You're saying there's a straight through mid-section on it? Can't remember whether the 99-00 PPP includes a centre decat or not but it doesn't sound as though what you have there is standard. The tailpipe on the PPP back box is relatively subtle as far as I remember it.

No, something different altogether. There's a small brass bit in the boost control pipe that runs from the turbo compressor outlet to the t-piece. If you look carefully (or squeeze along the pipe with your fingers) you'll be able to see/feel it.

The restrictor has a precisely sized hole drilled through it that regulates the amount of air flowing into the boost control system. Your car should as standard have a restrictor with a 1.1mm bore. A common cheap and nasty mod involves replacing either with a smaller one from an STi or with something like a MIG welding tip. The smaller hole will deliver a little more boost but makes the car prone to overboost as it reduces the amount of air the ECU can send to the wastegate.

Given the "retrofit PPP" indicates a clear intention on a previous owner's part to get more power, it wouldn't be too surprising to find that the restrictor diameter had been fiddled with.

Seeing as it's relatively easy to check and rule in/out, try taking the restrictor out and checking the diameter of the hole. The easiest way to do this is to buy a 1.10mm drill from a local engineering supplies shop/model shop/etc and see if it passes through the hole.

It's worth doing the boost control pipework too - including the one running from the boost control solenoid back to the inlet manifold. Ideal opportunity to do it if you're going to have a look at the restrictor.

 

Splitpin, again on top form mate - much appreciated!

Ye the exhaust system fitted is definately not anything prodrive related. I did a bit more searching and it seem others have suggested a decat coupled with a prodrive ECU can cause boost issues similar to mine. Never realised these cars could be so sensitive..

Can someone take a picture of this restrictor?? I think i know which piece you're on about but not 100% sure?

 

The standard 99/00 boost control restrictor is 1.2mm (I've changed lots) the PPP one is smaller, I think 1.0mm but don't see many and have never measured one.

It's also possible the wastegate actuator has been tightened up a little, or the boost control pipes are split, or come off.

 

Far too early for that, problem ain't solved yet.

Yes, this is why I asked you earlier if it had a decat downpipe. If it did, there would be an obvious cause for the effect. Decatting the centre section makes comparatively less difference - but can still be a factor, especially if it turns out that there are other contributors - for example tweaked restrictor size.

There are plenty of areas where seemingly miniscule changes can have quite a marked effect. For example, if you find the restrictor has been altered, going from 1.1mm diameter to 0.9 reduces the amount of air going into the boost control system by something like 33%. You can also probably see now why gunked up boost control piping can cause considerable weirdness.

Someone's already been there and done that for you (hint: Google Images is your friend ). This is what it looks like:


http://media.photobucket.com/image/r...ictorPill5.jpg

And this is where to find it:

http://media.photobucket.com/image/r...rPill1.jpg?o=1

Linked just in case Photobucket barfs at the image embeds.

 

Righto. I'll attack this again tomo and report back. Thanks once again for replies!

 

Ok then. So took it all apart on my lunch break earlier:



I noticed the T-piece was pretty contaminated with oil. Wierd or normal?



And then removed the restrictor pill from inside (i had to split the pipe open to get the pill so will need a replacement - should be a 4mm inside diameter std vacuum hose yes?):



I got my drill bits out and a 1.1mm passed through with ease, and a 1.2mm passed through perfectly. So obviously a 1.2mm restrictor pill - this is normal right??

 

Yes, it's the correct size then.

 

How do you mean mate? Sorry i'm retarted with turbo related jargon.

 

Hmmm. This could be the problem then, as ZEN said standard is 1.2mm and Prodrive ECU matched pills should be smaller?

Could someone clarify what size pill a car runnning a Prodrive ECU should have?

 

On the 2-port BCS, which is what you have, a smaller bore through the pill will raise the boost pressure going through the turbo (as the smaller bore is restricting the air pressure from building up to the w/g actuator spring's crack pressure).

So yeah, the Prodrive pill will invariably have a tad smaller bore (certainly not larger) than 1.2mm. As Paul eluded to, possibly 1.0mm -- which would then mean some 30% less airflow from reaching the w/g, thus delaying its opening, ergo, raised boost pressure.

I think you need the PPP pill - you need to contact Prodrive to see if they have one (or at least find out the bore so you can contrive one yourself...)

 

So you think this could be the cause of the problems??

 

Paul is spot on about the standard restrictor being 1.2mm - earlier references to 1.1 were due to being half asleep at the wheel! However, to the best of my knowledge (which is flaky and largely secondhand, so if anyone knows better, go for it!) the 99-00 PPP retains the standard restrictor, unlike other model years (the 2001MY for example) where it is replaced. I've just searched the board and anecdotal stories from other users suggest it isn't changed - there are also a number of posts from people who've simply dropped the PPP ECU in and got the correct boost straight away.

