What did I do wrong with the MBC

[montes24]

Today I recieved my MBC and I hooked it up and when I press on the Gas it is not giving me any power 2500rpm pedal to the medal. Here is a video of my setup.....
MBC video by 95gsxguy_2009 - Photobucket
I Spliced from my wastegate hose coming off the intake manifold and attached the MBC now its not giving me any power.. I saw some articles on here but it just got me confused on how to set it up.....

I'm going to eat with my wife so I will be on in a little bit...I know someone knows how to do it so thanks in advance...

 

[montes24]

I am bidding on another MBC slowboy racing one with similar design. Hopefully better product than this one. But This one has the breather hole so can that hole be causing the problem?

 

[toofast82]

That MBC sucks. My buddy was having problems with that exact one. The ball bearing is huge and it barely lets any air get by.

That looks the same as my NXS mbc. It works great on my car as well on many others. I've never read a bad thing about them

 

[montes24]

Its an NXS MBC...recommended by many on this forum but I am going to get another one anyways...but regardless of the MBC something is still wrong with the car.

 

[knochgoon24]

Try setting it up that way.

And build yourself a boost leak tester.

And I really hope you have a boost gauge by now. If so, what are you getting up to?

 

[FenixTX717]

If I am reading this correctly, you aren't able to rev above 2500RPM? If so this sounds like it could be a boost leak.

Oliver
[email protected]

1st, it should not be T'ed off from your BOV line period. 2ndly it looks like the MBC is backwards. Meaning you have the lines the wrong way...I can't exactly tell but just by the way it looks and the design of it, the lines should be the opposite of what you have it now. You also need to loosen your BOV, it sounds way to tight.

 

[Jimmer307]

Try setting it up that way.

And build yourself a boost leak tester.

And I really hope you have a boost gauge by now. If so, what are you getting up to?

+1 This is how mine is setup. BTW: that BOV Flutter your hearing is because your adjustment screw is WAY TOO HARD. If you T it off to where its shown than you will also prevent boost surge.

Montes: And if you were bidding on that Slowboy racing MBC on ebay, Sorry, I bought it... $40 Shipped not bad

 

[DSM4me44]

When I switched from having my MBC Tee'd off the bov line to my j pipe nipple i noticed very little difference. It was better but not life changing. He has already stated at this point that he will switch it in the future but not right now. Changing that will not fix the problem he is having.

Also, the BEST way to eliminate that surging you are hearing is to do a single spring mod on your BOV. Keep the LARGE spring ONLY. Click the link below.

EVO Motorsports - Evo VIII Performance Upgrades and Accessories - Type-S Single Spring Mod

When you reved up your car it sounded kind of odd. Almost sounds as if you have your spark plug wires switched around. What have you disconnected lately besides the vacuum lines?

 

[knochgoon24]

+1 This is how mine is setup. BTW: that BOV Flutter your hearing is because your adjustment screw is WAY TOO HARD. If you T it off to where its shown than you will also prevent boost surge.

Montes: And if you were bidding on that Slowboy racing MBC on ebay, Sorry, I bought it... $40 Shipped not bad

I never hooked my lower nipple up on my car. It was a Ebay Type-S and it either fluttered or leaked, there was no middle ground. I ended up getting an HKS SSQV.

 

[GS ice T]

I don't understand all the fuss about how the mbc is hooked up. I had it teed from the manifold to ebay type-s hose on one car and it worked fine. I had it hooked up from a nipple on the ICP on the compressor exit and it worked fine on my other car. So what's it matter if they both work?

From the manifold to bov line seems more logical to me though, since as soon as the throttle is closed it will vaccuum out the line and slam the WG shut as apposed to the nipple on a jpipe getting a surge of boost when the throttle is closed (depending on the response time of your bov) possibly causing the WG to fling open causing turbo lag when you get back on the throttle. Please let me know if there's a flaw in my logic or something I'm missing.

