restrictor pill size
 

Anyone know what size (And where to get) the restrictor pill for a 95 STI ?

my dyno run earlier in the month brought to light that my restrictor pill may be missing (Thanks Silver for the advice) as the car wouldnt rev over 5500rpm.

The pipe it goes in was original so I didnt give it a second thought and got new cam and crank sensors (The other two possible causes I was given).
Anyway, turns out the pill is missing after all! The engine and ECU are from a 95 STI-RA. I have seen various sizes given when searching the net so I figured it would be best to ask someone who knows rather than risk misunderstanding something.

The various sizes are all for variations of 2-port setups on 97> models.
All earlier models on the 3-port use a 2mm restictor.

Wouldn't the STI RA ECU be looking for a 5th injector?

My pill was missing too, 2mm hole drilled in a alloy tyre cap thingy worked fine :grin:

thanks you two, 2mm it is then.

an RA ECU wouldnt look use the 5th injector, it's non-functioning on the road cars and was only fitted because the rally rules were such that the rally cars could not use a 5th injector unless it was fitted to the road car. I remember reading something along those lines somewhere at least.

I think the problem may also be responsible for the CEL light I get when going down a long hill off the gas (Code is for IACV), which it did on my old ECU, so it can#t be a 5th injector thing

2mm buddy...mine had wrong pill fitted (to small) so drilled it out:doubleup:

Correct, 5th injector is unused.

So when you look at the sales blurb on a RA STI on eBay etc etc, and it says fifth injector, its pointless as its not functional? I never knew that.

not entirely pointless. I think you can use it if you have an after market ECU and map for it, but not entirely sure

can be mapped to be used but as above, homologation reasons only

You can change pill size to increase or decrease your boost pressure

What pipe is the restrictor pill in so that I know when I start to change my pipes I don't fling the old one away .

if you have a 3-port boost solenoid, it's the bottom pipe that goes in between the solenoid and the intake resonator box.
if you have a 2-port solenoid, it's the bottom pipe of the two

2-Port has the restrictor between the turbo outlet nipple and the t-piece, in the short pipe with a 90 degree bend in it.

. . .and that demonstrates why I asked about my restrictor pill size here rather than research it myself, so I dont get it wrong lol

LOL no worries......hopefully your pill will get yours boosting reliably.