EBC and MBC together?
 

I got sick of the EBC so I built a manual controller from home depot parts.

I like the ability to switch between a boost target and the wastegate, so I'd like to keep that functionality.

Below is what I have tried so far, with the DC for the EBC set to 100% across the board, and a regular switch wired in line to the solenoid.

Attachment 209210

The configuration on the left was a failure because when the solenoid was powered, it just dumped the boost signal out to the atmosphere, so it would just crash into the overboost fuel cut.

The configuration on the right hasn't worked so far, but it doesn't overboost anymore, so I would say it is an improvement. I just end up with wastegate pressure regardless of whether the EBC is active or not. I don't know if there is a problem with the configuration, the solenoid, or if the spring in my MBC is just too weak.

So here is my question: Does this idea hold merit, or is it doomed to failure for some reason I haven't noticed?

run it in series, not parallel.

oh wait, you want to run the MBC...but use the solenoid to allow to run wastegate?

I'm thinking the configuration on the left should work. When fully closed (100% DC) the solenoid shouldn't leak boost, so all the air will go into the MBC and would as if the solenoid isn't there. When fully opened (0% DC) the air should flow freely into the wastegate actuator.




why don't you like the EBC function?

edit:

disregard original post. the config on the right should work as long as the MBC is tight enough.

incidentally, dont hook the solenoid to the ECU. just wire in a +12 and GND with a switch.

it overshoots and changes a lot depending on ambient temperature. See this thread for more thoughts.

try a pressure regulator after the solenoid.

Post resurrection, with a good reason. See below:

I'll be trying the method that Deliverator linked to on NASIOC. I think it is brilliant. The EBC and MBC are hooked up in parallel.

1. The MBC acts as a max allowable boost controller. No matter what the EBC is doing, the MBC has ultimate control over the maximum allowable boost level. This is HUGE.
2. One could use this with an on-off switch on the EBC to switch between MBC control and straight-up wastegate control. Or...
3. One could use this with the EBC duty cycle control to regulate part-throttle boost levels with the MS throttle-based duty cycle function. This allows for better part throttle modulation. I like this personally as I have done it with the EBC.
4. Even if you do not use the part-throttle modulation, you can still set up the EBC to spool to a lower pressure than the MBC, and reduce the boost lag from running off of the wastegate only. But, ultimately, the MBC will clamp the upper boost level if the EBC overshoots ( due to cold weather, tuning, whatever).

So I have a question, hence the thread resurrection. Bear with me. If one wanted to, a 5th way to use this would be to have a switchable system. Stage one is regulated by the EBC, and Stage 2 is regulated by the MBC. If another power line was connected to the EBC solenoid, in parallel with the MS, then one could lock it to 100% by sending it a continuous voltage signal. This means the EBC would be shut, and the MBC would be in control. One could use this to have settable boost levels, but without the wastegate lag (that comes from just turning off the EBC). Or with a button on the shifter or steering wheel, have a two-stage boost system, for lower boost in 1st gear for example.

Question: Is it OK with the MS-I EBC driver circuit to have a parallel circuit (to the EBC) that is just a switched 12V signal, or will it damage the MS circuit?

The EBC output, like most of the other outputs, is a closure to ground. The EBC solenoid has +12 applied to one side of it, and the other connects to the MS, which provides a PWM'ed ground to drive it.

If you want to operate the EBC solenoid manually, provide a switched closure to ground between the EBC and the MS.


Is it possible that you are making this needlessly complex?

That's what i do. A simple $0.50 switch from radio shack on the ground line between the valve and MS.

Attachment 208140

Ahh OK right. I knew that actually, but forgot. So all it would take is a switched, parallel path to ground to lock the EBC at 100%, with no harm to the MS. Thanks.

No I don't think it is needlessly complex, in that it is potentially full of win compared to the standard approaches.


Method 1: Wastegate control only
Pros:
- Cheapest and simplest of all.
Cons:
- Slower spool
- More difficult to adjust target boost level
- Limited adjustment range


Method 2: MBC only
Pros:
- Simple and effective
- Easiest to tune (just turn a knob)
- Wide range of target boost settings.
Cons:
- Not switchable electrically.
- No part-throttle boost (wastegate) modulation.


