MBC install [Merged 10-7]

[b00sted99-X]

HERE, DAMMIT!

http://www.dsmtuners.com/forums/showthread.php?t=237982


ok n00b question here.. i got my MBC all hooked up fine (dejon tool.. sweet!) i'm just wondering what to do with the stock boost solenoid hoses.. i took the top one completely off (this is the one that was going to my intake pipe.. then capped that nipple on the pipe) .. the one on the bottom, that tees off and goes to both the wastegate and the turbo housing, is still there. i just bent it backwards and stuck it in the bracket that the top hose was at.. its still connected to the solenoid though. is this alright? can i leave it on there like that will it screw anything up?

 

[Kasprzap]

Last owner was a cheap ass so i am sure this was very inexpensive.

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[staticbrainwash]

Looks like a standard ball and spring. And you can't really get too cheap on one of those. Hell, people make them from home depot parts. I'm sure it's fine.

 

[forcefed 95]

+1^^. Looks like a ball and spring. The easiest way to tell losen the jam nut and turn the bolt out slowly and look inside, you will be able to see a spring inside of the housing. Dont worry it wont like just come flying out at you, jsut make sure you turn it out slow and you will be fine. If its a ball and spring your good to.

 

[staticbrainwash]

For future reference, watch the size of your pics. Thats rather large.

If you're still worried about the reliability of that thing, joe-p, dejon, and a few others make some killer mbc's for around 50 bucks.

 

[Talesin]

And for installation instructions, make sure your boost reference (line from the j-pipe) comes in on the side opposite the adjustment screw. The line to the wastegate should come from the one off the side. This lets the pressure coming in push the ball back against the spring, and flow through to the wastegate... if it's the other way around, the pressure will just assist with sealing the ball in place, and preventing any pressure from getting through to the wastegate.

You should also have a small bleeder fitting... just a vacuum fitting with a small hole drilled in the side, to eliminate pressurelocking your wastegate. Same concept as above, but with some pressure getting trapped between the ball and the wastegate actuator side of the vacuum system, pinning it open. The vacuum fitting (usually just cut your MBC/wastegate line in half and insert the fitting to re-join it) just allows a small bleed vent in case that happens.

 

[delta448]

Actually I disagree. I would run it off the manifold. It is the most absolute reading that is going into your engine, this the same reason you tap your boost gauge off of these lines. Of course, it's hard to say what line is a good line to tap into. I have a bit of a custom setup so you can't really do what I am doing.

A manifold tap doesn't make a mbc any more or less accurate as it does for a boost gauge because a mbc is adjustable. It doesn't care what exact number value the pressure is, it only cares how much it takes to overcome its spring.

Taking the pressure from the manifold really just makes the wastegate react a few milliseconds slower. The mbc will open up to the WG actuator at the same intake air pressure regardless of where it is tapped into if it is adjusted correctly for that location and desired pressure level. Longer piping differences between the compressor and mbc tap and longer vac line just means it opens/closes the wg fractions of a second slower, so you theoretically end up with a little more fluctuation.

It doesn't make any huge difference really, tapping the manifold for pressure usually works just fine. Everybody has their own preference, sometimes ease of installation rightfully takes precedence over a minor detail such as where to tap for the mbc.

 

[Talesin]

Tapping off the manifold will make certain that a given pressure level will reach the manifold, even if the turbo has to overspin to overcome any number of boost leaks. In a static pressure system (like a balloon), the same pressure is exerted over every point of the pressure system's surface. An intake system is NOT a static pressure system, which is where most people's misunderstanding comes into play.

Accounting for pressure drop across the dynamic pressure system is important. Imagine a garden hose, with a bunch of holes punched into it. You're putting in 15psi at the near end, and a gauge tapped right next to the source (before the holes) will show roughly that. But if you measure at the far end, all of those holes may have reduced the pressure to, say, 7psi.
You can GET 15psi on the far end, but you have to put a LOT more in to get it there.

Tapping from the manifold will result in slower wastegate actuation. Slower wastegate actuation results in boost spike, increased lag time, and potential creep. Tapping from the BOV line will result in slower BOV operation, which only exacerbates the overboost/overspin condition, resulting in compressor surge. You also have to deal with the increased volume of the (now unified) vacuum systems, especially with only a SINGLE boost/vac reference to actuate the whole thing... a bit like expecting a single garden hose to be able to provide enough water to run a water park.

None of these conditions may be obvious, or overtly noticeable to the vehicle operator. But basic physics say that they are there. For every one who has no boost spike problem, there are ten who fixed their boost spike problem by running their vac lines the right way.

