Noticed my car is overboosting hitting 2bar what causes this have checked vacuum hoses

 

could be cold weather

 

Car is mapped to 1.65bar would cold weather cause that much overboost

 

doubt it

probably sticky solenoid

 

Thinking that as its running 2 port as i forgot 3 port on mapping day

 

noticed mine shoot up to 1.7 the other day, mapped to 1.4 - 1.5.

cold conditions i expect, driving fine with no problems.

siv

btw way i have a 3 port

 

Mine drives fine was just worried as 2bar is a lot

 

Forged or standard block ?

Siv

 

Standard 2003 sti jdm over 400bhp

 

probably try cleaning out the 2 port and go from there

running 1.6 bar on 3 port long with target boost set up on ecu, so should never over boost

 

Forged Pistons then afaik.

My builder said my block would cope with 2 bar + without issue but I'm no expert on the strength of a jdm engine.

Sorry I can't help you more buddy.

Siv

 

Thanks for the info mate

 

if its mapped for 1.65 and overboosting to 2 bar its got a serious issue, get it looked at and keep it off boosting till its looked at.

 

Going in to garage this week

 

Guys forgot to mention i fitted a catch can so tmic was separated from recirc valve could it be the paper gasket leaking as reused it

 

Shouldn't the ECU be remapped to fuel cut well before 2bar?

 

pretty sure fuel cut has been removed to get it to that pressure anyway

 

Not sure but mapped to 1.65 bar so dont if fuel cut would still be working

 

i cant remember the exact figures, but when i asked the question myself, the standard ecu can only see up to a certain level of boost, you don t want to go above that because it wont know what the boost is doing and may not add enough fuel. So to stay safe it need to be set the target lower than than to allow some head room for overboost.

if that makes sence at all lol

 

It's entirely possible to retain the boost cut if you change the map sensor to one that can read above the boost pressure you run.

 

UK cars about 1.5 bar, JDM newage 1.65 bar is about the limit the ecu see's from memory

 

The ecu just sees voltage from the map sensor, it then converts that into a manifold pressure.

 

But will me reusing my tmic to recirc valve cause a leak

 

Gasket? Very very unlikely to be leaking, has mine appart more times than I can remember, never a problem.
A leak will not cause overboost anyway, very much the opposite.
Perhaps you have interfered with boost control pipe work though?

 

So look at 2 port and the two hoses attached to it

 

I had perished vacuum hoses going to/from my solenoid causing a 2bar over boost on my classic. Worth a look!

 

• Quote:

  Originally Posted by peter zippy reid

  Mine drives fine was just worried as 2bar is a lot

Mine drove fine too untill my boost gauge alarmed at 2.0 bar and flew round to >2.5bar and something just went tack tack tack up front.

All because my cheap MBC jammed as stupidly Id had fitted while waiting for my new WGA with adjustable spring tension to arrive from Kinguwa.

Do yourself a favour and check that the WG actuator is still opening smoothly, you need to get an air line on it with about 1 bar. If it does not move , you found your problem.

 

Just on this it should start to open around 7/8psi or 0.5bar I believe (mine does anyway).

 

That's probably fine for yours "starting to open" on a 2 port system, and unless you have a forged engine I imagine your aiming at considerably less than his 1.65bar ?

Whatever , it should open smoothly and as you cannot watch it while you drive you should test it statically, as they can jam. its also worth to take a look to check that you have 3mm of pretension on the WG rod , otherwise the WG will open later than you wish if the arm is too tight or you lent hard on the mount bracket while fixing something else ?

WGA opening rate ultimately depends on what engine /turbo/ BC system you have and if you previously did anything to improve boost control on a WGA.

I found on the 2 port STD boost solenoid for control that I could not even make target boost with the WGA that came on the New Turbo.
So If you are aiming to reach 1.65 bar then you either need a 3 port system or you probably need a spring rated at least 0.8 bar to avoid the WGA opening prematurely on a 2 port , (which kills your low rev range torque) That's why Kinugawa do a range of springs to fit. ( Rated at WG opening 1mm add 0.3bar for 5mm opening ) ,

I found I can use the 0.8 or 1.0 bar spring ok but the one rated 1.2 bar tends to overboost a little for my 1.5 bar target on a ported TD05 16G.

Now that I explained at that It will probably be something completely different , but at least you would have killed some time

 

Mine is targeting 1.2bar on a 3 port system. I tested mine statically using an air line and my refrigeration test manifold for accurate pressure readings and control. I should have said that its for the standard actuator on a TD04. My point was to the OP that it opens progressively with more pressure being applied so he knows what to watch for. I guess identifying his turbo and waste gate actuator would help.