Overboost on evo3 big 16g install

[oldman]

You know, I give up and I rarely do. Through out this entire thread, you don't answer questions, in rare cases when you do, your answers lack details that only you understand them, then you go and make your own ASSumptions that makes absolutely no sense. Where did you get information that timing being off will make you overboost and avoid fuel cut?

 

[flosho]

Clear this up for us as your post is kinda confusing, last time when you bypassed the old MBC by connecting the fitting on your J-pipe directly to the wastegate actuator, you got 11-12psi then creeps up a little.

haha.. that is correct. It worked(10-11 psi with a little creep) for an afternoon, then it started to boost higher again.

I'd say this answers your question.

This time after you bypassed the new MBC (which MBC and how is it hooked up in respect to the fittings on the MBC as well as direction of adjustment, some MBCs are reversed), boost shot straight past 15psi without pausing at 11-12psi, is this correct?

I hooked it up directly this after noon and it still boosts too high. I hooked the MBC up and it boost high still, only faster.

I assure you the MBC is installed per instructions here on the forum, and the ones that came with the MBC. I also tested it myself by blowing through the MBC.

You know, I give up and I rarely do. Through out this entire thread, you don't answer questions, in rare cases when you do, your answers lack details that only you understand them, then you go and make your own ASSumptions that makes absolutely no sense. Where did you get information that timing being off will make you overboost and avoid fuel cut?

Not to be an ass. I really do appreciate the help and I have tried to explain everything the best I could and answer every question I can.

Also, I'm thinking the timing may be off, because it has hit 18-20 PSI and there is no fuel cut. Reading through the vfaq, the timing may be retarded/out of time.

I've never said that the timing being off has caused it to over boost. I said, in all this time of overboosting and hitting 17, 18, 20+ PSI and it has never hit fuel cut.

Also...

I am running [x] PSI on my car, but I'm not going fast enough! Is there a fix?
I have my boost set to more than 15 psi, but I'm not getting fuel cut! What's wrong?
I'm running insane boost on my boost controller, but I'm not going fast enough! Is there a fix?

Owners who run high levels of boost to little or no effect on their cars may have their base engine timing set incorrectly. Although the ECU advances the timing as much as possible during operation, it has a limited range. If the timing is pulled back excessively, the ECU may not have enough adjustment to re-set it back into the correct range. Retarded timing leads directly to a loss of power.

The ability to run high boost levels and still go slow appears to be directly related to timing problems - DSMers who have run 18-20 psi with retarded timing suddenly find themselves hitting fuel cut at 14 psi, once their base timing is set properly. They also find their car is faster at 14 psi than it was at 18 psi, a direct result of timing advance. If you boost like crazy but still can't get decent times, check your timing straight away. See here for some info on how to do it.

I'm just going off what the faq says, I do realize that the 97+ models apparently don't have the ability to reset the base timing like the earlier models do.

I've tried to be as thorough as possible, I don't know what is so difficult to understand whats going on.

I installed evoIII.
Autometer vac/boost gauge installed.
I put it down.
It spools up to 20+ PSI
WG hooked directly to pressure nipple(not on j-pipe, on the turbo outlet)
Installed 2 different MBC, same result, uncontrollable boost.
No fuel cut ever.

I know what boost creep is and it is not creeping. It does not hit 9-11psi and then go slowly to 20+ PSI, it simply spools right to 20+ psi if I let it. And I know how to install a boost controller and I understand how these things are supposed to work.

 

[oldman]

1. There is no guarrenteed that you're suppose to hit fuel cut at 20psi, fuel cut is triggered by airflow and airflow is determined by many factors, boost level is only one of them, ambient temperature, your cooling capacity, VE, your exhaust system, bost leaks.....etc. all play a big role in when one should hit fuel cut, I used to creep up to 23+psi on my 16g without hitting fuel cut on my stock motor/cam/IM.

2. There are only two types of overboosting, infinite boost or boost creep. At this point, I'm still not sure which you have. You mentioned that you spool alot quicker with a MBC than without which lead me to think you have boost creep without MBC and infinite boost with MBC.

3. Because of #2, I asked which brand and type of new MBC you have and how it was hooked up, the reason this is important is because ball/spring type MBCs are different from bleeder types (like TurboXS) in both the way it's hooked up as well as the direction of the adjustment knob. Also, homemade or cheap ebay MBCs are known to leak causing infinite boost as you found out with your first MBC. I tried to get this point across but you completely ignored it because your thought process is way ahead of the task and question at hand.

This is the bottom line.

1. If you're 100% sure that when running without the MBC, you're getting infinite boost and not boost creep as you indicated on your first test run without the MBC, the problem is a defective wastegate or, if you have an aftermarket 3" intake pipe, the pipe may be resting on your atuator nipple causing a rip on the vacuum line.

2. If you're getting boost creep w/o MBC and infinite boost with MBC as indicated by different spool time between the two, then the issue is both boost creep and MBC/routing.

The reason this thread has become fraustrating is because this answer was already given to you ealier in the thread but instead of following the same principle and focus on narrowing down the cause, you keep getting distracted and going off tract with your random thoughts when the answer is just a step away. This is a very simple problem to troubleshoot and you're making it complicated.

