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

mine has some single electrode denso plugs that look ok, its not a miss fire... its a lack of boost lol,

on Qpeng there is just one map, all the "2 stage" boost button does is turn the N75 valve on or off... ie low power = N75 valve off so boost limited to what ever the actuator opens at. with it on the ECU will control the actuator and hence higher boost can be achivced.

I have also picked up my new shiney N75 "J" valve tonight, its not fitted yet but already theres something "odd" if you blow through the bottom connector as it would do on the car, the boost with it turned off is directed out of the right hand port, when looking at it with the plug facing you - ie the port that leads back to the intake pipe, and not the actuator... I will get it running on the car tomorrow to see what happens.

Im still now thinking Map... but then again god knows! so we will hoefully find out come Sat when I go to see ben (unless the new N75 works)

 

does your servo not plumb into the end of the inlet manifold ? i dont like the idea of it being in the same plumbing as all the other stuff

also might be worth plumbing the pipe on top of the tb straight to the n75 valve if it isnt already and testing the boost

 

on mine i have

servo pipe to inlet with one way valve

map sensor & fprto inlet nipple
boost gauge & boost controller & dimpvalve on 2nd inlet nipple

actuator to boost solonoid then to throttle body

your plumbing seems a bit all over the place? or is mine just simple

 

the servo is on the end of the inletmanifold... its attached to the big 10mm take off on the left hand end as you look at it (mine runs a inlet manifold with a rhs throttle) between the servo and the manifold is a 1 way valve with 2 small take offs before the valve... these are used to run the dump valve and boot gauge... then after the first 1 way valve is a second port, which has the pipe from the odd black tube attached... The idea as far as I could work out was that it would alway be under vaccume via the black tube, either from the throttle body take off or from the inlet pipe take off, depening if it is on boost or not.

then there is another 1 way valve and then the servo.

the map sensor has its own feed from the take off on the bottom of the inlet manifold.(the boost gauge was T'eed in to this before but my reasoning was less joints = more accurate as less chance for leakage)

it only loooks messy due to the magic black tube. (do you actually need this? or is it just vw being over safe to make sure there is always a vaccume on the servo pipe?)

my N75 valve is plubed in this way:

Bottom port is attached to the inlet pipe juts after the turbo on the oe take off.

LH port as you look at it with the wiring plug facing you goes to the actuator

RH port goes back to the inlet pipe pre turbo.

 

I put the N75 valve in this afternoon, I attached it with the actuator and intake hoses the other way round to the "F" valve... this ment that in the "OFF" position it was still allowing all the boost to the actutor and not back to the throttle which would have been wrong.

I also took out the black 2way valve that was attached to the throttle to rule this out, I pressure tested it to over 2bar but I wanted to be 100% sure..the set up is now pretty much as per bens cabs in terms of the 1 way valves etc for the servo...... as expected it made no change.

I am also tempted to put a forge actuator on there too just so the low boost and high boost modes are a bit closer together and less agrassive (like I have said the oe actuator seems to open at about 4psi when pressure checked with a bike pump and gauge)

 

if you clamp the actuator hose you will know straight away if the actuator is fudged

 

but surely running it with the N75vave off should also tell me... I am only getting 4-5psi which I think is too low... but then again I maybe wrong.

also I forgot to say after the run (off the drive 1.5 mile on low boost driving normally then off the island up the slip road on low boost mode giving it some then a mile in full boost mode and then 3 miles back home in low boost mode granny driving, and coating round my estate for 1/4 mile in neutral plus a couple of mind idling on the drive for the run down) I took the plugs out. they are denso iridium ones with very small tips. and they were also a bit coked up

edit - just thought this through again and I am looking for if the actuator flap in the turbo is forced open too early ie 1bar instead of say 2 bar when I clap the actuator hose. sorry Ben had a blonde few days

 

did the N75 J valve make any differance to the boost?

when did it start doin this, have you changed anything around that may have caused it?

 

the N75J made no change. as before when on the drive, ign on but engine not running there was no chnage in the valve position when the throttle was opened wide.

I havent changed anything, its come about as like I said before, when I got the car the last owner said it has been de-tuned to run the 8v fuel tank, and once the mk4 pump was on and running then the ecu could be sent back back to qpeng and have the k04 map put on for the full 270bhp... sent it back to Ben but he said it already had the k04 map on there, so then I started looking for the missing boost, it didnt run 100% smooth on WOT throttle before but I put that down to being on the limit of the 8v pump... althought now it seems thats not 100% right.

