Thinking about fitting a new actuator on my S3

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ash3435

flat out if in doubt
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hi everyone, i seem to be losing boost at high revs.as soon as it passes 5000rpm the psi drops from 20-22psi to 12psi at 7000rpm.the actuator most not be holding the pressure.the car is a 2001 with 70000 on the clock. Ive got a forge actuator sitting in the shed and was thinking about getting it put on.is this an easy job or will it need a garage to do it
 
K04's don't make much boost beyond 5k anyway.... you got VAGCOM or access to it? Do some logging first.... Messing with the actuator won't give you any extra boost at higher rpm on a K04 as it just can't flow the air but it can give you a fairly hefty boost spike that could potentially bend rods...

<tuffty/>
 
hi tuffty, i dont want it to make anymore boost.just want it to hold the boost for longer as mines dropping straight away.my friend has an s3 with the same map and his holds the same boost (22-22psi) but after 5000rpm it only drops to 16psi to the red line.don't have access to vagcom till the weekend and the guy only has the ebay version so im limited on logging at the moment.thinking bnout going and getting the full version from ross-tec.what do i need to log
 
no has we both have a revo map.my cars old and got 15 thousand more miles.but i cant see that making much difference
 
ash3435 said:
hi tuffty, i dont want it to make anymore boost.just want it to hold the boost for longer as mines dropping straight away.my friend has an s3 with the same map and his holds the same boost (22-22psi) but after 5000rpm it only drops to 16psi to the red line.don't have access to vagcom till the weekend and the guy only has the ebay version so im limited on logging at the moment.thinking bnout going and getting the full version from ross-tec.what do i need to log
Click to expand...

Blocks 020 (timing pull) ,031 (fuelling) ,115 (boost) and 002 (airflow) ,031 (fuelling) ,115 (boost)

Third gear runs from 2k to redline after the engine temp has reached 90degrees and post screen shots of the data.

Before assuming anything I would log your car as it could be something as simple as an airleak.... If the actuator was weak I am fairly sure it wouldn't get as far as 20 odd psi in the first place...

<tuffty/>
 
hi badger5.yeah i no it adjustable, ive got the select plus.its not the settings from the revo side, its that im losing boost higher in the rev range.both my brother and friend hold 16psi to the red with different maps revo stage 1 and custom code stage 1.after the weekend i should have an idea from logging it
 
request vs actual will be a guide
if actuator has gone slack then a couple of turns may restore the top end... *maybe*, else turbo wear may also be a factor or internal issues with it, crack etc
 
Do a screen shot of the actual runs as posting the data this way is not usable tbh...

<tuffty/>
 
Are you using Excel? Open the csv file in excel, freeze the top rows with the header info in it, scroll to the start of the data you logged on the run and take a screen shot... turn it into a jpg, host it somewhere and link to it... should look like this (borrowed one of yours Neil)

picture.php


<tuffty/>
 
B7T2F9.jpg

this was with the settings at b7,t2 and f9

B7T3F9.jpg

this is with the settings at b7,t3 and f9

B6T2F9.jpg

with settings at b7,t2 andf9
 
before doing any logs this fault appeared and will not clear.17861-exhaust gas temp sensor 1 (g235 open or short to plus p1453-35-00).
 
ash3435 said:
before doing any logs this fault appeared and will not clear.17861-exhaust gas temp sensor 1 (g235 open or short to plus p1453-35-00).
Click to expand...

I notice non of the runs included block 031... going by the fault I would expect this to show your fuelling running very rich which may be a reason for lack of performance.

Plenty of airflow though, 212g/s is not bad...

Request v actual on block 115 shows a huge deviation after 5k... Have you checked for boost and vac leaks?

<tuffty/>
 
tufftybloke said:
I notice non of the runs included block 031... going by the fault I would expect this to show your fuelling running very rich which may be a reason for lack of performance.

Plenty of airflow though, 212g/s is not bad...

Request v actual on block 115 shows a huge deviation after 5k... Have you checked for boost and vac leaks?

<tuffty/>
Click to expand...

Was just going to say that, 212 G/S looks good to me! Most I've seen out of mine is 196 :-(.

Roll on Stage 2.
 
leaks are my next port of call.going check fmic first.from inlet to charge pipe.what vac line do i need to check.Ive replaced a few vac line.done some research on that fault.its the temp sensor which goes in the turbo and Audi say they want 180 for a new.expensive!!!! could that be a factor in my poor performance.i no 212 g/s looks good.but my friend with a stage 1 leon with custom code map and he pulls lenghts on me.
 
ash3435 said:
leaks are my next port of call.going check fmic first.from inlet to charge pipe.
Click to expand...

...ahhhhh a FMIC... defo check that as its a classic for boost leaks especially around the 60mm joiners where they tend to get crushed and leak like a sieve.

ash3435 said:
what vac line do i need to check.Ive replaced a few vac line.
Click to expand...

...all of them really... mainly anything that hangs directly off the mani, PCV underneath, N249 pipework, DV pipework, N75 pipework etc...

ash3435 said:
done some research on that fault.its the temp sensor which goes in the turbo and Audi say they want 180 for a new.expensive!!!! could that be a factor in my poor performance.
Click to expand...

