Not hitting wastegate

Jagre.williams

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Jul 20, 2023
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Recently swapped out the motor on my single turbo 335i after swapping the motor I changed my jb4 out for a reflex + with Mhd. After flashing the reflex and loading the Mhd tune I take the car out for a log and it’s only hitting 10 psi but I have a 14 psi spring. It has a turbo smart wastegate with the red 14 psi spring have previous logs on the old motor making the full wastegate. I’ve checked for leaks with a smoke tester seeing nothing and I never took the wastegate off the manifold when swapping so I know that’s not the issue. Any ideas will help thanks. I attached the log below.
 

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  • 2023-07-17 15_14_17 IJE0S WBAPM73559A367581_ije0s _Jarge_ST_3port_rflx_e85_v1.1.mhd.csv
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browiththefro

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Jul 19, 2023
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Not sure if you resolved this issue, but I also have a ST setup with a Turbosmart GenV Hypergate45 wastegate with 14psi spring (the red one). What I've noticed is that the 14psi spring isn't always actually 14psi. According to my research, its somewhere closer to 9-10psi. I ended up adding an additional 5 psi spring (included with the kit) to bring the pressure up, which resolved my issue.
 

brandnewish

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Feb 28, 2018
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Not sure if you resolved this issue, but I also have a ST setup with a Turbosmart GenV Hypergate45 wastegate with 14psi spring (the red one). What I've noticed is that the 14psi spring isn't always actually 14psi. According to my research, it’s somewhere closer to 9-10psi. I ended up adding an additional 5 psi spring (included with the kit) to bring the pressure up, which resolved my issue.
I haven’t, I was going to tear into it again now that the weather is nice.

Interesting. I wonder if that’s isolated to the TS wastegate. I’m consistently getting about 5 psi under target – no boost or exhaust leaks have been revealed in smoke or pressure tests. I may swap out springs and see what happens.

A note though, the sky blue is the proper 14psi spring for the hypergate 45.
 

wheela

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Jun 4, 2021
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Not sure if you resolved this issue, but I also have a ST setup with a Turbosmart GenV Hypergate45 wastegate with 14psi spring (the red one). What I've noticed is that the 14psi spring isn't always actually 14psi. According to my research, its somewhere closer to 9-10psi. I ended up adding an additional 5 psi spring (included with the kit) to bring the pressure up, which resolved my issue.
I also have the TS Hypergate 45 (not installed yet) and have been debating which spring to start with. What was the max boost you were able to get with the 14psi spring? How about with the 14 + 5 psi springs?

I've done some bench testing with my Hypergate 45 with the 14psi spring, and verified it starts to open with about 14 psi in the actuator. I think the reason it opens earlier on the car is pre-turbine back pressure trying to push open the wastegate. The dataset for the Hypergate 45 lists actuator/valve ratio as 2.07:1. So whatever back pressure you have, divide it by 2.07, and that's about the additive effect it has on the boost pressure going into the actuator. For my turbo, at 16psi boost pressure matchbot predicts about 10psi preturbine back pressure. With 10psi back pressure at a 2.07:1 ratio, the 14 psi spring wastegate would probably start to open at around 9psi boost pressure going to the actuator because of the 5psi additive effect from preturbine back pressure pushing open the wastegate. At least that's my thinking, which seems to be supported by the math, and peoples' anecdotal observations😉
1000011291.jpg
1000011289.jpg
1000011134.jpg
 

wheela

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Jun 4, 2021
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I haven’t, I was going to tear into it again now that the weather is nice.

Interesting. I wonder if that’s isolated to the TS wastegate. I’m consistently getting about 5 psi under target – no boost or exhaust leaks have been revealed in smoke or pressure tests. I may swap out springs and see what happens.

A note though, the sky blue is the proper 14psi spring for the hypergate 45.
How much boost are you able to get from the 14psi spring?
 

browiththefro

Lurker
Jul 19, 2023
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I haven’t, I was going to tear into it again now that the weather is nice.

Interesting. I wonder if that’s isolated to the TS wastegate. I’m consistently getting about 5 psi under target – no boost or exhaust leaks have been revealed in smoke or pressure tests. I may swap out springs and see what happens.

A note though, the sky blue is the proper 14psi spring for the hypergate 45.
Agreed. It's supposed to be sky blue, but when I got my Hypergate 45 (from DocRace), it was supplied with springs shown for Hypergate 40 (red for 14 psi installed in the WG).

I also have the TS Hypergate 45 (not installed yet) and have been debating which spring to start with. What was the max boost you were able to get with the 14psi spring? How about with the 14 + 5 psi springs?

I've done some bench testing with my Hypergate 45 with the 14psi spring, and verified it starts to open with about 14 psi in the actuator. I think the reason it opens earlier on the car is pre-turbine back pressure trying to push open the wastegate. The dataset for the Hypergate 45 lists actuator/valve ratio as 2.07:1. So whatever back pressure you have, divide it by 2.07, and that's about the additive effect it has on the boost pressure going into the actuator. For my turbo, at 16psi boost pressure matchbot predicts about 10psi preturbine back pressure. With 10psi back pressure at a 2.07:1 ratio, the 14 psi spring wastegate would probably start to open at around 9psi boost pressure going to the actuator because of the 5psi additive effect from preturbine back pressure pushing open the wastegate. At least that's my thinking, which seems to be supported by the math, and peoples' anecdotal observations😉
I'll look though some logs and see what I can pull up.

