Boost problem
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From: North Beach, MD
Boost problem
I'm currently running the Hallman Pro RX MBC. It's been working great for me until now. Just recently I noticed I was currently hitting 18psi when I normally run 21psi. I had tweaked it a bit due to the constant changes in temps. here in Reno (one day it'll be 72 the next 46...). So I went to go adjust it recently and noticed the knob wouldn't turn anymore. Its completely at its max and I'm only running 18psi (4th gear pulls). I did install the hard spring when I 1st bought it and it was fine until recently.
I removed the MBC took the ball and spring out and everything was fine. I turned it down in case I somehow fixed the problem and it seemed to be working fine and I was hitting 20psi. Now its starting to do it again. I'm wondering if maybe the ball is getting stuck or something like that. Anyone have this happen or have any ideas? Maybe go to the hardware store and get a stiffer spring?
I removed the MBC took the ball and spring out and everything was fine. I turned it down in case I somehow fixed the problem and it seemed to be working fine and I was hitting 20psi. Now its starting to do it again. I'm wondering if maybe the ball is getting stuck or something like that. Anyone have this happen or have any ideas? Maybe go to the hardware store and get a stiffer spring?
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From: Reno, NV
Hey man, yeah remember I was having the same problem with my MBC? Turned out it was the stupid ball getting stuck and not able to move freely enough in the holder. I used just alittle bit of vaseline on the ball and havent had the issue since. Lets see what others here say.
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Hey man, yeah remember I was having the same problem with my MBC? Turned out it was the stupid ball getting stuck and not able to move freely enough in the holder. I used just alittle bit of vaseline on the ball and havent had the issue since. Lets see what others here say.
jk. Anyone else have any other suggestions before I tear into it tomorrow?
This is just a thought: Now, supposing that your MBC is functioning properly and that you have it hooked up correctly, then you might try raising the wastegate preload, especially if it's lower than 13 PSI or at base wastegate pressure(11 PSI).
It's been my experience that MBC's have a particular, limited range of operation. For example, let's say that range is 10 PSI. This means that if your turbo is set up at the normal Evo 16G base wastegate pressure of 11 PSI, then your MBC will control boost from 11 PSI on up to 21 PSI.
If you add 4# of preload on top of the 11PSI base WG pressure, then your MBC will control boost from 15 PSI on up to about 25 PSI. Does this make any sense to you? It's worth a try anyway.
It's been my experience that MBC's have a particular, limited range of operation. For example, let's say that range is 10 PSI. This means that if your turbo is set up at the normal Evo 16G base wastegate pressure of 11 PSI, then your MBC will control boost from 11 PSI on up to 21 PSI.
If you add 4# of preload on top of the 11PSI base WG pressure, then your MBC will control boost from 15 PSI on up to about 25 PSI. Does this make any sense to you? It's worth a try anyway.
Last edited by sparky; Apr 17, 2008 at 09:09 PM.
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From: North Beach, MD
This is just a thought: Now, supposing that your MBC is functioning properly and that you have it hooked up correctly, then you might try raising the wastegate preload, especially if it's lower than 13 PSI or at base wastegate pressure(11 PSI).
It's been my experience that MBC's have a particular, limited range of operation. For example, let's say that range is 10 PSI. This means that if your turbo is set up at the normal Evo 16G base wastegate pressure of 11 PSI, then your MBC will control boost from 11 PSI on up to 21 PSI.
If you add 4# of preload on top of the 11PSI base WG pressure, then your MBC will control boost from 15 PSI on up to about 25 PSI. Does this make any sense to you? It's worth a try anyway.
It's been my experience that MBC's have a particular, limited range of operation. For example, let's say that range is 10 PSI. This means that if your turbo is set up at the normal Evo 16G base wastegate pressure of 11 PSI, then your MBC will control boost from 11 PSI on up to 21 PSI.
If you add 4# of preload on top of the 11PSI base WG pressure, then your MBC will control boost from 15 PSI on up to about 25 PSI. Does this make any sense to you? It's worth a try anyway.
An easy, shortcut method of seeing how much preload, if any your WG has, is to turn the MBC adjustment knob out all the way, counterclockwise, to its absolute softest, lowest boost setting and then doing a WOT run in 4th.
This is easier than the "correct" method of hooking a section of 4mm hose directly from the compressor outlet nipple to the WGA port. I think that you'll find that your WG spring pressure is set somewhere between 11-13 PSI.
This is a soft , flabby setting that results in slow turbo spoolup. I have found that you get better spoolup and better control of boost as well by running as much preload as possible and thus limiting the MBC's effective operating range to a more reduced window. This is preferable to a low preload setting with the resultant wide MBC operating range.
This is easier than the "correct" method of hooking a section of 4mm hose directly from the compressor outlet nipple to the WGA port. I think that you'll find that your WG spring pressure is set somewhere between 11-13 PSI.
This is a soft , flabby setting that results in slow turbo spoolup. I have found that you get better spoolup and better control of boost as well by running as much preload as possible and thus limiting the MBC's effective operating range to a more reduced window. This is preferable to a low preload setting with the resultant wide MBC operating range.
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From: North Beach, MD
An easy, shortcut method of seeing how much preload, if any your WG has, is to turn the MBC adjustment knob out all the way, counterclockwise, to its absolute softest, lowest boost setting and then doing a WOT run in 4th.
This is easier than the "correct" method of hooking a section of 4mm hose directly from the compressor outlet nipple to the WGA port. I think that you'll find that your WG spring pressure is set somewhere between 11-13 PSI.
This is a soft , flabby setting that results in slow turbo spoolup. I have found that you get better spoolup and better control of boost as well by running as much preload as possible and thus limiting the MBC's effective operating range to a more reduced window. This is preferable to a low preload setting with the resultant wide MBC operating range.
This is easier than the "correct" method of hooking a section of 4mm hose directly from the compressor outlet nipple to the WGA port. I think that you'll find that your WG spring pressure is set somewhere between 11-13 PSI.
This is a soft , flabby setting that results in slow turbo spoolup. I have found that you get better spoolup and better control of boost as well by running as much preload as possible and thus limiting the MBC's effective operating range to a more reduced window. This is preferable to a low preload setting with the resultant wide MBC operating range.
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