**jay**

iTrader: (1)

Hi, im looking some help on this as its starting to anoy me,
i have a sti ra with simtek ecu vf35 turbo 550cc injectors runs a 3 port boost control,

It has dual maps 1.4 and a map 0f 0.8 just resently the 0.8 map has been creeping alot it hits 0.8 but higher revs its starting to rise to a 1.2 bar would a faulty 3 port cause this (cleaned it out but still the same)

Cheers
Jay

RA Dunk

The cold weather can cuse a bit of boost creep.

happydude303

iTrader: (1)

the 3 port could have had its day by a 3 port from simtec or even harvey smith for 65 quid and pop and go back to your mapper and get it check dude it happen to me a few years back i change the 3 port job done

**jay**

iTrader: (1)

Cheers for the quick replys, i may just order a new 3 port and see if it sorts the problem out, its only just started doing it and its not been as cold,
it seems to work well enough in the freezing conditions untill now

Grant74

iTrader: (10)

Did you have an intake temp sensor fitted with the Simtek? If so, make sure its setup and working properly- my understanding was that if you have the intake temp sensor, it should adjust for the air temp/ density.

However, the function does need to be switched on, nd 0.8 is very low- why not just 1 bar as standard- easier to control I would have thought, as 0.8 will be so close to actuator pressure on average.

**jay**

iTrader: (1)

i bought the car from bedford was mapped by jgm, it usually runs great it seems very well mapped, the 0.8 map was for lower grade fuel i always run it on v power though.

yeh a bar would be better but quite like the 0.8 as its very drivable in bad conditions .
It seems to hold boost on the 1.4 map though.

Its has a sensor on the pipe from the fmic but think thats the one for the i/c spray.

Grant74

iTrader: (10)

Ask jgm about what's switched on and what that sensor is- he will sort it out

Big 'D'

I know I will get slated for this but I will say it anyway , the VF35 is very prone to boost creep if it is run with a full decat and the only way to sort it is to port out the wastegate, have you tried running the car with the wastegate actuator connected directly by a pipe to the turbo compressor outlet so that it should only run wastegate pressure and takes the solenoid out the loop, if it still creeps then its defo the wastegate port.

Cheers Iain

Turbotits

iTrader: (2)

i tend to agree i dont think its at all simtek or control valve problem. i used to get the same on my vf35 with ecutek when on the low boost setting. at high revs in high gear on a cold night i could see maybe 1.3 bar, although should have only been running actuator pressure a 0.9

**jay**

iTrader: (1)

I've heard about the problems with the vf35 with boost creep, its just strange its held boost perfectly for ages and now its just starting, going to run it just off the actuator tomorrow to see if its the bcs.

dynamix

iTrader: (3)

Generally speaking the cut down map on the simtek runs very little wastegate base duty anyway so it will be unlikely to be the 3 port at fault here if it is not doing it in the 1.4 bar map... just characteristics of the turbo/exhaust.

If you port the wastegate to reduce creep on that map it may have the effect of reducing boost at the top end onf the proper map which will need to be compensated for within the map.

**jay**

iTrader: (1)

Its now started doing it on the high map aswell so defo got a problem somewhere, not sure what do do with this, dont really want to take a gamble and buy a new 3 port as subaru want silly money for one, its defo not the cold weather as the temps are very mild just now.

**jay**

iTrader: (1)

Just tried running off acuator only and its still creeping way up, car has had the vf35 on for a couple of years so not sure why its doing it now.

dynamix

iTrader: (3)

Make sure the actuator arm is moving freely - it could be sticking half shut or similar.

**jay**

iTrader: (1)

Cheers will have a check tomorrow as the car always ran great, and held boost perfectly.

**jay**

iTrader: (1)

Made an error with the turbo, its actually a vf 34 oops, is that also prone to boost creep

Big 'D'

Not really mate, it is more likely to be the actuator as Dynamix has said.