Method 3: EBC only
Pros:
- Electrically switchable (between wastegate and EBC target boost)
- Wide range of target boost settings, part-throttle boost modulation,
- Already available on MS
Cons:
- For MS (open-loop control) overboosting with ambient temp drops is a problem
- Takes more time to tune than the MBC
- Slow spool when EBC is off (wastegate mode)


Method 4: MBC and EBC in parallel, power interrupt to EBC (0% duty cycle)
Pros:
- MBC acts as a max boost clamp (greatly reduced overboosting with ambient temp drops)
- Part-throttle boost modulation
- Electrically switchable boost levels (between MBC and wastegate)
Cons:
- Slow spool when EBC is off (wastegate mode).


Method 5:
- MBC and EBC in parallel, Power interrupt to EBC (0% duty cycle), Ground bypass to EBC (100% duty cycle)
Pros:
- Same as Method 4
- Electrically switchable boost level with three states (EBC, MBC, wastegate)
- Electrically switchable between two boost levels without wastegate lag
Cons:
- Most complex of the above methods to tune and implement.

Pick your poison! I'll be trying Method #4 at least, if not Method #5

I might would try 5 maybe. Like you said, it should fail to MBC pressure if (when) temps change several degrees and EBC has a heart attack. I would like some boost by TPS control. Feathering second gear is hard as hell right now.

Exactly!

With the small turbos, the wastegate spool 'lag' might be OK, though I noticed a definite improvement with the 2560 after adding EBC. With the 2871 I am going to now, I would think improving the wastegate only spool would be even more dramatic.

Well damn you, I might have to try this over the weekend. I bought the shit to build EBC stuff, but never did the mod. Actually, I need to redo how my supErior Waste Gate is controlled first to help with boost response, then do this mod. Maybe next weekend. :)

You will be trying it out before I then, since I am still building the new motor. Please post up when you have some results.

You know, there are some other options here if one gets creative.

For example, WI fault protection. It would work with any of the EBC methods above. Interrupting power to the EBC as we know causes it to go to 0% duty cycle, and thus the boost defaults to the wastegate level. This is presumably the lowest boost level of all, since the EBC and MBC can only raise boost from the wastegate level.

So, if one were using WI, then one could put a normally-open pressure switch in the water feed line to the mist nozzle. The power to the EBC would be run through this. That way, if there is a WI failure (anything short of a clogged nozzle), then the EBC goes to 0% duty cycle, and boost does not go above the wastegate pressure. No WI, no high boost. There is a potential Catch-22 here though if one wants to set WI to come on above the wastegate pressure.


EDIT: Attached is a PDF of the vacuum diagram and electrical diagram of what I am talking about for Method 5 as described above. There are three modes: wastegate control, EBC control, and MBC control. I am not sure what to call the switch, but it could be thought of as two, three-position rotary switches that move in tandem.

Just to update, the original drawing never did work. It would just keep building boost until I hit the overboost protection, even with absolutely not tension on the ball in the MBC. I could flip the switch and run wastegate just fine, but the "high boost" never worked. I removed the EBC and just ran the MBC, and it works just like it's supposed to.

Here is another way to do it with two simple SPST on-off toggle switches which are easy to find, like at Radio Shack. The first switch 'arms' the system. The second switch selects EBC or MBC.

Check me on my math here :)

Are you using the GM EBC valve? If so I do not understand why it did not work so maybe I am missing something. The guy on the NASIOC site that did this successfully had the vacuum lines connected like I have in my diagrams, and like you have yours shown in the left diagram. And judging from the picture he is using the GM (Delco) valve.

Today I checked the way the EBC valve works with a power supply to be sure I have it right. No power (0%) air flows from the inlet to the wastegate connection. Power (100%) air flows from the wastegate connection to the vent (where the foam filter is located). I was concerned at first that at 100% the EBC would just vent the boost signal to ambient, and keep any pressure from actuating the MBC valve. But, when at 100% EBC, there is a lot of resistance to flow between the wastegate port and the vent. So it would seem like since there is so much available flow from the turbo, that the flow would overpower the vent, and still allow pressure to build and actuate the MBC. In other words, the vent would not bleed off boost fast enough to prevent the MBC from actuating the wastegate. This would have to be true for it to work for the NASIOC guy.

But like you said, it did not work for you, so something here is amiss.

I am using the GM valve, and I don't understand why it does not work. Everything on paper indicates that it should work great, but actual execution proves otherwise.