Here is the boost with 14+5psi springs:
<removed log, as it includes boost control, which confuses the investigation>
 
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wheela

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Jun 4, 2021
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Agreed. It's SUPPOSED to be sky blue, but when I got my Hypergate 45 (from DocRace), it was supplied with springs shown for Hypergate 40 (red + grey for 14+5 psi).


I'll look though some logs and see what I can pull up.

Here is the boost with 14+5psi springs:
Thanks! Are you running any kind of boost control in this log, or is this just boost line plugged straight into the wastegate actuator?
 

browiththefro

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Jul 19, 2023
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Thanks! Are you running any kind of boost control in this log, or is this just boost line plugged straight into the wastegate actuator?
AH that's my mistake. There is boost control in this log (as seen by the WGDC). I don't seem to have a log with no boost control after installing the additional 5psi spring.

Here is a log that has no boost control with the 14psi spring ONLY:


It is possible to see here that the spring was not actually hitting up to 14psi of wastegate pressure.
 
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wheela

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Jun 4, 2021
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AH that's my mistake. There is boost control in this log (as seen by the WGDC). I don't seem to have a log with no boost control after installing the additional 5psi spring.

Here is a log that has no boost control with the 14psi spring ONLY:


It is possible to see here that the spring was not actually hitting up to 14psi of wastegate pressure.
Thanks for that extra log! Yeah, that makes sense, that 10-11ish psi to the actuator plus back pressure pushing on the wastegate piston probably causes it to open earlier than 14psi.
 

Maroon_e90

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Sep 30, 2021
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2009 335i - xdrive 6MT
Since we are on the wastegate topic, I am having an issue myself. I have a ST with external 44mm wastegate. It is controlled via boostbox and a 4-port mac solenoid. On wastegate spring pressure only I can hit 15 PSI and with the mac solenoid I have no problems hitting 26 PSI.

My issue is when I drive the car for a while it will only build to 7.5 PSI which is really weird. It seems to only be above 225 oil temperature that this happens so I am not really sure what is causing it as I logged torque limiters and even fuel mode and nothing seems out of the ordinary.

Any pointers?

 

wheela

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Jun 4, 2021
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Twin Cities, MN
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2015 e84 X1 35i Msport
Since we are on the wastegate topic, I am having an issue myself. I have a ST with external 44mm wastegate. It is controlled via boostbox and a 4-port mac solenoid. On wastegate spring pressure only I can hit 15 PSI and with the mac solenoid I have no problems hitting 26 PSI.

My issue is when I drive the car for a while it will only build to 7.5 PSI which is really weird. It seems to only be above 225 oil temperature that this happens so I am not really sure what is causing it as I logged torque limiters and even fuel mode and nothing seems out of the ordinary.

Any pointers?

Your throttle plate is stuck at 81% for some reason. Not sure if that's the only thing going on (or why that's happening), but if you can't get enough air in through the throttle, you'll be limited in the amount of exhaust the engine can make to drive the turbo. Though I'm not sure if 81% throttle is low enough to limit your boost to 7.5 psi🤷‍♂️
 

BloodyZ4

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Mar 17, 2021
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Z4 35i DCT
81% is the max throttle angle in the DME, so its fully open, look at the Accel. Ped. Pos. that's how much the pedal is pressed down.
1717611816606.png
 

wheela

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Jun 4, 2021
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81% is the max throttle angle in the DME, so its fully open, look at the Accel. Ped. Pos. that's how much the pedal is pressed down.
View attachment 95540
Are all n54 like that? I can't believe I've never noticed that on n54 logs before.

Yeah, I saw his pedal position was maxed out, but on n55, throttle position actually goes up to 99.9% with request maxing at 100%. Here's a screenshot from one of my logs.
 

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Maroon_e90

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Sep 30, 2021
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2009 335i - xdrive 6MT
Thanks all for the pointers, I ended up getting rid of the boost box and repinning the DME. Im thinking maybe the boost box was getting too hot and no longer was converting the signal. The car behaves differently now tho. I will be continuing to test and tune but am hopeful, the car is feeling better everyday. Still thinking about going to a smaller turbo cause this turbo is so laggy it takes the fun out of driving.

 

BloodyZ4

Specialist
Mar 17, 2021
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Germany
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Z4 35i DCT
God damn that's super laggy, what turbo are you running? Are you sure you don't have a boost leak? Even a 7180 wouldn't spool that late :D
Also I would suggest to use the MHD+ custom boost target so you get a nice flat Target.
 

Maroon_e90

Specialist
Sep 30, 2021
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2009 335i - xdrive 6MT
The turbo is a precision 6765. Its an old school journal bearing, however thats what I meant by it drives different, I was boosting 18 psi at 4400 RPM now I dont see that until 5400 RPM.

Another note: how do you get MHD+ custom boost target because I set Load to 220 then enabled the MHD+ setting and set the 3D boost map to 26PSI I believe and it did not do anything so I just stopped messing with it since I have been out of the tuning game for like 3 years.
 

BloodyZ4

Specialist
Mar 17, 2021
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Germany
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Z4 35i DCT
A 6266 Next Gen would completly transform your car :grimacing:
MHD+ Suite -> MHD+ Config -> Enable Custom 3D Boost Ceiling Table set this to 1.
Then you set your target boost under Custom Base Table Maps ->Boost Control -> Boost Ceiling (Relative) (Gear x RPM) (Map 1)
You can ignore the WDC stuff, I prefer to use stock WGDC Control.

I would also do a log with WGDC Base (maybe PID is timing out) and fuel mode since you have that timing dip at ~4600RPM.