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Das Beast: My E30 track / street build

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  • dvallis
    replied
    Boost

    So, adding a boost control valve. How hard could it be, right?

    This arrived yesterday. No instructions in the box. "Derivation is left to the student." Thanks guys.



    First off, I figured out the wires have no polarity. 12V goes to one switched source. The other end goes to your ECU boost control. (That's for later)

    I also found these specs for the solenoid:

    15 Hz: 8 - 91 %dc
    20 Hz: 10 - 87 %dc
    30 Hz: 15 - 80 %dc

    But also saw it spec'd as 10 - 40 Hz.

    There are threads showing this solenoid works best at 20 Hz. (1), (2), (3)

    What about plumbing? Of course, it's not straight forward either. This picture gives a good idea of how the valve operates. Path 2-3 is normally open. When 12V is applied, the valve closes and path 2-1 is open. You apply a 12V PWM signal with specific duty cycle and frequency so it is open for a percentage of any given time cycle. 0% duty cycle path 2-3 is open, path 1-2 is closed. 100% duty cycle, path 1-2 is open and 2-3 is closed. Stare at it a while and it will make sense.



    However, just how the solenoid gets attached to the waste gate is ambiguous. This thread has a good discussion that let me figure it out.

    This picture is the same configuration as the last one. As the solenoid opens, it routes more pressure from port 2 to port 1 and the bottom (normally atmospheric) side of the waste gate. This holds the gate closed longer, increasing boost. Seems simple, right? However, this configuration does not control boost as well, according to many posts. One guy finally coughed up the right answer: When you come off boost, path 1-2 closes and there is no path for pressure to bleed from the bottom waste gate actuator. This will give weird response in a PID controller.



    Conversely, plumbing the valve as shown below achieves the same thing. As duty cycle of the PWM is increased, more pressure is fed on the 1-2 path, increasing the waste gate opening pressure. However, when the PWM drops to 0%, there is a straight connection between ports 2-3. The waste gate control diaphragm bleeds directly to atmosphere. It seems logical this would result in much quicker closed loop response of the system. One more mystery solved.



    At least the MSPNP Gen2 hardware is easy. Boost control output is pin 7 on the option connector.

    "The Boost control solenoid pin on the option connector is an output for boost control. To use boost control, connect one terminal of an electronic boost control solenoid valve to a 12 volt source that turns on with the ignition, and the other terminal to this pin of the option connector. The boost control solenoid valve plumbs into the line running from the intake to the waste gate."



    Tuning this thing is going to be .... interesting. You're dialing in a PID loop, connected to 500 HP of gasoline fueled rotating inertial mass!.

    Oh joy. What could possibly go wrong? Glad we have a Zen Master helping. This thread is an interesting preview.

    To tune closed loop boost control, first set up the boost control target table. You will enter the desired kPa reading as a function of throttle position and RPM. You should not enter in any values lower than waste gate pressure as the valve cannot reduce boost any further, your mechanical wastegate's pressure is the baseline and can only be added to by electronic boost control. Next you will tune the PID values under Boost Control Settings to make it better hit these targets.

    We'd recommend starting to tune CLEBC (closed loop electronic boost control) at a lower boost pressure than you ultimately intend to run. This will allow you to get a handle on tuning this feature prior to running more serious pressures. Before you start, make sure you've adjusted your VE and ignition tables conservatively around and above the boost pressures you are targeting, that means keep the fuel a bit richer than you expect to need, and the ignition a bit retarded from where you expect it to be.

    You must change "Closed loop boost tuning mode" to "Advanced" for PID parameters tuning. They are greyed out for "Basic" mode.

    To tune the PID parameters, start with 100% proportional gain, 0% integral gain and 0% differential gain. If the boost overshoots above its target get out of the loud pedal quickly, and increase the proportional gain. If it does not spike, you may reduce the proportional gain until you get just a very small amount of overshoot. Leave the proportional gain there. At this point, the boost is likely to creep up slowly after reaching the target. Add a bit more integral gain until the boost stays on target, then increase differential gain until you have minimal overshoot when the turbo first spools up. At this point the boost should track right along with the target boost pressure you've set your MSPNP2 to target.