Jason, you're making this more complicated than it needs to be, test run with the MBC/BCS bypassed. If problem persists, your actuator/wastegate is stuck closed. If problem solved, it's your mbc/bcs.

 

[flosho]

1. There is no guarrenteed that you're suppose to hit fuel cut at 20psi, fuel cut is triggered by airflow and airflow is determined by many factors, boost level is only one of them, ambient temperature, your cooling capacity, VE, your exhaust system, bost leaks.....etc. all play a big role in when one should hit fuel cut, I used to creep up to 23+psi on my 16g without hitting fuel cut on my stock motor/cam/IM.

Thats understandable and was just doing some random searching on the subject.

2. There are only two types of overboosting, infinite boost or boost creep. At this point, I'm still not sure which you have. You mentioned that you spool alot quicker with a MBC than without which lead me to think you have boost creep without MBC and infinite boost with MBC.

I will tell you what I have. Infinite boost. What I said earlier is this: without mbc it has INFINITE boost. With mbc it has INFINITE boost but it seems to spool faster, it may only be in my head though.

3. Because of #2, I asked which brand and type of new MBC you have and how it was hooked up, the reason this is important is because ball/spring type MBCs are different from bleeder types (like TurboXS) in both the way it's hooked up as well as the direction of the adjustment knob. Also, homemade or cheap ebay MBCs are known to leak causing infinite boost as you found out with your first MBC. I tried to get this point across but you completely ignored it because your thought process is way ahead of the task and question at hand.

The mbc is an ebay mbc, voodoo3 or something, one that has been on my other car and worked flawlessly, and does not leak.

This is the bottom line.

1. If you're 100% sure that when running without the MBC, you're getting infinite boost and not boost creep as you indicated on your first test run without the MBC, the problem is a defective wastegate or, if you have an aftermarket 3" intake pipe, the pipe may be resting on your atuator nipple causing a rip on the vacuum line.

That I am sure about, its infinite boost. I have no aftermarket intake pipe and the vacuum hose running to the wg is in good shape, no cuts, crimps or blockage.

2. If you're getting boost creep w/o MBC and infinite boost with MBC as indicated by different spool time between the two, then the issue is both boost creep and MBC/routing.

The reason this thread has become fraustrating is because this answer was already given to you ealier in the thread but instead of following the same principle and focus on narrowing down the cause, you keep getting distracted and going off tract with your random thoughts when the answer is just a step away. This is a very simple problem to troubleshoot and you're making it complicated.

I dont think I made this complicated. I had it hooked up right without the mbc. I was suggested to buy an MBC. I have, installed it per the instructions that came with the mbc and it had no effect on the infinite boost.

It seems pretty clear to me that something is actually wrong with the wastegate itself. It is not user error.

I've been in contact with turbochargers.com tech support, so ill bug them instead of this thread.

 

[oldman]

I had it hooked up right without the mbc. I was suggested to buy an MBC. I have, installed it per the instructions that came with the mbc and it had no effect on the infinite boost.

You were told that abased on your own statement which obviously contradicts your statement now.

, i was just doing some more searching, I ended up going back outside last nite and running the vacuum directly and it solved the over boost problem, it would hit ~12 psi and then creep up a bit towards redline.. but its not out of control..

It seems pretty clear to me that something is actually wrong with the wastegate itself.

Which is exactly the answer that was given right from the begining.

Jason, you're making this more complicated than it needs to be, test run with the MBC/BCS bypassed. If problem persists, your actuator/wastegate is stuck closed. If problem solved, it's your mbc/bcs. If you suspect the turbo fitting was not tapped all the way through, blow into the vacuum line connected to it.

I've been in contact with turbochargers.com tech support, so ill bug them instead of this thread.

I don't know what else is ther to bug them about, the question has been answered but you go right ahead and do that.

 

[romeen]

Jason, try doing a boost leak test from the compressor inlet of the turbo. Run a line from the boost source directly to the WGA. No mbc. Look for two things in particular:

1) Check to see at what pressure the WGA begins to open the flapper. Do this a few times and make sure the lever arm begins to move at the same pressure each time.

2) Make sure that you are not leaking where the hose connects to the nipple on the WGA. The o.d. of that nipple is 5mm. It sounds like you tapped a nipple into the compressor housing. I don't know what size fitting you used but more than likely it is larger than the WGA nipple. Unless you are using an inline reducer it is possible to not be getting a good seal at the WGA end. This will in effect act like a bleeder type mbc and may account for the inconsistent boost control. I'm not saying that this is likely but it is possible.


If you don't already have a boost leak tester then I highly suggest you make one. It will prove invaluable as for as long as you own a turbocharged car. I highly suggest the one with a pressure guage attached. It makes things much easier. Some recommend using the car's aftermarket boost guage since it is reading pressure directly off of the manifold and replicates actual driving conditions more closely. But if you have both you can use the attached guage for convenience and still reference your regular guage when needed depending on the task at hand.

Let us know what you find.