 

[kenamond]

The biggest problems I see with tapping the MBC off the IM are what was mentioned w.r.t. boost leaks and another one that hasn't been mentioned.

If you're at partial throttle but under load, there can be a significant pressure drop across the TB (butterfly is partially closed). The MBC will see the lower side of that pressure. Let's say that there is a 5psi drop across the butterfly. That means that your MBC is not going to limit the turbo boost until it is 5psi above what you set the MBC to.

It would be interesting to have 2 boost gauges: one off the compressor outlet and one off of the IM just so someone could demonstrate the actual pressure difference and settle this issue with real numbers.

Anyway, that's something to think about.

 

[laserspeeddemon]

What everyone is saying has some truth. It really is about personal preference. I would prefer that my WG wait for the the very last second to open. I want the whole tract to be pressurized at the level I set before that sucker opens to rid myself of as much boost lag as possible. That is why I went with an EBC and not an MBC. But for now I'm going to pick on a few of you, just because I like a good debate.

Right, which is fine, but thats why the gauge is there. Pray you never get a boost leak anywhere before that fitting because you are instantly overboosting your turbo to compensate.

I believe you mean overspinning, but lets run with this for a second. If you car was blowing out smoke, wouldn't you fix it before you race it. Why would it be any different with boost leaks. A boost leak would make the car feel like a slug. I know I got a dyno sheet to prove how much power a boost leak can take away. So why keep driving it around with boost leaks, why not fix it first.

We have had several long threads discussing where to tap in, and why. A majority of people say to run off the compressor housing or j-pipe, as does physics. A smaller vacuum system leads to quicker overall actuation across the system. Many have had boost spike problems when teed into the BOV line. It's just much easier to take the lazy route than to install the proper vacuum fitting, and run off the compressor housing or j-pipe. Tapping in properly will help to preserve your turbo, both avoiding overspin and reducing surge.

.

When properly installed and with the correct hardware, you should not be experiencing either of those. You would only overspin, when you have a boost leak, but this will stop overspin regardless of the source, I will explain that in my conclusion. But there is no point to put on a MBC if you have boost leaks. You are just making your turbo work hard to make less power.

Make sure your MBC is hooked up right way 'round (assuming it's a ball-and-spring, and not a bleeder type) or you'll get no boost reference to the wastegate and overboost like crazy. Just keep an eye on your aftermarket boost gauge (you DO have one, right? raising boost without an ACTUAL boost gauge is just plain stupid, given that the in-cluster one is just a guesstimate on the part of the ECU) and if it starts popping over 16-18psi, let off immediately.

Agreed.

Not sure if I would agree, under the "normal" circumstances. For most DSMers, that would mean lengthening one or the other lines that feed to/from the MBC (or the lengthening of both). This would presumably delay reaction time; not something most people would be looking for.

But thats exactly what I am going for. I want the WG to open only the engine (and by that I mean the manifold) has reached desired boost level. Your other comment is another issue, you have to do some work to make the car fast AND reliable.

to be honest i have my mbc tied into my bov and i hold 12psi all the way to redline with no spike or creep, and i i got a full 3in exhaust from turbo back. and i never seen any negitive side affects from it aside from ppl just hating on the ppl that have it done.

When I had a MBC I had it tapped into the BOV line, I did not experience creep or boost. I had a full 3" but I also had some very good port work done. That is what I mean by proper hardware.

No one is hating, it's been pretty proven why it's bad. If you choose to run this way thats your prerogative, but after seeing even all the potential problems that could arise, i'm not messing with it. Not to mention i get much better boost readings from the j-pipe.

It has not been proven. It has been opinionated. And also, you can not get better boost reading from the J-pipe, because When boost pressure reaches 15 psi (assuming that is a desired boost level) your intake manifold is less then that until that pressure increases the rest of the way to manifold.

Yeah i will be tapping into the j-pipe. When i bought the car it already had the mbc tapped into the bov line. I do not know what type of mbc i have. Does it matter what type of mbc i use? And yes i have a aftermarket boost gauge.

Good for you.

make sure its a ball and spring type

Agreed^^

Agreed, but it looks like a cheap one.

And for installation instructions, make sure your boost reference (line from the j-pipe) comes in on the side opposite the adjustment screw. The line to the wastegate should come from the one off the side. This lets the pressure coming in push the ball back against the spring, and flow through to the wastegate... if it's the other way around, the pressure will just assist with sealing the ball in place, and preventing any pressure from getting through to the wastegate.