...as I said in a post above, EGT probe (as that is what it is) is there to check if the engine is running hot (usually an indication its running lean) which will melt stuff... ECU compensates by overfuelling which acts as a coolant for the combustion chamber. If this probe is non functional in any way, the ECU will assume a safe 'mode' and overfuel all the time. Logging the block 031 as previously mentioned would show if this was happening...

Do some more logging with the blocks I mentioned previously...

<tuffty/>
 
yeah will do.ill try log it 2moz and post asap.that will be y its been smelling of fuel so much.this will also explain the fueling issue i had before Crimbo after having it mapped.the vag com version my friend has is different to your and 031 is something else.it the lambada readings i need isn't it.thanks for the help.this cars driving me mad at the moment
 
after searching last nite on the EGT probe.i found out that it is connected by the side of the dip stick.i couldn't help myself and went for a look on my car.i could not believe my eyes, the sensor was unplugged.not vag com it yet but 99% sure it will clear.its been unplugged for weeks as i replaced the vac line under the manifold.what an idiot i am.at least ive foud 1 problem, just the boost problem to find now
 
I got mine initially pressure tested when I was fitting it at AH Fabs, Alex has a couple of ali tubes capped off and one has a tyre valve in it. Removed the top hose from the charge pipe and blocked that end with one then pulled the other hose from the throttle body and plugged the vavled cap into that. Used a compressor airline to bung the air in to 2bar...

Bill has something similar which I used to test mine more recently to 2 bar with no leaks.

Had an S3 and a LEON Cupra in recently that had boost leaks, the LCR was just due to not tightening the clips enough and the S3 had classic crushed joiners and really shoddy T-Clamp clips. Replaced those with hi-torque jobs from Forge and both held 2bar with no leaks.

<tuffty/>
 
im looking around for a blank and a end cap.got some plactic caps 10mm thick with a flange. but dont no if they will hold.i will give it ago anyway and see what happens.im going for the tyre valve idea aswell.
 
done my pressure test and i was losing some pressure from a clamp.sorted now.done some logs as-well but wait for them from my friend.my recirc valve is a 006 i think.its round at the top not flat edged.with that in line on the reloation it would only hold 10 psi.so had to take it out and blank the hole.is this right
 
ash3435 said:
done my pressure test and i was losing some pressure from a clamp.sorted now.done some logs as-well but wait for them from my friend.my recirc valve is a 006 i think.its round at the top not flat edged.with that in line on the reloation it would only hold 10 psi.so had to take it out and blank the hole.is this right
Click to expand...

You have removed the DV??

<tuffty/>
 
yeah i did the system sat there ok.but with it on it only held 10psi.should it do this
 
Ive tried both ways and still the same.Ive got it now so the vac line is pointing towards the front of the car
 
Boost dropping away after 5k is normal but I would have thought it would have spiked higher at 2.5k +

Just so I understand right... you have done a boost leak test on your car, when the DV was connected it only held 10psi??? but blocking the DV outlet from the charge pipe sorted it?... am I understanding this right?

Based on that, did you pressure test from where the charge pipe connects to the turbo (orange coloured pipe)? What pressure did you test too?

Trying to understand what you did before suggesting anything else... Normally I would pressure test from the hose at the end of the charge pipe by the front of the car and the end of the hose going into the throttle body as if you are gonna have a leak it will be somewhere there... I test to 2bar/30psi to be sure....

What DV do you have? if its a Forge then maybe a yellow spring if you have a green in there... if its still an OEM DV then it may well need changing if its leaking boost at 10psi

<tuffty/>
 
yeah the dv only held 10psi before dropping the pressure.ive got a relocation kit for the dv and ended up blank that hole off.ive only tried from charge pipe to throttle body, so basically the fmic.i tested to 2 bar and all was ok.the dv is round at the top 006 maybe.got a yellow spring in it.i had the dv in both way and still only 10psi.
 
just an update on my car.had the stat done this weekend as it was not getting warm on journeys.logged another s3 with revo stage 1 and his reading are the same as mine.both of us lose 350mb higher up the on act vs req.going the actuator way now, could it be possible that the standard actuator can't hold the pressure the map is asking for.
 
Ok, so I understand you properly... your problem is the boost pressure dropping off higher up the rev range??? If this is the case, as mentioned before K04's do not hold boost much beyond 5/6k... they are designed to provide more power lower in the rev range which makes the car feel quicker under normal driving conditions... they simply do not have the flow capacity to maintain over a bar of boost to the redline.

The map may well request 1.3bar of boost but the K04 simply will not produce that pressure at that RPM...

If the actuator was going weak then it wouldn't be producing nearly 1.4bar at 4k rpm.... Manifold pressure would push the wastegate open if the actuator was weak... What is plausoble is that the wastegate penny is damaged or the turbine housing is cracked and is leaking exhaust pressure there.
su
However... the fact that you logged anouther Revo'd S3 that produced similar results to yours suggests there isn't a prob at all and looking at the way boost tails off further up the rev range suggests normal operation of a K04 turbo...

Fitting a new actuator thats of the same rating (0.5bar) and corectly adjusted preload won't give you anything IMO... fitting an actuator that's of a higher rating (1bar for example) or with the preload adjusted incorrectly will result in boost spikes that while will give you more performance for the short amount of time it will take for a rod to exit the block of your engine...

<tuffty/>
 
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