 

[Jimmer307]

Here is another good diagram of how to instal a MBC if you don't feel like doing anything with that bottom nipple on your BOV...

http://www.dsmtuners.com/forums/articles-turbo-system-intercooler/237982-best-way-install-mbc.html

If you continue having problems with your ride after doing this, i would retrace your footsteps and make sure you didn't mess with anything else.

 

[95GSXCO]

I don't understand all the fuss about how the mbc is hooked up. I had it teed from the manifold to ebay type-s hose on one car and it worked fine. I had it hooked up from a nipple on the ICP on the compressor exit and it worked fine on my other car. So what's it matter if they both work?

From the manifold to bov line seems more logical to me though, since as soon as the throttle is closed it will vaccuum out the line and slam the WG shut as apposed to the nipple on a jpipe getting a surge of boost when the throttle is closed (depending on the response time of your bov) possibly causing the WG to fling open causing turbo lag when you get back on the throttle. Please let me know if there's a flaw in my logic or something I'm missing.

1. Your wastegate is there to control the turbo from over spinning and blowing its self up! Thats it, nothing else.

2. Since your MBC is there to delay the wastegate from opening. You want your MBC hooked up as close to the turbo as you can. This way the MBC is seeing the same PSI as your turbo.

3. Your wastegate is not controlled by vaccum! Its controlled by + pressure hence why you want it hooked up to the turbo or as close as you can get it. If it blows open you need to put more pre load on it.

To the OP!

Take the MBC out and put the car back to how it was before you installed your MBC. See if it revs past 2500 RPM or whatever. If not then stop worrying about the MBC and get that fixed. After your rev problem is fixed then look at the pics that have been posted. If you do not have a nipple on your j pipe go down to your parts store and get somthing like a 1/4 barbed fitting, drill your j pipe and thread the fitting into the j pipe. Take your MBC and install your line off your j pipe to the lower nipple (opp side as the screw). Take the line off your wastegate and install in on the nipple that is T'd off the MBC.

 

[montes24]

Montes: And if you were bidding on that Slowboy racing MBC on ebay, Sorry, I bought it... $40 Shipped not bad

Come on men I always get out bid last minute..Next time I'm not mentioning nothing on here on what I'm bidding...but anyways I bought new hoses and hooked it back up to where I had it before the install..It revved fine. all the way to 7000rpm..I then hooked it back up to where it was and still the same problem.. Only I checked my boost gauage this time and I wasn't getting any pressure but I can hear my BOV is this normal or do I need to try to change the MBC back around and see what it does..Coz according to the diagram I had it setup right..

 

[viperlp01]

I dont know what was going on with my buddys but there was something wrong with it.. It is nuts that you have a problem revving the engine when you simply install a MBC... I mean it really shouldn't effect u that bad unless the MBC was a huge leak..

 

[Jimmer307]

Come on men I always get out bid last minute..Next time I'm not mentioning nothing on here on what I'm bidding...but anyways I bought new hoses and hooked it back up to where I had it before the install..It revved fine. all the way to 7000rpm..I then hooked it back up to where it was and still the same problem.. Only I checked my boost gauage this time and I wasn't getting any pressure but I can hear my BOV is this normal or do I need to try to change the MBC back around and see what it does..Coz according to the diagram I had it setup right..

ha, sorry bro, i honestly didn't even see this thread till after I won the thing... I have had my eye on these 4 a while...

 

[DSM4me44]

I dont know what was going on with my buddys but there was something wrong with it.. It is nuts that you have a problem revving the engine when you simply install a MBC... I mean it really shouldn't effect u that bad unless the MBC was a huge leak..

That is exactly what I am thinking. I have never heard of a MBC install that could cause such a mess....

For the heck of it, try this. Replace your MBC with a T fitting and leave the one end open. Now see what your car does when you rev it.

I knew a guy with a Starion who used vacuum T's to increase his boost.

