Speedtech EFR 7670 on e84 X1

wheela

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Jun 4, 2021
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Ayeee we love to see the progress. I gotta come see this in person soon. Haven’t been in MN as often lately.
As for my car, I’m still lost, but it’s snowing back home anyways. Can’t drive on PS4S’s in the snow😭
Thanks! For sure, it's mostly a pile of parts at this point but slowly making progress👍

You need some winter tires for your stock rims! Or do you plan on just parking it for the winters?
 

SLOWESTN54

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Feb 9, 2021
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Thanks! For sure, it's mostly a pile of parts at this point but slowly making progress👍

You need some winter tires for your stock rims! Or do you plan on just parking it for the winters?
It all starts with a a pile of parts.

And I have Michelin Pilot sport 4 all seasons on currently. Great tire for all types of weather. I meant if I get wheels I’m getting PS4’s and you can’t drive in the cold with those
 
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wheela

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Jun 4, 2021
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Twin Cities, MN
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Update sir, hows this goin
Very small update - ebay water pump bolted up, and got an ebay injector/plug harness, as this acts as a spacer for where the oem air duct pipe screws on. I already twisted the head off that scew before I realized it needed a spacer, so I need anotger $2 part from FCP Euro🤦‍♂️. (Spacer part of harness circled in blue) Got some vacation time in late January, hope to make some more progress then👍
 

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wheela

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Jun 4, 2021
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Twin Cities, MN
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Thank you!!!

Yeah, that's the plan. It's not designed to run on the high frequency duty cycle the DME outputs, but hardparker tested it out in this thread, and it seemed to work:


He used a 7.01024.02.0 valve which I was planning on buying. But I see the turbo came with a 7.01024.00 valve. I've been searching, and it seems these may actually be the same valve.

I plan on testing functionality of this valve on the higher duty cycle first though. So I bought this fully adjustable duty cycle generator. I'll connect the valve to an air compressor and measure the pressure output vs. duty cycle at the higher frequency with this generator. Then I'll know for sure if it will be sufficient. I'm guessing it may not be linear at the higher frequency, but it will certainly be interesting to compare it's performance at 32Hz vs. 200 or 250 (don't remember off the top of my head if it's 200 or 250).
So, I finally got around to testing this boost solenoid at a higher duty cycle frequency.

But first, I tried a baseline test at the 32Hz duty cycle frequency (what the valve was designed for). With about 23 psi supply pressure, It worked as expected. From 100% to 81% WGDC, the wastegate was fully closed with no boost pressure hitting the wastegate. Reducing from 81% WGDC gradually sent more pressure to the wastegate. By 30% WGDC, pressure in the wastegate had reached about 14psi, at which point the gate started to open (it had a 14psi spring, so it was nice to see the results align👍). Continuing to reduce WGDC gradually opened the gate further until at 13% WGDC the gate was fully open, with full boost pressure (about 23psi) holding open the gate. This would allow for a good range of wastegate positions, and varying boost force on the gate by varying duty cycle.

Testing at high frequency:
At duty cycle frequencies above around 100Hz, the valve fell on its face. It essentially turned into an on/off switch. There was no gradual transition or pressure control to the wastegate, beyond all or nothing. At high duty cycles, the gate was closed, with no pressure sent to the gate. As duty cycle decreased, pressure sent to the gate was relatively unchanged, until some point, the valve transitioned and sent all pressure to the gate, and it would fully open. And then increasing WGDC back up, there was a lot of hysteresis, as you needed a higher WGDC% to get the gate to transition back to closed than was needed for it to open.

So. I'm not liking how this valve performs under the high duty cycle frequency range our DME runs in. I'll be sourcing some different valves to test to see if I can find one that seems to work better at the 250Hz range.

Attached are some pics of the setup, and some videos of testing at 32Hz and 200Hz.

Testing at 32 Hz:

Testing at 200 Hz:
 

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wheela

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Jun 4, 2021
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I've been reading about the stock pressure converter and how it works. Attached is some information about them. In summary, they have a diaphragm with vacuum on one side, and vent to atmosphere on the other. Vacuum level is controlled by balancing the pressure differential on the diaphragm against the magnetic force from the solenoid (which increases with duty cycle).

So I've been thinking if these work by the magnetic field pulling the diaphragm away from the vacuum from the vacuum supply, it should work just as well if the vacuum supply was vented to atmosphere, and the vent was instead connected to boost pressure - at least up to around 14psi (because the pressure differential across the diapgram would be the same magnitude, and in the same direction as its intended use condition). And obviously, it's designed to work on out stock 250Hz duty cycle frequency😃

However, our stock pressure converter doesn't have a port on its vent, it has a built in filter to keep crap from getting pulled in when vacuum is released. So I perused for a Pierburg pressure converter that had a barb connection on the vent, and the same style electrical connector. I found Pierburg valve 7.21903.70.0.
 

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wheela

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Jun 4, 2021
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Twin Cities, MN
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I tested this valve by connecting the boost supply to the valve's vent, and venting the valve's vac port. And it works!!!😎 This will allow external wastegate control by the DME with no external boost controllers required!!

Usable duty cycle range is about 15% to 100%. It's pressure output is quite linear between 15% and 100% duty cycle. At 100% duty cycle, it reduces boost pressure by around 13.5 psi or so. Should be plenty to work with either the 10 psi or 12 psi wastegate springs I'm considering using.

I still have some details to work out - since it's only rated for vacuum (worst case pressure differential across the diaphram of about 14.7 psi) I don't know how much over-pressure it will handle in my configuration. So I'll incorporate either some kind of regulator upstream of it, or a relief valve after an orifice in the boost line venting back to the intake to keep boost pressure hitting the valve below a 14-15 psi.

Attached are some videos of it in action, as well as pressure output vs. duty cycle graphs I made at various boost (supply) pressures from my air compressor.
 

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wheela

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Jun 4, 2021
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Twin Cities, MN
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Gotta get that classic side-by-side comparison😃
 

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wheela

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Jun 4, 2021
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Twin Cities, MN
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2015 e84 X1 35i Msport
Starting mock-up👍
 

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