-range. It's 13.5 PSI at redline. All is normal. Enjoy your tune.

Thanks i never knew that, i thought 13.5 PSI was max boost at any rpm range

Jewber · 08-06-2013, 05:00 PM

Quote:

Originally Posted by Jeff@TopGearSolutions

Just for the record a proper datalog would be a more accurate method to use. (You should also be measuring boost in a 3rd gear pull from 2000 RPM to redline).

Second, 16 PSI is fine in the mid-range. It's 13.5 PSI at redline. All is normal. Enjoy your tune.

While you're right on both counts, map 1 is only 13.5 max and begins to taper down at 5500rpm.

bmwhp · 11-11-2014, 11:38 PM

Quote:

Originally Posted by Jewber

While you're right on both counts, map 1 is only 13.5 max and begins to taper down at 5500rpm.

so why does it overboost?

jb4store · 11-12-2014, 12:34 AM

I would datalog it before you begin to worry. That gauge isn't the most accurate measurement, especially in 1st and 2nd gear.

HeavyMetalRocker · 11-12-2014, 08:40 AM

Quote:

Originally Posted by jb4store

I would datalog it before you begin to worry. That gauge isn't the most accurate measurement, especially in 1st and 2nd gear.

+1 definitely datalog it. If indeed it is overboosting then we can suggest the proper actions!

volcom8190 · 11-12-2014, 09:34 AM

are you backend flashed? 4-3 will pick the higher of the two targets, which could explain the spike. That or some other things (vac lines, etc)

tjobeid · 11-12-2014, 12:29 PM

Probably doesn't have the diods cut on the jb4. That causes overboost, if running an iso firmware without the diode cut.

08-06-2013, 02:56 PM	#1
bmwhp Private First Class 12 Rep 149 Posts Drives: 2020 m550i Join Date: May 2012 Location: az iTrader: (1)	jb4 map 1 why does it get to 16psi? why does jb4 map1 get to 16psi? i thought it only goes up to 13.5 video __________________
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08-06-2013, 03:46 PM	#2
Jeff@TopGearSolutions 3441 Rep 79,211 Posts Drives: C6 Z06, 09 335i, 10 335xi Join Date: Dec 2008 Location: www.TopGearSolutions.com iTrader: (37)	Just for the record a proper datalog would be a more accurate method to use. (You should also be measuring boost in a 3rd gear pull from 2000 RPM to redline). Second, 16 PSI is fine in the mid-range. It's 13.5 PSI at redline. All is normal. Enjoy your tune.
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11-12-2014, 12:34 AM	#6
jb4store New Member 0 Rep 6 Posts Drives: Fast Join Date: Sep 2014 Location: . iTrader: (0)	I would datalog it before you begin to worry. That gauge isn't the most accurate measurement, especially in 1st and 2nd gear.
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11-12-2014, 09:34 AM	#8
volcom8190 Private 4 Rep 92 Posts Drives: 14 Sierra 1500 Join Date: Jun 2014 Location: RTP Area, NC iTrader: (0)	are you backend flashed? 4-3 will pick the higher of the two targets, which could explain the spike. That or some other things (vac lines, etc)
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11-12-2014, 12:29 PM	#9
tjobeid Banned 53 Rep 558 Posts Drives: 2007 335i coupe Join Date: May 2013 Location: houston,tx iTrader: (1)	Probably doesn't have the diods cut on the jb4. That causes overboost, if running an iso firmware without the diode cut.
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