o2 housing and boost problems

[LTUDSM]

my question is:
i have a leak between turbo and o2 housings,cause there is 4 bolts and one of them is broken so that means that half bolt is stock into the turbine housing (the top bolt) and now i can't go over 10 PSI ,i bought new Hallman boost controler cuse i thought that my old boost controler passed out,but no same thing,then i tryed to run the vac line grom turbo nipple stright to wastegate,but nuttin same thing 10 psi no more,Would that Turbo and o2 housing leak would be the problem of not going more than 10 psi???? thanks alot

 

[kenamond]

my question is:
i have a leak between turbo and o2 housings,cause there is 4 bolts and one of them is broken so that means that half bolt is stock into the turbine housing (the top bolt) and now i can't go over 10 PSI ,i bought new Hallman boost controler cuse i thought that my old boost controler passed out,but no same thing,then i tryed to run the vac line grom turbo nipple stright to wastegate,but nuttin same thing 10 psi no more,Would that Turbo and o2 housing leak would be the problem of not going more than 10 psi???? thanks alot

I don't see how a leak there would limit your boost. I'm not sure what the stock WGA actuation pressure is for the 1g, but the 2g will give you about 10psi. Might double-check that your MBC is properly connected.

 

[LTUDSM]

it is conected right way,maybe my wastegate actuator arm went out??!!,cause some guy did the adjustable actuator arm,he made threads,made like 5 inch long nut and extended my actuator arm,why he did that cause my wastegate flapper wouldn't open all the way up does the wastegate has to do something with my problem?

 

[boostnhard]

I would say its not closing cause of that mod they did to the arm. im preetty sure thats your problem

 

[DSMDirkah]

By modifying the wastegate arm in that manner, you are increasing the base spring pressure rate. So in turn, the tighter you adjust the arm, the more boost you get because the spring rate in the wastegate is higher. The Flap will open all the way but, it might take more pressure to do so. I like adjusting the boost this way because it still gives the ECU a fighting chance to pull boost if it sees too much knock.

 

[kenamond]

By modifying the wastegate arm in that manner, you are increasing the base spring pressure rate. So in turn, the tighter you adjust the arm, the more boost you get because the spring rate in the wastegate is higher. The Flap will open all the way but, it might take more pressure to do so. I like adjusting the boost this way because it still gives the ECU a fighting chance to pull boost if it sees too much knock.

WTF

The ECU doesn't have any control over boost except fuel cut (which is based on too much air flow and is a safety measure agains WGA failure). If it senses knock, it retards the timing. The only thing that controls boost is the MBC/EBC/BCS and the WGA which aren't connected to the ECU.

As for the OP, the WGA has to hold the WG flapper inside the housing closed while you're building boost. When the boost starts to get close to the desired level, the WGA starts opening the WG flapper. Many WGAs don't have enough throw to open the flapper the full 90* that the flapper arm is capable of opening - 45* is typical - but if you increase the effective length of the flapper, it may be either holding the flapper open at low boost or not holding it closed hard enough to withstand the backpressure in the upwind end of the turbine housing. Make sure the WG is being held shut.

If the turbo was creeping or something, and this led to the WGA tinkering, maybe you need to adjust the actuator arm back a bit (shorten it).

 

[Eastwood95]

ditto, double check your MBC hook up and WGA. I've seen many cars run 10psi when the MBC wasnt hooked up correctly or the WGA wasn't working properly.

 

[LTUDSM]

well i tryed to connect my MBC two ways (switching vac lines) but still same thing ( my flapper have an access to open all the way up (90 degrees),so if ill try to shorten the actuators arm then the flapper wouldn't open all the way up.but yeaah ill try to work on it tomorrow,and see whats gonna happen.Today i went to the shop where the guys did my wastegate job,and they told me to leave the car and we will check it out,so i was like ok no prob,today they called me and said that its gonna cost 210$ to fix the problem,and then i almoust wanted to pounch those as***les for telling me that,they should fix that for no cost at all cause i think they messed up something,and after that i asked them what is wrong with my wastegate cause i don't want to spend money on you carappy job that you did twice,but they didn't told me WTF so now i need to slove the problem by my self

 

[kenamond]

First of all, what model of Hallman MBC do you own? Someone will be able to tell you exactly how to hook it up if they know that. They'll also be able to tell you how to turn the boost up and down.

