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Old 07 April 2007, 10:52 PM
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jameswrx
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Question Boost restrictor question, sti V2

Been reading through some threads and all say there should be a 2mm restrictor in the bottom (or waste) hose from solenoid to intake pipe.

I've read this stated a lot and also everyone says that is the only restrictor in the pipework (pre 96 3 port)

Now..

I've just picked up a 95 STI V2 which is only making 0.7bar on WOT (hence me coming on here searching threads)

I've had a squeeze of the pipework to solenoid and the bottom restrictor appears to be missing (there is a white mark where the restrictor should be) which I know should = more boost spike

Also this car appears to have a restrictor fitted in the pipe to the actuator (again where the white mark is)

What I'm interested in is why everyone says there is no other restrictors when mine has the white mark and what feels like a restrictor in the actuator line. Also see the pic below (not my car) and it has the white mark on the actuator pipe too which I would of thought indicates restrictor?



Or is the white mark not relevant to restrictor on that pipe? and someones taken it from waste pipe and put it in actuator line?


Also does anyone know peak boost on std STI V2 95? I can't blumin find the info... 0.9bar?
Old 08 April 2007, 09:07 PM
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Scott.T
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white marks mean nothing.
restrictor should be in the hose from the very bottom of the boost control solenoid iie the hose coming out of the base of the solenoid and not the hose coming out of the side of the solenoid.
This is a brass restrictor inserted inside the pipe and should not be confused with white plastic pipe adaptors which step down/step up between 3mm and 5mm mbore pipes.

Edited to say : 13.64psi and a 6K ECU
Old 08 April 2007, 10:49 PM
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Thanks Scott.

After having a look today there was actually no restrictor in the actuator line (just felt like a hard part in the pipe)

There was no restrictor in the bottom hose either...

There was however a bolt in the bottom hose completely blocking off the pipe. I can only assume the restrictor was removed at some point and overboost issues caused someone to block the pipe.

Now, I made my own restrictor using the end of a pen, drilled it to 2mm and took the car out. Boost was now too high, didn't give the car WOT but saw 1.2bar on part load and backed off.

Stuck another restrictor in drilled to 1.5mm and now have 1bar. I have 2 restrictors in line, one 2mm and one 1.5mm. I'm wondering if it's because I used a plastic lid (which is obviously thin) that it wasn't right at 2mm.

Also it could be that drilling thin plastic allways ends up a larger hole as it's so soft. I was in a rush (as was off out) and grabbed the 1st things I could find. I think I'll make a circa 5mm long one out of metal starting with 1.5mm.
Old 09 April 2007, 09:42 AM
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Glad you found the problem i.e the bolt in the pipe.
If you do a search on my name and the word 'Restrictor' you'll probably find the Pt.No you require.

I'm not 100% sure size the hole should be as never measured it, some people have posted saying it's 2mm, but I don't think it's that big TBH. The VF28 and TD04 use 0.9mm and 1.1mm IIRC.

Last edited by Scott.T; 09 April 2007 at 10:03 PM.
Old 10 April 2007, 12:46 AM
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vessy
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Give the solenoid a good check over and clean, someone could have put the bolt in cos the solenoid is bust

Last edited by vessy; 10 April 2007 at 12:46 AM. Reason: Can't spell !!
Old 10 April 2007, 07:44 PM
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Made another restrictor tonight out of a bit of metal, started with 1.5mm..

Took car out and getting 1.3bar easy not on WOT, had a little stab at WOT and saw 1.4bar peak!

Suddenly hit me.. module! Whipped the ecu out and there is a chip in the ecu with 52R 1,2 in big white print on a black sticker.

Removed chip, soldered a bit of bell wire in to re-connect J1 and..


Just been out for a play and it's hitting fuel cut now ffs

At first it seemed perfect, hit just under 1bar on WOT through all the gears then it started fuel cutting in 3rd, gauge would read a tiny bit over 1bar and it cuts now!

Would an induction kit make it do this?

The car is otherwise a standard sti v2, std exhaust, std downpipe.

And I'm only running a 1.5mm restrictor (should be 2mm iirc) With 2mm restrictor it'd be even worse.
Old 10 April 2007, 07:46 PM
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Ah, sorry Scott. Just seen this

I'm not 100% sure size the hole should be as never measured it, some people have posted saying it's 2mm, but I don't think it's that big TBH. The VF28 and TD04 use 0.9mm and 1.1mm IIRC.
So maybe the STI isn't even 1.5mm? That's interesting..

I'm wondering if those part no's relate to an sti too.

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Old 10 April 2007, 07:46 PM
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dan83590
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Buy the kit from Subaru..
Old 10 April 2007, 08:03 PM
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AFAIK all the Pre96 use the same restrictor as they all use the TD05 (except for WRX Wagon).

Fuel cut in a 7K is 15.96psi so 1.1bar. sounds like you found that with your tests.

Drop the restrictor down to 1.2mm, thats what I reckon they are.
Old 10 April 2007, 08:15 PM
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Buy the kit from Subaru..
Dan, thanks but my main concern is whether my 95 sti would have this exact part.

For example, an old post I found through google..

Post 96 - from invoices from when I dabbled to get boost to peak at 21-22psi.
part number 22326AA260 is for a 0.8mm (£2.28 +VAT back in 2001 !!
22326KA120 is for a std (on a UK98) 1.2mm - £2.02 + VAT (2001).
I found 1.0mm gave the desired peak with the ppp ecu and decatted exhaust and KN57 filter. All the experts of the day said I would melt pistons and the engine would blow - how wrong they were !!
Stan
Old 10 April 2007, 08:19 PM
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Fuel cut in a 7K is 15.96psi so 1.1bar. sounds like you found that with your tests.
hmm, it didn't seem like 1.1bar to be honest..

Also you say 6k and 7k ecu poss, but I'm sure it was a w6 or something (knew I should have written it down) maybe someones used that because of the module being in there (if it's the wrong ecu)
Old 10 April 2007, 08:42 PM
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dan83590
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Originally Posted by jameswrx
Dan, thanks but my main concern is whether my 95 sti would have this exact part.
If pre 96 models all had different size restrictors then all pre 96 ECU's wouldn't be interchangeable.

Originally Posted by jameswrx
Also you say 6k and 7k ecu poss, but I'm sure it was a w6 or something (knew I should have written it down) maybe someones used that because of the module being in there (if it's the wrong ecu)
This is a very high possibility. Don't know how you would find out which it is without the label on the top. The serial numbers inside must correspond to something eh???
Old 10 April 2007, 08:43 PM
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Well after a search.. it's an early wrx ecu. Seems someone's used the w6 as a vessel for this chip in Japan (presume they bought the whole ecu done)
Old 10 April 2007, 09:18 PM
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W6 fuel cut ia around 14.5psi and should boost to 11.47psi as standard.
Re: you PM, yes I can supply either a chip or a bespoke remap using the new live mappable adaptor and software....depends how much you want to spend.

Get the restrictor down in size so it's around 0.8/0.9bar and we can work from there....
Old 10 April 2007, 09:55 PM
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So with this ECU you should get about 0.8bar boost? In your picture is this a 2 port or 3 port boost solenoid? On my 3 port (93WRX) the bottom hose goes to the air intake and this is the only vacuum pipe with a restrictor in place. The pipe between boost solenoid and actuator is clear.
If you see post #3 I explained that there wasn't actually a restrictor in the actuator line in the end.
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