turbo kicking in at 4000rpm..wtf?
 

Lo people i have a my96 wrx z4 ecu with decat and green panel filter[standard TD05h turbo]...my turbo apears to be kicking in to late ..its starts to spin up at 3500 rpm and finaly kicks in at 4000 rpm..this means im practicaly changeing gear as soon as it kicks in.Am i correct in thinking its the ecu that controlls the turbo spool up?..my friends my95 wrx kicks in at 3000 rpm with the same modds.Also up to the point where the turbo spools the car seems abit sluggish to me.Can anybody shed any light on this all sugestions welcome[ it holds boost at correct level and ive checked pipes and cleaned boost solenoid ,also have afr and knocklink both are working within aceptable peramiters]....help me im so slow.

get a dawes or something along those lines to controll the boost so your turbo will come in earlier, had a similar problem with mine so i fitted an avcr;) problem was gone after that

what avcr did you use and how much was it if u dont mind me asking?

Sounds to me more like there's something wrong with the wastegate/solenoid - changing the method of boost control won't make any difference until that's sorted. My guess is that the wastegate is effectively 'hanging open' - or at least not clamped shut hard enough to force the exhaust at spool-up through the turbo. This will mean that boost will eventually be fine, but it'll take a lot more flow to get there...
I'd check the solenoid/wastegate connection to ensure that the preload is ok. I'm not entirely sure what it should be on your turbo, though :). Basically tightening up a bit (a turn or two) whould see if it makes any difference :)

My money would also be on the wastegate. Alternatively, there could be a leak somewhere in your exhaust system between headers/up-pipe/turbo. Has the lambda been replaced recently? Are there any unusual noises...?

hmm no theres no leakage that i can detect and the lambda hasent been replaced....ill double check the wastgate /solenoid conection for leaks[although wouldnt i loose power if the wastegate had a leak?]ive got a dawes comming on friday as well so that may isolate /cure the problem.This problem has always anoyed me and ive repeatedly gone over the pipes etc looking for something wrong but ive had enough now:}

As nom/Judge have said, I'd check the wastegate preload. The wastegate link should have between 3 and 5mm preload on it ie you need to pull the wastegate rod out by this distance to hook it over the closed wastegate link arm.

Andy

Not really, it would just take longer to build boost pressure.

It will do if the wastegate solenoid is at fault, but from what you've described, I don't think it's that.

Have you also had the heatshield off and checked the play in the wastegate actuator arm? As Nom said, it more than likely just needs a couple of turns. :)

ill check the wastgate actuator arm tonight and post how i get on thanks for the information ladds ,very helpful:D

yup forgot about that, it was the wastgate that needed adjusting on mine, and i needed the apexi avcr to get the boost right

hmm i just did it up a couple of turns and it has made a minute diffrence it now spools up at about 3700 rpm ...ill try another turn or so tomorow but ive got a nasty feeling the wastegate isnt makeing a good seal inside the turbo....

yup ive played with the wastegate actuator and it makes no diference ....its back to 4000rpm today ...also checked hose and cleaned actuator with carb cleaner out of desperation...looking like a leaking wastegate inside the turbo...omg thats bad news i got a daws comming tomorow so might make it tolerable...i dont realy want to fork out for a new turbo let alone finding the time to fit it........does anybody know how much for a new TD05H turbo?

I have a 93 wrx and the waste gate is not adjustable are you sure yours is , you may just be spinning it round ? Mine was doing the same as yours and it was the up-pipe blowing changed that and ported standard headers out now get full boost at 3000 rpm .

Mark

Yeah definately adjustable...could u hear the up pipe blowing or was it hard 2 detect?...cause i cant hear anything but i cant see becuase of the sheild...tbh im sure id hear it.

A leaky up-pipe is quite noticeable!
If you adjusted the wastegate & it temporarily fixed it, my guess is that the ECU is the thing that's pushing it higher up as it's the only thing that'll adjust automaticaly.

So... why's it doing it? Presumably 'cos it's getting sent false readings from somewhere.
Anyway, if this is the case, the Dawes should sort the problem out :)

Ok got and fitted the MBC and although im now running 1 bar the spool up time hasnt changed at all so its not the solenoid.....i dont think theres a leak in the headers/up pipe but im going to take off the heatsheilds tomorow on the desperate chance that theres a leak and i cant hear it over my decat[unlikely i know]......so the finger apears to be pointing at a faulty turbo wastegate...[totaly gutted]..now is there anything else that im overlooking that afects when the turbo spools up?........does any1 else have a my96 wrx ?when does your turbo kick in?


does anybody have a rough ideah how much a new/recon TD05h turbo is and the best place to get one?....any information or coments are most welcome.

thanks smashy.