Secondly, if the MBC is turned all the way down, you won't be able to boost past about 10psi even if it's hooked up correctly. Find out the correct way to hook it up and make sure it's hooked up that way. Then start turning up the boost setting, doing a test run, then turning it up more. Eventually, it should start to raise the boost past 10psi. You can do this sort of test while "brake boosting" in a lower gear (I used 2nd gear); hold the brakes just enough to be able to keep your car from speeding up too fast with the pedal to the metal. If you use a lower gear, you can do this in a 35mph zone without worrying about a speeding ticket. Watch your boost gauge and rpm. You should hit full boost by around 4k rpm, but it can be higher. You don't want to go too high for now. All you want to do is see if you can raise the boost up to maybe 13psi. Once you figure out what rpm your turbo hits full boost, you can use the brakes to keep the car at that rpm for a second or two. The boost may "spike" to a higher boost pressure and then settle back down. You want to know what boost pressure it settles to, not what it spikes to. So get the car to the right rpm, floor it and add brakes to hold it there, and watch the boost gauge. If it goes up past 15 (not the spike, but what it settles on), let off. If it's too high, pull over and turn down the MBC a bit and repeat. It only takes 4 or 5 tries to get it where you want it.

Anyway, start by posting the type of MBC you have, and we can go from there.

 

[LTUDSM]

i got Hallman PRO RX Boost Controller

 

[GVR4592]

WTF

The ECU doesn't have any control over boost except fuel cut (which is based on too much air flow and is a safety measure agains WGA failure). If it senses knock, it retards the timing. The only thing that controls boost is the MBC/EBC/BCS and the WGA which aren't connected to the ECU.

The ecu does have control over boost. What do you think the boost control solenoid is for? If the ecu detects knock, it lowers boost, pulls timing, AND adds fuel.

I don't understand what you mean by the ecu having control over boost for fuel cut.

 

[kenamond]

The ecu does have control over boost. What do you think the boost control solenoid is for? If the ecu detects knock, it lowers boost, pulls timing, AND adds fuel.

I don't understand what you mean by the ecu having control over boost for fuel cut.

I disagree.

The ECU doesn't adjust the boost. The BCS is just a bleeder-style boost controller which drains boost pressure so that the WGA gets its 8-or-so psi when boost is actually at 11-12psi. There is no way to adjust the BCS unless you pull the restrictor out (so it bleeds more and requires more boost to pass 8psi to the WGA), but the ECU obviously doesn't do that.

The compressor generates boost, this pressure signal controls the WGA via the BCS or MBC or EBC which controls the "openness" of the flapper in the turbine housing. I have an MBC which isn't connected to the ECU, the WGA isn't connected to the ECU, etc., so the ECU can't change the behavior of these components.

The ECU does have the "fuel cut" safety net, but the purpose of that is to guard against a WGA failure which results in the flapper being locked shut (which would most likely lead to unsafe boost levels and engine damage). But it does this when the air flow rate exceeds a pre-determined value. Then it cuts spark and the injectors. But I wouldn't equate complete engine shutdown to boost control by the ECU.

I'm not trying to be an ass. I honestly don't see how the ECU can possibly control boost. Also, if I'm wrong PLEASE explain why so that I learn something.

 

[kenamond]

i got Hallman PRO RX Boost Controller

I couldn't find a thread describing which vaccuum line goes where, but I'm pretty sure I can guess based on a picture I saw of this MBC.

The nipple that sticks out the bottom is where you connect your vaccuum line from your compressor housing - it's the inlet to the MBC.

The nipple that sticks out of the side is where you connect your vaccuum line from the WGA nipple - it's the outlet from the MBC.

The knob is basically lefty-loosey and righty-tighty where tighter (clockwise) is more boost, and looser (counterclockwise) is less boost.

You should be able to loosen the knob all the way (without the thing popping apart) and blow into the bottom nipple and have the air leak out fairly easily from the side nipple.

As you tighten it and repeat the test, it should get harder and harder to blow air through the bottom nipple.

I'd start out tightening it a turn or two from the weakest setting, installing it, then brake-boosting to see where your boost settles. It may start out at around 9 or so psi boost, and that's just because the WGA can't go lower than that. Make half-turn adjustments, not 3 or 4 turns. Repeat the test until the boost starts to go beyond 10psi.