Joz's description of the function of the boost control system is correct but not quite complete. It doesn't "invariably" follow that the PPP will have a smaller restrictor, for example.

It's also worth pointing out that if Paul is correct, and your car should have a smaller pill than it runs at the moment, putting one of this size in will give you higher levels of boost than you have at the moment. Therefore if your current problem is caused by fuel cut, putting a smaller restrictor in would make it even worse, not better. Indeed one of the easiest ways of fixing boost spiking on a car suffering from it is to drill the restrictor out a fraction bigger.

The one thing you are still not certain of is whether your "cutting out/holding back" problem is caused by overboost fuel cut or not. It's something we've taken forward as an assumption to rule in or out, but now you've ruled out an undersize restrictor, you really need to narrow it down a bit further.

Oh - and to answer one of you prior questions, good 4mm bore vacuum hose is the stuff to use to replace the broken bit, yes. The length and the relative position of the restrictor within that length of pipe are important so try and replicate the previous setup as closely as you can.

Before you put the bits back on, you said earlier that the pipes and T-piece were contaminated with oil. It's normal to see some in there coating the walls of the pipes, but heavy contamination (i.e. enough for it to be dripping out), isn't usual at all. This is commonly caused by overfilling with engine oil (that gets vented out through the breather system and finds its way into the boost control pipework.

As I said a few posts back, oil contamination in these pipes can cause overboost all by itself, so if it's as heavy as it sounds like you're suggesting, so one thing to do right now would be to shoot all the existing boost control pipework, and the solenoid, through with brake cleaner before reassembling it all and trying it again.

If that doesn't make any signficant difference, at this juncture it's possibly worth you either having your car looked at by someone who knows their beans, or, if you don't want to go that far yet, fit a boost gauge so you can actually see what's going on in this area. If it's spiking or consistent overboost leading to fuel cut, you'll be able to see it clearly on a decent gauge.

 

Well i've emailed prodrive direct to get a definitive answer on the restrictor pill - shame as i thought i was onto a winner.

Splitpin in regards to fitting a 4mm diameter pipe as a replacement its a definitie no no - i tried earlier and its way too loose, plus the restrictor pill 'floats'/moves about in the pipe which is obviously a big fail. I contacted Subaru earlier to try and supply the correct pipe but their parts screen schematic doesn't show up the pipe i need . They even faxed me a copy of what they could see on screen which, surprise surprise, shows everything but the T-piece plactic and the three attached pipes. So if anyone has the part number for this i'd be hugely appreciative.

Oh and in regards to the carb/brake cleaner, do i fire it into the actuator nipple and also solenoid with the green cables connected?

 

4mm *is* the correct diameter. If what you describe is happening it's because the pipe you are using is the wrong sort and has far too soft/pliant a wall construction. Most of the silicone-based stuff sold as vac pipe in ye olde chav tuning shoppes is too soft for this purpose.

Lol, probably more likely that whoever you phoned was too lazy to look through the different illustrations (or too clueless to realise there's more than one). The pipe is on the system - the part number is 807403060.

Not much point spraying it into the actuator. If I were you I'd probably take the solenoid off the car and jury rig a 12 volt supply to keep it permanently energised - then spray through it. However doing it on the car with Test Mode running should be good enough. The important thing is to see the cleaner flowing clearly out of the other port in the solenoid during the moments it's energised. It's easy enough to pull the control pipes off and spray them through.

Edit - when I was searching earlier there are also a number of anecdotal stories of people fitting the 99-00 PPP ECU on cars with decats needing to drill their standard restrictors out a bit (commonly to 1.3mm) to cure transient overboost. In most cases those were full or downpipe decats though.

Boost gauge would help you a lot here.

 

Saviour Splitpin on the part number.
As said though RE the decat, mine is only decatted downpipe/1st cat.
This help and searching you're doing is sincerely appreciated - if you were local i'd owe you a few beers.

 

No probs. It remains to be seen whether your dealer will be able to get you one quick at a price you want to pay though, this is IM we're talking about.

Yeah, I know, that's why I've been non-committal on ascribing the symptoms you're experiencing to overboost, while at the same time raising it as a possible explanation. If you had a full decat I would put money on it, as things stand it's not so obvious.

 

Sorry i meant to say 'mine is decatted AFTER downpipe/1st cat (2nd cat removed)' if anyone got confused reading this all later on..

Don't really know what to do now then as i'm 99% certain the cleaning of pipes and boost solenoid will make no difference. Getting it diagnosed at a garage is my last resort as i hate going into a garage with the mentality of 'i have no idea what's wrong, but i want it fixed' as it's typically a route of trial and error which equates to more money.

And Splitpin i'm sure the pipes fitted atm are all correct, they have a stiffer outer grey coat and softer black rubber insert so pretty rigid.

