DeanS15

iTrader: (1)

i need some help if anyone can....

Basically I installed a prosport boost gauge as soon as I got my car to check the standard boost level (tee'd into the bpv), it seemed correct, peaking at 16 psi.
The other day I removed the intercooler to clean the bulkhead and put a dab of grease on the tip of the clutch piston to stop a squeak, while I was there I renewed the vacuum hoses to the solenoid for silicone, they were the same bore and same length as the originals. Unknowingly I didn't refit the restrictor pill and was only getting 10 psi of boost afterwards. I've since refitted the restrictor pill in the new hose and put everything back together, re checking the lines go where they're supposed to, and now I'm getting 20psi, I've been watching the boost ever since and being careful not to go over 15psi but obviously I need to find out why it's doing this to sort it out properly but I'm starting to scratch my head... I thought maybe a boost leak would cause it but idle seems good under vacuum so maybe there just at leak when I get into boost but I can't think where from.

The only connections touched were the vac lines in the boost control system and the breathers that attach to the tmic also the throttle body hose and turbo inlet and bpv and everything is tight with a smear of sealant on the bpv gasket.

The car is an 06 blobeye sti uk with a cat back 3" green panel, pfr7b's and no tune. It was fine before, any ideas why it's over boosting now would really be appreciated

Thanks in advance.

XDevil666

WAstegate pipe on right?

riiidaa

iTrader: (2)

you renewed the bit the restrictor pill sits in? With an aftermarket alternative?

DeanS15

iTrader: (1)

The original restrictor pill is back in between the turbo outlet and tee, no splits in the hoses and they're on properly...

DeanS15

iTrader: (1)

Has anyone else got any ideas? Gonna strip it again today and recheck everything but I can't really understand it still. I drove it last night and noticed a whistling on boost - this tells me boost leak - is the bypass valve gasket prone to not sealing properly? Thanks in advance

DeanS15

iTrader: (1)

Well I stripped it all down again, checked everything and put it back together. Still 20psi... Can't see the source of any leaks.,

propofol

Is the original pipework for the restrictor pill still useable? Could try putting that back on and seeing if it solves the problem. My pipe with the pill in is quite stiff so I was wondering if pressure was getting past your pill in the silicone house?

DeanS15

iTrader: (1)

I did wonder that, but according to loads of info if extra pressure got by it would cause less boost as the smaller the opening the higher the boost which would fit with only making 10psi without the pill in place. This is a real head scratcher ive never had anything like this on other turbo cars. I've now tried cleaning the solenoid with no difference, refitted the cooler again and no difference. I must be missing something but don't know what. Thanks for the suggestion anyway. I was looking to get it mapped soon, I've brought that forward and am going to avoid driving it if I can until then, that way they can tell if there's a leak, check for det and afr's etc to see if the problem shows up there...

propofol

A real head scratcher for sure! My understanding was that the line with the pill in it bled the pressure away that was going to the wastegate actuator. If the pressure bled away too fast then it would take more pressure to trigger the actuator and lead to higher boost. however this doesn't fit with your experience of having no pill in at all! I'll have to think it all through again!

propofol

I've reread this article which explains the difference between 2 and 3 port solenoids: http://www.scoobypedia.co.uk/index.p...tRelatedIssues
Being an older car mine has a 3 port design where an increase in flow through the restrictor will increase boost. A 2 port design works differently and an increase in flow will reduce boost pressure. Unfortunately this doesn't really solve your problem!

DeanS15

iTrader: (1)

Thanks for even having a look into it for me, any suggestion is worth looking into. My previous cars have aftermarket controllers fitted which just interrupt boost between the turbo outlet and actuator, 2 short lengths of hose and no restrictors or anything. I have a feeling that it's a leak of some sort, response isnt great despite the overboosting and there is a slight whistle on boost, also I think the turbo is having to work a little harder as the car is warming up quicker - it's not cooling related as nothing has been touched. My main concern about this is air getting in post maf under vacuum and causing a lean out in the mixture which is why I don't want to drive it till it's sorted, but how this explains overboost I don't know...

madscoob

iTrader: (3)

get another pipe make sure its the same internal diameter and length as the origional and refit. oh and fit the pil to it lol

propofol

One last thought. I don't suppose the pill got squashed when you removed it from old pipe thereby reducing its internal diameter? Bit ofa long shot!