Another thing worth mentioning is that the EX comes with two springs to choose from. One is a lighter spring which can only raise your boost about 5psi above the WGA actuation pressure (that would be a max of around 13 or so psi). The heavier spring will take you well into the 20s. If you have two springs, you could pull the one out of the MBC and see if it's the heavy or light spring. The heavy spring is much more sensitive than the light spring, so one turn on the heavy spring might give you 1 or 2 psi more boost.

Anyway, try it out and see if it's the MBC. If you end up tightening the MBC all the way and still see 10psi, let us know.

 

[GVR4592]

The ecu sends a pulsed signal to the BCS that raises boost above wastegate pressure. When knock is detected it slows the pulse so the solenoid won't bleed as much pressure and the wastegate actuator will open the wastegate sooner. Boost can be controlled with the stock BCS if you can manipulate the table in the stock ecu. Evo guys are doing it with ECUflash.

 

[oldman]

LTUDSM, go for a test run with the actuator fitting open (no vacuum lines), this should result in infinite boost so careful not to let it skyrocket, this purpose is to see if you can boost past 10psi. If you can, the problem is your mbc/routing. If you can't, the problem is wastgate/turbo. This is assuming you have already done your leak test.

kenamond, you're correct that "fuel cut" is a way for ECU to control boost (preventing infinite boost) by cutting fuel. However, it shouldn't be too hard to apply the same logic to "knock/pulling timing/flooding" as a way for ECU to control boost (preventing fuel starvation) by not spooling the turbo. Also, ECU does lower boost via bcs with high knock count, isn't an issue here since the OP has an MBC.

 

[LTUDSM]

I couldn't find a thread describing which vaccuum line goes where, but I'm pretty sure I can guess based on a picture I saw of this MBC.

The nipple that sticks out the bottom is where you connect your vaccuum line from your compressor housing - it's the inlet to the MBC.

The nipple that sticks out of the side is where you connect your vaccuum line from the WGA nipple - it's the outlet from the MBC.

The knob is basically lefty-loosey and righty-tighty where tighter (clockwise) is more boost, and looser (counterclockwise) is less boost.

You should be able to loosen the knob all the way (without the thing popping apart) and blow into the bottom nipple and have the air leak out fairly easily from the side nipple.

As you tighten it and repeat the test, it should get harder and harder to blow air through the bottom nipple.

I'd start out tightening it a turn or two from the weakest setting, installing it, then brake-boosting to see where your boost settles. It may start out at around 9 or so psi boost, and that's just because the WGA can't go lower than that. Make half-turn adjustments, not 3 or 4 turns. Repeat the test until the boost starts to go beyond 10psi.

Another thing worth mentioning is that the EX comes with two springs to choose from. One is a lighter spring which can only raise your boost about 5psi above the WGA actuation pressure (that would be a max of around 13 or so psi). The heavier spring will take you well into the 20s. If you have two springs, you could pull the one out of the MBC and see if it's the heavy or light spring. The heavy spring is much more sensitive than the light spring, so one turn on the heavy spring might give you 1 or 2 psi more boost.

Anyway, try it out and see if it's the MBC. If you end up tightening the MBC all the way and still see 10psi, let us know.

i know bout boost controlers alot im not a newb into that,i have a huge experence on them evan manual or electronic boost controlers,so boost controller doesn't have anything to do with that,

TO Oldman
UMM i did that what you told me i ran wastegate with no vac lines on it,and guess what i ran crazy man haha i wish i have a suport mods for 30 PSI )) so i ended up that my wastegate actuator isn't working good,so i think i would changes my internal to external right now,what do you guys think?? would it be worth,or just get a new Internal wastegate atuator?

 

[oldman]

TO Oldman
UMM i did that what you told me i ran wastegate with no vac lines on it,and guess what i ran crazy man haha i wish i have a suport mods for 30 PSI )) so i ended up that my wastegate actuator isn't working good,so i think i would changes my internal to external right now,what do you guys think?? would it be worth,or just get a new Internal wastegate atuator?

Didn't I tell you to expect all out boost and prepare to let off the throttle?

Your test result shows that it's not your wastegate, turbo, boost leaks or exhaust leaks, it's either your mbc or the hook up of it. You're running 10psi only because you're constantly supplying full pressure signal to the wastegate as if the mbc isn't there at all. Which mbc and how is it hooked?

