Electronic boost control
 

I am using a gm ebc solenoid that i have attached to my car in a way so that i can run wg pressure (7psi), or flip a switch and run the ebc (11psi) program in the adaptronic.

I have it set so that as soon as it spools up to 11psi (roughly 3600rpm) it adjusts the EBC solenoid so that it holds within .5 psi of my target up till red-line.

My issue is that, if i stab the throttle at anything above 4500 rpm or flat-shift, the boost pressure spikes to 14psi (where my over-boost protection is at).

I am currently using open loop wastegate control since i can't see any difference when i activate any of the closed loop settings.

any idea how to remedy this spike? i already have a MBC connected in parallel with the EBC and it does not fix the spikes. If i set the MBC to a point where it reduces the spike to 11 psi, it vents pressure after that initial spike down to 8 or 9 psi.

If you have not done so already, set the EBC at 100% across the board, then adjust the MBC for the cutoff pressure you want. Then, go back and retune the EBC.

When I first installed the EBC/MBC hybrid it was doing some weird stuff like that. Once I tuned the MBC with the EBC closed (100%) and then retuned the EBC, everything was fine.

ok, i will try that again. Even with just the MBC i was getting a similar spike. any idea how to fix a spike from a MBC

Does your MBC have a small bleeder port on it? Where is your boost source for the wastegate?

Yeah good questions. I am assuming you installed and plumbed everything correctly. Post up some picts of your install, or describe in detail.

also you have the Solenoid hooked up like this on the right:

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

This works too; that is how I did it.
http://lh3.ggpht.com/_jh2HiMm4nKQ/Sg...C-MBC-ASSY.JPG

Read this, specifically post #25...
https://www.miataturbo.net/forum/t30067/#post372400

Brain that avatar is really... disturbing... :eek:

:) that's exactly the same as the diagram I posted.

yes the MBC does have a small bleeder hole in it. Should i enlarge it slightly?

My pressure source is on the compressor outlet.

My EBC and MBC are configured similarly to your first diagram (left side) Brain

i will post pics as soon as i get home.

Do I need to even say what I'm planning on suggesting? :brain:

wait till i get a picture to you before you suggest it

Brain, the way you have posted on the right doesn't make any sense at all. if 0% duty cycle sent all of the charge to the wastegate, 100% duty cycle would send absolutely no charge to the wastegate. none of it would be sent to the MBC or the wastegate.

At least not with the GM, ebc

why did you say you had the GM Solenoid?!

.... I would have posted this:

http://www.boostedmiata.com/gallery2...serialNumber=1

this is have i do mine and it works perfectly.

I cannot tell for sure from your picture but it looks like you have it hooked up the same way I use it. The EBC and MBC are in parallel. It works for me. But, we have two things that are different. The MBC (yours is DIY) and the EBC (but I believe it is functionally identical).

Are you sure everything with your MBC internals is fine? No leaks anywhere in any of the fittings? How big is your bleeder hole?

there are no leaks in the mbc, permatex on all threads. as for internal functionality, how would i check that? it is just a plain old ball and spring. i got it from a company on ebay called NXS

the bleeder hole is really tiny, 1/16"

DO IT LIKE I JUST FREaKIN POSTED AND PROFIT HARDCORE>....


http://www.boostedmiata.com/projects/ebc_mbc_combo.jpg


WHY Do YOU DOUBT GLORIOUS BRAIN!?!??! :brain:


although it makes perfectly good sense that it will work in your configuration....You can always try to lengthen the wastegate rod something like 2 turns. so the same boost levels will crack it open ever so slightly more.

Because you are a damned terrorist that is trying to blow up his car!








:giggle:

The way he has it is functionally 'exactly' the same.

In his configuration, if the solenoid is off, the boost will bypass the mbc. If it's set to 100% DC, the boost will try to escape through the blocked port but have no place to go but back through the MBC. Instead of blocking the port I utilize it.

So I suggest lengthening the wastegate rod a touch, should help with the spike without noticeably affecting spool-up.

Yeah I know. It's all good. Not saying yours does not work, just being silly.