Does the factory boost control have a restrictor pill in the red tip pipe?

Hi All,
i have never found one in any boost control pipe work i have looked at.
but i have not owned a VR4 from new so any of the previous owner could have removed it for some reason.

the restrictor pill is designed to limit the volume of boosted air that actually goes to the boost solenoid and the wastegate actuators.
It does not limit the boost pressure getting there just the volume. so when the boost solenoid bleeds off some of the pressure it is not immediately replaced by more boosted air which kind of works against what the boost solenoid is doing.

there is a restrictor pill in the entry port on the boost solenoid valve itself but this is not what i am talking about. i am talking about a restrictor pill in the red tip boost pipe before the T piece that splits off to the boost solenoid and wastegate actuators.

is there supposed to be one fitted in the standard factory pipework.

Pretty certain there was one in the red-tipped pipe on mine.

I remember removing it from the pipe and inserting it into another piece of silicone pipe when re-piping either my Legnum or Anglia.

Hmm, that is interesting.
this might be the reason why some people struggle setting up the boost control.
the wastegate actuators are getting overwhelmed by the volume of boosted air being forced down the pipes, the boost solenoid has difficulty bleeding off the volume of air it is seeing.

i am sure i bought a load of boost pills a good few years back with the intension of trying to see what difference it made to my cars boost control.

but i have a 3 port solenoid and it should not be plumbed in in the same place as the original 2 port solenoid, it should be in line with the boost pipe from the boost source inlet elbow direct to the wastegates. you remove the original first T piece.
which makes sense when you think about it.

i am not sure if you need to leave the boost restrictor pill in place when using a 3 port solenoid or not.

I was looking through the VR4 workshop manuals recently and could not find any mention of restrictor pill.
buti did find this little marking where the restrictor pill would be located, but it is not labelled up and it is a kind of double arrow pointing inwards which might suggest a restriction.

Attachment 82588Attachment 82587

garry could you correct my spelling of restrictor on the title of the thread so it is more findable in a search i missed the 'r ' out.

Spelling correction Done.

I kept the red tipped pipe for my three port. I figured restricted flow still makes the boost easier to control. I am pretty sure you can feel the pill in the red tipped pipe if you squash it along the length.

The problem is most people just replace all the pipe work without even considering there may be restictors in there for a reason.

hence the issues boost control that people have

According to this page, the 2nd most common mistake listed when installing a 3 port solenoid is "Not removing a “restrictor pill” that is often used with and OEM 2 port boost control system".

Yes Dave there is a pill in red pipe.

any idea what the size of the hole is?
i don't have a red tip pipe on the black car i have as it has been replaced at some point.
it seems to be about 0.8mm to 1.5mm on other cars like subaru and evo's depending on the boost level range you are going for.

i did buy some boost pills to test some time ago but like normal i have put them somewhere and can't find them any more. they will turn up at some point but they could be anywhere.

Quote:

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Originally Posted by Confused

According to this page, the 2nd most common mistake listed when installing a 3 port solenoid is "Not removing a “restrictor pill” that is often used with and OEM 2 port boost control system".

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It doesn't explain why it would be a problem. Theoretically if you remove the pìll you will get more flow to the 3 port, so you would need a higher duty cycle to bleed off actuator pressure and raise boost.