Interesting. Hmmm... You know it occurrs to me that I could play around with this on the workbench using an air compressor (while the car is offline). A regulated shop compressor will make a decent air source to simulate the boost signal.

Please do. I wanted to do that myself but I don't have an air compressor to play with.

Hook up your vacuum cleaner hose to the exhaust port and get out some Jesus tape.

Theres quite a few uses for a vacuum cleaner other than just cleaning you know!:naughty:

OK here is the deal. I played around this weekend with the hybrid setup using my new (to me) TurboXS BC-HPBC MBC. I used my shop compressor regulator to create various pressures between 7-20 psi and ran several tests using my turbo's wastegate (set to about 8-9 psi). The connection going to the bottom right is what I had the shop air connected to. The long and short of the test is this:

FTW - Hook up the connection on the vent side of the EBC to the incoming air, which is the opposite of how the NASIOC guy has it in his picture. This way it works. When the solenoid is off (no power, 0% DC) the wastegate responds normally. When the solenoid is on (powered, 100% DC) the MBC controls the wastegate and it takes more pressure to open.
http://lh6.ggpht.com/_jh2HiMm4nKQ/Sa...g/s640/FTW.JPG
.
.
.

FTL - Hook up the connection on the vent side of the EBC to the outgoing air, which is how the NASIOC guy has it in his picture. This way it does not work. When the solenoid is off (no power, 0% DC) the wastegate responds normally. When the solenoid is on (powered, 100% DC) the wastegate will not open at all.
http://lh3.ggpht.com/_jh2HiMm4nKQ/Sa...0/P2220249.JPG

FIXED: Skidude try plugging the vent port (see below).

What seems to be going on in the FTL configuration is the EBC is venting too much air (at 100% DC) for pressure to build and open the wastegate. Even when I increased pressure it still would not open. Why this is not also the case in the FTW configuration is strange since the EBC is still venting air from the system. But whatever, on the bench top it works.

Even I can understand that!

:bigtu: ZX Tex

It gets better. So it occurred to me to try a third configuration, that is, with the vent plugged. And, it works, even in the FTL configuration.

http://lh4.ggpht.com/_jh2HiMm4nKQ/Sa...ged%20vent.JPG

Though I thought about plugging the vent before, I kept thinking the vent had to be left open because the system needs a way to bleed off the air in the wastegate diaphragm; this allows the wastegate to close when boost is released. But, then it occurred to me... When the EBC is in 0% DC, the wastegate acts just like it is connected directly to the manifold, and thus the pressure just vents back into the manifold like it normally would. No problem there. When the EBC is at 100%, the air is vented out through the bleed port in the MBC when boost is released, so no problem there either.

So the answer is, just plug the damn vent port and it should work!

And, blankity blank blank, wouldn't you know it, but I went back and read the NASIOC thread more carefully. It turns out the vent is plugged in his setup. You just cannot see it in the picture, and he only mentions it after someone asked about it. Easy to miss :vash:

EDIT: Attached is a corrected connection diagram.

makes sense it works in that configuration.

I must say I am quite disappointed in this thread.

Here I thought I had a new idea that nobody else was doing and then I'm directed here. It's funny, my emails to a few friends actually lay out the exact same reasons and benefits of the different setups and why it made sense to go this route. It almost looks like I plagiarized. That'll teach me to stop reading up on mt.net.

Anyway, I didn't have any concerns about the GM solenoid not working, I knew I could just cap off the vent from the beginning. Wasn't concerned about that boost pressure not being vented afterward and keeping the wastegate open since the ball&spring MBC I purchased had a small vent for this very same reason. What did concern me was the vent(on the MBC) being too large and bleeding off too much pressure when the solenoid was open for the wastegate to be pushed open. Well I set it all up today on the Machine(begi cold air box was in the way on the daily and I didnt feel like getting too into it). Turns out it's fine, the ~1/32" only made a small difference which I wanted anyway. Straight wastegate pressure went from 9 to about 10.5 which is perfect for me.

Here is how I am running it.

