Rich D

iTrader: (12)

It seems that one of the previous owners of my car replaced the actuator & solenoid pipework with silicone hose and they have (probabaly unknowingly) discarded the restrictor pill

Now I've only had the car a few weeks and always thought it was lacking in performance and didn't really come on song until 5000rpm, but thought it's because I had been used to 283bhp & 294lb/ft previously. However after a discussion with another scooby owner at work yesterday, I checked last night and discovered the restrictor pill was missing.

So after hooking up a boost gauge today I now know why it feels slow, I'm only getting 0.6bar of boost!

Now on the early cars no restrictor would have meant an increase in boost, but on the later Classic's it has the opposite effect and a larger (or no) restrictor decreases the boost, which ties in with what I'm seeing.

Therefore I need a restrictor pill for an MY99 (V5) Turbo 2000 UK car, I believe it's the 1.2mm one?

Although I am about to fit a PPP ECU, so do I need a different size?


I've searched on here, but not found a definitive answer...

scooby1doo1

iTrader: (7)

Yes 1.2 standard and 1.2 for ppp. All the info you need, is below.
https://www.scoobynet.com/technical-topics-archive-427/

Rich D

iTrader: (12)

I've already seen that sticky, thanks

although in the sticky thread you've contradicted what you've just told me?

mrmarc

iTrader: (6)

pm sent

scooby1doo1

iTrader: (7)

yes but I did not no at the time that my car had been mapped with a 1mm pill, but standard is 1.2 on your car.

Rich D

iTrader: (12)

great, thanks for the help

Rich D

iTrader: (12)

well, I fitted a 1.2mm restrictor pill today and it's now overboosting...

according to the gauge, I'm peaking at 1.3bar now!?

so it's quick, but I can't keep it like that, otherwise it will end in tears very quickly and I need to get this sorted ASAP

I've even checked the hole in the pill and confirmed that it is definately 1.2mm

so why is this happening, I thought standard boost on a UK spec MY99 was 0.9bar?

any ideas?

Splitpin

You're right about the boost target being iro 0.9. However, if you have a standard MY99, 1.3 shouldn't be possible as fuel cut is set at 1.22. There are a couple of obvious possible explanations:

1. Your car has had an EcuTeK remap
2. There's something wrong with the MAP sensor
3. You're misreading the gauge and are actually seeing 13psi rather than 1.3 bar.
4. Your gauge is misreading.
5. There's something fundamentally wrong with the ECU or boost control package.
6. There's a fuel cut defender/boost clamp or other piggyback device in play somewhere.

And no, I'm not insinuating you're thick on #3, but more than a few people have done it, so it's worth a double check. 0.9 bar is 13.05psi so it does fit the facts as we currently know them!

Couple of obvious things to look at would be the ECU can to see first of all what part number's on it, and also check for the presence of unusual stickers or odd looking little black boxes spliced into the loom.

Also, if your gauge really is reading 1.3 bar, it'd be worth trying to get hold of another gauge to act as a control, or even DeltaDash/ECUExplorer etc to have a look at what the ECU's doing - and in particular the level of boost it thinks it's setting.

Rich D

iTrader: (12)

I'm going to pull the carpet up shortly and invesigate the ECU, will report back

are the MAP sensors known to fail?

the gauge is a 60mm Blitz mechanical one, so not some cheap eBay special, however I am finding myself questioning how accurate it is

I'm seeing approx 1.3kg/cm2 according to the gauge, which is near as damn it 1.3bar and yes I am reading it correctly

thanks for the help

Rich D

iTrader: (12)

ok, the ECU appears to be standard and it also looks like it's not been disturbed since it left the factory, no extra wiring or piggy back units in sight

it's this one >>>



how would I know if it had been ECUTek'd?


the next thing I need to check is the accuracy of the boost gauge, which I'll try to do tomorrow

although if it is wrong, I can't see it being massively wrong and showing 0.4 bar higher


after that, I'm going to see if I can borrow another known good MAP sensor, trying that on my car and going for a run to see how the boost behaves

I'm actually hoping this is the case, as it would be a quick & easy fix


I've got a PPP ECU to fit, but I won't be doing that until I get it running correctly on the standard ECU

Rich D

iTrader: (12)

what are the chances of it being the MAP sensor?

if the restrictor is removed, it runs a solid 0.6bar in all gears, no tailing off at higher revs and the car does run well, albeit not as quick as it could be, I've been driving it like that for 2 months

could I not just drill the restrictor pill out (I've got a set of tiny drills in 0.1mm increments) until I'm seeing the correct boost?

or is that just going to be masking another problem?

Jamz_

iTrader: (12)

To know if there is a piggy back unit you will have to open the ecu up

Ie:

*look at the top right hand side of the ECU (i have a chip fitted but if you have ELS or something like that you'll see a big piggy back block going over the ECU)

Splitpin

It's possible, but not particularly likely that the sensor would malfunction in exactly the sort of way you're reporting here - i.e. causing a consistent over-boost.

Aye, AE800 just as you'd expect to see on an early MY99.

Take it to a TeK mapper and ask them to plug in and check it. Will be able to tell in 10 seconds.

Or, if you already have (or can get hold of) a bare ISO interface and the ECUExplorer software, you can find out yourself whether it's still running a standard ROM image - if this is an option pm me and I'll tell you how.

