Not hitting boost target. MHD log help

bL79 · 09-23-2024, 10:07 PM

Ok just got a 2015 E84 X1 35i. N55 with PWG I'm pretty sure. ~117,000 mi

Installed the Evolution Racewerks CP and VRSF 7.5HD FMIC over the weekend.

Have the car on XHP (stg3) and MHD (stg 2) OTS tunes.

Filled up with some ethanol to make ~E30 today and try the Stage 2 MHD E30 maps. Also decided it was probably a good idea to look at logs finally. I did a quick before and after but realized I'm far short of boost targets.

What's curious to me is the WGDC doesn't seem to much exceed 50%. If I had a boost leak shouldnt I expect the WG and thus turbos to be commanded to near max?

After some reading and inspection I'm pretty suspicious of the boost solenoid vacuum system. I can pretty easily crush the fabric covered line with my fingers. Could that cause the issues seen? I can see the boost solenoid installed is Pierberg, were they OE or does that indicate it was replaced at some point?

https://datazap.me/u/bl79/x1?log=0&data=3-4-14-19

wrevilo · Yesterday, 03:06 AM

A lot of detail is over my knowledge, but I am certain the OE solenoid is Pierburg. I recently had mine replaced and used a Pierburg unit.

bL79 · Yesterday, 02:10 PM

That's helpful, thanks.

Debating if I should R&R the solenoid and hoses or just the suspect fabric covered hose. The fabric wastegate hose routes over the exhaust manifold so seems like an insulated option is desirable.

Doesn't seem like that difficult a job but I'm not super looking forward to wresting the hose off the WG or solenoid nipples.

I guess sometimes when the solenoids fail they make a pretty obvious noise but I haven't noticed anything like that.

Hmm maybe Ill try to pull the line off the solenoid and vacuum test it with a mityvac

swellengear · Today, 03:11 AM

Always a good idea to replace the old vacuum lines with the upgraded silicone options. It's cheap, and then at least you can rule that out.

Seeing as you installed a new charge pipe and intercooler, double check all your fittings. Hopefully something as simple as that!

minulache · Today, 09:20 AM

You can test very easily the vacuum line that goes from the boost solenoid to the WG and also from the valve cover to the boost solenoid. All ypu need is a small vacuum pump like this: https://www.amazon.com/HTOMT-Automot...s%2C205&sr=8-5

If it holds vacuum, the lines are ok. Next step would be the boost solenoid. Unfortunately, there is no proper way that I found to test it, so maybe just changing it would be the deal. But before that, I would do a boost leak test so you have all the leaks tested and leave the solenoid at last. The testings are easy to do and straight forward, in tops 1 hour you can diagnose

wheela · Today, 09:24 AM

In addition to making sure the vacuum lines hold vacuum, also check that none are collapsing shut under vacuum. I've seen some people post that they had no leaks, but the short vac line between the valve cover and solenoid was collapsing shut under vacuum. If vacuum can pinch it shut, you may not get sufficient vac to the wastegate canister to pull the gate closed strongly enough to make proper boost.

09-23-2024, 10:07 PM	#1
bL79 New Member 0 Rep 7 Posts Drives: E84 X1 35 /// E36 M3 (RIP) Join Date: May 2013 Location: CA iTrader: (0)	Not hitting boost target. MHD log help Ok just got a 2015 E84 X1 35i. N55 with PWG I'm pretty sure. ~117,000 mi Installed the Evolution Racewerks CP and VRSF 7.5HD FMIC over the weekend. Have the car on XHP (stg3) and MHD (stg 2) OTS tunes. Filled up with some ethanol to make ~E30 today and try the Stage 2 MHD E30 maps. Also decided it was probably a good idea to look at logs finally. I did a quick before and after but realized I'm far short of boost targets. What's curious to me is the WGDC doesn't seem to much exceed 50%. If I had a boost leak shouldnt I expect the WG and thus turbos to be commanded to near max? After some reading and inspection I'm pretty suspicious of the boost solenoid vacuum system. I can pretty easily crush the fabric covered line with my fingers. Could that cause the issues seen? I can see the boost solenoid installed is Pierberg, were they OE or does that indicate it was replaced at some point? https://datazap.me/u/bl79/x1?log=0&data=3-4-14-19 Last edited by bL79; 09-23-2024 at 10:19 PM..
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Yesterday, 03:06 AM	#2
wrevilo Private First Class 74 Rep 144 Posts Drives: 2010 E92 335i N55 6MT Join Date: Feb 2023 Location: Wiltshire, UK iTrader: (0)	A lot of detail is over my knowledge, but I am certain the OE solenoid is Pierburg. I recently had mine replaced and used a Pierburg unit.
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Yesterday, 02:10 PM	#3
bL79 New Member 0 Rep 7 Posts Drives: E84 X1 35 /// E36 M3 (RIP) Join Date: May 2013 Location: CA iTrader: (0)	That's helpful, thanks. Debating if I should R&R the solenoid and hoses or just the suspect fabric covered hose. The fabric wastegate hose routes over the exhaust manifold so seems like an insulated option is desirable. Doesn't seem like that difficult a job but I'm not super looking forward to wresting the hose off the WG or solenoid nipples. I guess sometimes when the solenoids fail they make a pretty obvious noise but I haven't noticed anything like that. Hmm maybe Ill try to pull the line off the solenoid and vacuum test it with a mityvac Last edited by bL79; Yesterday at 02:18 PM..
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Today, 03:11 AM	#4
swellengear Private 86 Rep 54 Posts Drives: 2008 135i Join Date: Feb 2023 Location: Swellendam, South Aftica iTrader: (0)	Always a good idea to replace the old vacuum lines with the upgraded silicone options. It's cheap, and then at least you can rule that out. Seeing as you installed a new charge pipe and intercooler, double check all your fittings. Hopefully something as simple as that!
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Today, 09:20 AM	#5
minulache Private First Class 52 Rep 120 Posts Drives: BMW 4 F36 & E92 N55 LCI Join Date: Jun 2023 Location: Bucharest iTrader: (0)	You can test very easily the vacuum line that goes from the boost solenoid to the WG and also from the valve cover to the boost solenoid. All ypu need is a small vacuum pump like this: https://www.amazon.com/HTOMT-Automot...s%2C205&sr=8-5 If it holds vacuum, the lines are ok. Next step would be the boost solenoid. Unfortunately, there is no proper way that I found to test it, so maybe just changing it would be the deal. But before that, I would do a boost leak test so you have all the leaks tested and leave the solenoid at last. The testings are easy to do and straight forward, in tops 1 hour you can diagnose
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Today, 09:24 AM	#6
wheela Captain 426 Rep 924 Posts Drives: 2015 BMW X1 35i M-sport Join Date: Mar 2021 Location: Twin Cities MN iTrader: (0) Garage List 2015 X1 35i M-Sport [0.00] 2025 X7 M60i [0.00]	In addition to making sure the vacuum lines hold vacuum, also check that none are collapsing shut under vacuum. I've seen some people post that they had no leaks, but the short vac line between the valve cover and solenoid was collapsing shut under vacuum. If vacuum can pinch it shut, you may not get sufficient vac to the wastegate canister to pull the gate closed strongly enough to make proper boost.
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