It's plumbed the same way as in the FTL pic above except the vent is capped.
The EBC is still connected to my MS with a toggle switch in line. Toggle switch off gives me wastegate pressure, about 10.5psi. On gives me MBC pressure, ~16psi. I am using the Boost duty target table to give me throttle sensitive boost control assistance. It's set up as follows:

http://www.miatamx5.com/ms_files/mbc+ebc_bdt.gif

This way in low traction conditions such as rain or snow I don't have to worry as much about the thing getting squirrly, I just flip off the switch. And by using the boost duty target table the transition from wastegate pressure to mbc pressure is much less abrupt. So now I have a boost controller that actually does what I expected the EBC function of MS to do. BRING ON THE VARYING AMBIENT TEMPS! I'm very happy with the setup. I already purchased for all 3 of our squirted turbo miatas, actually I did a group buy for 8 of them from NXS for a few friends. $14.75 each instead of $20. To me that beats visiting a few Home Depots and Lowes to source the parts $12/ea and then spending an hour or so making them.

See I couldn't run a MBC after I went with a 3" exhaust because I had such horrible boost creep. This is an interesting concept, in the least i could bleed the EBC to control the creep as well. I might give it a try.

My 3" dp/exhaust setup caused mad over boost till we ported the wastegate. I mean the thing would make 15 with the flapper door held open. I could make 6-7 revving in neutral.

I already ported mine, but I should have done more when it was off a few weeks ago. I still hit 10-11psi at redline on a 6psi wastegate.

Mine wasn't quite as bad as Paul's, but with the 3" Absurdflow and puny wastegate on the IHI turbo, I easily made 12-13 psi with no boost controller and an elongated actuator rod. Then I swapped the turbo for a BEGI ported version. Non-boost-controlled pressure dropped to 10-ish.

Realized there is no need for the 2nd T/Y if you route like this

http://www.miatamx5.com/mbc+ebc_reroute.gif

Turns out a little cleaner.

I'm really sorry Paul, but .... you just posted the exact same diagram as the OP's "current" configuration in post #1. :)

If all you do is toggle it on and off, then whats the point of having the table have different DC%? Just make it all 100.

Because even when you do want full boost, you don't necessarily want it immediately upon pressing the gas pedal. That's the whole point of using an EBC at all -- variable boost based on throttle position. Having a middle row of 30 or 40 percent smoothes the power delivery.

Duh. ;)

wait

isn't the single port on the GM solenoid the "common" port? ie should go to turbo?

Yes, it is. But in this configuration we're using it backward on purpose.

Typically I have the metal port to the boost source. That's the one thats alone on one side. But You can't use the solenoid as a switchable Y in that direction. Power off it flows through. Power on it's blocked, it doesn't flow to the vent side. Now if you swap the thing around and put the boost source to the port that typically would go to the wastegate it works perfectly. With power off it flows through to the metal port on the other side. With power on it closes the metal port and directs air out the vent port. Perfect.

At least that's the way it works in my house with as much pressure I can blow through the line.

I just looked at the OP's diagram and no I have it different and that's why mine works. He has the solenoid in the typical orientation which works fine if you just want to open and close a single path but does not work if you want a switchable path through the solenoid.

http://www.miatamx5.com/EBC.jpg

Paul, what's the MBC you buy?

I bought NXS ones. Regular price is $20 shipped. I ordered 8 total for a bunch of these jersey fuckers and got em for $14.75 each. And Phil threw in a 9th one free. So $13.11 each shipped. From the DIY MBC sites it looks like you'll spend $12 in parts to make your own plus an hour or so in labor. For the few extra bucks it's worth it to me.

NXS Motorsports

ive built one before, cant find it, dont feel like doing it again.

im going to give this a shot, i like you, have got tired of random boost levels with temperature changes.

I was a lil weary about this one. eBay Motors: High Quality Manual Boost Controller Toyota Subaru Audi (item 320355035550 end time Apr-01-09 18:53:11 PDT)

Just wanted to update and say I installed the ebc+mbc as in my updated configuration diagram and it is working as planned.

http://www.miatamx5.com/ebc+mbc.jpg

Just for the hell of it I set my boost duty target table all to 100% to see how the Machine would respond if I didn't run this setup and only ran a simple MBC setup. Well it hits boost target which I happened to have set at 17psi with only 49% throttle so fuck that. That's the exact reason I use an EBC to begin with, so I don't build boost too violently at low throttle.

Eh, I bought one of those cheapy ones. It's such a simple mechanism, what is there to be wary about? (seriously, tell me if something horrible is going to happen)

You are probably right that it will be fine but if it does vibrate and fall apart, like that knob end comes out you will not be telling your wastegate to open and you will overboost. if you have boost cut set you should be fine.

