micra turbo help

[kristian]

hello, to you turbo owners and builders

Im suffering severe boost loss with my car.. the turbo spools up as it should, it reaches full boost around 3.5k Rpm then the boost is lost, its very sudden..

When the boost is lost the car has no power at all..

I can build the Rpm quite High with only slightly touching the throttle in order to keep the boost less than full and the car pulls nicely, Albeit with much less force..

Its definatly not a loss in the intercooler piping and couplings as ive tested them all... several times...

the Loss of boost it quite instant.... taking less than a second.. from 0.8bar to nothing..

Could this be the actuator or somthing else..

Ive been on the RR again and the car powering up and developing 108bhp repeatedly at the fly until boost loss ( 3500/3800 ).. then the power drops completly..

It Started all of a sudden and has been constant ever since..

Also.. There is No wooshing noise like its been dumped through the Dumpvalve although its lost JUST as quick..

Possibly the Dumpvalve????

Ideas???

Id love a solution before sunday night as im attending the RWYB at Santa Pod on monday..

Cheers

 

[Ed]

block off the dumpvalve. Remove all the too obvious to bother potential problems. such as that, and check the turbo actuator, unlikely but it is possible a problem.

 

[kristian]

block off the dumpvalve. Remove all the too obvious to bother potential problems. such as that, and check the turbo actuator, unlikely but it is possible a problem.

cheers, will try that first thing..

What do I do to check the actuator..?

It does cherge up to full boost then holds for just a moment then drops it..

 

[Ed]

Yeah its not likely to be the actuator to be honest unless its sticking. Much more likely to be the dumpvalve or something.

 

[djlee_dj]

could the RR not tell you ? if not i wouldnt go back

did you check round the engine when on the RR ? you couldve checked dump valve then.

block it and see, actually keep it blocked, pidgeon pidgeon pidgeon

 

[kristian]

Ive Blocked the Dumpvalve off, I actually took it apart and cleaned everything.. it all seems to be functioning fine..

So yes, with the Dumpvalve blocked off the car still powers up to boost holds for just a moment..then it drops it all...

When I lift off at the same time I get a Hint of Chatter and Atmospheric Purging..

Ive heard the car with the Dumpvalve blocked off before and It Chatters like an angel.. This Is just BARLY noticable now.. Even When I lift off just before the pressure drops in order to purge the lot, its still just as quiet...

So basically the symptoms are exactly the same just with No Dumpvalve noise..

could the RR not tell you ? if not i wouldnt go back

did you check round the engine when on the RR ? you couldve checked dump valve then.

I was only booked in for a power run this time.. and when it was on we tried to source the problem where we could.. without dismantleing to front end..

We could seem to hear it leaking but from where who knows..

IDEAS???..

 

[Ed]

You have little choice but to remove all the boost pipework and take a look.

 

[Antony]

sounds like the actuator.

the boost may come on to full, but what youve got to realise is that when rpm's raise the turbo is wanting to boost more than your actuator spring allows, wich regulates boost.
if its sticking as i think ed mentioned, it will produce full boost at lower rpm levels but as the boost rises above this threashold the actuator opens the wastegate and gets stuck open untill the boost levels / rpm dies down..

sounds like a sticky wastegate...