Pure Stage 2 PWG not hitting boost target (WGDC maxed out) above 6000 RPM

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ganque

Private
Jan 22, 2018
43
Pure Stage 2 PWG not hitting boost target (WGDC maxed out) above 6000 RPM
Hi Everyone,

I need some assistance from the Pure turbos gurus on my car. It's a 2013 135i N55 PWG with DCT.
The car is not able to hit >21 PSI above 6000 RPMs. I have already checked for boost leaks by adding pressure with a Boost leak tester. Boost solenoid was replaced the same day I got the PS2 installed. I'm running E40 with Fuel-It Port Injection controlled via JB4.

Running MHD with Jb4 BEF Pump flash for N55.

Any thoughts or suggestions would be greatly appreciated.
Thanks!
 

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ganque

Private
Jan 22, 2018
43
That is a very good question. I'm at 5,138 ft over sea level. Are PS2 turbos known to be affected at these elevation levels?
 

Twisted Tuning

Lieutenant
Platinum Vendor
Oct 25, 2016
910
New York
That is a very good question. I'm at 5,138 ft over sea level. Are PS2 turbos known to be affected at these elevation levels?
All turbos are affected by elevation. The higher the flow, the less affected on the big end, but affected none the less.

But considering at sea level the PS2 maxes out around 22-24psi in the upper rpms being over 5000ft above sea level would certainly lower that.
 

ganque

Private
Jan 22, 2018
43
Yeah that makes sense. That was one of my theories, and I brought this up several times to the Pure guys and BMS as well. They always said it was a boost leak, despite that I performed 3 boost leak tests in 2 months.

Now, does a bad PCV / Valve Cover leak could also cause this? I haven't had any weird noises yet but I think I should be replacing it by now.
 

hardparker

Private
Jan 23, 2018
40
Ganque, I'd say elevation is the culprit in your case. If you can log ambient pressure or even just look it up locally, you'll see that your altitude loses you about 2.5 psi.

Doodlebro, you either have a bad boost leak or bad boost solenoid. That's on a PS2? Your ambient pressure is down -2.7 psi at your altitude in the log, but that doesn't explain your boost issues.
 
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hardparker

Private
Jan 23, 2018
40
I should add that the other thing altitude affects is the amount of vacuum the pressure converter has to work with. It'll be down a few in/mg of vacuum, so it won't be able to exert as much force to keep the wastegate closed, either. Lower ambient pressure at altitude kind of sucks like that. On the plus side, normally aspirated cars suffer far worse power losses at altitude than turbocharged ones, making it easier to beat up on those big V8s.
 
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doodlebro

Private
Nov 23, 2018
48
Interesting, I'll post a log once the solenoid is replaced. I have a pretty good hunch that it's not a boost leak, but we'll find out in a week or so. I also need to check that the wastegate actuator can hold vacuum sufficiently up top. It looked good below 10" Hg, but I should test up around 20" to ensure that's not where the vacuum leak is coming from.
 

ganque

Private
Jan 22, 2018
43
Ok so in my case being altitude a possible culprit that would bring me a to a new question.
Should I shift earlier to maintain my boost pressure curve above 21 psi?
Using datazap I can see that the car can hit 22 psi starting from 4200 RPM and dropping from 5500 RPM. Should I just shift at that range? Or continue shifting all the way to 6700 RPM?

Thanks in advance
 

hardparker

Private
Jan 23, 2018
40
Ok so in my case being altitude a possible culprit that would bring me a to a new question.
Should I shift earlier to maintain my boost pressure curve above 21 psi?
Using datazap I can see that the car can hit 22 psi starting from 4200 RPM and dropping from 5500 RPM. Should I just shift at that range? Or continue shifting all the way to 6700 RPM?

Thanks in advance
Shift early. Max power is typically around 5800 RPM anyhow. Max torque is closer to 4000. The earlier shifts will keep you spooled better, with more boost and in the most effective part of the power band. Shift at 6000 and see for yourself. Can't wait until that can be programmed with XHP.
 

ganque

Private
Jan 22, 2018
43
Shift early. Max power is typically around 5800 RPM anyhow. Max torque is closer to 4000. The earlier shifts will keep you spooled better, with more boost and in the most effective part of the power band. Shift at 6000 and see for yourself. Can't wait until that can be programmed with XHP.
Yeah, now that you mention that I took a look into my Dyno chart taken last year and I can see the 450tq curve starts at 4200 RPM and starts going down again after 6000 RPM. So Yeah I definitely agree on shifting at 6000 from now on. I will test tonight using my draggy and compared to my current numbers.

This is my current draggy video to use for reference:

 

bradsm87

Corporal
Dec 15, 2016
162
Do not shift at 6000rpm. You want the highest average POWER used during any gear pull, not torque. If peak power is at 5800, you want to be shifting at around 6500 so you end up coming in to the next gear not too far before peak power.

OP, why don't you just run 21psi flat across the whole rev range? You'll get more timing possible, leaner AFR possible and less heat generated all round. The little bit extra midrange running more boost isn't worth the disadvantages IMO.
 
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ganque

Private
Jan 22, 2018
43
Do not shift at 6000rpm. You want the highest average POWER used during any gear pull, not torque. If peak power is at 5800, you want to be shifting at around 6500 so you end up coming in to the next gear not too far before peak power.

OP, why don't you just run 21psi flat across the whole rev range? You'll get more timing possible, leaner AFR possible and less heat generated all round. The little bit extra midrange running more boost isn't worth the disadvantages IMO.
I was thinking of that. Maybe 22 Psi since I do see a peak?
I'm curious if there is a way to make it hit those boost targets maybe by working the turbo manifold. Maybe a 50 nitrous shot.
 

doodlebro

Private
Nov 23, 2018
48
Replaced my boost solenoid, still not hitting targets (though, it feels like I'm hitting boost a lot sooner). Old one had 50K on it anyways.

Today I'm test fitting a custom F10 inlet which I hope will solve this. It could also be that DME control of the wastegates just sucks... I have a hunch that a JB4 might fix this too.
 

bradsm87

Corporal
Dec 15, 2016
162
A bigger turbo inlet is a must for these turbos and will help, however, there is nothing to "fix". Over 20psi at redline is a massive acheivment. I'd be super happy running 17psi flat on an upgraded turbo.
 

ganque

Private
Jan 22, 2018
43
A bigger turbo inlet is a must for these turbos and will help, however, there is nothing to "fix". Over 20psi at redline is a massive acheivment. I'd be super happy running 17psi flat on an upgraded turbo.
Yeah I installed the Pure Turbo kit including the upgraded inlet that Pure also sells. New OEM Boost Solenoid, no boost leaks.
Has to be elevation, unless I have some stupid wrong setting in the JB4. I raced yesterday and took some logs, lowered to a 22 psi target and the car is just getting a one-time 22 psi peak then drops to 19 at higher revs.
 

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bradsm87

Corporal
Dec 15, 2016
162
Yeah I installed the Pure Turbo kit including the upgraded inlet that Pure also sells. New OEM Boost Solenoid, no boost leaks.
Has to be elevation, unless I have some stupid wrong setting in the JB4. I raced yesterday and took some logs, lowered to a 22 psi target and the car is just getting a one-time 22 psi peak then drops to 19 at higher revs.
19psi at high altitude is incredible. Embrace it. Definitely no problems.
 

doodlebro

Private
Nov 23, 2018
48
In my case, the issue is in fact a boost leak on the turbo to intercooler pipe. Going to get it fixed this week and I should be able to hit targets. Strange that I never got codes or other symptoms aside from not hitting targets.
 
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