Would be worth getting hold of an interface and the software so you can cross-check the ECU reported manifold relative pressures against your gauge anyway. They should obviously read the same!

While it isn't conclusive and is still in the ballpark for "normal" that 0.6 bar actuator pressure you're seeing is on the high side of the expected number.

That could simply be because the actuator's on the tighter side of normal though, it doesn't directly imply that the gauge is over-reading. Could also be because a previous owner has tightened it a bit - but even if that was the case, if everything else was normal the ECU would compensate by dropping a bit of wastegate solenoid duty cycle to maintain target boost.

As a matter of interest what sort of idle vacuum are you seeing when the engine's hot, and, most importantly, does the gauge needle sit right next to the "0" when the engine's off, or does it read slightly positive?

Also where are you connecting the gauge, the spare takeoff on the front of the inlet manifold?

Fingers crossed but it doesn't sound at this point like things are going to be quite that easy.

Ahh, that's interesting. I can understand your logic totally and would normally agree but given where you are at the moment, if you can't diagnose the ECU directly, fitting the PPP one is probably a legitimate passive diagnostic step. Albeit driving carefully at first, if you find it boosts at 1.1bar or thereabouts on the PPP, you probably have your answer (i.e. the other ECU is non-standard).

Splitpin

It's more likely to be masking another problem, or possibly interfering with an ECU running a custom map. If you do have a standard ECU, then it should run properly on a 1.2mm restrictor (and should be constantly fuel cutting rather than maintaining 1.3 bar boost).

Under these circumstances drilling the restrictor is trying to treat the symptoms rather than identifying the cause. The latter is the way to go. If it turns out you bought a car with a TeK custom map on it - great, you can flog the PPP unit. If there's something in there causing it to overboost, again, you need to know and fix it the right way.

While we're on the subject are you using a real Subaru restrictor or a homebrew/MIG tip? If the latter, how long is it? Also are you sure it's in the right place? Needs to be in the pipe between the compressor outlet and the T-piece, approx an inch away from the T.

As Jamz suggests, it's also worth taking the four screws off the top of the ECU can to check for an internal piggyback board. The pic he's posted is of an older unit - yours will look completely different inside, but what he's saying is correct. If you look inside and see anything with wires sticking out of it soldered onto parts of the board, then post us up a picture.

When it boosts at the moment, by the way, does it get up to 1.3 and sit there consistently, or is the gauge needle flicking round all over the place?

Rich D

iTrader: (12)

all sorted now

after checking the car over this morning I found a loose pipe, on the MAP sensor intake, which would allow boost to leak and the MAP sensor to misread, causing it to run more boost than it should

I then went over the whole boost control system, checking every pipe, making sure it was all fitted correctly & securely, then I hooked up the boost gauge, crossed my fingers and went for a test drive

it now hits 1.0 kg/cm2 on the gauge and tails off to around 0.7 kg/cm2 at higher revs, no spiking and the car feels to be running well

had it on the rollers at Prosport this afternoon, it made 252bhp & 248lbft


thanks for all your help & advice

Splitpin

Result, and kudos for the perseverance and attention to detail.

Was that rolling road session done on the standard ECU or the PPP one?

Rich D

iTrader: (12)

in answer to your other questions:

- yes, it's a genuine 1.2mm Subaru restrictor pill

- the boost gauge is taken off the spare middle port on the inlet manifold

- the needle sits exactly on 0 when off, can't remember vac readings at idle off hand

- I wasn't holding the throttle open to maintain the 1.3bar for more than a couple of secs, but I did get boost cut sometimes

- boost was also varying, 1.3bar was the highest I saw


I am still going to try another boost gauge to compare readings to mine

Rich D

iTrader: (12)

that was with the standard one, as I wanted to make sure it was running correctly as it was without introducing something else into the equation

incidentally I had the lowest result of the day, LOL

wrighty338

iTrader: (33)

is there ever a point you dont need a restrictor pill then, what about all these big hp cars? do they have suitably massive ones?

Rich D

iTrader: (12)

you've got it the wrong way round... a larger pill means less boost

however for big power cars they'll most likely be using another form of boost control and not the factory setup

I had an Apexi AVC-R on my previous car

wrighty338

iTrader: (33)

junked mine ages ago, got both simtek + AVCR now, didnt think i needed it

Jamz_

iTrader: (12)

I was reading somewhere before saying that earlier cars were the other way round... no pill = less boost and a smaller pill = more

Rich D

iTrader: (12)

on early cars, a larger pill = more boost and a smaller pill = less boost

on later cars, a larger pill = less boost and a smaller pill = more boost

Jamz_

iTrader: (12)

Thats the one... and also 3 ports on an early don't need a pill?

The Rig

iTrader: (13)

Glad you got it all sorted

why would anyone want to remove/fit smaller on later cars, the restrictor pill to gain more boost,im guessing only if othe rmods are done, remapped to suit more intake etc, i see some guys and they tell me they are running like 1.1/1.2 boost and im thinking,surely more boost will cause the blok to go pop if bigends/headgaskets arent uprated etc ?

i have a 95 import which hits 0.9 bar,(standard) if i increased boost im sure it would go bang

or have i got it **** over t1t ?

Rich D

iTrader: (12)

if you run more boost without a remap, you are just asking for trouble as it will not be fuelling correctly and running lean is baaaad