MBC install... no good

[screwdgie]

Well i installed my mbc from dejonpowerhouse.com tonight. I followed the directions they gave me, and no matter how far i back the adjusting screw out, I cannot keep my boost near stock levels.

The only part i am not sure about in the install is the wastegate actuator connection. In this pic, http://www.dsmtuners.com/forums/attachment.php?attachmentid=46910&d=1108474460, there is a straight line going from the mbc to the actuator. Well my car stock has a t-fitting in between the mbc and actuator.?

If there is anyone with the dejon mbc, and followed the directions they give you with it, please help me out here. Its driving me crazy.

 

[JCMDSM]

Try attaching the boost source line to the nipple on the J- Pipe rather than on the bov. Then feed the other line to the wastegate. Hope that helps---Jon

 

[Quasimondo]

1. Leave the hose between the intake and the blow-off valve alone. If you've already installed the T-fitting there, cap it off.
2. Remove the lines from the wastegate, the compressor outlet valve, and the air can.
3. Cap the nipple at the aircan.
4. Run a line from the compressor outlet to the bottom of the MBC.
5. Run a line from the top of the mbc to wastegate.

When done it should look like this:

Compressor outlet -->bottom of MBC
Top of MBC --> Wastegate.

 

[K_Hill]

Here is the page I used when I installed my MBC. Just follow all the instructions and it should work.

http://www.plymouthlaser.com/joep.htm

 

[screwdgie]

Well I switched it from the bov line to the compressor elbow, and it seems to help. My spool is much slower yet it will still boost alot. I will try what quasimondo said tomorrow. I am also thinking that i am getting some nice boost creep too, because I am running an open downpipe at the moment. Old exhaust broke Have everything i need, just waiting on a damn o2 housing gasket .

Thanks for the help everyone. I think everything will be fine once i get my exhaust back on.

 

[screwdgie]

Well I tried doing that today, and still no good. Turbo spools slower, but will still boost past 15 easy. I need to keep it as low as possible for a while because im maxin out my injectors and maf. Plus i need my clutch to last as long as possible.

I am really hoping it is just boost creep b/c of the open downpipe. I hope to get my exhaust put back on this weekend tho. full turbo back finally

 

[Lordpaxin]

going from turbo back full system, to dP shouldnt create any noticeable amount of boost creep if you already had an after market setup.

Considering your turbo Now spools slower, WHO wants that?
Ive always sourced my Boost Controllers with a T at the BOV. is this wrong now? a while back it was the thing to do, .

seems like your turbo is spooling slower now, because since you are directly hitting the Wastegate from the compressor outlet the wastegate is opening up sooner, partially allowing some of that boost building exhaust to slip out. (this is good?)

Ive been out of the loop for a year or so now, Am i losing it?

Are you switching from one MBC to this Dejon one?
your profile stated you were running 15psi, yet you are just now installing a MBC?

When I had my 1g with KN filter and otherwise stock, it would run about 13-14psi with the bcs restrictor removed, simply installing the RNR 3inch system, made it creep to 17+ psi and fuel cut.

i installed a 190 and turbosmart mbc, and got boost to hold right around 15.5 - 16psi but at top RPM it would still creep

small turbo's + big exhaust = creep!

hopefully what im saying makes scense, it sure doesnt to me, I just came in off midnights at toyota engine plant, and im exhausted and tired and half coherant. mabye reading this post i completley misunderstood it, and answered the wrong things? I dunno, I appologize in advance for the meanderings of a lost mind.........

 

[ECLIPSEGST25]

LOOK AT THIS http://www.turboxs.com/faq/tyrboxsstd.htm THE SILVER NIPPLE GOES ON THE INTERCOOLER PIPE OR THE TURBO NIPLE AND THE BLUE NIPPLE GOES ON THE WASTEGATE NIPPLE. YOUR MBC MIGHT LOOK DIFFERENT BUT THEY ARE THE SAME SHAPE SO JUST MATCH IT UP. DON'T USE THE BOV IT SUCKS. IF IT DOESN'T WORK IT COULD BE THAT YOU MBC IS MESSED UP.

 

[Quasimondo]

The only other reasons I could think of that you would have a slow spoolup is either from a bad wastegate flapper that could be craked and be partially open, or your boost controller in't a ball-and-spring unit. I had the same slow boost response when I used a turbonetic mbc, and when I switched over to a hallman, the difference was very noticeable.

Does anybody know if the dejonpowerhouse mbc is a bleeder type or if it's a ball-and-spring unit?

 

[robs90tsi]

1. Leave the hose between the intake and the blow-off valve alone. If you've already installed the T-fitting there, cap it off.
2. Remove the lines from the wastegate, the compressor outlet valve, and the air can.
3. Cap the nipple at the aircan.
4. Run a line from the compressor outlet to the bottom of the MBC.
5. Run a line from the top of the mbc to wastegate.

When done it should look like this:

Compressor outlet -->bottom of MBC
Top of MBC --> Wastegate.

This is a preferred method????? Not hacking your thread, is this setup more reliable??

 

[Quasimondo]

This is a preferred method????? Not hacking your thread, is this setup more reliable??

I'm on this setup right now. It holds 17 psi with no problem. I really don't see why people wouldn't set it up this way unless they have an aftermarket compressor outlet pipe without that nipple.

 

[Dream On]

If I read it right, you still have it hooked up to the stock BCS at that T. I would take it off and run it directly into the MBC and see what that does, and unplug the BCS.

 

[robs90tsi]

good to know, thanks

 

[oldman]

This is a preferred method????? Not hacking your thread, is this setup more reliable??

Indeed it is, this is what I posted on another thread the other day.

