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Discussion Starter · #1 ·
Hiya guys I don't know how to use this furom lol

it all looks abit confusing for me so let's start ,i have a alfa 147 2.0 selespeed turbo petrol .

I need a dump valve on there as I have changed the set up from auto delta set up

I have put a BMC CDA air filter directly on to my turbo direct because before there was so much exses piping that use to go in to the original alfa air box and so much lag and heat coming out of the pipes so I eliminated a lot of ppiping now the power is more should I say BRUTAL

but I have a lot of back pressure because there is no dump valve fitted

The turbo sits under the manifold under the air con compressor towards the drivers side wheel

were would be the best place for me to situate the dump valve ?

My air maff sensor I have moved it by the throttle very close to the battery or I think on top of the battery lol I can't remember.

I am planning to fit a front mount INTERCOOLER as the one fitted is in front of the passenger side wheel and there's a lot of exses piping there wich ill have to get rid off as well ..

This is like my first time fitting all this to a car so help would be appreciated and I will post pics soon when I find them
 

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Best to put things like this in the tuning forum - this is far from OEM stuff
http://www.alfaowner.com/Forum/tuning-and-upgrades/

A dump valve is put in place to protect the throttle and piping from over-boost when the throttle closes and the turbine still spinning - the dump valve must be close to the throttle.

The MAF is designed to work in atmosphere pressures and temperatures, not boost pressures. The MAF must be just after your air filter, before the turbo.

You might get injection errors if you dump to atmosphere as your MAF registered the AIR coming in, but then it disappears - best to recirculate the dumped air back in front of the turbo, after the MAF to release the pressure, but not register more airflow
 

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Morning fella, sounds like an awesome motor turbo selespeed; what kind of power you getting it to run do you know?

I am guessing you're experiencing a phenomenon known as turbo flutter when you come off throttle and is evident down the exhaust as a fluttering sound because the turbo has stalled.

As said above, a dump valve, or blow of valve as they're sometimes referred, is designed to release excess pressure between the compressor side of the turbo and the throttle body. The compressor obviously doesn't stop turning when you lift off the throttle but the throttle body will shut, so you're trying to compress additional air into a closed system, creating a spike in pressure. The dump valves works on a basic spring, just like the valve in your tyres really but to let pressure out not keep it in. When the pressure on the valve (built up inside your intake) exceeds the strength of the spring, the valve opens and pressure is released.

The problem is when the pressure builds up and isn't released the pressure builds also in the compressor, causing the turbo and compressor to slow down very quickly, as the back pressure acts on the compressor, so the benefit of having the pressure released allows the turbo to continue to spin and you'll in theory achieve less lag and spool times as a result.

There are two types or BOV, atmospheric and recirculating and both do what they say on the tin really. they either release the excess pressure to the atmosphere or divert it and recirculate the pressure.

As said above it depends on the setup of your system on which you need as it depends how the car is measuring the boost and what air is coming into the engine, as you don't want to be getting rid of air the engine believes is being delivered to it.
 

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Discussion Starter · #5 ·
Mate because my cars a turbo conversion it has no recirculating piping .how would i and we're should i recirculate to so i can carry out the work my self
 

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Mate because my cars a turbo conversion it has no recirculating piping .how would i and we're should i recirculate to so i can carry out the work my self
Put the BoV after turbo, before throttle best to recirculate the dumped air back in front of the turbo, after the MAF to release the pressure, but not register more airflow
Here are two pictures to explain what I have said:
http://us1.webpublications.com.au/static/images/articles/i27/2778_8lo.jpg
http://www.enginebasics.com/Advanced Engine Tuning/Images/Blow off valve recirculated.jpg

Personally I will put the BoV AFTER the intercooler, before the throttle so you recirculate colder air, rather that warmer air close to the turbo...
 

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Discussion Starter · #7 ·
Here are two pictures to explain what I have said:
http://us1.webpublications.com.au/static/images/articles/i27/2778_8lo.jpg
http://www.enginebasics.com/Advanced Engine Tuning/Images/Blow off valve recirculated.jpg

Personally I will put the BoV AFTER the intercooler, before the throttle so you recirculate colder air, rather that warmer air close to the turbo...
Pictures 2

What I can figure out from the picture is its recirculating to the turbo air intake pipe right?

In between turbo and maff sensor and then air filter ?
 

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Pictures 2

What I can figure out from the picture is its recirculating to the turbo air intake pipe right?

In between turbo and maff sensor and then air filter ?
No, Air filter always 1st!!! You need to protect all the other items!
then MAF - it does not work right with high pressure or high temperatures,
then recirculation feedback connector,
then TURBO intake.

From Turbo outlet you can choose:
to BoV immediately, before intercooler - piping is usually easier this way
or go through intercooler 1st, then BoV - benefit by sending colder air back to turbo
then throttle.

As in picture 2: Air filter is out of picture below the wording DRIFTOPIA, the wording DRIFTOPIA is on the MAF. On the bend pipe you can see the recirculation feedback, before the TURBO intake. From the TURBO the bend closest to the blue engine cover is the BOOST side, in front of the engine on the bend is the BoV recirculator with the small reference pipe coming from the left.
 
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