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Go All Electric
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Discussion Starter · #1 ·
I'm finishing wrapping up some info for an FAQ that I wote a while back.

Let's compare 3 of the most common ways that I know of, that most mk3 owners would manually controll boost.

1) Shim waste gate.

I have not yet used this method or driven an mk3 that has this mod so I have no personal experience to add. I have heard that boost has a tendency to spike (rise above a tuned point for a short period of time and then fall to tuned point). I would not think that boost would be able to fall below a tuned pont though because this mod actually puts a physical object in "obstuction" of the gate instead of tuning by pressure/vaccum.

2)JMBC/Bleeder mbc/pressure regulator via vacum etc.

I currently have this installed. I have experienced boost spike of (described above) of anywhere from .5 to 2 psi and I have no idea of any way that could remedy this. I heard that shortening vacum hoses may work .. but I do not know so that should be discussed.

I have also experienced boost creep to fc at about 13psi steady, possibly only due to elevation because this only happened once since install.

I have also experienced boost falling back to stock 6.8/7psi and have been tuning this lately with the bleeder edjustments. I haven't fully remedied this yet because I have not had a dry day where I had time to yet. Today I had plenty of time to tune, but it was very wet and foggy out. Hopefully tomorrow I'll be able to tune it to hold bost perfectly.

3) Doc Jonez/Dawes MBC.

I have not used this and I would like to hear info from Doc and from anyone else who may have used or experienced this. It seems to be the best one but I want to know what drawbacks it may have.


Anyone that has any relative input is encoraged to comment. The purpose is to determine the most effective/most easily installed/most easily adjustable/most precise/most relaible/ all around best mbc possible.

If anyone knows of any other types of mbc(s) to compare then please give info on that type.
 

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boost freak
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10,042 Posts
there really isn't a drawback to the ball+spring MBC.....its fast acting, keeps all boost from the WG until the set pressure is reached (resulting in faster spool). many consider the ball+spring to be the "gold standard" of boost control.

only drawbacks i can see-
1. have to pop hood to adjust boost
2. max boost limited by spring pressure (mine make it to about 22psi or so...)

HTH...
 

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Eclectic
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1,139 Posts
ball and spring user here aswell. i like it, no problems, cheap.
but as Dr J said.... have to pop the hood to adjust grrrrrr.
not hitting max boost yet ;)
 

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Go All Electric
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1,183 Posts
Discussion Starter · #4 · (Edited)
Doc, just found this quote from you:
"Since last fall, I have been unable to control my boost accurately (nasty boost creep). So, the wastegate actuator is shimmed so that it creeps up to about 14psi then falls down to 12psi by 4000rpms."

So you were also experiencing boost creep with the wastegate shim mod?

Good to hear about the ball+spring, but from info found here: http://www.dawesdevices.com/SDinstructions.html ...

Under "Problems" they suggest spiking problems are possible. This seems to be only possible if the vacum/boost lines that you run are too long. Want to address this Doc? Also, soup, what did you use as your boost source and have you experienced any slight spike/creep .. anything?

Also, Doc, do the controllers you sell have any of the mods listed under "Modifications"?

Lets hear from more people who have used these one or more of these boost control methods. Share every experience that you had with install/operation/etc etc etc. This should be a good thread for people to refer to in the future, IF people participate.

Best regards.
 

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I live in a giant bucket.
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1,237 Posts
My friend was running a TurboXS Manual Boost Controller on his 6M-GTE set at (10?) PSI. It spiked to 22PSI and blew his motor.
 

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Go All Electric
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1,183 Posts
Discussion Starter · #7 · (Edited)
Mostly Thumbs said:
That doesn't sound like spike that sounds like a blown hose from or to the boost controller.
Agreed.

But, let's not diagnose this here. Stay On Topic, please.

Turbo XS concept is very interesting though. They have standard (which looks to be ball+spring), High Performance (which combines ball+spring+bleed), and a dual stage. Too expensive though. The unavoidable, yet kind-of OffTopic statment: somebody that has the TurboXS MBC should see how easy it is to clone because I bet we could make our own for a lot cheaper than they sell for.

Let's hear MBC/Shim experiences.
 

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Registered
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372 Posts
Just clarifying that MBC don't blow motors. I have had my wastegate shimmed for 2 years to 9psi and it is pretty good. The boost falls off at higher rpms during long pulls to around 7.5psi. But for the 35cents I spent on washer I'm pretty happy. I would definately condsider a ball/spring controller if it would keep the boost more consistant through the RPM range.
 

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Banned
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676 Posts
My ball and spring unit works perfect, spools quick and holds 10psi from 2700-6k, if i snap the throttle quickly it will spike to 11 or 12 psi though.
 

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Registered
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A cheap, minor boost increase can be had by T'ing into the BOV's vacume hose and routing that to the wastegate. You cap the stock charge-pipe nipple. The will raise boost by whatever the stock IC/piping pressure drop is.
 

