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Working OT
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Discussion Starter #1 (Edited)
Before anyone says it I've read mkiv tech articles and searched the forum. From what I'm looking at its set up right but it won't make more than 15psi. I'm using a brand new hallman manual bc and when I had it just barely opened it made around 10 psi them after a few turns makes 15psi after a few more turns .... 15 psi it just want to make more than 15 so I'm trying to figure out if I'm missing something simple here. I've called both the vsv nipples and have the lower nipple on the wastegate capped. What am I missing here. Any reason it wouldn't make more than 15 psi?

Mods are intake, dp, full exhaust, Greddy bcc, spring mod
 

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Reverend Hillclimb
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2,661 Posts
Is your BCC set right?
15psi is the "typical" boost cut number I notice.
Also are you sequential or TTC?
Checked for boost leaks?

If you need help with the install of an MBC feel free to PM me. If you know its right then I think its the BCC

You went by this?

 

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Working OT
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Discussion Starter #3
I'm assuming it's set right. It's not hitting fuel cut it hits 15 psi and holds to redline it just doesn't seem to want to go past that. I used the diagram in the pick. I tried it with the both of the vsv nipples capped to see if it made a Difference and it didn't.
 

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Working OT
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Discussion Starter #5 (Edited)
Yes. You do remove both vsv hoses right? The boost controller directions didn't mention the second hose that's on the passenger side but mkiv tech says to remove that hose and cap it too.
 

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Banned
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Why don't you go electronic and never worry about it again
 

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Working OT
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Discussion Starter #7
Why don't you go electronic and never worry about it again
Most people complain about their electronic boost controllers. Manual boost controllers also help you spool faster and are less prone to boost spikes.
 

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Registered
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Most people complain about their electronic boost controllers. Manual boost controllers also help you spool faster and are less prone to boost spikes.
False. It's 2016. You are stating that you manual boost controller which simply bleeds off pressure from a vacuum line spools faster and you have better control than a properly setup electronic boost controller? (PID)(Proportional, integral, derivative)
 

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Stock Twins King
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4,490 Posts
This is the proper way..very simple. http://97supraturbo.com/Tech Stuff 2007/Boost Control Hose routing.jpg
If you really want to see what boost level you "can" go to just remove the hose off the front actuator. Or remove the downward facing nipple cap (shown as capped in picture)...This opens it up so no boost can bleed off. Be careful as you could go over 20psi. If you still only get 15psi then your actuator is bad.
 

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Working OT
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Discussion Starter #10
This is the proper way..very simple. http://97supraturbo.com/Tech Stuff 2007/Boost Control Hose routing.jpg
If you really want to see what boost level you "can" go to just remove the hose off the front actuator. Or remove the downward facing nipple cap (shown as capped in picture)...This opens it up so no boost can bleed off. Be careful as you could go over 20psi. If you still only get 15psi then your actuator is bad.
Ok thanks stu. That's how I've got mine set up. I was going to try giving it a few more turns and see if that gets me a little more today. But I may try removing the nipple and just watching the gauge closely. If the actuator was bad why would it limit it to 15psi. I would think it wouldn't be really high all the time.
 

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Working OT
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Discussion Starter #11
False. It's 2016. You are stating that you manual boost controller which simply bleeds off pressure from a vacuum line spools faster and you have better control than a properly setup electronic boost controller? (PID)(Proportional, integral, derivative)
Matter of opinion man. A lot of guys swear by manual boost controllers
 

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Working OT
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Discussion Starter #12
Alright so with the boost controller tightened all the way down its making 16psi. I was going to try to set it at 17psi so 1 psi isn't a huge deal. Im more bothered by the fact that I should be able to make more if I want to. I may try calling hallman on Monday. I believe there are different springs you can use. It's just strange that the adjustments seemed normal 10-15 psi then to get to 16 psi I had to turn it probably 10 full turns.
 

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Stock Twins King
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A good actuator has a tight internal spring. If it is weak, then It cannot hold pressure to keep the internal gate closed. If it is weak, it opens by less and less boost pressure. An open actuator = no boost perse.
Hence why you see people add a helper spring to the actuator rod to "stiffen" it up cause it is breaking down. The turbo internal wastegate valve works closed = MAX Boost, open = no boost.
An analogy is 6 guys pushing against a door your trying to open from the other side vs 1 guy....You may have a 1 guy actuator lol.
 

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Working OT
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Discussion Starter #14 (Edited)
Well the previous owner did the spring mod. I pulled the nipple/cap off the bottom of the actuator and took it for a spin 15 psi at redline. Didn't go up or down.

It just seems odd that the boost controller let me make adjustments from 10-15 psi.
 

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Banned
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A manual bc is good for nothing besides holding absolutely one pressure setting on a drag car. Manual has never been more reliable than electronic it isn't a matter of opinion really. I would get the new profec and call it a day, enjoy multiple boost settings, and you'll never have these problems again.
 

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Working OT
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Discussion Starter #16
A manual bc is good for nothing besides holding absolutely one pressure setting on a drag car. Manual has never been more reliable than electronic it isn't a matter of opinion really. I would get the new profec and call it a day, you'll never have these problems again.
Exactly. I have no desire to adjust it. I had an electronic boost controller on my last supra and I set it to 18psi and never touched it again. You can move along now. Thanks for your opinion.
 

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Working OT
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Discussion Starter #18
So figured it out. I didn't even think about this. But I was doing the pulls in 2nd gear. So today after doing a pull in third I hit 19psi before letting off so I need to turn it down. Thank god!!! Just wanted to update the thread in case anyone does a search in the future.
 

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A manual bc is good for nothing besides holding absolutely one pressure setting on a drag car. Manual has never been more reliable than electronic it isn't a matter of opinion really. I would get the new profec and call it a day, enjoy multiple boost settings, and you'll never have these problems again.
I feel like for most people the added cost and complexity of a electronic boost controller isn't worth whatever extra "reliability" they offer. Never had an issue with a manual boost controller and they only take 5 minutes to install.
 

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Working OT
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Discussion Starter #20
I feel like for most people the added cost and complexity of a electronic boost controller isn't worth whatever extra "reliability" they offer. Never had an issue with a manual boost controller and they only take 5 minutes to install.
Most people haven't..... For a bpu car I think electronic is overkill. Just set it for 16-18 psi and be done.
 
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