Booosty Issue

[Sam_M]

Right first of all, a few weeks ago I killed a Turbo, basically the impellor was not well and it had so much play in the shaft the fins ended up hitting the housing causing damage to the turbo, anyway, I have another Turbo on there now, boosted up fine, but ive noticed if I give it some beans and take it to about 6.5k and do a quick gear change, sometimes it looses all boost, then suddenly picks up again, this only happens when I hit higher revs. I thought this would maybe be the recirc dump valve sticking or leaking, but ive changed it for another and its still doing exactly the same thing.

The only difference today is after I had the lack of power after hitting high revs there is a slight difference in sound when the turbo spools up and for a second on initial boost up it sounds like there is an air leak somewhere.

Its so annoying ive had all the pipes off when changing theh dump valve and everything was nice and tight, couldnt feel or find any leaks in the pipe work.

I was wondering the initial problem with it loosing boost pressure after high revs would down to a sticky Actuator? anyone had anything similar?

Theres no hesitation, and pulls very freely up the rev range when its boosting ok, generally drives fantastic, no missfiring, idles perfectly. If there was an air leak I would have thought the idling would have been a bit rough.

Any thoughts would be great
Thanks Sam

 

[gtir_pimp]

this may sound stupid but are you sure all intercooler pipes are tight and boost pipes back on? did you use your actuator or the one that came with the turbo? and did you check the conditon of the turbo, like cracks around the wastegate penny, etc?

 

[Sam_M]

Definately 100% tight, checked and double checked, unfortunately didnt change the actuator, so cant dismiss that as not being a problem. There were no cracks at all on the wastegate either, and no play on the shafts either. Its just such an odd and annoying problem.

I have an ARC TMIC on there, so I may try the standard one again just to narrow the problem down, I would be suprised if its the ARC. Im tempted to even blank off the DV just to narrow that down aswell.

 

[PobodY]

So it's not a new actuator, just a new turbo?
It just sounds a bit like the wastegate is opening, but not snapping shut again immediately; like the spring is weak or something.

 

[Sam_M]

Yeah im starting to put my money on the actuator, because when it actually boosts up its great, I think a roller bearing Turbo is in the pipeline though, and a new actuator might be wise!!

 

[gtir_pimp]

did you change the turbo yourself? get a known good actuator and replace it to see if that works. done mine the other day and now i know excactly how to do it, im confident i could get it off in about an hour and a half easily. coz it has to come off to change the actuator im afraid.

 

[Sam_M]

Well it looks like turbo is fooked, not sure how so quickly, makes me worry thats theres an oil feed problem, but the turbo had no play, no cracks, and didnt smoke when it was first on, now it sounds like the bearings have gone and its squeaking a bit. Im kinda glad I didnt put a brand new one on there before this.