 

kjet pump is the way ahead...

i can only suggest to redo all the pipe work with the vacumes etc as if the N75 isnt getting the right pressure it needs it just wont operate the actuator correctly...enless your turbo is dieing so wont create the boost but i doubt thats it, more likly to be somthing simple...

are you goin to vw/audi day this sat as ill have mine there if you want to have an idea of how mine an yours differ?

also have a club stand to which needs filling up?...

 

im running a mk3 tank with a mk4 1.8T pump now but I maybe going over to a mk3 vr6 pump as a down side to the mk4 pump is no fuel gauge at the mo.

TBH the lines to the N75 valve cant be any simplier... on the turbo front there doesnt seem to be anything wrong... theres a smige of end float but theres naff all movement up or down,

I have now made the lines even simplier, as the inlet manifold is no longer connected to the intake ipe via the 2 way valve thing... I just have 1 take off on the end of the inlet manifold with 3 1way valves in it for servo and the 3 take offs for the dump, boost gauge and MAP sensor.

Im not going to combe sorry, its nearly 3 hours from me if it was closer I would just to say thanks in person for you help! its most appreciated, as is everyone else help.

 

cool cool, must be somthing simple, dump valve seeping atall?

when you said the last owner had it de-tuned did he say it was just in the ecu or did he wind the actuator rod?

ill try an measure mine when i get home friday afternoon an let you know bud...

 

he didnt say what had been done, and I cant seem to get hold of him to find out, but he did say about getting the ecu re mapped, so I assumed it was just a software tweak - ie boost was limited via the ecu.

dont think the dumps seaping, its a blitz one and holds pressure fine at idle.. so I think its ok. and you can hear it dump when it does... its not quiet, (wheen spooling up all you can hear is the induction noise and the whissle from the turbo)

worse comes to the worse, I go and see Ben next week and he puts another map on there just in case there has been a setting tweaked that he didnt see if that doesnt work im scuppered (but I am ordering a forge actuator as a mate has a voucher for forge that he says I can buy off him cheap )

 

k04-001 or k04-022/23 ?

sorry if ive missed it.

i would measure my Actuator length but mines been adjusted as its slighty weak.

Actuator pressure is about 7psi.

 

its a 023 I belive (the spare one off the car is that), it appears that my actuator may well be weak then, as mines open at 3-5psi...) but no worries I should have a forge one next week.

 

FIXED!!! it now go like a scolded cat thats been kicked!!!

The culpurate - the crappy denso plugs!!!

I picked up some Bosch 4 electrode ones for the BAM engine last night from halfords as on trade they are 12! pooped them in this morning and things seemed a little better, it was smoother and no longer stuttering when floored etc, but I still appeared to me missing boost on the gauge.

drove for nearly 3 hours to see Ben from Qpeng and after a quick chat and checking it all at idle we went for a drie while Ben watched his laptop... and it is boosting correctly! 1.5bar on the engine sensor so its my boost gauge thats playing up!

Ben still took the time to double check everything, he upped the duty cycle of the N75 a smidge and upped the peak boost from 1.49bar to 1.51bar as he say the engine was in good health and would happly take it. he then also tweaked the cold start to make it a little smoother too.

the drive back was alot of fun! the tweak to the N75 has made it a bit smoother and the new plugs mean that over taking is now a doddle... hehehe

moral of the story... dont runny dodgy looking plug (Ill put a pic up later) and dont trsut your boost gauge. even if its is supost to be super accurate and costs 70+!!!

but at least I now know all is well, Ben even checked the intercooleer was working well and the intake temps, and even on a long climb up a steep hill in 4th from low revs the intake temps didnt go over 50 deg so he said he was very happy with that (and it can be cooled more if I open up more of the cooler so I will be doing that soon)

A very good day all in all

heres the plugs that were in...

 

glad its sorted mate.

bosch super 4's in my 20v make it run like poo.

 

I will take the new plugs out after some more miles, I took one out when I got home and the electrodes were the proper tainted with white speckles colour as was the centre probe and the ceramic was a golden colour, so they seem to be ok at the moment.

im sooo glad I know its got a clean bill of health though nice to have peace of mind

 

when i was wide open throttle mine just misfired like a *****.

 

what ones do you run now? and what boost was that at just out of curiosity