Let me know what your car does.

 

[montes24]

Ya I will update you guys after when I get my boost guage in but There is a breather hole on the MBC itself I guess its made like that but as far as revving its only at like 2500rpm no higher. I have the video and you can hear that its so different before the install with the MBC refer to the first page and I have video of both befor and after install but I also been getting suggestion on not hooking up to BOV so I dont really know which to follow..I would do both but dont have time to really do it yet. I have 2 jobs so when I get time to work on my car Its really limited. Thats why I try to be detailed with the problems I am trying to solve. And thanks for outbidding me jimmer I forgot I bought the JOEP MBC when i bought the NXS....

 

[GS ice T]

1. Your wastegate is there to control the turbo from over spinning and blowing its self up! Thats it, nothing else.

2. Since your MBC is there to delay the wastegate from opening. You want your MBC hooked up as close to the turbo as you can. This way the MBC is seeing the same PSI as your turbo.

3. Your wastegate is not controlled by vaccum! Its controlled by + pressure hence why you want it hooked up to the turbo or as close as you can get it. If it blows open you need to put more pre load on it.

1. It's also there to control it from overboosting and blowing the motor up as well. The turbo might not necessary go first.

2. With it hooked farther away from the turbo, the pressure downstream will be slightly less than directly post-turbo, so just decrease the load accordingly on the mbc and it should fuction the same at your desired boost level.

3. The wastegate works the exact opposite from the bov. The bov, connected to the manifold, stays shut under boost and uses vaccuum to help open the valve. The wastegate opens under boost and should benefit from a vaccuum source to help close the valve. If the bov, during blow-off, only sees a weak vaccuum then it will flutter. Same should apply to a wastegate only connected to a pressure source, it will stay open until enough pressure is blown off. So if you shift fast enough you lose some boost response because the wastegate will be wide open unless you powershift and never spike the pressure in the intake.

Like I said, I have ran mbc's both ways and both work. So I think the benefits to either method are personal preference really. Once I swap in my motor in the next couple weeks, I'll try both ways again and tee a second boost gauge to the wastegate to see what it actually spikes to during blow-off.

 

[Colt4G63 also]

1. Your wastegate is there to control the turbo from over spinning and blowing its self up! Thats it, nothing else.

2. Since your MBC is there to delay the wastegate from opening. You want your MBC hooked up as close to the turbo as you can. This way the MBC is seeing the same PSI as your turbo.

3. Your wastegate is not controlled by vaccum! Its controlled by + pressure hence why you want it hooked up to the turbo or as close as you can get it. If it blows open you need to put more pre load on it.

To the OP!

Take the MBC out and put the car back to how it was before you installed your MBC. See if it revs past 2500 RPM or whatever. If not then stop worrying about the MBC and get that fixed. After your rev problem is fixed then look at the pics that have been posted. If you do not have a nipple on your j pipe go down to your parts store and get somthing like a 1/4 barbed fitting, drill your j pipe and thread the fitting into the j pipe. Take your MBC and install your line off your j pipe to the lower nipple (opp side as the screw). Take the line off your wastegate and install in on the nipple that is T'd off the MBC.

^^^YAY someone who understands how a turbo, a wastegate, and a BOV work.^^^

I can't understand why anyone would want manifold vacuum to the wastegate, that's just dumb. It would seem that anytime you close the throttle, or drive part throttle, the turbo would build immense pressure in the piping. Hence your surge, and the impending damage to the turbo.

Hook your MBC from a BOOST ONLY source, directly to your wastegate. NOTHING ELSE!

 

[viperlp01]

^^^YAY someone who understands how a turbo, a wastegate, and a BOV work.^^^

I can't understand why anyone would want manifold vacuum to the wastegate, that's just dumb. It would seem that anytime you close the throttle, or drive part throttle, the turbo would build immense pressure in the piping. Hence your surge, and the impending damage to the turbo.