You should also have a small bleeder fitting... just a vacuum fitting with a small hole drilled in the side, to eliminate pressurelocking your wastegate. Same concept as above, but with some pressure getting trapped between the ball and the wastegate actuator side of the vacuum system, pinning it open. The vacuum fitting (usually just cut your MBC/wastegate line in half and insert the fitting to re-join it) just allows a small bleed vent in case that happens.

Actually, if there wasn't a hole to vent the pressure between the WG and the MBC, the ball would stay shut under less then desired boost, but the wastegate would stay open. Take for example, your MBC is set at 12 psi. You reach 12 psi, and push the ball back and it reaches the WG which now opens. When you let off the throttle. The pressure will drop. The ball would close with say 10 psi. Since the WG is requires 8 psi to open. It would stay open. The MBC would have to make 12 psi to make the ball open, which it can't with the WG open. And you would forever lose boost (theoritcally).

A manifold tap doesn't make a mbc any more or less accurate as it does for a boost gauge because a mbc is adjustable. It doesn't care what exact number value the pressure is, it only cares how much it takes to overcome its spring.

Taking the pressure from the manifold really just makes the wastegate react a few milliseconds slower. The mbc will open up to the WG actuator at the same intake air pressure regardless of where it is tapped into if it is adjusted correctly for that location and desired pressure level. Longer piping differences between the compressor and mbc tap and longer vac line just means it opens/closes the wg fractions of a second slower, so you theoretically end up with a little more fluctuation.

It doesn't make any huge difference really, tapping the manifold for pressure usually works just fine. Everybody has their own preference, sometimes ease of installation rightfully takes precedence over a minor detail such as where to tap for the mbc.

I can agree with this one.

The biggest problems I see with tapping the MBC off the IM are what was mentioned w.r.t. boost leaks and another one that hasn't been mentioned.

If you're at partial throttle but under load, there can be a significant pressure drop across the TB (butterfly is partially closed). The MBC will see the lower side of that pressure. Let's say that there is a 5psi drop across the butterfly. That means that your MBC is not going to limit the turbo boost until it is 5psi above what you set the MBC to.

It would be interesting to have 2 boost gauges: one off the compressor outlet and one off of the IM just so someone could demonstrate the actual pressure difference and settle this issue with real numbers.

Anyway, that's something to think about.

I don't think the difference is going to be that far at part throttle. Diffently not enough to make a drastic offset in pressure from opposite sides of the throttle plate.

In the end. I have to say this. Now something everyone keeps saying is that if you change the source of the MBC that it will not overspin the turbo. This is not true, because the setting of the MBC is based on what you see on the boost gauge. So you set the tension of the spring to that. Now lets take things to the extreme. Lets say you are running at 20 psi. In order for the turbo to produce pressurized air, it relies on the properties of the air iteslf. In order for air to be pressure at all it has to push against the air around it (and the wall of the piping). So when the starts to flow. It has to hit something for the air to fight against. Air moves like a river, the path of least resistance. Before it puishes that ball 20 psi it is going to move all the way into the intake manifold. Once it has nowhere to go, it will push back into the intake tract and all the way to the J-pipe until it reaches 20 psi at which point the air pressure over comes the spring in the MBC and allows it to open. Since the air has to go ALL the way to the manifold for it to push back into the MBC, it will expeirence the same effects relevant to boost leaks, regardless of where the MBC boost line is sourced from........



Wheeeew!!!

 

[laserspeeddemon]

I'm really going to have fun with this one.

Tapping off the manifold will make certain that a given pressure level will reach the manifold, even if the turbo has to overspin to overcome any number of boost leaks.

The turbo is going to overspin regardless of where the source is. You can see my last post for an explanation.

In a static pressure system (like a balloon), the same pressure is exerted over every point of the pressure system's surface. An intake system is NOT a static pressure system, which is where most people's misunderstanding comes into play.

Boy, did you pick a bad example for a static pressure system. A balloon constantly expands, so the size of the balloon is dependent upon the air inside it. The same amount of air forced into a balloon will produce less pressure then air forced into a true static pressure container, like a metal canister. This true because the amount air in the ballon will expand until the the pressure is equal to the resistance of the expanding rubber around it.

But your are very true about the intake tract, it is FAR from static.

Accounting for pressure drop across the dynamic pressure system is important. Imagine a garden hose, with a bunch of holes punched into it. You're putting in 15psi at the near end, and a gauge tapped right next to the source (before the holes) will show roughly that. But if you measure at the far end, all of those holes may have reduced the pressure to, say, 7psi.
You can GET 15psi on the far end, but you have to put a LOT more in to get it there.