    Here's the ultimate goal.

    Last edited by dvallis; 02-16-2019, 06:12 PM.

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  • kid8
    replied
    Should be in good hands over there, I just had work done on my car and couldn't be happier. It wasn't tuning, but I've heard great things about them in that department as well.

    Build is looking great, excited to see what it puts down!

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  • wworm
    replied
    holy moly 4-500 horsepower jeeeeez louise das BEAST indeed

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  • dvallis
    replied
    The good, the bad, the ugly

    Getting the waste gate off was not too bad. Thank god for V-bands.



    We decided on the 15 psi spring set. According to everything I read, it should give us 400 - 500 HP on this built cammed 2.8L stroker with wasted spark. All depends on the tune.



    Engine ready to go.



    Car is buttoned up and ready for the dyno. Or so we thought. (More on that later) I'm liking the final product. Looks good. DTM livery will be killer.









    Minor loading issues. Our car dolly sucks. Not enough clearance to load with the air dam on. Will have to upgrade it later. For now we just took off the front end.



    Some auto porn next. This stuff was sitting around at the dyno shop:

    Our tuner's E30 M3



    And this random truck. Booring, right?



    It has a freaking twin turbo LS1 stuffed into it.



    Ferrari anyone?



    Godzira!



    Once we met the tuner, it was a case of Good, Bad and Ugly.

    The Good: Our tuner KNOWS HIS SH-T. Literally asked us 100 questions about the engine and build. He could have just strapped Das Beast on the Dyno, blew the engine and said "You guys suck. Try again." He has an E30 M3, and is building an M60 swap for his day job. THAT'S THE GUY I want tuning my car. He also walked me through the tuning process. I get it now. Very detailed. Also commented that this is a "good build". Hey, that's encouraging. :devil:

    The Bad: These cars are in front of us for tuning. No problem. For this guy, I'll wait..





    The Ugly: We have homework before the tuner will strap it on a dyno:

    1. Our turbo is clocked too far. If the oil inlet is any more than 15 degrees off vertical, Precision turbos start blowing oil past the seals and will burn up. No wonder our exhaust was a bit blue. We thought it was the rings seating. Wrong! LoL

    2. Add an oil catch can for crank case venting

    3. Figure out why the oil pressure is at 60 psi, even when water temp shows 180F. Only drops 5 psi when we blip the throttle. Check AIM sensor vs VDO

    4. Check actual timing against MS2. Previous customer said "All good, but had 30 degrees advance, on TOP of what MS2 thought". Coolant splattered dyno bay ceiling when engine blew.

    5. Get a turbo blanket

    6. Leak down test. Reduce valve clearance from 0.010 to 0.012 if too high. Schrick recommends 0.010 for this cam, so we may be Ok.

    7. Tuner strongly recommends solenoid boot control. As in "Please get one before you come back". In his experience, it holds boost better at high RPM, and does not creep. Allows him to get the most out of the engine. Will use MAC 12V 3 port boost controller MPN 35A-AAA-DDBA-1BA. Spring now determines minimum boost. Tuner said use ~1/3 of max boost, say 7 psi.



    8. He's concerned our intake manifold might starve cylinder 6. Told him it was from a known good turbo M20 build, so we'll see. He will read the plug and tell us. Worst case we get a different manifold.


    Well then. Back to work. More fun for you guys to watch, LoL.

    Last edited by dvallis; 02-13-2019, 03:18 PM. Reason: More content

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  • dvallis
    replied
    Dyno Prep

    Speaking of mechanical issues, I decided to dig into the throttle response a bit more. It's acting wonky at low TPS percentages. Once I disconnected the pedal and pedal return spring, the problem was obvious. I had mechanical interference with the other end of the throttle linkage, way up under the dash. Linkage was binding against my pedal box.



    Here's the culprit. Too long. Some work on the grinder took care of that.



    While I was at it I replaced my wimpy throttle stop with this. With the free moving linkage and lower stop I picked up another inch of pedal travel. Much better feel now.



    Put the wing back on for the hell of it. This might not be long for the world anyway. Will probably end up with a high wing. We'll see.

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