Too much boost! help with mbc install

M

mooserov

Member
:
07 speed3 gt
I am hitting 23 psi and creeping to 25 in 4th. As soon as this happens I get off it to keep from blowing up. I'm using a dash hawk for afr's and a prosport boost gauge.
JoeP boost controller. I've plumbed it 2 ways with identical results:
1. pulled the hose between waste gate and compressor housing, adding a hose to each, and plumbing there. capping the other waste gate nipple and the factory boost solenoid.
2. plumbed in place of the factory solenoid, leaving all other hoses stock.

What can be causing this? the mbc does not limit boost at all. Where is the proper place to plumb it? I've read about both. I know a few people have this mbc, can it be faulty? I'm really confused, and don't want to blow my motor. Please chime in with any advice.
Thanks,
Moose
 
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mooserov said:
I am hitting 23 psi and creeping to 25 in 4th. As soon as this happens I get off it to keep from blowing up. I'm using a dash hawk for afr's and a prosport boost gauge.
JoeP boost controller. I've plumbed it 2 ways with identical results:
1. pulled the hose between waste gate and compressor housing, adding a hose to each, and plumbing there. capping the other waste gate nipple and the factory boost solenoid.
2. plumbed in place of the factory solenoid, leaving all other hoses stock.
Click to expand...

First thing I would do is edit my profile (don't but your zip / location) so that a Mazda rep doesn't void your warranty!
 
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Go back hook it up like #1. Then make sure you have the MBC on the right way. If you have it backwards, the boost will spike high and adjusting the knob will have little to no effect.
 
When I had it like number 1 and swapped the hoses, the boost went way over 25 psi very fast. This was with the boost controller screwed all the way out. I am not against trying it all again from the beginning, but I don't think that that is it. Why is number 1 better than number 2? Can you see my reasoning for putting it in place of the stock solenoid? Am I just retarded?
 
Got it sorted out. Went with option 2. More details to come soon because this is a much easier and faster way to add a mbc. Holding strong at 19 and a half. Car rips with afr's in the 11's
 
ok, as i stated before, I went through all the hassle of hooking up the boost controller like it says in this post http://www.mazdas247.com/forum/showthread.php?t=123683964

and could never get the stupid thing to work correctly. I tried all permutations of hosing and valve adjustment to no avail. Finally, I sat down with a pencil and paper and figured out how the factory system works. After this I basically replaced the factory boost solenoid with the JoeP manual boost controller and wonder of wonders, it works perfectly. This is a very simple install, no getting under the car and no busted knuckles. I'm doing a howto on this, but if anyone can see a problem with how this is hooked up, put words to it.

Factory control works as follows:
The compressor housing has a nipple that allows boost pressure to reach the wastegate actuator through a short hose. This is the fatter hose pictured in the above link. There is a smaller diameter hose that comes off the top of the wastegate actuator that leads to the factory boost control solenoid. The second hose coming off the solenoid goes to the intake pipe to recirculate the metered boost. I am reasonably sure that the factory control solenoid is pulse-width modulated, which means it is sent 12 volt pulses to open it partially. The slower the pulses, the closer to closed. The faster the pulses, the more open.
The two fittings on the wastegate actuator are a straight passthrough. I did an experiment by leaving the hoses as stock, and capping the actuator. Boost was limited to around 15 lbs by the spring in the actuator. Then I installed the controller and made run after run slowly adjusting it. Here are some pics.

This is the factory boost control solenoid, The cap is where the hose ran to the wastegate actuator, the hose went to the nipple on the intake.
solenoidpointer.jpg


This is the wastegate actuator, the hose attached to it goes to the inlet side of the Manual Boost controller
Wastegateactuator.jpg


This one is hard to see. The pointer is resting on the nipple on the intake. The hose in the picture runs to the outlet of the Manual Boost Controller. Follow the hose from the solenoid to find it, it can be pulled off and installed by feel.
intakehosepointer.jpg


Here's a pic of the solenoid and actuator together, without pointers in the way. Very easy to get to, and can be put back as stock in about 5 minutes.
wastegateandsolenoid2.jpg
 
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so let me see if i understand what you did....
you left the fat hose that connects the turbo housing to the WGA intact. then you basicaly just put the MBC in place of the factory solenoid, just re-using the original in/out lines ?
is that right ? i suppose that would give the same effect as doing it the other way. i did infact use the same method as loloosh's how to and have perfect results.
 
that's exactly what I did. For some reason, the mbc I have would steadily creep. Works perfect where it is now, and I can inspect the hoses periodically without getting under the car
 
I would really like to know if there is any negative effects from installing a boost controller like this. If there is none, it is a much easier way to do it. Any boost gurus have an opinion? This is my first boosted car and I'm building a stupid fast boosted honda, so I'm trying to absorb as much info as I can.
 
na why cuase you said so... the standback is a coool little computer, you can data log, add fuel , remove fuel, add timeing, remove timeing, plus I run vta with no backfie thanks to the standback..for 600 bucks its good deal. Also you didnt pay 50bucks cuase you had to also buy the fuel cut defender....
 
mooserov said:
I would really like to know if there is any negative effects from installing a boost controller like this. If there is none, it is a much easier way to do it. Any boost gurus have an opinion? This is my first boosted car and I'm building a stupid fast boosted honda, so I'm trying to absorb as much info as I can.
Click to expand...

i know all of the MBC instructions i have ever seen say to place the MBC directly between the compressor and the WGA, then do away with all other hose connections. if it is working out for you, i see no harm in it. the only for sure NO, NO for an MBC on our car is trying to install it with the factory solenoid still in use.
 
tru-boost said:
i paid $50 you paid $600 ! and messing with anything other than boost with a piggyback "tuner" on a forced induction direct injected car is the worst idea ever.....sorry.
Click to expand...

why we made s*** tons more power with one and it hasn't blown yet (everything else has though)
 
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