Why is Boost so low?

s!ke · 10-30-2014, 11:18 PM

Is this normal? It seems like my boost is only 1-6 psi. I thought it should be around the 10-16+ range?

Datalog: http://www.datazap.me/u/sike/fbo-run-1?log=0&data=1-19

I'm running COBB Stage 2 Sport+

Mods include:
Downpipes
FMIC
DCI
(Running on stock charge pipe until I get my new coupler in the mail in the next couple days. )

335NJ · 10-30-2014, 11:29 PM

Something doesn't look right, especially if you're only seeing those boost numbers. That log is hard to read though.

Try to get a log of only 3rd gear across the entire RPM range.

My guess would be boost leak somewhere, do you have any codes?

s!ke · 10-31-2014, 03:12 PM

I'm not throwing a single code. Am I right that it should be much higher? What other parameters should I log to give you a better view?

WedgePerformance · 11-01-2014, 12:11 AM

This map is not working well with your car. Lot's of throttle closer. Boost solenoids could be weak. Vacuum test them.

s!ke · 11-03-2014, 01:54 AM

Alright I have a new log.
http://www.datazap.me/u/sike/low-boo...og=0&data=1-19

I didn't change the map, but I did do the Solenoid bypass mod on the rear solenoid (thinking it would be helpful until I can get my hands on a vacuum test gauge and kit). It looks like my boost levels are much higher, going up to 12psi in some cases. Do these look better or correct?

Also, in about the middle of the graph I actually tried to start in third gear. Difficult but I wanted to see if it showed in the graph going up to about 6500 RPM.

I'm going to either have a shop do the vacuum test while I'm there for something else, or try to buy all the parts to do it myself.

Would this writeup be a good one to follow? Any others?
http://www.n54tech.com/forums/showthread.php?t=13114

Hopefully I can get to the bottom of this before I go and spend $300 on new solenoids.

s!ke · 11-03-2014, 02:01 AM

So I'm looking at the chart and I don't really understand what some of these mean, but I see a "req. boost" and a "boost mean" and a "boost" What do these mean?

I'm assuming it means the requested boost from the ECU and my Actual boost? Which is SIGNIFICANTLY lower than the requested boost.

Req. Boost = 25.59
Boost = 9.32

Am I reading this right? I should be pushing 25psi and im only pushing out 9psi?

10-30-2014, 11:18 PM	#1
s!ke Captain 43 Rep 802 Posts Drives: e92 335 6MT Join Date: May 2009 Location: Bay Area, CA iTrader: (13) Garage List 1991 Toyota Supra T ... [0.00] 2008 BMW 335i [0.00]	Why is Boost so low? Is this normal? It seems like my boost is only 1-6 psi. I thought it should be around the 10-16+ range? Datalog: http://www.datazap.me/u/sike/fbo-run-1?log=0&data=1-19 I'm running COBB Stage 2 Sport+ Mods include: Downpipes FMIC DCI (Running on stock charge pipe until I get my new coupler in the mail in the next couple days. ) __________________ /// 2008 e92 335i 6sp JB/CR \| COBB AP \| AR DP's \| AFE DCI \| FMIC \| BMS Cowl Filters \| Stett CP \| Forge DV's \| Sig photo by jMeas!
	Appreciate 0 Tweet Quote

10-30-2014, 11:29 PM	#2
335NJ Colonel 533 Rep 2,872 Posts Drives: 2008 335i 6MT E90 Join Date: Feb 2014 Location: NJ/Philadelphia Suburbs iTrader: (1)	Something doesn't look right, especially if you're only seeing those boost numbers. That log is hard to read though. Try to get a log of only 3rd gear across the entire RPM range. My guess would be boost leak somewhere, do you have any codes?
	Appreciate 0 Quote

10-31-2014, 03:12 PM	#3
s!ke Captain 43 Rep 802 Posts Drives: e92 335 6MT Join Date: May 2009 Location: Bay Area, CA iTrader: (13) Garage List 1991 Toyota Supra T ... [0.00] 2008 BMW 335i [0.00]	I'm not throwing a single code. Am I right that it should be much higher? What other parameters should I log to give you a better view? __________________ /// 2008 e92 335i 6sp JB/CR \| COBB AP \| AR DP's \| AFE DCI \| FMIC \| BMS Cowl Filters \| Stett CP \| Forge DV's \| Sig photo by jMeas!
	Appreciate 0 Quote

11-01-2014, 12:11 AM	#4
WedgePerformance BimmerPost Supporting Vendor 1334 Rep 1,701 Posts Drives: Slot Machines.. Keep Taking $ Join Date: Oct 2013 Location: Portland, OR iTrader: (0) Garage List 2007 BMW 335i Sport [9.67]	This map is not working well with your car. Lot's of throttle closer. Boost solenoids could be weak. Vacuum test them.
	Appreciate 0 Quote

11-03-2014, 01:54 AM	#5
s!ke Captain 43 Rep 802 Posts Drives: e92 335 6MT Join Date: May 2009 Location: Bay Area, CA iTrader: (13) Garage List 1991 Toyota Supra T ... [0.00] 2008 BMW 335i [0.00]	Alright I have a new log. http://www.datazap.me/u/sike/low-boo...og=0&data=1-19 I didn't change the map, but I did do the Solenoid bypass mod on the rear solenoid (thinking it would be helpful until I can get my hands on a vacuum test gauge and kit). It looks like my boost levels are much higher, going up to 12psi in some cases. Do these look better or correct? Also, in about the middle of the graph I actually tried to start in third gear. Difficult but I wanted to see if it showed in the graph going up to about 6500 RPM. I'm going to either have a shop do the vacuum test while I'm there for something else, or try to buy all the parts to do it myself. Would this writeup be a good one to follow? Any others? http://www.n54tech.com/forums/showthread.php?t=13114 Hopefully I can get to the bottom of this before I go and spend $300 on new solenoids. __________________ /// 2008 e92 335i 6sp JB/CR \| COBB AP \| AR DP's \| AFE DCI \| FMIC \| BMS Cowl Filters \| Stett CP \| Forge DV's \| Sig photo by jMeas!
	Appreciate 0 Quote

11-03-2014, 02:01 AM	#6
s!ke Captain 43 Rep 802 Posts Drives: e92 335 6MT Join Date: May 2009 Location: Bay Area, CA iTrader: (13) Garage List 1991 Toyota Supra T ... [0.00] 2008 BMW 335i [0.00]	So I'm looking at the chart and I don't really understand what some of these mean, but I see a "req. boost" and a "boost mean" and a "boost" What do these mean? I'm assuming it means the requested boost from the ECU and my Actual boost? Which is SIGNIFICANTLY lower than the requested boost. Req. Boost = 25.59 Boost = 9.32 Am I reading this right? I should be pushing 25psi and im only pushing out 9psi? __________________ /// 2008 e92 335i 6sp JB/CR \| COBB AP \| AR DP's \| AFE DCI \| FMIC \| BMS Cowl Filters \| Stett CP \| Forge DV's \| Sig photo by jMeas!
	Appreciate 0 Quote