Not hitting wastegate

wheela

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Jun 4, 2021
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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.
Something still seems wrong. Clearly you showed something was effed with the boost box, but you used to be able to get 15psi on spring pressure only, and now with the same turbo and wastegate/springs, you're only able to get about 7.5 on spring only? Am I understanding that correctly? If so, just a bad boost box doesn't explain only hitting 7.5psi on spring, when you should be getting 15psi on spring.
 
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BloodyZ4

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Mar 17, 2021
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Yeah that's why I suspect a boostleak or maybe a kinked/damaged/incorrectly connected lines to the MAC Valve.
Wastegate is shut 100% until ~4400RPM.
 
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Maroon_e90

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Sep 30, 2021
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2009 335i - xdrive 6MT
Yeah you are right something is up, I was thinking the Mac solenoid was causing the slow spool but I will check spring pressure again and get a solid log, then double check the plumbing on the solenoid and start from there.
 
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Maroon_e90

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OMG, okay so I feel like such a dip but every post I checked for the Mac Solenoid plumbing said that port B goes to the top of the Wastegate. However I did some research and I found that the boost source should run straight across the solenoid to the bottom of the wastegate.

Long story short I switched the plumbing and it appears to me all my problems are fixed. Logs look much better

Thanks for all the help, now we can actually get into the fine tuning. Side note I did all that was said to enable the MHD+ boost control and it still did not do anything lol. I am okay for now tweaking load to fine tune the boost where I want it to be at, guess we will figure that out later.



 

carabuser

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Oct 2, 2019
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I don't see the final WGDC in that log but the base is reducing as the maf climbs which is strange. Make sure the base table is scaled up to the maf req you are hitting then you should see the boost hold longer up top. Also check the maf airflow adder table.

Tuning using the original tables is the right way to go. Just use the load target as the maximum load you want and adjust the boost limit multiplier and load limit table to get the curve as you want it. Using the boost ceiling as anything other than a safety will just give poor throttle response, you'll end up having a pedal movement that doesn't translate to torque delivered, it'll just be vague like a JB4.
 
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Maroon_e90

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Thanks! I just wasn’t sure the characteristics of this turbo so I was being conservative but I am working on holding that boost to redline. I am going to be fuel limited so that’s why timing is so low as I’m running 93 knock-tane.

Why were the load tables removed on the new xdf’s?
 
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wheela

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Jun 4, 2021
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2015 e84 X1 35i Msport
Thanks! I just wasn’t sure the characteristics of this turbo so I was being conservative but I am working on holding that boost to redline. I am going to be fuel limited so that’s why timing is so low as I’m running 93 knock-tane.

Why were the load tables removed on the new xdf’s?
Wow, you can run 25psi midrange on 93 knock-tane (knock-tane🤣🤣🤣)? How high do you think you'll be able to run? I'll be sticking with 93 on a big turbo too, I thought the octane limit would end up somewhere around 20psi.
 

carabuser

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Oct 2, 2019
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Thanks! I just wasn’t sure the characteristics of this turbo so I was being conservative but I am working on holding that boost to redline. I am going to be fuel limited so that’s why timing is so low as I’m running 93 knock-tane.

Why were the load tables removed on the new xdf’s?
They were just replaced by the load per gear table.
 

Maroon_e90

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Haha right yes just gotta adjust timing with the boost im not sure others opinions but thats what I am trying out. I think I want to make an e40 map. Id love to run around 28psi but need to test it.

Either my turbo is running out of steam already which is really shocking to me, or My wastegate spring needs to be stiffer to hold more boost. On my current setup it seems to be maxed out at 25psi. To answer your question I tried 4.5 degrees of timing and got a superknock code at 6600+ RPM so ill be dropping it to 3 degrees or so I need to do more testing.

 

carabuser

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Your playing with fire there, i'd keep boost lower and make up the power with timing rather than max the turbo out. You'll get really high EGTs by pulling timing.

I also think there is a boost leak or the wastegate isn't closing since that spool is glacial considering you still run out up top.

Edit: just saw this is a 6765 journal. So maybe that spool is normal.
 
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BloodyZ4

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Mar 17, 2021
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Tuning using the original tables is the right way to go. Just use the load target as the maximum load you want and adjust the boost limit multiplier and load limit table to get the curve as you want it. Using the boost ceiling as anything other than a safety will just give poor throttle response, you'll end up having a pedal movement that doesn't translate to torque delivered, it'll just be vague like a JB4.
Even just using the MHD+ Boost Target? I was not talking about the custom WGDC logic, not using those for the reasons you mentioned.

@Maroon_e90 It shouldn't run out of puff up top, but I wouldn't be comfortable running more than 20 PSI on 93 fuel :O At least consider some water/meth injection, your ringlands won't last long like that. Also log your WGDC Bank 1.
 
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carabuser

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Even just using the MHD+ Boost Target? I was not talking about the custom WGDC logic, not using those for the reasons you mentioned.

@Maroon_e90 It shouldn't run out of puff up top, but I wouldn't be comfortable running more than 20 PSI on 93 fuel :O At least consider some water/meth injection, your ringlands won't last long like that. Also log your WGDC Bank 1.
Do you mean the 3D boost ceiling table? If so then that works exactly the same as the normal ceiling but would be worse if you actually try and generate a boost curve using it.

I just don't understand why the tables were added. I can see they would be useful as a crutch when dialing in a map as you can protect the rods by limiting the boost down low until you have the base table finalised but should always be above the actual boost target in the final tune.

If having an arbitrary boost target at WOT was a good idea then BMW would have skipped the whole load model and saved themselves a lot of time and DME memory.
 
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Maroon_e90

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The log shows boost dying because a cylinder deactivated due to superknock. Thats the only log I had at the time of posting but it will hold 25 to redline I will get a better example, I really just think the Mac solenoid needs a slightly stiffer spring to hold more so ill add a new spring and check. Thats why I dont believe the WGDC either, the turbo should not be maxed out as its rated for much higher than I am making right now.

Isnt 3-4 degrees of timing fairly normal on 93? My IAT's are pretty chilly