turbo chatter and boosting over the moon!!!

[let_nova]

put all the car back together tonight after spraying the bay and after it was all back together i drove it home. now before i done all this when you let off the gas it would give off a mini dumpvalve noise even though it doesnt have one. so when i drove it down the road tonigh it was giving off a chatter sound instead and the further i got down the road the louder it got and was boosting over 1bar!!! i had removed intercooler,AFM,airfilter,radiator,fan.

please any help would be great im meant to be going to knockhill tommorow!!!!:mad:

[vx kev]

Hmm sounds strange that the boost has gone up on its own, u possibly had any vacum pipes or that off and put them on the wrong way etc. :confused:

Ive had 2 Lets now and they both had the chatter from the standard wastegate coming back through the air filter, think this is pretty normal :wtf:

[let_nova]

na didnt do it last time i drove it.....thursday night. browney has pointed out to me that it may be the vacuum to the actuator if it has come off or split it will be running unlimited boost????? would explain why it herly put me off the road!!

[vx kev]

Sounds about right to me, if the vacum pipes are the wrong way round or split the amil valve wont be controling the boost properly ;)

[djbrowney]

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[let_nova]

sorted 2 vacuum hoses off 1 on the turbo and 1 on the amal valve!!!!! feels slow now....how do you turn up the boost slightly?? lol

[let_nova]

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you gay boy.... i will forgive you since you solved my problem lol

[let_nova]

rep to both.

[vx kev]

sorted 2 vacuum hoses off 1 on the turbo and 1 on the amal valve!!!!! feels slow now....how do you turn up the boost slightly?? lol

Adjust the Nuts where the actuator goes onto the wastegate, only a few mm's needed to increase. Its been a while but im sure if you turn it in towards the actuator it increases it :thumb:

Dont go mental tho or the amil valve will tell the ecu to cut the boost.......

[let_nova]

ok ill adjust it an inch that should do lol...............







joking. thanks.

[vx kev]

If i see smoke signals coming from the Knockhill direction tomorrow then i'l know its you lol
Over boosting out your nut :D

[vaughanmc]

lol

Rep left to 'vx kev' and 'browney'

[let_nova]

lol

[djbrowney]

what chip set you running buddy ?

[let_nova]

apparently it is eds phase 2? apparently!!

[djbrowney]

you should be able to run 14 psi held 16 psi overboost on that chip set before it will boost spike iirc

[let_nova]

not even sure if it is chipped?

[djbrowney]

undo the tabs on the ecu, pull it apart an check it will be written on the chips mate

[let_nova]

ok i will do it tommorow. if not i will buy evo 5 tommorow night.

[djbrowney]

good boy, you can run 20 psi on evo 5lol

[vx kev]

I ran 20 psi quite comfortably on EDS Phase 2 switchable on both my lets, done the biz like :D

[Jack]

Ive had 2 Lets now and they both had the chatter from the standard wastegate coming back through the air filter, think this is pretty normal :wtf:
You're hearing the sound of the turbo stalling, not the wastegate bashing open and shut. If you're getting turbo stall, fit a DV else you could end up shattering the turbine blades or damaging the shaft.


na didnt do it last time i drove it.....thursday night. browney has pointed out to me that it may be the vacuum to the actuator if it has come off or split it will be running unlimited boost????? would explain why it herly put me off the road!!
It won't run "unlimited" boost, there's a hard limit where pistons will melt, turbo falls apart, and things go bang.

[let_nova]

You're hearing the sound of the turbo stalling, not the wastegate bashing open and shut. If you're getting turbo stall, fit a DV else you could end up shattering the turbine blades or damaging the shaft.



It won't run "unlimited" boost, there's a hard limit where pistons will melt, turbo falls apart, and things go bang.

browney has pointed out to me that it may be the vacuum to the actuator if it has come off or split it will be running unlimited boost?????

[Paul]

browney has pointed out to me that it may be the vacuum to the actuator if it has come off or split it will be running unlimited boost?????

effectively yes, but something will go bang is what RJ is trying to say.

[djbrowney]

effectively yes, but something will go bang is what RJ is trying to say.

which i did send in the next text i sent him lol

[Jack]

Aye.

The wastegate is a valve in the exhaust which, when open, allows exhaust gases to bypass the turbo. The ECU will open this valve when boost reaches a certain pressure to stop it going too high and damage occuring.

If the valve fails to open, inlet pressure could rise beyond safe levels and things cold break. A similar problem is boost creep, where the wastegate is not big enough to divert enough gas round the turbo (usually happens when a larger bore exhaust is fitted), so boost pressure "creeps" upwards when the turbo is on maximum rpm. Again, bang lol

I assume LETs don't have fuel cut then? Thats pretty bad... Most turbo engines will monitor boost pressures and cut the fuel supply if it still rises too high. You'll know you've hit fuel cut as you'll go from full throttle to scraping your face off the windscreen :D

You could of course just manually control the turbo using the throttle and not letting exhaust flow push it to maximum rpm, but I wouldn't rely on that lol

The chatter noise you speak of, coming from the air filter, is the turbo stalling. When you let off the accelerator and the throttle closes, the turbo takes a moment to spool down, during which time its still creating pressure against a closed throttle plate. As the air can't get into the engine, it bounces off the throttle and hits the turbo blades, stalling it. Fitting a dump valve prevents this, as a vacuum pipe from the engine side of the inlet creates a vacuum on closed throttle, which opens the DV and allows this air to escape rather than hit the turbo.

[burgo]

can someone give jack some rep for me please as apparently ive gotta spread it around abit

[Lee]

Loos like when I build my Turbo, Mr Deacon will be helping me out :)

[craig green]

I assume LETs don't have fuel cut then? Thats pretty bad... Most turbo engines will monitor boost pressures and cut the fuel supply if it still rises too high. You'll know you've hit fuel cut as you'll go from full throttle to scraping your face off the windscreen :D



Thats good is it? !!

Turbo chatter is often the noise heard from the wastegate (penny valve) snapping shut. You could simulate it (slowly) by moving the actuator rod back & forth.

[meritlover]

Turbo chatter is often the noise heard from the wastegate (penny valve) snapping shut. You could simulate it (slowly) by moving the actuator rod back & forth.

no, the "PTTTchchchchcRRRRR" sound on the lift off is often mistakenly called wastegate chatter, when infact it is (as Mr Jack so correctly put it) the compressor stalling.
when the discharge pressure from the compressor is high due to the momentum of the turbine shaft, the air has no where to go against the closed T/B. because there is no more energy in the exhaust gas, the air then rushes back through the compressor impellor and stalls the blades. this is known as compressor surge. it ruins turbos if the boost is too high as the stresses involved are huge. We have sheared turbine shafts running a compressor past its surge line. and also by snapping the throttle shut after full boost.

explain to me in what series of events during lifting the throttle under boost, causes the wastegate to 'chatter'

[Jack]

Thats good is it? !!
lol it doesn't sound good, but it is. Its the engine defending itself against turbo overboost induced melty piston action. I'd rather peel my face off the windscreen than have to pick up bits of engine from the floor!


Loos like when I build my Turbo, Mr Deacon will be helping me out :)
ME helping YOU with engine stuff? Does that not scare you? lol

[Lee]

ME helping YOU with engine stuff? Does that not scare you? lol

Yes, yes it does lol

[Paul]

Turbo engine eh Lee?