MBC Installation Procedure
I guess I should have updated this. We cured this problem by switching out the spring in the MBC. I must of overlooked it, but our MBC came with an extra spring which was actually a stiffer spring. Swapped it out and am able to get up to 21psi no problem. Just make sure when you swapped the spring to turn the MBC all the way down as you don't want to overboost.
My boost level was about 24psi with a Flash, I added the Hallman and am now at 12-13psi - I'll add the stiffer spring, but..........
Yes, but the original spring it came with wouldn't allow us to boost passed 13psi. The hallman wasn't made specifically for the evo, hence the softer spring.
Our flash tuner doesn't deal with tuning with the stock solenoid, so we were limited to the stock solenoid pressure. We ended up getting the Hallman so we could get tuned for 24psi. The hallman and the stiffer spring made this possible.
Our flash tuner doesn't deal with tuning with the stock solenoid, so we were limited to the stock solenoid pressure. We ended up getting the Hallman so we could get tuned for 24psi. The hallman and the stiffer spring made this possible.
Yes, but the original spring it came with wouldn't allow us to boost passed 13psi. The hallman wasn't made specifically for the evo, hence the softer spring.
Our flash tuner doesn't deal with tuning with the stock solenoid, so we were limited to the stock solenoid pressure. We ended up getting the Hallman so we could get tuned for 24psi. The hallman and the stiffer spring made this possible.
Our flash tuner doesn't deal with tuning with the stock solenoid, so we were limited to the stock solenoid pressure. We ended up getting the Hallman so we could get tuned for 24psi. The hallman and the stiffer spring made this possible.
I have mine hooked up from the turbo outlet and the Wastegate - recommended by another Evo guy. What way did you hook it up?
We actually used the intake manifold as boost reference instead of the turbo. So ours is hooked up to the wastegate and intake manifold/DV. I believe it is Option #2 at the beginning of this thread.
Thread Starter
Evolving Member
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From: St. Louis, MO
Here are the pros and cons of both hook-ups
1. Hooking it up the compressor outlet nipple:
A. This way gives you less spikes but slower spool up.
B. It does not seem to give repeatable boost. It seems to fluctuate more with the temperature.
C. Boost seems to be harder to control below 15 psi or above 22 psi. Almost everyone who wrote me said this.
D. It is easier to hook up this way. No cutting any boost lines. Plus the lines are kept shorter. (Thus the less spikes).
2. Hooking it to the hose between the BOV and the intake:
A. This way seems to give slightly faster spool up than the other way.
B. It gives more repeatable boost. It doesn't seem to fluctuate as much with temperature differences.
C. The boost seems to be more controllable down to stock turbo levels. (Like down to 7 or 8 psi for a 1G with a stock 14B turbo).
D. It is more work to hook up. You have to cut the hose between the BOV and intake and tee it in. (Not that this is hard, its just
an extra step so I put it in here)
E. Both Hallman and Extreme tell you to do it this way
I'm not sure how accurate this is because I haven't done any testing.
Dan (drb)
1. Hooking it up the compressor outlet nipple:
A. This way gives you less spikes but slower spool up.
B. It does not seem to give repeatable boost. It seems to fluctuate more with the temperature.
C. Boost seems to be harder to control below 15 psi or above 22 psi. Almost everyone who wrote me said this.
D. It is easier to hook up this way. No cutting any boost lines. Plus the lines are kept shorter. (Thus the less spikes).
2. Hooking it to the hose between the BOV and the intake:
A. This way seems to give slightly faster spool up than the other way.
B. It gives more repeatable boost. It doesn't seem to fluctuate as much with temperature differences.
C. The boost seems to be more controllable down to stock turbo levels. (Like down to 7 or 8 psi for a 1G with a stock 14B turbo).
D. It is more work to hook up. You have to cut the hose between the BOV and intake and tee it in. (Not that this is hard, its just
an extra step so I put it in here)
E. Both Hallman and Extreme tell you to do it this way
I'm not sure how accurate this is because I haven't done any testing.
Dan (drb)
We would never recommend to go with route #2. If you're hooked up using route #2, there is a good probability that if your boost curve is much flatter than going with the compressor for the source, then it is because your BOV/DV is being boost regulated by the MBC. There is no flatter or smoother boost curve than one produced by boost regulation via the BOV/DV, period. However, most people don't have a clue what the truly detrimental effects are of using the BOV/DV to control boost on an exhaust driven turbocharger.
As for #1, there is a reason why the OE uses restrictors in the compressor line signal to attenuate the flow from the compressor so that it isn't so overpowering for the MBC. Using a restrictor will also minimize the post-MAF leak that an MBC creates, since the bleed isn't being brought back into the system like a 3-port or factory BCS does.
If you really want to use vacuum, use a separate line from the BOV/DV straight to the intake manifold. Just bear in mind that you are introducing a vac leak this way since most MBC's are not designed to take vac.
We would never recommend to go with route #2. If you're hooked up using route #2, there is a good probability that if your boost curve is much flatter than going with the compressor for the source, then it is because your BOV/DV is being boost regulated by the MBC. There is no flatter or smoother boost curve than one produced by boost regulation via the BOV/DV, period. However, most people don't have a clue what the truly detrimental effects are of using the BOV/DV to control boost on an exhaust driven turbocharger.
As for #1, there is a reason why the OE uses restrictors in the compressor line signal to attenuate the flow from the compressor so that it isn't so overpowering for the MBC. Using a restrictor will also minimize the post-MAF leak that an MBC creates, since the bleed isn't being brought back into the system like a 3-port or factory BCS does.
If you really want to use vacuum, use a separate line from the BOV/DV straight to the intake manifold. Just bear in mind that you are introducing a vac leak this way since most MBC's are not designed to take vac.
As for #1, there is a reason why the OE uses restrictors in the compressor line signal to attenuate the flow from the compressor so that it isn't so overpowering for the MBC. Using a restrictor will also minimize the post-MAF leak that an MBC creates, since the bleed isn't being brought back into the system like a 3-port or factory BCS does.
If you really want to use vacuum, use a separate line from the BOV/DV straight to the intake manifold. Just bear in mind that you are introducing a vac leak this way since most MBC's are not designed to take vac.
Thread Starter
Evolving Member
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From: St. Louis, MO
I'm confused as well. The way I read it they recommend option 1 and they recommend keeping the resrictor pills. I have tried option 1 & option 2 exactly as I described above (without the restritor pills) and both methods worked well for me. Hallman and some other MBC manufacturers recomend option 2.
Either option will work to control boost. But an MBC manufacturer doesn't exactly care what it is doing to the BOV/DV. With the OE and Synapse DV, using option 2 opens up the DV when the MBC starts to boost regulate. You wouldn't really know this unless you can measure the discharge flow at the DV, which we've done and validated. No bueno.