Taking the pressure source from the j-pipe fitting has many benefits.

1. The main reason why alot of mbc instructions and some tech articles suggests to tap from the BOV line is because it's connected to the intake manifold, the argument is that this is more accurate because it's the same pressure the engine sees. In reality this is a non issue because the boost gauge is tap to the intake manifold no matter where you tap your mbc so there is no advantage in tapping the bov/manifold pressure as previously thought.

2. The proper functioning (opening and closing) of the bov depends greatly on the accuracy of the pressure in the vacuum hose you're thinking of tapping on or off boost so it's best to leave it connected directly to the manifold without any interference.

3. Tapping off the compressor/j-pipe offers the shortest vacuum hose route which greatly reduces the chance of boost spike.

4. In the case of boost leaks, tapping off the compressor/j-pipe will help prevent over boosting the turbo.

5. Hooking up a bleeder type mbc like the TurboXS standard mbc to the bov line will result in a vacuum leak as well as affect the working of the BOV.

I think the reason the original poster thinks spool is slower now is probably because on the previous setup from the BOV line, the mbc outlet was connected to the T (I suspect along with the bcs) instead of directly to the wastegate actuator resulting in all out boost. After hooking up the mbc as suggested by Quasimondo, you solved your all out boost but encountered boost creep instead, we all know how slow spool can seem during boost creep comparing to out of control boost.

screwdgie, Are you hitting 10-12psi fairly quickly, pause and then slowly creeps up as rpm increases?

 

[oldman]

Another possiblity is that you have massive boost leaks, tapping off the bov line resulted in quicker spool and higher boost level due to the delay of pressure reaching the actuator because of boost leaks. If this turned out to be the case, it would be a perfect example of #4. The problem isn't the compressor source reaching the actuator too quickly, that is exactly what you need for precise boost control, the problem is the BOV line source reaching the actuator too late making the turbo work over time to maintain your desired pressure while a portion is leaked out to the atmosphere. This brings us to this question by Lordpaxin,

seems like your turbo is spooling slower now, because since you are directly hitting the Wastegate from the compressor outlet the wastegate is opening up sooner, partially allowing some of that boost building exhaust to slip out. (this is good?)

There shouldn't be a significant difference in spool and pressure level between BOV line and compressor/j-pipe, when the difference is significant, usually it's an indication of other issues. In the above example, the issue is boost leak, tapping off the compressor help revealed the problem before you realize your fuel economy has gone to shit and your turbo has taken a dump, so I would say it's a good thing.

 

[screwdgie]

My profile says i was running 15 psi before. This was with 3" cat, catback, k&n, hacked mas, uicp, intake pipe, 2gmani, and bcs restrictor removed, and no mbc. It ran fine, it would creep every once and a while, but rarely. The reason for me getting a boost controller was because I logged the car, and it appears i am overrunning the mas and my injector duty cycle was reaching 117-118%. So i figured if i turned my boost down till i get injectors, I would be fine.

Oldman- The turbo spools about as fast as stock, it doesnt stop at 10-12 psi, it just keeps going till 15-16+, I have to let off before it gets any higher.

To whoever asked- The dejon mbc is a ball and spring. should i try a bleeder type? I really dont have money to throw around at all different parts right now.

Thanks for the help guys.

- Would having my bcs connected or disconnected make any difference for me?

 

[Quasimondo]

My profile says i was running 15 psi before. This was with 3" cat, catback, k&n, hacked mas, uicp, intake pipe, 2gmani, and bcs restrictor removed, and no mbc. It ran fine, it would creep every once and a while, but rarely. The reason for me getting a boost controller was because I logged the car, and it appears i am overrunning the mas and my injector duty cycle was reaching 117-118%. So i figured if i turned my boost down till i get injectors, I would be fine.

Oldman- The turbo spools about as fast as stock, it doesnt stop at 10-12 psi, it just keeps going till 15-16+, I have to let off before it gets any higher.

To whoever asked- The dejon mbc is a ball and spring. should i try a bleeder type? I really dont have money to throw around at all different parts right now.

Thanks for the help guys.

- Would having my bcs connected or disconnected make any difference for me?

If it's a ball-and-spring manual boost controller, keep it. The bleeder type mbc's are worthless. If you're using a mbc, there's no need to have any vacum lines running to your bcs.

 

[screwdgie]

ok Well i disconnected the bcs, although I still have a line running to the t-fitting at the wastegate. It works much better now. Boosts to about 12 psi, then creeps to about 15. I am going to totally get rid of the pos bcs, but its raining out, and Im lazy.

I love how the directions dejon gave me said to keep the bcs connected, When that was the problem was the whole time .

Thanks for all the help everyone.

 

[oldman]

Definitely leave the BCS out, if Dejon's instruction indicates to hook both up in series then the instruction is wrong. I kinda suspected the BCS was still hooked up after reading about the T fitting on the wastegate line, glad you got it worked out.

The reason for me getting a boost controller was because I logged the car, and it appears i am overrunning the mas and my injector duty cycle was reaching 117-118%. So i figured if i turned my boost down till i get injectors, I would be fine.

My money is on boost leaks, probably the only way you can overrun the MAF at the same time reaching 118% IDC besides a defective MAF possibly caused by hacking at 15psi. I strongly suggest performing a boost leak test.

 

[screwdgie]

Yea I plan on doing a boost leak test and a compression test too. No point in modding more if the motor isn't up to specs.

I also ran 2 logs today with the lower boost. I have virtually no knock up until i start creeping, then the knock comes on. Also, my IDC is lower. It reached 101% once. So I am headed in the right direction.

Hopefully after I get my exhaust back together, and any possible boost leaks fixed, I should be in better shape.