TII lag/response - mine vs other people?

[papercutout]

Isn\'t a boost controller to limit the amount of boost, without one it\'ll just boost to the maximum it can?

[m1tch]

Isn\'t a boost controller to limit the amount of boost, without one it\'ll just boost to the maximum it can?

There is an OEM solinoid that measures the boost, the wastegate spring is set to about 5psi, the OEM boost solinoid then bleeds off a set amount of air/pressure so that the wastegate stays closed for longer (as in the boost might be 10psi, but the actuator is only \'seeing\' 5psi. My AVC-R boost controller has its own solinoid to bleed of the correct amount of air electronically, the manual boost controllers do this by bleeding it off using a needle valve. The car will boost up due to boost creap if its free flowing but thats not something that can be controlled, you need to control the amount of boost getting to the wastegate to be able to increase boost. The turbo on the FC is a wastegate turbo, its not a VNT turbo like on my Volvo that is ECU controlled.

[Prof]

Ok - put a picture up of a stock Turbo and it\'s plumbing.
 
The stock system has a spring that gives 5 psi with stock intake and exhaust - assuming you plumbed the actuator into the output of the compressor. What Mazda do to get a bit more is to bleed off some of that air through a solenoid which results in just over 8 psi.
 
OK - so now assume that you\'ve not got Mazda\'s funky solenoid but just the straight connection from compressor to actuator and you put a freer flowing exhaust and intake on - the boost will now be much higher - probably about 12 psi unchecked - and you\'ll get boost creep. The stock solenoid can\'t really understand what\'s happening now - so the ECU will try and do stupid things - unless you\'ve got a chipped one which should handle the unexpected extra boost.
 
HOWEVER - you\'re best bet is to take the stock boost solenoid off and block the pipe that was feeding it so that you\'ve got the simpler plumbing.
 
Then you have a choice of how to put a boost controller in:
 
Manual boost controller - pill type - this goes in series with the pipe from compressor to actuator - this type doesn\'t bleed off air.
 
Manual boost controller - bleed type - this would go where the stock boost solenoid plumbed into
 
Electronic boost controller - follow the instructions from the manufacturer - but basically these have a 2 way valve that allows compressor boost to go to actuator or be blocked off, and the actuator to see the compressor or vent to air. The valve operates several times a second as the boost controller works out the desired amount of boost to operate the actuator.
 
NOW FOR THE CAVEATS:
 
A boost controller cannot lower the standard spring boost - that\'s the lower limit of control.
 
A boost controller cannot stop boost creep either - boost creep is the inability of the wastegate to lose the extra boost and thus higher revs / higher gears you see more and more boost - \'creep\'. The only solution is a bigger wastegate - basically that means porting the stock one
 
Porting the wastegate increases the area that exhaust gases are acting on the flapper - so now the natural boost will be lower because the actuator can\'t keep the flapper shut because of the extra exhaust pressure - so you\'ve controlled boost creep but lost a little boost. The up side is you can now control a wider range of boost - by replacing the actuator with an aftermarket one with better spring.

[papercutout]

Prof, this is the MBC I have, what type is it? :

http://www.driftworks.com/shop/dw-manual-boost-control-valve.html

As I said, I have an R-magic ECU, which is why I\'ve been surprised, surely it should have just upped the fuel to cope? It\'s meant to cope upto 0.9 bar. I\'ve just dropped Liam a message so he can check the specs for me again)

So you are telling me to:

take off the stock boost solenoid
fit MBC
(check ECU too)

[Prof]

Those ones on DW are ball and spring - so they are a restrictor type (pill type) so they go in line.  Basically one barb of the MBC goes to the outlet on the compressor, the other to the actuator - simple as that.
 
By adjusting the MBC you are moving the sprung ball to allow air to pass - the amount is adjusted to suit your desired boot.  Imagine it like a variable resistor for air.  By restricing the amount of boost \'seen\' by the actuator, the engine must create more boost to operate the actuator - hence boost control
 
These things are very reliable.

[papercutout]

So just cut the t-pipe in the middle, plumb MBC in, and remove/block off stock solenoid thingummyjig?

[Prof]

So just cut the t-pipe in the middle, plumb MBC in, and remove/block off stock solenoid thingummyjig?

I\'d be tempted to take the T pipe off altogether - and connect two thick walled silicon hoses one on the actuator and one on the compressour outlet and take the 2 free ends onto your MBC - ideally you want to keep the pipework short too.

[L18M]

hi hi, i think im ment to be here.
the r-magic ecu was for 3" exhaust, aftermarket intake and allows higher boost. think was stock ic. only some re amemiya ones (type a i think it was) was for larger ic

sorry if this is bit random. im tired.. its the weekend x.x

[L18M]

maybe actuator arm not tightened up properly?
as everyone else check vac lines etc.
to check the fuel cut on the ecu i guess can plug in a fcd into the stock map sensor and see if you still have the \'mild fuel cut\'
i just sold one but not sure if i have a spare, need to have a poke around through all my rubbish.

[papercutout]

Okay ladies and gents, lets see how things go shall we?

I nicked the \'long\' pipe that ran from the stock solenoid to the metal tubing round the turbo, cut it in half, and put the MBC in the middle (this sounds really easy, it wasn\'t at all - got several new cuts on my hands!) then used another piece of pipe with a big bolt in to block off the stock solenoid pipe. See photos.

To get to it all I had to remove the air pump. I didn\'t have this \'connected\' anyway (I\'d removed the belt) so it wasn\'t running. But I still have a big pipe open, the one that goes from the pump to the rest of the air pump gubbins. I plan on getting block off plates sometime, but will this affect things at all? Draw warm air into the engine etc? (I know with the pump disconnected it shouldn\'t, but no harm in asking).

What do people think? Everything OK? I know the MBC is in an awkward place to adjust, but I had to use what I had, and I had very little!

Thanks

[papercutout]

Okay, update (questions from the last post are still 100% relevant though!)


No difference today! So once I got home this evening I have wound the boost controller a lot further out, so it is active at a much lower boost level.

Lastly (for now!) I am getting lots of turbo whistle on boost, is it that it\'s finally working properly, or is it on it\'s way out? Sounds pretty awesome really tbh

[Prof]

That wistling could be a vac leak of course -

[papercutout]

Okay, then please can you drop me a pic of where to look, and what to look at? I\'m still used to N/A engines, so you have to show me everything once turbo wise, then I\'ll get it and not ask again!


Anything else regarding my other q\'s? (I know, I know, I ask lots of questions, but please excuse my ignorance)

[B.Martin]

Wait till I get mine.... Prof\'s going to be hiding behid his keyboard

Glad your starting to get to the bottom of the problem (hopefully)

[TiddlesRX7]

I also get a lot of turbo whistle. I just thought it was gonna take off! Maybe it\'s cause the wastegate is still being opened because of the boost pressure. The actuator is trying to hold it back but can\'t after 0.5-0.6 bar.