MartynJ

It is possible that the pill is partially blocked making the restriction even smaller and therefore raising the boost.

DeanS15

iTrader: (1)

The pill is perfect and clear... I've ordered a new 90 degree turbo to intercooler hose as the one I took off isn't in the best shape, it's darting to separate here the metal bracket is but doesn't look completely split. I'm guessing now if I refit everything and plumb turbo outlet straight to the actuator I should see around 5psi and that will point all fingers to the solenoid bleed hose circuit, if that's the case I'm going to get it set up again in case whatever has altered just needs to be dialled out with a tune this would be best ase scenario...

propofol

Best of luck and hope you get the problem sorted mate.

jason_2013

Can you manually open the wastegate ok and it springs back ok?

jason_2013

double post

Globy

I've a stock 00'classic turbo, and I'm reading 16psi max, and then lower to around 12psi.
Is this the normal boost pressure??

Globy

up

riiidaa

iTrader: (2)

start your own thread

DeanS15

iTrader: (1)

Thanks for any input, now I've a slightly different question relating to the same thing...

I'm getting it ready for a tune and I've now fitted the turbo back catless dp, the boost issue is still there I think but in the meantime I'd like to run the car around to empty the fuel tank so I can fit the walbro....

So...

I've connected the turbo outlet direct to the actuator to run spring boost only and plugged the hose to the solenoid. Will this be safe for the time being until I get to my tuner?

Thanks again people, I appreciate the help. The impreza is a bit of a mystery to me, the sr20det's I come from seems so much more simple

DeanS15

iTrader: (1)

Anyone? I'd just like to know it will be safe driving the catless car around on actuator boost until I reach my tuner in a week or two. I've driven it and although it's now making only 8 psi and not being driven hard it still seems to drive fine I just wanted to know if there are people who run safe boost levels after changes until they get mapped. Cheers again

tubbytommy

iTrader: (20)

if its only for a short while just drive it off boost until its mapped then it cant overboost.

DeanS15

iTrader: (1)

Also whilst it's being mapped I'm gonna get a 3 port (that im used to) set up on interrupt and do away with all the bleed and restrictor pill nonsense.... Are there any recommendations?

DeanS15

iTrader: (1)

Cheers, that was my thinking, but I was concerned about the second lambda sensor post cat, wondered if it might tell the ecu to lean off the mixture now it's seeing pure emmissions

tubbytommy

iTrader: (20)

??

I think you need to speak to a mapper as im not sure you have a clue what your doing.

a 3 port is recommended but a bleed valve.........if your car has one of these bin it asap as its been messed with by a tool and the restrictor pill needs to be there.

changing the boost without adjusting the fuelling will cause a large and expensive bang

DeanS15

iTrader: (1)

Mate I know what I'm doing I just don't know the Subaru setup - they seem to have made things a bit more complicated than Nissan do I'm talking about the standard bleed type boost control system Subaru use, I want rid of it and switch to direct interrupt and do away with the restrictor pill arrangement. I wouldn't use a mechanical bleed valve or Dawes device or anything like that when there's already a tuneable boost control system built in, just want to go with something I know.

tubbytommy

iTrader: (20)

decat will be fine, just drive off boost until its mapped.
id speak to whoever your mapper is and explain what your trying to do and im sure they will advise you.

DeanS15

iTrader: (1)

Cheers. Well I'm In contact with him anyway, just wondered if there's a general consensus on 3 ports here. I'll just go with what the tuner likes to set up then...