boost issue

popsy b4

Sunday Drivers
Have this wierd boost issue with the car sometimes i change from first to second say at 6k and the car pulls in second no prob other times i get what i can only describe as lag then boost

sometimes if i am in second and accelerate the first turbo wouldnt come in at all even when i change i wont hear the dump valve other times i get. 8 bar and feels lovely to drive then no lag at all

caught me out badly on a secondary road overtaking i went from 5th to 3rd pulled out and tge car was just like an na car no boost


i was thinking either actuator on first turbo, bad map on ecu, maf sensor? ??? Any opinions?
Any one from cork is free to take a spin if they want kind of hard to describe the problem
 
Hey popsy,

Same thing happens in my Legacy, pain in d hole!! Ye sometimes it feels like the turbo isn't there. Changing from 2nd to 3rd and the first turbo wont work, depending on the revs!
Hard to explain alright.
I haven't an answer for you but at least its good to know your not the only 1!!!!
 
[quote author=Jasper link=topic=34634.msg396911#msg396911 date=1338665704]
Hey popsy,

Same thing happens in my Legacy, pain in d hole!! Ye sometimes it feels like the turbo isn't there. Changing from 2nd to 3rd and the first turbo wont work, depending on the revs!
Hard to explain alright.
I haven't an answer for you but at least its good to know your not the only 1!!!!
[/quote]

must be something common so must do some further investigating
 
:happybday:[quote author=dave b link=topic=34634.msg396919#msg396919 date=1338666513]
no doubt 1 of many sensors
[/quote]

any idea of the best way to go testing the sensors? i have a diagnostics reader but i am getting no error codes on dash so that might not be any good
 
Did have a HKS SSQV on it but took it off a while back.

Been hearing that they dont run great with them. But I dont think thats the problem, mines been off a while an it still happens. Im in d middle of gettin a new gear box, should have the car back by thursday hopefully. Will give it a good spin an drop it from 5th to 3rd like you did and let u know how i get on.

But the same problem definitely happens to mine. Ill ask davelegacy when im down there.

Hows your car when it starts from cold? Mine takes a few min to get going right, has to warm up, or it stutters and is very jumpy. I heard that this can be a problem with the MAF sensor, maybe yours is the same an its related? Im only new to Subarus so im just guessing.
 
Ya can be a bit funny when cold also come to think of it ,might try cleaning the maf sensor or replacing see how it goes
 
Try cleaning the boost solenoid out and make sure all the boost pipes are in good condition

if any of them look suspect try sealing them with silicone etc and see if that solves the issue!
I know boost pipes on b4s are tricked flicker so i wouldn't suggest removing them unless you know what you are doing
 
Im using a hks boost controller and it has its own solenoid so is the standard solenoid still in use?
 
[quote author=goosie208 link=topic=34634.msg396988#msg396988 date=1338710894]
When you change down into third from fith were are the revs? Sure your not just changing into the VOD??
[/quote]

Sounds like it. Used to happen me changing from 1st to 2nd an odd time if i changed around 4,000 rpm
 
The vod should literally last the time it takes you to say "bang, bang" and by that time you will have surpassed the primary turbo boost. The only time it should cause a problem is when you change gear back right into the middle of it and its effecively confused as to whether it should be in primary or secondary setup and it takes couple of second to boost again.

There is a black box on the driver's side turret full of solenoids. Any one of them could cause a problem, those solenoids control the changeover actuators and valves on the secondary turbo exhaust inlet and intercooler inlet.

So if one of them is sticking closed when you move from the primary stage to the secondary stage, then you will experience a big drop off in boost which will cause a huge increase in vod. If you get no boost at all in the secondary stage, then its more than likely the exhaust valve thats stuck closed. If you get minimal boost, then its more than likely the intercooler valve thats stuck closed.

As well as the solenoids possibly causing the problem, it could also be either actuator or its very possible that the exhaust flap just before the turbo is completely caked in carbon build up which is causing it to stick.
 
Its not the vod i know how that feels its something different, its only on the ptimary turbo i get issues secondary turbo boosts perfect every time
 
The same as I described still applies to the primary, if you are in the primary stage and the secondary exhaust valve is open, the you are only going to get minimal boost.

If you are in the primary stage and the secondary intercooler valve is stuck open, then you will get no boost whatsoever..
 
[quote author=Sweetcakes link=topic=34634.msg397012#msg397012 date=1338728144]
The same as I described still applies to the primary, if you are in the primary stage and the secondary exhaust valve is open, the you are only going to get minimal boost.

If you are in the primary stage and the secondary intercooler valve is stuck open, then you will get no boost whatsoever..
[/quote]

ok thanks must get time to go mess about with it now im a very busy guy ha
 
Your using a stand alone boost controller?

Put it back to stock see what that does

Just out of interest what have you set the boost at :ponder2:
 
The boost controller in conjunction with a hks f-con ecu so should be set up correctly as per when it was mapped originally.
 
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