Volvo/ Ford St225 PCV SYSTEM

 

The Volvo/ FORD ST

The pcv system is made of two parts like most cars.

There is high vacuum /low throttle side, and then wide-open side, Low vacuum high positive pressure side and it’s a complete closed system.

Now let’s look at the high vacuum side.

During this state oil vapor inside the engine is sucked into the intake manifold through the oil filter housing which is open to the bottom of the cylinder block and connected to the cam cover.

Inside the OFH you will find a diaphragm which regulates the flow as the vacuum pull is rather strong.

Strong enough to suck in the oil seals on the cams and the crank, causing them to leak.

This particular diaphragm also acts as a shut off valve when the car is in boost to prevent block pressurisation but helped by the little reed valves situated inside the intake manifold runner gasket.

Now the WOT/High positive pressure side.

Under wide open throttle the vacuum in the intake manifold turns to positive pressure. Now the little reed valves get blown against their seats to close the system from the pressure and to make sure no pressure gets past them and pushes on the diaphragm and all is well.

In turn there is still a lot of vapor pressure and positive pressure inside the block that must go somewhere, this is where the secondary system kicks in

Volvo utilizes an anti-pollution regulating valve at the turbo, now this is connected at the throat of the turbo which under boost will suck on this valve, which is connected via the lower manifold to the cylinder block, oil vapour pressure gets pulled into the high-pressure air stream and pushed through the intercooler and piping and the burnt inside the combustion chamber.

And all is well! 

BUT 

Thats where the oil filter housing problem stems off.

So in the past we focussed on the Boost / high pressure side  

Some boost leaked past the reed valves, causing pressure on the Diaphragm located in the OFH, causing it to rupture.

End result was usually a high pitch scream at idle.

Our fix at the time was a swing action one way valve with an enclosed catch can.

It worked, saving numerous diaphragms in its stride  

BUT

then we found more and more Tuned cars with a smoking habit!

Now where do we start......

So, we started looking at the low pressure / vacuum side 

For some reason oil mist must be suck or blown into the combustion chamber.

Secondly the pressure in the block tries its best to escape.

We tried venting the pressure side. Which didn’t help as the car would suck in unmeasured air and would run lean under high vacuum low throttle..........................................

 

 

 The Volvo/ FORD ST pcv system

 

Consists of two systems integrated into one housing.

 There is high vacuum /low throttle side, and then wide open, high positive pressure side and it’s a complete closed system.

 Now let’s look at the High vacuum side.

 During this state oil vapor inside the engine is sucked into the intake manifold through the oil filter housing which is open to the bottom of the cylinder block and connected to the cam cover.

 Inside the OFH you will find a diaphragm which regulates the flow as the vacuum pull is rather strong, strong enough to suck in the oil seals on the cams and the crank, causing them to leak.

This particular diaphragm also acts as a shut off valve when the car is in boost but helped by the little reed valves situated inside the manifold runner gasket.

 Now the WOT/High positive pressure side.

 Under wide open throttle the vacuum in the intake manifold turns to positive pressure. Now the little reed valves get blown against their seats to close the system from the pressure to make sure no pressure gets past them and pushes on the diaphragm, and all is well.

In turn there is still a lot of positive vapor pressure inside the block that must go somewhere, this is where the secondary system kicks in

Volvo utilizes an anti-pollution regulating valve at the turbo, now this is connected at the throat of the turbo, which under boost will suck on this valve which is connected via the lower intake manifold to the cylinder block, oil vapour gets pulled into the high-pressure air stream and pushed through the intercooler and piping and then burnt inside the combustion chamber.And all is well! 

 BUT 

 That is where the problem stems off.

 So, in the past we focussed on the Boost / high pressure side.  

 Some boost leaked past the reed valves, causing pressure on the Diaphragm located in the OFH, causing it to rupture.

 The result was usually a high pitch scream at idle.

 Our fix at the time was a swing action one way valve with an enclosed catch can.

 It worked, saving numerous diaphragms in its stride.  

 BUT

 then we found more and more Tuned cars with a smoking habit!

 Now where do we start......

 So, we started looking at the low pressure / vacuum side. 

 For some reason oil mist must be suck or blown into the combustion chamber.

We tried venting the pressure side. Which did not help as the car would suck in unmeasured air and would run lean under vacuum............................................

 

Now we found that intercepting the hose from the rocker cover works. 

By directing the gasses to a vented can and then back to the OFH.

This way pressure vents via a pod filter and any leftover oil are directed back to the ofh.

This help the OFH last longer and none of the oily mess associated with it.

ST225 Symposer delete

First. Open bonnet.

Then find the throttle body.

Check. 

 

Now to the left of the throttle is a plastic thingies.

With a concertina pipe that runs to the windshield area.

Pull the pipe of.

Do not through it away. 

Can be used to steal petrol at some later stage. 

Now.

There is two very shitty clamps holding this plastic thing to the throttle pipe.

A special pliers or a lot of blood it required to unclamp this thing.

Head light removal is an option.

Once off pull the plastic thing out and through the it far away.

Now.

 

Get your 38 mm irrigation plug. (builders ware house)

 

Push it into the pipe.

Fight that shitty clamp back in position.

And there you go. Done. 

Just replace everything else that got in the way whilst doing this. 

No more boost leaks. 

O ja that bracket on the head… remove and discard.

Focus ST225 to Focus RS maf pin out.

On the ST MAF pin 1 is not used.
On the RS MAF pin 3 is not used.


- Pin 2 on the ST goes to Pin 1 on the RS MAF GN/BU wire
- Pin 3 on the ST goes to Pin 2 on the RS MAF BN/BU wire
- Pin 4 on the ST goes to Pin 4 on the RS MAF WH/RD wire
- Pin 5 on the ST goes to Pin 5 on the RS MAF BN/RD wire

Intercooler basics

Your car’s stock intercooler is a fraction of the size it needs.
Even with a stock vehicle, any time you step on the gas you are robbing yourself of horsepower, because your stock intercooler does not have the ability to cool enough air.
It runs hot air into the engine, giving your turbo engine sluggish throttle response, acceleration and an increase in turbo lag.

TIME TO STEP IT UP!!!

The 2 key factors in how much power an intercooler will produce on your car are:

 Pressure drop!!

If your boost system is restricted it will create pressure drop, which in turn will heat up the charge.

By improving the pressure drop between the air filter and the turbo. Or by having a more efficient compressor wheel. 

Which allows you to run the same amount of boost in the intake manifold while having a lower turbo discharge pressure. This will in turn yield a denser air charge.

You can also reduce the pressure drop through the intercooler. By selecting the right size core for the job

 Temperature Drop!!

Getting the temperature of the intake air as cool as possible at the outlet of the intercooler.

This requires a carefully selected high performance inter cooler core, High flowing with the best cooling efficiency.

Professionally designed end tanks either cast or constructed with the smoothest flow. Air scoops or diffusers can help to force more air through the cooler core.

A high-performance intercooler that reduces the pressure drop allows your engine to make more boost pressure at the throttle body without your turbo having to work harder than it was working with a less efficient intercooler.

In turn it can allow your car to produce more power because of a cooler, denser airmass. Allowing optimal timing and lower knock threshold.

A high-quality intercooler core coupled to high flowing inlet and outlet tanks can make a big difference to inlet temperatures and pressure differentials through the system

Scoops and the effect on intercooler core

Stock intercooler performance on an ST225

Upgraded intercooler performance test

Torque app shows how the Intake temps behave in a K16 RS turbo'd Volvo with 90mm SAIC inter cooler