This is true to extent. There are variables that you do not account for, like the size of the holes. And the fact that WATER DOESN'T COMPRESS!!!

However my argument would be this:

Wouldn't it be a better idea to just fix the friggin' hose? In other words. Fix the boost leaks first, then worry about boost source placement.

Tapping from the manifold will result in slower wastegate actuation. Slower wastegate actuation results in boost spike, increased lag time, and potential creep.

This is a bit of a contradiction. If the WG opens slower then wouldn't that reduce lag. While I do agree this may increase the chances of boost spike and/or creep, I come to question your logic. Your first argument was the potential overspin caused by a boost leak, you now argue the potential for boost spike/creep; both of which can be remedied by other means.

Tapping from the BOV line will result in slower BOV operation, which only exacerbates the overboost/overspin condition, resulting in compressor surge.

Somebodies been listening to oldman, however you got somethings confused. Because there is a leak in the BOV signal lean under boost, it may cause the BOV to open, under full boost causing increased lag/decreased performance. You could remedy this simply by adding a stiffer spring or like Greddy BOVs, tightening it. To properly tune this you would have to understand the operation of a BOV. I would agree, though, this is a BAD place for a MBC source. In my case, it is good, but again I have a slightly unique setup.

You also have to deal with the increased volume of the (now unified) vacuum systems, especially with only a SINGLE boost/vac reference to actuate the whole thing... a bit like expecting a single garden hose to be able to provide enough water to run a water park.

The funny thing is you speak of a dynamic system. In actuality, this portion of the vacuum system is closest to a static pressure system. Simply because this system is only a push/pull, it's not constantly feeding air out. It pushes until it hits something and then stops. It's not feeding anything else then a small diaphragm.

None of these conditions may be obvious, or overtly noticeable to the vehicle operator. But basic physics say that they are there. For every one who has no boost spike problem, there are ten who fixed their boost spike problem by running their vac lines the right way.

Boost leaks are very obvious, you should be hitting fuel cut if you are overspinning the turbo. Those 10 fixed their problem, but they are not optimizing their setup. First things first. Get rid of the boost leaks.

 

[dontfeedphils]

Well just as the title says I'm not entirely sure what to do with the stock boost controller after I've installed the new manual boost controller.

I'm not asking how to install the MBC, just what has to be done with the stock one? Also the wiring harness that plugs into it?

Thanks for any help guys.

 

[CrazyM]

I found this helpful when doing mine..

http://www.dsmtuners.com/forums/showthread.php?t=257587&highlight=MBC+install

In the middle of the 2nd post it tells what to do with the BCS as well.

EDIT: To make sure you have everything hooked up properly, read the diagram in the link. To clear up what to do with the stock one(BCS) you can unplug the hoses from it, but dont disconnect it or you will throw a Check Engine Light

 

[steve]

1G's don't throw DTCs for missing solenoids like 2G do but consider leaving it plugged in and stashed out of the way so that water won't get into the connector and blow up the driver chip on the ECU.

Steve

 

[alancapino]

i'm not sure if this is a MBC vac source problem, but i tapped mine on the BOV line.

i have a crushed 1G BOV, SSAC fmic kit and an EVO3 turbo.

boost (i believe is set at 18psi), 1st gear boost at 10psi, 12psi at 2nd and 18psi at 3rd gear.

i have an 02 dump, so i hear the WG opening at this boost levels. why is this so?

thanks.

 

[Chicken Patty]

The way i've done it on my three DSM's. From the wastegate to appropiate side on the MBC, from the MBC to either the nipple on the housing on the turbo, or the J-pipe. The factory boost control solenoid just make sure its not hooked up to nothing just take the lines out and you can leave it open if i'm not mistaken, if i'm wrong somebody please correct me. Although you have to leave the actual sensor connected if i'm correct. One line from the solenoid does go to a small nipple on the intake pipe after the MAF/MAS. That one just cap it and thats it.

 

[oldman]

i'm not sure if this is a MBC vac source problem, but i tapped mine on the BOV line.

i have a crushed 1G BOV, SSAC fmic kit and an EVO3 turbo.

boost (i believe is set at 18psi), 1st gear boost at 10psi, 12psi at 2nd and 18psi at 3rd gear.

i have an 02 dump, so i hear the WG opening at this boost levels. why is this so?

thanks.

I'm not even going to get into the mess up top, reading some of LSD's post really made my head hurt. I will just answer your questions.