Cheers Iain

**jay**

iTrader: (1)

Just checked the acuator arm and its moving freely, also put 15psi on the actuator through a footpump and its opening and holding.
could a week actuator cause this? always thought a week actuator would strugle to produce and hold boost rather than creeping.
It also flutters at between 1.4 - 1.5 bar
cheers for any help on this as i have run out of ideas.

Big 'D'

You are correct weak actuator spring would cause the opposite ie low boost and slow spool, to allow creep the actuator would have to be leaking servo air or blocked which would slow/prevent the wastgate port from being opened enough to control the turbo. Is your actuator a standard one? Although the actuator has visibly moved and is holding perhaps it is stiff to operate or restricted in some way, for example a turbo heat shield rubbing on the linkage etc (just an idea), any restiction in movement would increase the effort required to open the wastegate.

Have you altered anything in the exhaust or intake recently? Is your intake a std Subaru one?

Cheers Iain

**jay**

iTrader: (1)

I can move the actuator quite freely( has good tension on it) does not seem to stick on anything.
Yeh its just the standard actuator.
only thing differnt latly was i changed the plugs from 6b's to 7 b's gaped to 0.65 and it started not long after that.
Cant see why plugs would be anything to do with it though.

Big 'D'

Also have a look at the outlet nipple on the turbo compressor housing and make sure that it is not damaged, cracked or gunked up at all, obviously if there is any leak or restriction there it will have a huge effect on the control of the wasetgate.

Cheers Iain

harvey

iTrader: (48)

What you are describing is boost creep. The VF34 particularly and the VF35 to a lesser extent can suffer from boost creep. This is a build up of exhaust gas in the exhaust housing unable to escape fast enough with the wastegate open.
We never work on a VF34 without porting the wasyegate and generally will do the same on a VF35. Common problem and well recognised.
All the porting does is increases the volume of gas that can flow through the exhaust section or wastegate. Obviously the turbo has to be removed to do this.
We also use a Mityvac pump to check and set the wategate actuator.

I am sure it is not your 3 port boost solenoid valve, these tend to operate or fail 100% but 3 port boost solenoid valves are £65 delivered inclusive of the two fittings you need.
HTH.

**jay**

iTrader: (1)

No nothing has been altered, it runs mafless with a samco inlet pipe, was all mapped for the mods.
It just seemed to start doing this, would a faulty dump valve cause boost creep, its just the standard one no vta.
The nipple is also free , air passes through it with no problems.
Cheers
Jay

**jay**

iTrader: (1)

Cheers harvey
i may just pull the turbo off it and get it ported least that will eliminate that.
Just weird it ran so well for a this amount of time and now it boost creeps, nothing has been changed.
I would probably just change to a better turbo if the turbo is at fault, i have had many turbo cars in the past running with good power and never any boost creep.

Big 'D'

If you are certain that the boost creep has only just started and it never did it before it seems odd that it would just start doing it. It was defo worth going through all the other checks first .

Cheers Iain

Grant74

iTrader: (10)

Maybe worth replacing vacuum hoses as extra insurance? I had an issue like this on an mr2 turbo and it was a very small split that had formed over time- maybe you removed vacuum hoses when you changed plugs? Worth £10 on vacuum hoses before all else

**jay**

iTrader: (1)

I have ran it just off the actuator pressure and it was still doing it( putting a pipe directly from compressor side to actuator)
Starting to think it is a faulty standard bov pumping pressure back into the inlet, not had time to remove it yet, will take it off through the week.
Cheers
Jay

Grant74

iTrader: (10)

New or existing pipe? May not be the issue, but did same as you, and it was a split on the pipe going to actuator, which I then use to bypass the boost controller, so replicated the problem.

**jay**

iTrader: (1)

No mate used a new pipe directly to actuator, still boost crept as the rpm rised

Big 'D'

It will not be the DV mate as if it were pumping anything back into the intake it would be underboosting due to the boost leak

Cheers Iain