you can talk Mr pong!!

and bringing Mothers into this..

well the exhaust housing has been fitted and was perfect fit for the turbine wheel..... Yet car will stiil not boost, and now we're getting to a stage where there is nothing else we can do.... Fleas says in tuning over 400 cars he's never known anything like it...... He's been through everything.... Twice probably.! Leak down test.... Re-timed cams... Inlet manifold and exhaust system have been off etc etc...

The bigger exhaust housing has changed things.... No boost spike now... Just boost to 1.1 bar and stays there... But will not go any higher?? Only thing left to try is changing the whole turbo as may be boost leak on compressor side.... Very unlikely tho as turbo is new and in the word of flea "everything about it looks mint"....
so Joe has been an absolute star and offered to lend us a standard turbo just so we can rule the turbo out!!

gutted as we obviously thought the exhaust housing issue was the problem!!
Again thanks to Flea for percivereing with my SHED!!

Hoping leighton will update this thread to show the lengths he's gone to ..... Also hoping some of you 16v guys have any ideas as to what problem could be??

Nick

Nick

No good that it hasn't come right

Just remind me, you have a decat don't you? I ask as I owned a nissan that wouldn't boost and it was actually a block cat that stopped it boosting due to huge backpressure - but I assume you don't have have one? sure there are no collasped mufflers etc?

I ask as this wouldn't show up in a leak down test

As a test I just ran my nissan straight out the dumpipe (ensuring nothing could catch fire) and tried a quick burst to check, which proved the exhaust was the issue

i have de-cat and leighton has checked it i think bud.... I'm racking my brain to think if anything has been changed since last visit other than obviously engine rebuilt.... All i can come up with is boost controller, map sensor and larger k&n air philtre which i fitted before car went to Flea!!

nick

Oh gawd!! After all the time and effort....

I just hope someone comes up with some inspiration (and aspiration) after all the perspiration. Good luck,

Tim

is the waste gate actually closed or is it opening too easily. Sounds like a shed like you say. Tried running it with no signal to the waste gate?

i honestly don't know the answer to that question bud??
i would have thought so as Flea seems to think we're pretty much stumped after replacing the turbo if that doesn't work?
may just have to have the car back and just run it at 1 bar....
leighton reckons its already more powerful than before but only running 1 bar is just a waste of time and money really.... And the car will be no where near its potential!

It made 248 on the dyno before we realised timing was way out.... On the the leak down test the results were what you'd expect from a knackered engine, flea reckoned only 20%... This has been remedied by the re-timing and now flea is happy with the leak down test results.... Yet it still won't boost!!

have you cheked the inlet donut on the intake manifold under boost??

yes the intake manifold has been off.... Doughnutss checked... Manifold replace and system pressurised to 30 psi without any probs!

nick

Have you tried clamping the wastegate shut so it cant open at all?

What about the actuator and the actuator bracket?

yes waste gate has been clamped shut...
and leighton replaced my standard actuator with new Forge one!
keeps the ideas coming tho guys!!

you checked for cracks in the exhaust manifold and exhaust housing?have you pressure checked from the turbo inlet to the engine?ie leaks from the compressor housing,split intercooler etc?is the wastegate penny valve seating correctly?

All that has been checked i think.....
really hoping this donor turbo boosts up as that will mean its deffo my turbo that's the prob.... Flea thinks this is unlikely tho as turbo seems and is mint..... Don't get how it spools quickly then just stops??
there is a small chance that the tips of the turbine blades are the wrong height for the exhaust housing but leighton says it seems like a perfect fit and doesn't think its this...
we'll soon find out when other turbo is fitted!!

nick

Blimey, id be going out of my mind by now, all the best with it!

have you tried removing the air filter?clutching at straws a little but if the turbo is in good condition and theres no leaks then you need to consider all possibilities.other than that im thinking bearing damage to the turbo, restricting the main shaft

heres the list of all possibilities from aet turbos,who know their onions.