Yeah, that's what I figured. The worst that can happen is hitting the boost cut.

Do you guys ever experience different boost levels with the MBC based on the temperature of the spring inside it? Isn't the spring stiffer when it's cold, effectively raising the boost limit? One thing I experienced soon after putting the MBC in (i just did it this week, and was going to setup the EBC with it this weekend) was that I hit the overboost cut once (the first time i floored it), but then never again. I had my overboost set to 187kPa, and every subsequent pull was topping out at 170kPa. So I can't explain why I would hit overboost that one time... except with spring temp or something like that.

edit: after some more driving and reading, I realized there are a lot more variables involved and this is a simpler issue relating to the common MBC issues of spiking, creep, etc... I'll have to experiment with this MBC and my overboost settings.

Since when??? I'm in search of a new bottom end now cause of it.

Well thats because you didn't set it right, no fault of the equipment. User error on DIY stuff is far more likely than an honest-to-god screwup on the manufacturers part, especially with such widespread use and effective dissemination of good information.

Overboost fuel/spark cut worked fine for me on my MS and also works fine on the Adaptronic.

Artie's boost cut was set for like 225 to get it out of the way when he wanted to run 17psi. He refused to re-tune his eBC when the weather got colder and he was hitting 20psi

I finally jumped on board. Dealing with a lot of boost loss due to ambient temps that I've never really dealt with before. The last two mornings were 65*F out and at lunch it had hit over 80*F. Would go from 13-14psi down to 10psi once it got hot out.

My initial results are good. I need to tune it a little better, as I have to bleed boost with the EBC since I get bad boost creep, but so far so good. But from 5K to 7K I've never seen it so flat.

Here's my plumbing using the ARO solenoid:

http://boostedmiata.com/technical/ebc_mbc.jpg

I'm about to go back out and see now that it's about 10*F warmer out if I'm still making the same boost.

blah. it's performing good, but the problem is my boost creep.

If i tune it in the morning to get flat boost, it's bleeding too much when it's hot out. likewise, when i tuned it in the afternoon when it was warm, I had too much boost past 5.6K in the morning.

I'm thinking maybe I need a pressure regulator after the MBC to prevent any more boost to push the wastegate open after the MBC has been overcome....because all the way up to 5.6K the boost is perfect and I want to continue using the MBC...


thoughts?

Let me get this straight, your boost control issues change with ambient air temp, right? Mine is doing a similar thing but i'm boosting fine when cold but as underhood temps rise and my spring heats up i'm back to stock WG pressure presumably because the spring is getting softer as it warms up. If I adjust for my target boost when everything is as hot as its going to get, I hit overboost in the morning when everything is cold.

I have reported this to Rick as being racist. Thanks for a link to an overpriced MBC that will not do me any good.

That was my issue with EBC only. I was hoping that when I went to this mbc/ebc combo I could bleed boost with my solenoid and since the MBC was the main controller, it wouldn't be effected by the temperature change. It doesn't seem to be the case, so when I bleed off boost, it's still temperature dependent how much I bleed off.

So I guess i really just need to port my wastegate more, because now that i think about it I don't think a regulator will work, because I need the wastegate to open more with higher revs, not keep it at the same level.

Keep in mind I've only had it installed a day, so i might need to play with it more, but right now I see a perfectly flat 12.5psi from 3800-5600RPM. In the morning, at 5600RPM it would rise to 14psi, with my solenoid bleeding from 100% to 65% Duty cycle. When I drove home and it was around 82* out, I made 12.5psi till 5600, and then it dropped down to 11psi at redline with the same solenoid settings. So it seems it's still effected by temps...

Did you try locking the EBC at 100% and tuning the MBC? I had some boost creep wierdness, even with the EBC at 0% until I tuned the MBC, then it was fine.

It's cockpit adjustable. You're going to have problems with creep when temperatures change; the ease of adjustment on this one is why I suggested it.

yeah. Here's how I have it setup, this morning it was pretty much perfect.

http://boostedmiata.com/MS/duty_targets_mbc.jpg

deliverator, that wont help me, I'm not going to sit there twiddling a knob once i starting overboosting due to creep....

If anything I'll go back to just the EBC, Once I tuned for summer afternoons, it will be perfect until the weather gets cold again where I'll have to lower the numbers in the table a little. I've run this thing for 2 years now, I never remember it being so bad due to temps, but i dont really boost all the much driving to and from work.