LTUDSM, go for a test run with the actuator fitting open (no vacuum lines), this should result in infinite boost so careful not to let it skyrocket, this purpose is to see if you can boost past 10psi. If you can, the problem is your mbc/routing. If you can't, the problem is wastgate/turbo. This is assuming you have already done your leak test.

 

[LTUDSM]

Didn't I tell you to expect all out boost and prepare to let off the throttle?

Your test result shows that it's not your wastegate, turbo, boost leaks or exhaust leaks, it's either your mbc or the hook up of it. You're running 10psi only because you're constantly supplying full pressure signal to the wastegate as if the mbc isn't there at all. Which mbc and how is it hooked?

i got Hallman PRO RX Boost Controller,and its hoocked up like that : from the bottom niple to turbo's J pipe nipple,and side nipple is coneccted to WGA
did a boost leak test and at 41 Psi i had a lilttle leak from TB

 

[oldman]

i got Hallman PRO RX Boost Controller,and its hoocked up like that : from the bottom niple to turbo's J pipe nipple,and side nipple is coneccted to WGA

Are you using the light weight spring/ceremic ball? Turn your mbc all the way in, apply pressure in small increments to the inlet, report back at what psi does air flow out of the outlet.

did a boost leak test and at 41 Psi i had a lilttle leak from TB

I'm assuming, as well as hoping, 41 psi was on the regulator gauge, not boost gauge unless you own a 0-60psi boost gauge. When people talk about psi in context of a boost leak test, they're talking about your boost gauge readings.

 

[kenamond]

Sounds like you haven't turned up the MBC enough. I outlined a set of instructions for doing this, but you just replied that you knew what you were doing, but then go on to say that you think your WGA is bad, which doesn't seem to be the case. Try cranking your MBC all the way tight (like oldman suggested) and do a test run to see if you get rediculously high boost (like when you left the vac line off the WGA), but let off the gas if you hit past 15. If you hit 15+psi on that test, you just don't have your MBC set properly, but everything is functioning properly.

Oldman and GVR4592. Thanks for the correction on the BCS. I still don't quite agree that pulling timing or adding fuel is a boost controller. The ECU adds fuel based on a fuel vs. mass airflow vs. rpm map, right? And it has a similar map for timing advance. The front O2 sensor is used to correct for a lean condition and fuel trims to remember from past experience, and the knock sensor is used to retard timing. But boost is dictated by exhaust backpressure, the turbo, WGA, and the MBC - if you don't change any of those, you can't change boost. I assume that the ECU could do things to the motor to decrease exhaust backpressure, but is that what you're saying? I just don't see any evidence that the ECU controls boost other than fuel cut (and the BCS if you have it). What am I missing?

 

[LTUDSM]

i turned my boost controler all the way up and i can't pass over 10 psi,the only reason i can think of right now it maight be that i bought defective boost controller,im gonna try tomorrow with other boost controller and post the results

 

[GVR4592]

Oldman and GVR4592. Thanks for the correction on the BCS. I still don't quite agree that pulling timing or adding fuel is a boost controller. The ECU adds fuel based on a fuel vs. mass airflow vs. rpm map, right? And it has a similar map for timing advance. The front O2 sensor is used to correct for a lean condition and fuel trims to remember from past experience, and the knock sensor is used to retard timing. But boost is dictated by exhaust backpressure, the turbo, WGA, and the MBC - if you don't change any of those, you can't change boost. I assume that the ECU could do things to the motor to decrease exhaust backpressure, but is that what you're saying? I just don't see any evidence that the ECU controls boost other than fuel cut (and the BCS if you have it). What am I missing?

I never said that pulling timing or adding fuel was a boost controller. I said the ecu pulses the bcs to lower boost, and at the same time pulls timing. This strategy is used to prevent knock from occuring.

The front 02 isn't for correcting lean condition's, it for maintaining a stoichiometric A/F ratio in closed loop.

You're somewhat correct about boost being dictated by backpressure, turbo, wastegate spring pressure, and the boost controller, but it doesn't have to be a mbc, the bcs can do the same thing.

You know how a manual boost controller works, apply the same principles to the bcs and the ecu. The ecu pulses the BCS, allowing boost to be vented. When the boost is vented the full amount doesn't reach the WGA and the boost pessure increases. When knock occurs, the ecu stops pulsing the bcs, the full amount of boost reaches the WGA. The WGA opens the flapper at 9 psi, instead of the ecu's preset level of 12 psi. The ecu then pulls timing, and in some cases add's fuel.