Hook your MBC from a BOOST ONLY source, directly to your wastegate. NOTHING ELSE!

Well the wastegate only sees boost pressure. It NEVER sees vacumm because the ball is stopping it from seeing it... The vacumm is blocked off in the line that goes to the wastegate, there is ZERO pressure in either direction when the ball is close between the MBC and wastegate...

exception^^ There is sometimes pressure in the line when there is no bleeder in a MBC because the pressure gets stuck inside the line..

You are fine T ing off of the BOV line.. I hated using the boost source nipple on my t-25(this is an example). It was so inconsistent. especially from gear to gear.. So i used the manifold pressure that is sent to the BOV which is the exact pin point of what your boost gauge reads from. Now i would suggest you do boost leaks before you take my method. They stated aboce that you can over spin a turbo if the source is to far away from the turbo... The only reason that would happen is if you were loosing boost which is what a boost leak test would find..

quote:

3. The wastegate works the exact opposite from the bov. --The bov, connected to the manifold, stays shut under boost and uses vaccuum to help open the valve. The wastegate opens under boost and should benefit from a vaccuum source to help close the valve. If the bov, during blow-off, only sees a weak vaccuum then it will flutter.-- --Same should apply to a wastegate only connected to a pressure source, it will stay open until enough pressure is blown off. So if you shift fast enough you lose some boost response because the wastegate will be wide open unless you powershift and never spike the pressure in the intake.--

--My greddy type-s flutters when i go into low boost or if i only let off the throttle alittle... Low boost makes it flutter because the pressure in the pipes isn't pushing up on the spring enough to open it all the way and the vacumm isn't pulling up enough on it... Im pushing 20psi so anything over 8 psi it will open... The reason i flutter is because my spring is tight to hold the boost in... The spring is the most important part along with the diaphram ect. but the spring is what holds the BOV shut and then the boost helps the spring.

--The reason you have slow boost response when you shift is soley because you intercooler pipes need to fill back up because your BOV released alot of pressure all at once... Take it that when you did shit you release the throttle which lowered the load on the engine which slowed the exhaust gases making the turbo spool slower but the wastegate really has nothing to do with any of that.. It all has to do with getting the turbo back up to speed because when you shift that ball in the MBC gets slammed close so the wastegate slams closed..

 

[FenixTX717]

I hated using the boost source nipple on my t-25(this is an example). It was so inconsistent. especially from gear to gear.. So i used the manifold pressure that is sent to the BOV which is the exact pin point of what your boost gauge reads from.

I never had a problem with my boost source coming from the t-25. I also put a spring on the outside to help hold the boost since the t-25 pretty much sucks, but the extra spring on the outside help a lot! It was also a cheap easy mod to do

 

[viperlp01]

Ya i mean i guess everyone is different.. I have had several DSM's have problems using that nipple and controlling boost... I guess it is luck of the draw but i think my point is a very valid point

 

[GS ice T]

Yes it is a valid point. That way if there are boost leaks you'll know from the decrease in desired manifold pressure. I never thought about that. So as long as there are no boost leaks either way is still fine. I was trying to think theoretically to be fair to both sides. My setup in progress will be from the ICP nipple though just to minimize hose clutter.

 

[montes24]

Alright so from what I am reading you guys say move my mbc closer to my wastegate. But the hose on there is only 2 feet long if that... Will it really affect my car rpm? I can hear my bov whenever I let off the gas so I am pretty sure It is getting boos. But even with a boost leak I should be able to rev past 3000. So anyways like I said before when I hooked it back to the way it was before the MBC install it was revving fine. I dont know what could be causing the engine to revved only at 2500 rpm when on wide open throttle...

 

[viperlp01]

Its truly a DSM mystery .. It simply should not happen...

 

[DSM4me44]

Its truly a DSM mystery .. It simply should not happen...

I agree. I need to see this car in person to believe it.