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boost freak
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if you read the update on that quote you posted by me, you would have found that the weird boost problems were caused by a cracked IC.....

shimming the WG puts too much stress on an already old WG act.

boost spikes are mostly caused by the vac lines being too long.

no, my MBCs do not have any of the listed mods. you can do those if you can't get enough boost.
 

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Premium Member
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4,409 Posts
from my experience...

I never liked shims, due to the fact they werent all that consistent, boost would creep instead of hit, youll easily gain more torque going with a diff type of controller. Not to mention you cant adjust them spur of the moment kinda thing.

HKS valve kind without extra valve to recirculate air... PITA to setup, once setup very VERY unreliable IMO... With extra valve, ti was a little better but not great. I hear the jmbc one will hold <15psi perfectly...

I made a ball and spring from home depot stuff, with dr jonez directions back in the day. Excellent, it held 15 psi like a champ, spiked a little as initial boost hit (i think all of em do) but after that it held boost very well. Only problem is after a certain level 17-18+psi (on somone elses car) it started being inconsistent, but i guess thats due to the spring tension as dr j said... Freind has the one drj makes and it holds boost really well too, so its not just me...

For what its worth Ball and spring is by far what ide reccomend out of the MBC's... only reason i went evc is because i run two types of setups for boost, and its easier to just push high/low, otherwise i woulda just kept my ball spring...

Ang
 

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SuprAng said:
only reason i went evc is because i run two types of setups for boost, and its easier to just push high/low, otherwise i woulda just kept my ball spring...

Ang

Same here, although I noticed a dramatic difference in spool-up with the ebc and now that I'm used to it, I don't think I could go back. :)
 

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DON'T reroute your wastegate hose to the manifold, yes it gets you extra boost, but for 1 it will cause the turbo to work excessively hard trying to boost against a partially closed throttle under some conditions and for 2 the diaphram inside the actuator probably isn't designed to handle vacuum and will most likely fail relatively quickly.

I think shimming is great for a first step and at some point the extra preload on the spring can come in handy and allow other boost control methods to work better (just the back pressure in the manifold could be enough to force the flapper open even if there was no boost at the actuator, i.e. MBC or EBC fully closed), but it probably is shortening the life of the actuator.

FWIW I run a spring/ball vavle myself, my own design. Probably sold about 100 of them before the guy I was selling them to farmed the project out to a cheaper labor source. They have been used up to 30 Psi. Mine are billet aluminum. We were working on a redesigned one that made some small improvements, I was thinking about finishing it up, but I kind of need a retailer to buy in quantity and deal with the customers :) I guess I could always try EBAY :D

GLEN
 

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A Happy Dad
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I built this one which I understand is very similar to drjones, if I had do do it again I'd just buy one from him, that 0.020" hole was a pain to drill. Cost about $20 in parts and pieces and like $11 for a solenoid off a newer model Ford truck for 2 stage affect.... have had it in operation for 9 mo or so currently running 16 with no spiking. I've turned it up to 20 but fear for my autobox.

http://www.gusmahon.org/html/boostcontrol.htm

http://pages.cthome.net/gus/pictures.html

BTW, I took out my washers a long time ago.
 

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Republican
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I had a MBC, and ya it worked good, but once you go to ebc, thier is no turning back......
 

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the clever guy
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Just to add: I have had the Turboxs MBC since I became and addict. It does what it's designed to do but I wouldn't really recommend it. I was a noob when I bought it, thinking the extra money was worth it.

I get spikes every time I spool up and this causes unwanted FC if I'm set to just 10 psi on a cool day/night . I recently shimmed my actuator to try and help hold boost up top and all I got was bigger spikes and *maybe* 1 psi at 5k (metric guage). I wasn't aware of long hoses being a spike contributor: would from the wg actuator to the AFM mounting braket be considered long? Eh, in any case, an EBC is in the near future for me. I wan't stable boost and more neat lights in the car :D .
 

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Premium Member
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ya spool is good and with fuzzy logic i hold more boost to redline... ebc is nice...

And ya i did have a relief hole in it, like i said it was awesome till someone used it for 18+psi, probably hte spring.. it spooled up really fast

Ive tried to tune like 4-5 valve mbc on random ppls cars and its never worked out for me, i hate the HKS ones especially...

Ang
 

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I have the Hallman ES (old style) ball and spring MBC. I have only had it installed for a few days, but it seems to hold boost okay. Sometimes when I downshift, it will drop the boost from 15psi to like 10psi or so, which is the opposite of what I want when I downshift... Also it hits fuel cut in 5th gear at WOT, but not in any other gear at WOT. I'm thinking of turning it down a tiny bit so it wont hit FC ever. On an unrelated note, is it dangerous to run 15psi on stock ct26 with stock 440s? My car was running really rich (judging from the backfires from my cat), now that it's at 15psi instead of 10, the car doesn't backfire anymore, which I guess means it's either lean or good. My ghetto A/F tuning...heheh
 
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