Boost Creep

wrc

wrc

Member
Had a search for this, but doesnt seem to be very common on gti-r's.


Recently got mine on the road, so only minor driving experience of her. The one thing i have noticed is i have bad boost creep. Starts at a bar but sure as hell as the revs rise, so will the boost.

All vacuum lines are correct, using a dawes ball & spring copy. Boost hoses all tight, no leaks. Spec is 87mm, JE's, 1.2mm HKS, Stoc turbo, Mines ECU. Ive got lots of turbo exprerience but am fairly new to gti-r's and also never suffered with boost creep on any of my cars.

I *think* its the fact im still running the t28? i.e. wastegate too small. But ideally i'd lie to combat it before it becomes more of an issue.
Any i

Any ideas? Cheers guys.
 
wrc

wrc

Member
Stock turbo, ive taken it to 1.4 bar but looked like it wanted to go more.


Ideally i'd like to get it sorted before i come to see you on the 5th March Ed! ;)
 
P

pulsar_stu

Active Member
You still using a top mount intercooler? I had this on my first gtir and it turned out I had clamped one of the hoses when I put the top mount back on.
Other than that it must be your bleed valve!
If you haven't got it fueled for 1.4bar I wouldn't run it!
A mate of ours had a bleed valve and it wasn't boosting right, the boost presure was to much for his fueling. On the way to santapod he blew his engine.
If your going to see ed anyways, why not just remove the bleed valve and do the 1bar loop and make do with that until ed sorts you out.
 
Fusion Ed

Fusion Ed

Active Member
Never seen a stock turbo boost creep ever, so something is not right. As Stu says, if you don't have it setup to run this, you'll kill it. I'd check to see that the waste gate is even working!

And yes get it sorted first please haha :)
 
PobodY

PobodY

Moderators
Staff member
Ditto. I never had my bleed valve creep, and certainly not my dawes-style device... but then I'm not trying to get anything like that boost out of mine.
 
wrc

wrc

Member
hmmmm, i'll have a good inspect tonight - something must be wrong adrift somewhere...
 
S

skiddusmarkus

Active Member
Check under the right hand side of the topmount if you still have one.As someone said, there's a vacuum pipe that copnnects onto a hard pipe on the underside and if its off you probably wouldn't notice it.
 
wrc

wrc

Member
Right, absolutely nothing untoward under bonnet. All vacuum lines present and correct. Running tmic so that shouldn't be an issue.

The only things I can think of that would cause it would be the very low ambients, or my Dawes is up the spout - but if the Dawes was at fault then the oonly think I can think of is the spring being weak in it, but them I would technically loose boost...

Argh :(
 
wrc

wrc

Member
I have a bleed valve spare in the garage (I know, I know..) so I will try that and see if it solves my issues...

At least with a bleed valve I will only get some spike and hopefully rid of the creep lol...
 
Fast Guy

Fast Guy

Moderators
Staff member
The cold would probably give you 1psi maybe compared to mid summer, but certainly not 4psi. Check your wastegate hoses don't have a split anywhere and are leaking. Minght be worth pulling it off the plenum and see if you can put some air into it.(footpump?)
 
wrc

wrc

Member
Ok tonight the Dawes came off, bleed valve on - although it drives better, the boost is still creeping up.

All vacuum hoses have been renewed with good quality silicone hose. I'm at a bit of a loss to find anything 'wrong'. I'm wondering if it's actuator related but that would surely loose me boost.

The only clue I have is that if I hold half throttle and raise the revs slowly, no creep. If I plant it, major creep.


Why am I the only Gtir owner that seems to be suffering with this lol why me :(
 
Fast Guy

Fast Guy

Moderators
Staff member
Try it with no bleed valve. Put it back to factory set up. Is the bleed valve set to the same as the dawes device?
Would a split diaphragm in the actuator cause this?

Did you try pressurising it to see if you could hear any leaks?
 
wrc

wrc

Member
Cant put it bac to standard as i have no standard solenoid fitted or availible :(

Split diaphram in the actuator is my next call - Can i test this by pumping pressure down the vacuum hose to the actuator and making sure it holds xx psi?? Therefore i take it if it looses pressure and wont hold i have a split diaphram ? :lol:


Cheers guys.
 
wrc

wrc

Member
That line is very basic, off the manifold straight to actuator with bleed valve inserted and all hoses are new & tied.

I'll try it in a mo and post back.
 
wrc

wrc

Member
Righty, I'm back...

Actuator changed for a known good item from bob, still the same - better but still climbing the boost 1psi per 1000rpm.

Changed the actuator hose too a different pressure source, same.

The ONLY thing I can think of is that I noticed that before fitting the turbo that the waste gate 'arm' that is connected to the end of the actuator (controls the waste gate penny) is at a slightly off angle and is at an angle compared to the actuator rod - the rod does fit over and control it fine - but what I'm thinking is that if the waste gate is getting pushed/pulled at an angle obviously there is going to be resistance. Am I clutching at straws here???

Bleed valve, Dawes - still the same. Change the pressure source, still the same - I'm convinced that it's waste gate related but it does move freely with pressure behind it (quick bit of air from an air line)



Please anyone any ideas - this is really getting me down :x
 
Fast Guy

Fast Guy

Moderators
Staff member
How much preload do you have on the wastegate rod? If you have too much that can increase boost. I think half a hole is normal.
 
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