1. DO NOT TAP YOUR BOV LINE FOR YOUR MBC, it should come off your compressor/J-pipe.

2. Sounds like you have boost creep.

3. Your wastegate is opening because your MBC is probably set to 12psi, the reason you're hitting 18 psi in 3rd gear is because of boost creep.

4. Please use proper grammar, punctuation and caps in tech sections.

 

[SexyDSM95]

I'm not even going to get into the mess up top, reading some of LSD's post really made my head hurt. I will just answer your questions.

1. DO NOT TAP YOUR BOV LINE FOR YOUR MBC, it should come off your compressor/J-pipe.

2. Sounds like you have boost creep.

3. Your wastegate is opening because your MBC is probably set to 12psi, the reason you're hitting 18 psi in 3rd gear is because of boost creep.

4. Please use proper grammar, punctuation and caps in tech sections.

Bumping this back up because I have a slight issue...I am currently putting everything back together from a 6 bolt swap in my 2G. I have a FMIC and JMFabrication made my short route piping. I don't have an outlet/nipple coming off my 14B "J-pipe". Am I stuck/screwed into using the BOV as a source?

 

[steve]

I don't have an outlet/nipple coming off my 14B "J-pipe". Am I stuck/screwed into using the BOV as a source?

No your stuck/screwed into tapping the compressor housing or J-Pipe to provide a boost source or connecting to one of the other non-BOV lines on the intake manifold and perhaps suffer from boost spiking due to the long hose.

 

[SexyDSM95]

No your stuck/screwed into tapping the compressor housing or J-Pipe to provide a boost source or connecting to one of the other non-BOV lines on the intake manifold and perhaps suffer from boost spiking due to the long hose.

I will tap. How far up the charge pipe would you recommend? Also, does it matter where I tap as in facing the rear (towards the head), dead center, front (towards the rad)? Thanks for the info.

 

[steve]

I will tap. How far up the charge pipe would you recommend? Also, does it matter where I tap as in facing the rear (towards the head), dead center, front (towards the rad)?

None of this should matter. Pick the easiest place for you to access and that you think will work without leaking. How are you planning to connecting the hose to the pipe?

 

[purpleraingsx]

alright here is the scoop, im kind of new with dsm so bear with me, so me and my friend hooked up a mbc to my 2g gsx right....we unhooked the mbs and so on and hooked up the boost controller though the wastegate and turbo...still with me...took it for a spin turned up the boost control took it on a spin nothing happened psi stayed the same, turned it all the way still nothing psi stayed the same. my friend knows way more about cars than me was stumpped..i need help what can be wrong with it? wastegate probley? i have no clue!! any one with ideas or anwsers email me at [email protected] thanks so much

 

[Maxboost1010]

Could be your MBC, or how you hooked up your MBC, or your wastegate. Thats where I would start based on the problem you described.
Try hooking your MBC like this. http://www.dsmtuners.com/forums/articles-turbo-system-intercooler/237982-best-way-install-mbc.html
Make sure you clamp all 4 parts of the hose, and if you can do a boost leak test after you install the MBC, make sure you are not leaking out the boost from the MBC. What is the max boost you are putting out? Are you having problems with getting past a certain RPM? What turbo are you using? If the psi does not change at all, I would make sure that your boost guage is working correctly, so to find this out just bypass the MBC and everything else by hooking up a vacuum hose straight from the nipple off the turbo/j-pipe directly to the wastegate this will give you base boost the turbo is capable of and will atleast let you see some change in PSI reading. If this shows a change in PSI then see if you can borrow any buddy's simple MBC and see if that fixes your problem, on the other hand if you still do not see a change in PSI then make sure your boost guage is working, and if it is then the next step is to test your wastegate normally tested with a air pressure source, I don't know what turbo you have but if its an ebay knock off they have a problem with the waste gates being stuck but can be fixed pretty easily. But before all that make sure you have a good MBC.

 

[toojung2die]

...took it for a spin turned up the boost control took it on a spin nothing happened psi stayed the same, turned it all the way still nothing psi stayed the same.

Are you still using the stock 2G BOV?
http://www.dsmtuners.com/forums/bolt-tech/175220-wastegate-actuator-2.html#post1470449

 

[purpleraingsx]

my max psi is at 14, my boost gauge is new i just got it the other day everything work i was just getting stressed that the mbc wasnt working ill try to hook it up again. my friend said it might be the wastegate i have the stock t25 how would i test it and see if its working normally? and yes i have the stock bov.

 

[toojung2die]

and yes i have the stock bov.

If you had clicked on the link in my last post you would have read that the stock 2G BOV can't hold the kind of boost you're trying to get. You need to get a 1G BOV or better.