About a possible replacement - probably the place to start would be Andy (username Andy.F I think? Oh yup - there he is, higher up the thread :)). I think he may have already sold the world's supply of the things, but this does mean he probably knows where to get his hands on them more than most :)
But check over the manifold, joints, etc. first. The standard manifolds I believe can split - and you may not be able to hear this over the decat, depends on the system! But the manifold is also behind a heatshield so may be hard to tell. Check the joins between the manifold/up-pipe, block/manifold, up-pipe/turbo - in that order is the easiest at seeing them. You can do it with the engine cold - just look for soot. Another potential problem is a bung coming out - I'm not too sure where they are on a MY96, but one may have split or popped off. A bung popped out on mine once which gave me a bit of a shock - sounded like a tractor, but not a very noisy one & could have been missed if I hadn't had my bespoke ultra-quiet decat :D. Anyway, spool was utter ****e after that (5,000rpm+ but it's a larger turbo...;)).
Anyway. Soot. You see it, that's bad. Or good, depending on what else it might be, I suppose :D

Ok right well ive taken off the heat sheilds from the manifolds bar the up pipe as that is welded and part of it.....there are no leaks anywhere.I then took off the down pipe so i could guive a visual inspection of the wastegate flap and that seems ok as well,i disconected the actuator rod so i could move out the flap and there apears to be no gap anywhere around it[indeed there is a shiny ring all the way round where it seats]...now im totaly flumoxed wtf could it be ???

Could possably be one of the cats breaking down(if youve still got any),causing too much back pressure.

Back-pressure would bring the boost in earlier (why people think backpressure is good, when actually it's just showing that the exhaust is bunged up :rolleyes::))

When you fitted the Dawes, was it with completely new tubing? There can be splits which can't be seen until they're under pressure.

Next... it's possible that the turbo is spooling fine, but there's a leak between the compressor outlet & the inlet manifold - most likely a split in the tube somewhere around the intercooler. Not too hard to check, so might be worth a look?

yes i used new tubeing on the daws so thats ruled out ,but ill re-check the after turbo hoses as well although about 2 months ago i fitted the samco turbo hose kit in preperation for raiseing the boost and i had a good look around then..but not 100% inspection .Also after dredging the search facility i have found that some people with similar aged wrx,s have complained about long spool up times.[although admittedly not quite as long as mine] ..this apears to be the fault of the larger TD05 turbo..as the english ones seem to have the TD04.....but tbh i think mine comes in a little to late.My turbo has done 42k and is the original...ill also have a good look at the impeller blades for feathering and damage when i check the after turbo hoses,,perhaps its not working eficiently?..although tbh im clutching at straws now:D

ok checked hoses after turbo and intercooler[it did uccur to me that the intercooler might be leaking..unlikely i know ]and it all seems good.Im realy fed up now ...the only thing i can think of is that the turbo is a little tired[42k]....even though the impellers seem in reasonable condition from what i can see of them at the rear.

i always have this luck on cars i buy theres always a niggly problem with no aparent reason for the cause of it:D

shuffles of degectedly.

Less exhaust back pressure allows the turbo to spin up quicker due to the flows being faster/free'er-which is why a decat allows quicker spoolup LOWER down the revs,and higher boost up the top end of the revrange.
If the cats are breaking down or there is a blockage,you arent getting the exhaust gas flow to allow the turbo to spool up untill the engine is physically reving high enough to push/force more gas flow,which can account for low spoolup times.

Am i not correct on this ?

I stand to be corrected though;)

easy

yup your right thats why on turbo cars the less restrictive the exhaust system the better,,,,,incidentely when i fitted my decat i remember being quite disapointed with the gains especialy that the spool up time didnt get any lower.

Is it fully decatted????

yup turbo back system[H&S].:D

What gear are you in when you are observing 4k max boost?

1st is about 4500/5000 the rest are all about 4000rpm.

I think you are not meant to get full boost in first gear anyway , try fith gear at 1500 - 2000 rpm and put your foot to the floor and see what rpm you get full boost .


Mark

The best gear to use is 4th/5th as you will get a true reading,1st/2nd isnt a good gear to gauge it really,as it will rev too quickly for the turbo to get max pressure at low revs,next time youre out try it in 5th at wide open throttle from say 2k revs and see what point it reaches 1bar.
As you probably know,the td05 will always be laggier due to its size,but in 5th it should reach max by about 3k,my td04 reaches max by about 2.6k in 5th at WOT.
It could be that your wastegate actuator is weak,and even though youve adjusted the preload,the wastegate may be being opened by the exhaust gasses.
Sounds like an awquard one though!
Anyway-give it a go in 5th and let us know the results.

easy