Stupid bloody turbo cars, think i might go back to n/a cars - much easier

 

Don't knock that til you've tried it, if the pipes had a lot of oil in them, it will make a difference. As for not knowing what to do next, you're getting frustrated at the moment because you don't know for certain what's causing the problem and don't have the equipment to diagnose it, so either go about addressing that or find someone who does.

Next moves are as above, clean the pipework out and try it. If it makes a little difference but doesn't entirely solve the problem, buy a boost gauge. If it doesn't make any difference at all, either buy a boost gauge or find someone reasonably local who knows their stuff. How far from you are Martyn and Alan Jeffery for example? You're likely to find a solution far more quickly and efficiently from someone like that than you will taking your car to some backstreet garage without the specialist knowledge.

Hang on, you said earlier that:

...and then when you said that "a 4mm diameter pipe as a replacement its a definitie no no - i tried earlier and its way too loose...", I read that to mean you'd bought some pipe locally to replace the split one. That's what I was referring to re. pipe walls being too soft.

Dude, you've bought a 9/10 year old secondhand car. As part of that deal you clearly accept that it might come with the odd glitch. Given that you appear to have discovered after the fact that it's got a PPP fitted, you've got more than you paid for - you just need to put a bit of effort into getting it 100%.

 

I work in a parts store/motorfactors so i just tried out the vacuum pipe we had here . 4mm inside diameter was the smallest we had and it was slightly too big. I called up Pirtek and they couldnt help either. But yes i need a replacement pipe for the one that houses the restrictor pill as mine split when i was removing the pill.

I think a trip to Alan will be needed, can't do that yet though as the car needs new bloody front discs and pads - 500 odd quid from godspeed which is the cheapest place ive found so far.

 

Just put it all back together and thought that the Prodrive ECU requires an upgraded intercooler? Mines the standard one so this will obviously be the cause of my woes? ?

 

Whatever it was you tried, bottom line is that it's too soft. The restrictor pill is something like 5mm OD and so should sit tight in stiff (enough-) walled tubing. Subaru stuff's 4mm and, as you found out when you tried to get the pill out of the original one, is clearly tougher than the stuff you tried. Don't forget this pipe has to deal with pressure rather than vacuum so needs to be a little tougher than regular vac pipe.

You don't know that yet. Have a proper go at cleaning the pipes, fit the standard dumpvalve and, if you're still having problems, a boost gauge. At least then you'll know whether or not it's overboost you're dealing with - and if it is, you will probably be able to fix it yourself via enlarging the restrictor slightly.

No and no. The PPP doesn't use an uprated intercooler, the only thing that is upgraded in that area is the y-pipe between the turbo and IC, which changes from a horrid moulded plastic one to a cast Y with a Prodrive branded silicone elbow. It looks from those pictures like you either have the proper part - or a third party copy of it.

 

I don't want to get too involved as splitpin has it covered, but.. Reading through this post I cant see if we have confirmed whether this is overboost or not. Have you got a boost gauge? Perhaps rule that out first?

 

Splitpin do you know the part number for the pipe arrowed below (the one with the elbow that contains the pill? I ordered the part number you suggested and it was the shorter one. Cheers

 

Damn and blast to dealers' parts databases!

 

Yeh tell me about it - that inch piece of pipe was 6 quid too!! Biggest **** was though I got a parking ticket whilst I was there. FML

 

The anger you must have felt, all round.

 

So with the parking ticket thats a 41 quid piece of pipe.. and it's the wrong one. Fuming

 

Ouch. I gave you the correct (according to the parts database) number for that pipe before Greeny, just double-checked it. If you got the other one, the parts system must have an error on it somewhere.

The number for the "other" hose (the one between T-piece and wastegate) on the parts database is 14449AA080, which has a description of "Hose, turbocharger". Given the possibility that the two hoses have been switched around in the parts database, it might be worth ordering that one and seeing what it turns out to be - although there's obviously a risk of ending up with another of the "wrong" ones.

If in doubt get the dealers to look up figure 040 on their system.

 

Opposedforces has the numbering the same way round too:

http://opposedforces.com/parts/impre...turbo_charger/

According to them it's 807403060 for the one between the compressor and the T-piece and 14449AA080 for T-piece to wastegate. Odd! Hopefully it's just Subaru transposing the two in their database and so ordering the "other" number will get you the one you want. If it turns out that way one would hope that the dealer will give you a refund on the wrong one, seeing as it's clearly Subaru's mistake.

Edit: When your dealer gave you that pipe Greeny, was it in a polythene bag complete with a part number sticker, or was it just supplied loose?

 

Yeh because i work for a parts company we're in constant contact with main dealers so they knew who i was and said it'll be fine to get a refund as i said as soon as i saw it that's the wrong one but was hoping it might work - but obv not.

In answer to your question splitpin, look below: