KO4 Actuator length - low boost and surging! FIXED! see page 3

does anyone know what the actuator length should be on a k04 turbo? as I am still chasing my missing 0.5 bar of boost, and the engine isnt as smooth as it should be when on full boost

the story so far: the engine is AUQ thats had all the k04 kit fitted but it was running a 8v fuel pump so the last owner told me the car had been set up to 250bhp and confirmed this with a rolling road print out due this being the max power you can run on the 8v fuel pump.

so far I have:

installed the mk3 tank with mk4 fuel pump so the fueling is now man enough to support 270bhp.

Sent the ECU back to Qpeng to check the ecu is demanding 1.5 bar and had not been "turned down" it came back all ok with the proper k04 map installed

checked the throttle is opening to full as Ben @ qpeng told me that if the euc does not see 100% it wont demand full boost

and this weekend I have now re done all the boost and vac hoses on the engine, there didnt appear to be any leaks on the previous set up but they are all new and the number of joints have been reduced, 1 less on the main induction hoses and there are now 3 less for the boost gauge which now has its own feed (it was Teed into the feed for one of the boost sensors which again now has its own feed with new hose and the connections zip tied with a tiny tie to help stop and leaks)

personally I dont think the boost gauge hose etc will have been losing me 0.5 bar (the gauge currently shows 1.1bar between 3500 - 4000rpm which then tails off to just over 0.5bar as the revs go up which is ~0.5bar less than it should be according to Ben) so does anyone know if the actutor can be wound up / down to raise / lower the boost on a K04? as I suspect some one may have wound a turn off to drop the boost level a bit..

anyone have any measurements I can check against?

 

ive read they do it on the number of threads showing 10 on a ko3s so id check you have that as a minimun then do it up one thread at a time

seems of it was there now it isnt any oil in the intake being blown from the turbo?

 

not really any oil, I cleaned the system out quickly a few months back when I set the oil breather up to a catch can and then to atmosphere, and when I took it all apart there was a smidge of oil in the pipes but very very small amounts.

as far as I know I have never had the full 1.5 bar of boost... when I had the car it idled high which was traced to a split vac hose... since then its always boosted to 1.1 bar (before then it boosted to about 0.9 / 1 bar iirc)

 

not a weak n75 valve? friend of mine had similar issues, fitted n75 H valve an problem solved...

 

erm i have no idea.... do the codes mean different boost levels? ie x = 1 bar max, y = 1.3bar max?

I would guess that the N75 valve fitted is the one from the AUQ engine in which case its whats ever fitted as stock to a 180bhp engines running a K03s turbo.

 

i had the F which was on the 225 as std an i was suffering from the boost dropping off to much, the initail spike was 1.5 then it would trail off as they all do but mine was trailing off to much...

fitted the H valve bought from audi, fitted to the S4 i think an never had any issue's, now boost's to 1.75 though its mapped for it an it hold's 1.5 to around 5k then starts to drop.

fitted my H valve on friends octavia VRS an it was soo much better but the std ecu didnt like it.

the only thing id say is the H valve is quite aggressive as in the inital spike, the J valve is the one down from the H an is a bit less aggressive...

an also dont think about buying the N75 "race" valve from awsome as its the same as the N75 H valve...

 

hmm Ill check whats on mine tomorrow then, and dont worry I will just get a gen part from VW as I get trade at TPS so hopefully it wont be mega bucks.

as I run Qpeng there shouldnt be any issue with the euc not linking it but if the J is ment for pretty much the same boost as H then I might just play it safe and get that one..

 

on aftermarket ecu's there fine well ive never herd of any issues, i think its the sudden boost spike the std ecu's dont like...

the J is used by alot of the ibiza Cupra R people as i read up about them on seatcupra forums before i bought mine...

 

cool I will check mine, get the car running and then see if I have fixed it, if not Ill pop a J on there and see what that does....the its on to winding the actuator I think

Id still like to know the stock actuator length / if it can be adjusted to get more boost as I am still thinking this may have been tweaked a smidge

 

emailed ben at Qpeng and he reccons that the N75 shouldnt really make an change... so I will see what happens this weekend and then look at maybe adding 1 turn to the actuator (which way raises the boost????? ie making the number of turns after the nut more or less?

 

cool cool, the N75 controls the boost though an if its weak then it wont allow the actuator to open as much as it should so would lead to less boost...

with the rod length im pretty sure the shorter the rod the more the it opens...

 

right I will check the N75 this afto and if needs be ask my mate to order me a new one... if it doesnt work I can always return it

also on the actuator length when you say shorter, do you mean as in more turns after the nut? ie

[actuator]---------[nut]--------- wiill give more boost that [actuator]---------------[nut]---

thanks very much for your help

Karlos

 

im 99.9% sure the distance between the actuator an the nut is the one that needs to be shorter...

 

cheers, I will try 1 more turn if needs be.. as I have been out tonight finally and I still have the same problems.

when on High boost mode that turns the N75 valve on (if you flick the button but dont have the N75 valve electrical wire plugged in you wont get high boost) I am still getting 1.1 bar and I get surging thats noticeable, its like the cars being held back... also tonight when full throttle between 3200rpm and 4000 rpm I got a very loud pop like it was a 1 off miss fire...- reminded me of back firing through a carb!!! I back off straight after that - pulled over and checked for a popped hose but all was ok so tried again...with the same results... 1.1 bar max and surging!

any one know what to try or what this points too? as I am pulling my hair out doing this, Qpeng have said they will look at the car but want 40 ph so I am leaving that as a last resort!!! as they say the map installed in the correct K04 map and nothings been changed on the software side of things.

cheers

Karl.

edit: I wound on 1/2 a turn extra to the actuator (ie made the gap between the actutor and the first nut smaller) and went for another drive... no extra boost but it did pop again - sounds like the its firing in the turbo! and I also noticed that it feels to run faster when the throttle is only 90% open... if you floor it it feels like it slows down and struggles... back off again slightly and it appears smoother and quicker.

I also dug out the spare K04 I had in the garage, I have no idea if its been played with or not though... so Im not confidant the actuator hasnt been played with, but the measurent on that from that one for between the cut on the actuator before the thread to the nut is 23.62mm but on the one on the car its only 22.99mm!!! now from playing with the one off the car it appears that the bigger the gap the less pre-testion on the waste gate and the wider it opens when at full pressure... the one off the car is wide open by 15psi or so (ie 1 bar)... so the length on the one off the car makes the waste gate open approx 6 or so mm... but when its set to the same length as the one on the car it opens a fraction late and the widest it opens is about 4-5mm so in theory the boost should be higher I think than stock.......

so anyone have any more ideas or able to measure their K04 for me please? this is how I measured mine, from the cut before the start of the thread to the face of the nut

 

can anyone runnung Qpeng confirm what boost level they get on low power - ie N75 valve turned off?

I also turned the car on today, switched on the high boost mode and opened the throttle full... should the N75 valve make a noise / viabration??? as there was nothing.

I then thought I would measure the voltage suplied to the N75 valve, and it was changing between 4.99V and down to about 3.8v or so...but it wasnt changing that fast (then again that could be how fast my multimeter logs) but the voltage was always above 3V

anyone have any suggestions for what to check tomorrow? I have ordered a new N75 valve but that wont be here untill tuesday.

 

you say it runs faster at 90% throttle could it be a iffy tps?

if the valve is working and theres no boost leaks then the only other test is the actuator itself or the tps

with the acutator i took the pipe of the n75 valve and put a set of molegrips on it then went for a drive to see if the boost increased if you do this be gentle as it will more than likely go of the scale if it does then you know the actuator is ok

with the tps are you getting the right readings all the time on the tuning software?

 

I still have sod all idea how to use the esimap software and dont want to cock up the map thats on there, but when I used the live output I had this

http://www.clubgti.com/forum/showthread.php?t=218406

also I was tempted to remove the actuator and see if its boost correct but I am concerned it will over boost and blow something up.... am also going to connect up the bike pump to the turbo on the car tomorrow and pump it up to see what pressure the actuator starts to open at.

 

if you do the actuator test dont thrash it drive it until you hit the boost you should then let off theres no need for the boost to over shoot if your watching it i did with mine soon as i hit a bar i was happy the actuator was ok

 

could this be done on the drive with the engine not under load?

also on qpengs site it says about the throttles " We can use either the Mk3 Golf 2.0 8v GTi 2E, ADY or AGG engine code throttles or the 20v AGU unit. Please let us know which you intend to use when ordering."

Now I know when I got the car there was reciepts from ebay for 2 throttles, when askd why the lad said he got the wrong one first but I wonder if runing say a AGU throttle instead of a 2.0 gti one make any odd? as from the qpeng site it reads like it does

 

you need load on the car for the boost to increase i had similar issues and did the actuator test just so i had peace of mind like i said you dont need to go mad just give it enough in 3rd gear for the boost to hit the magic number then stop and connect the n75 back up if then the boost drops you know that the fault is either the n75 or something to do with the way the ecu reads the boost if its via the tps then id go with the tps

my money is on the n75 valve tho