impreza restrictor pill missing help
19 April 2015, 12:11 AM
#1
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impreza restrictor pill missing help
Had a whole heap of problems with the scoob in last few months. Judt realised that the restrictor pill I think I missing.
What would the implications of this be?
Car won't go on boost properly, and hesitatant like mad.
Any idea where I can get one from and what size do i need for a 2001 wrx.
replaced tonnes of things trying to fi d the problem, will be fuming if it's due to the idiot who fitted the engine leaving off the tiny pill
What would the implications of this be?
Car won't go on boost properly, and hesitatant like mad.
Any idea where I can get one from and what size do i need for a 2001 wrx.
replaced tonnes of things trying to fi d the problem, will be fuming if it's due to the idiot who fitted the engine leaving off the tiny pill
19 April 2015, 02:48 PM
#6
1mm is maybe 0.1-0.2mm narrower but shouldn't cause any bother. The td04 turbo is quite a hardy bugger and could well improve spool ever ever so slightly and will hit full programmed boost well, on the flip side it may cause very slight over boost but not enough to cause any bother (wrx runs rich as it is so even 1 or 2 psi spike over a second or two while the ecu reigns it in should be fine). Would certainly be useful in diagnosing your problem, even as a stop gap. I am using a 0.8mm welding tip on mine as I am running an ihi vf 24 (same as vf28) and have mapped it to suit.
Do you have a boost gauge fitted?
Do you have a boost gauge fitted?
Last edited by brendy76; 19 April 2015 at 02:51 PM.
19 April 2015, 06:15 PM
#7
Technically, a 0.1mm increase in diameter can actually be quite a big difference, depending on what size you're changing from/to, because it's the area of a circle you're changing. I think my fairly basic maths below is correct [ pi*(diameter/2)² ], and as you can see, the difference between a 1.2mm and a 1.0mm reduces the size of the hole by almost a third of its original size!
When I played around with restrictor sizes, I found even going from 1.2mm to 1.15mm made a noticeable difference to the amount of boost/overboost produced.
Code:
Diameter Area 0.1mm 0.01mm² 0.2mm 0.03mm² 0.3mm 0.07mm² 0.4mm 0.13mm² 0.5mm 0.20mm² 0.6mm 0.28mm² 0.7mm 0.38mm² 0.8mm 0.50mm² 0.9mm 0.64mm² 1.0mm 0.79mm² 1.1mm 0.95mm² 1.2mm 1.13mm² 1.3mm 1.33mm² 1.4mm 1.54mm² 1.5mm 1.77mm²
Last edited by ben.harris; 19 April 2015 at 06:23 PM.
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19 April 2015, 06:44 PM
#8
Technically, a 0.1mm increase in diameter can actually be quite a big difference, depending on what size you're changing from/to, because it's the area of a circle you're changing. I think my fairly basic maths below is correct [ pi*(diameter/2)² ], and as you can see, the difference between a 1.2mm and a 1.0mm reduces the size of the hole by almost a third of its original size!
When I played around with restrictor sizes, I found even going from 1.2mm to 1.15mm made a noticeable difference to the amount of boost/overboost produced.
Code:
Diameter Area 0.1mm 0.01mm² 0.2mm 0.03mm² 0.3mm 0.07mm² 0.4mm 0.13mm² 0.5mm 0.20mm² 0.6mm 0.28mm² 0.7mm 0.38mm² 0.8mm 0.50mm² 0.9mm 0.64mm² 1.0mm 0.79mm² 1.1mm 0.95mm² 1.2mm 1.13mm² 1.3mm 1.33mm² 1.4mm 1.54mm² 1.5mm 1.77mm²
Short term it won't do any harm unless he will be ripping the **** out of it.
Last edited by brendy76; 19 April 2015 at 06:58 PM.
19 April 2015, 07:02 PM
#10
That's fine if it's just for testing. I was just advising to err on the side of caution, as I found going from 1.2mm to 1.15mm increased my 1 bar boost limit (MY97 PPP) up to about 1.35 bar! - So far too high to be safe and that was just a 0.05mm diameter increase!
21 April 2015, 09:32 PM
#14
originally my car had no pill, i picked up a set of pipes from an STI and that sent it into fuel cut (standard rom), tried a 1.2mm and got 14psi, tried a 1.1mm and still got 14psi but got it a little quicker. I think although it's smaller it's not enough to upset the standard boost control tables so it works nicely. I've read in a few posts that PPP cars had a 1.1mm pill as well.
21 April 2015, 11:38 PM
#15
originally my car had no pill, i picked up a set of pipes from an STI and that sent it into fuel cut (standard rom), tried a 1.2mm and got 14psi, tried a 1.1mm and still got 14psi but got it a little quicker. I think although it's smaller it's not enough to upset the standard boost control tables so it works nicely. I've read in a few posts that PPP cars had a 1.1mm pill as well.
22 April 2015, 12:03 AM
#16
we've got a thread on it 
https://www.scoobynet.com/technical-...locations.html
and remember the older cars with a 3port solenoid the restrictor worked the other way with a bigger pill giving more boost (the pill restricts the amount of air leaving the solenoid instead of the amount of air entering the solenoid to be blead).
https://www.scoobynet.com/technical-...locations.html
and remember the older cars with a 3port solenoid the restrictor worked the other way with a bigger pill giving more boost (the pill restricts the amount of air leaving the solenoid instead of the amount of air entering the solenoid to be blead).
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