Dirty air filter system
Induction and intercooler pipes collapsing
Excessive flow resistance in exhaust system/ leakage upstream of turbine
Fuel system/injection feed system defective or incorrectly adjusted
Valve guide, piston rings, engine or cylinder liners worn/increased blow by
Restricted intercooler or charge air cooler
Boost pressure control swing valve/poppet valve seized in the open position
Pipes to actuator and boost control valves incorrectly fitted
Turbocharger bearing damage
Foreign body damage on compressor or turbine
Turbine housing/flap damaged
Insufficient oil supply to turbocharger
Engine valve timing incorrect
Accelerator cable maladjusted
Insufficient fuel flow/pressure

yes bud.... Its been ran with no filt er and still the same...
i really do hope its the turbo although if there was bearing damage would this not have been picked up when turbo was off... I.e there would have been noticeably more play in the shaft.... Pretty sure they had a good look at the turbo when exhaust housing was changed last week!?
hoping flea will update this thread soon so you can see everything that's been tried and tested!

Is the boost just dropping off???

As in power climbing climbing climbing then it tails off??

worldly sounds like the problem I had... Holds around 1 bar then decides it does not like it an more and decides to vent boost into my engine bay.

What RPM does the boost stop/ drop off??

Flea, what do you think it is??
Any ideas?

You Both have put a lot of time in on this and I think it's a case you will need the car to work this fault out.

Really sounds like its the turbo.

I wish I knew more about 16v turbo's so I could help more....

the problem is that the bearing could be starting to go,so the problem is not apparent util higher in its rpm range,so without a turbo balancing machine it may go unnoticed with a casual wiggle and spin check,a dti through the oil return may give more accurate results if no balancing machine is available.

Blocked intercooler/piping?

intercooler and piping has been ruled out....
i'll be very surprised if it is the turbo bearing as it is brand new... Although i guess there have been premiture failures before??

marco.... I don't think it is venting boost it is just stopping at 1.1 bar.... Flea said it tails off to just over 1 bar at redline...

as i said really hope its the turbo and not some of the other things on GS racing's list!
funny thing is i bet its pushing 310-320 bhp as is... Frustrating.com!

Still sounds like exhaust to me but am clutching at straws as well, I know it doesn't have a cat but has it been run straight out the dump pipe?

yes saint it has been run with the whole exhaust system off i believe!

nick

However small the chance is of a mis-match here, I think it needs to be checked accurately, by a turbo rebuild company or similar, to eliminate this from your enquiries.

Process of Elimination from Inlet to Exhaust Side

Filter > Checked, ran without, rulled out.
MAF > ?
Induction Pipe Work > Pressure tested to 30 PSI without fail.

What else connects to induction pipe work:

BOV > Checked? (Would have thought it was)
Boost Controller > Checked?

Engine side:
All leak down tests done etc and all came back good.
Compression Test revealing piston ring blow-by?

Exhaust side:

Exhaust checked for blockages > Checked

Turbo:

Only thing left in my mind is actuator but has been checked.

could piston ring blow by occur if engine hasn't been "run in" for long enough? Only managed aroung 200 miles due to the issues with cutting out.... I just gave it to leighton to sort the cutting out and then map it...
if the answer to this is yes then maybe i'll just need to run it for a while as is then take it back.??
a compression test should show up this problem though shouldn't..?? Don't know if this has been done, i know the leak down test now passes tho!

nick

200 miles is run in enough. It's not going to cause boost problems like you have anyway. The most worn out engine will still develop all the boost you want.

the best way to check would be to get a turbo rpm gauge fitted,and see whats happening,if there is blow by or leakage the rpm will drastically increase after maximum boost is reached,if its an exhaust or bearing/turbo failure then the rpm will be slower to increase and not run at too high a speed.

well my compressions were 125.. 95..95..125 on my old fubarred engine and turbo had no problem spinning upto nearly 1.5 bar prob would have gone higher if i'd have had uprated map sensor.... GOTTA BE THE TURBO!
hopefully will have an answer soon.... If its not then will prob just have car back running whatever boost we can get and hope problem irons itself out over time!

nick

You were gettign 1.5 bar boost on rings which were recorind 95 PSI?! WTF?!

Number 2 cylinder on mine was at 80 PSI and would not hold past 1 bar boost, would then push past the rings and push oil through the vac pipes in to the ccontroller thus hesitating even further!