MMP1k logs -- Boost leak?

langsbr

Captain
Apr 5, 2017
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07 335i 6MT e90
I built my own version of this. I think it's funny they make a setup specifically for MMP inlets now. I'm sure it would work for the other company inlets too if they have 2.5" openings.

http://turboboostleaktesters.com/bm...-boost-leak-tester-for-mmp-relocation-inlets/

They are asking a pretty penny for what can be built for 20 bucks or so in parts from Amazon. Granted, I had some silicone couplers lying around, so it made it even cheaper for me.

Mine found a leak that didn't start until 5psi. Fixed that and it pressurized to 15psi when the inlet started to leak. Sealed that and went to 20psi. I didn't want to risk the inlets popping off and having to redo it so I didn't go above that.
 

Rcboosted2007

Lieutenant
Jan 28, 2018
902
90
0
Parts unknown
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07 335i
FYI, a fog machine will spot major leaks that will appear at standard 0psi testing. But if you have a leak that doesn't show up until say...4psi of pressure has been applied to your system then a fog machine is worthless.

Pressurize your intake system. It's the only way to be sure.
My car still made 30 psi of boost
 

dyezak

Major
May 4, 2017
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My car still made 30 psi of boost

That's awesome that you had a leak so bad a fog machine found it.

But make no mistake. You can still have leaks and make 30psi easily. Especially on big hybrids or a single. There's a thread out there somewhere that chronicled Terry at BMS making 30psi with a 1/4" port open on his manifold. The turbo was just outflowing the leak (and that leak would have been found by a smoke machine).

This is why almost all factory boosted cars have ditched the MAF and gone to Speed Density or Alpha N (this is what the N54 uses) calculations for fueling. With these calculations you are not as effected by a leak. With a MAF you start going rich really quick even on the smallest leak.
 

Rcboosted2007

Lieutenant
Jan 28, 2018
902
90
0
Parts unknown
Ride
07 335i
That's awesome that you had a leak so bad a fog machine found it.

But make no mistake. You can still have leaks and make 30psi easily. Especially on big hybrids or a single. There's a thread out there somewhere that chronicled Terry at BMS making 30psi with a 1/4" port open on his manifold. The turbo was just outflowing the leak (and that leak would have been found by a smoke machine).

This is why almost all factory boosted cars have ditched the MAF and gone to Speed Density or Alpha N (this is what the N54 uses) calculations for fueling. With these calculations you are not as effected by a leak. With a MAF you start going rich really quick even on the smallest leak.
Also i did have a fuel variance indicating on jb4. When i pressurized and sprayed soapy water the leak was large enough to just blow soap away and not foam
 

dyezak

Major
May 4, 2017
1,768
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Plano TX
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335is
Also i did have a fuel variance indicating on jb4. When i pressurized and sprayed soapy water the leak was large enough to just blow soap away and not foam

This open forum isn't about you specifically, and this thread isn't even about you. It's about disseminating the *correct* way of doing things so that people who search for this stuff on Google in the future find the right answers, not half truths and partial fixes.

I'm glad it worked out for you, really I am. But let's not mislead people into thinking this works all the time....or even relatively frequently.

Pressurize your intake system, that's the right way.
 
  • Agree
Reactions: langsbr

Rcboosted2007

Lieutenant
Jan 28, 2018
902
90
0
Parts unknown
Ride
07 335i
This open forum isn't about you specifically, and this thread isn't even about you. It's about disseminating the *correct* way of doing things so that people who search for this stuff on Google in the future find the right answers, not half truths and partial fixes.

I'm glad it worked out for you, really I am. But let's not mislead people into thinking this works all the time....or even relatively frequently.

Pressurize your intake system, that's the right way.
Ooooo its about you and your suggestions, and hypothetical situations that you read about. Gotcha. Just saying this advice is for OP NOT you. As your car is not experiencing the issue that him and i share in common. I went through this issue last week.I wasted a lot of time pressurizing. Trips for parts,assembling. Diy searches etc to pressurize and it didnt work to Pin point this issue. It worked to find port injection gasket leak but not this one, anymore then seeing high wgdc did.thanks again for your forum policing.
 

langsbr

Captain
Apr 5, 2017
1,266
771
0
Ride
07 335i 6MT e90
Ooooo its about you and your suggestions, and hypothetical situations that you read about. Gotcha. Just saying this advice is for OP NOT you. As your car is not experiencing the issue that him and i share in common. I went through this issue last week.I wasted a lot of time pressurizing. Trips for parts,assembling. Diy searches etc to pressurize and it didnt work to Pin point this issue. It worked to find port injection gasket leak but not this one, anymore then seeing high wgdc did.thanks again for your forum policing.

How did pressurizing the intake system not find a hole that a smoke test did find? Did you pressurize the intake and know you had a leak but couldn't find where it was coming from or something?
 

dyezak

Major
May 4, 2017
1,768
1,518
0
Plano TX
Ride
335is
Ooooo its about you and your suggestions, and hypothetical situations that you read about. Gotcha. Just saying this advice is for OP NOT you. As your car is not experiencing the issue that him and i share in common. I went through this issue last week.I wasted a lot of time pressurizing. Trips for parts,assembling. Diy searches etc to pressurize and it didnt work to Pin point this issue. It worked to find port injection gasket leak but not this one, anymore then seeing high wgdc did.thanks again for your forum policing.
facepalm.jpg


I'm out...

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