Overboosting - Mk2 20v - AMK

[classy]

I've had this problem for longer than I've known it's been a problem - because of never driving a 1.8t before, I have no experience on how they deliver boost, power delivery etc especially in a mk2. The conversion was finished back end of november, a AMK engine on OEM managment in a MK2 golf.

Notable mods: B5 TIP, 007, N249 bypass, bypassed & simplfied some of the hoses under the manifold, assumed leak free after a smoke test revealing the above manifold hoses leaking, now being fixed. ECU is running an unknown map as I got it off ebay as the original was knackered.

After fitting a B5 Tip a few weeks back, went to erase the fault codes & had left the N75 unplugged. At the time, VCDS was saying the N249 was unplugged. After checking wires back to the ECU, turns out the electrical connector for the N249 had been plugged into the N75 & vice versa. Essentially I'd been running with the N75 unplugged for a month or so. On that night, I plugged the plugs back into their correct sensors & went for a drive...

The results were a massive 2.0bar+ Spike, (Boost gauge stops at 2.0bar) @ 2500rpm, dropping off to 1.5bar & maintaining to redline. Mental to drive but the engine internals are standard. Didn't drive the car until I'd spoke to B5 during this week to confirm all was NOT well.

Initially before I noticed the problem & still how the car acts now with the N75 unplugged it'll run at just under 0.5 bar until approx 4000rpm then gradually rise to 1.5 bar around 4500rpm & maintain to redline.

I replaced the N75 valve today with a new one & checked the correct plumbing. The valve was originally an 'F' but has been superseded to an 'E' type valve. It's made no difference.

Tomorrow I'm going to have a look at the actuator adjustment, the turbo was a recon K04-023 from Midland turbo so don't want to rule out incorrect actuator setting up from them. I've read to adjust - slacken off the nuts on the rod, push the wastegate closed, wind the nuts up to touch the arm in the closed position then +5 turns for preload & bring the second nut up to tighten?

No related fault codes at the moment. I'll post logs below but I'm struggling to work out what's actually going on. I don't understand when the N75 is unplugged that it manages to eventually build boost pressure later on, rather than just maintain actuator pressure. Also don't get where this huge spike is coming from when it's plugged back in?

First Log is of the N75 plugged in & running silly boost - 3rd gear to near redline:

Second Log is with the N75 UNplugged - 4th gear, ran out of road is why it stops at ~5k

Any ideas much appreciated, I'll report back tomorrow but decreasing time & money with other commitments means I don't have a lot of time to look into the fault.

 

[badger5]

hmmmm. dejavous perhaps

read this> http://www.audi-sport.net/vb/a3-s3-...4-off-ebay-china-have-read-inside-beware.html

 

[classy]

I've literally just read your facebook post, Bill. Sounds identical to the symptoms I'm having. (Also spoke to over the phone last week about the problem).

Midland Turbo supplied this turbo to me as a Re-con unit! I will NOT be best pleased if this turbo turns out to be anything other than a recon KKK Borg turbo.

Are there any tell tale signs to see if it's a non gen copy?

 

[Broken Byzan]

I was just thinking the same thing, Chinese hotside.

 

[superkarl]

IF it is, it could be ported right??

 

[badger5]

I've literally just read your facebook post, Bill. Sounds identical to the symptoms I'm having. (Also spoke to over the phone last week about the problem).

Midland Turbo supplied this turbo to me as a Re-con unit! I will NOT be best pleased if this turbo turns out to be anything other than a recon KKK Borg turbo.

Are there any tell tale signs to see if it's a non gen copy?

chinese hotside will be tapped M10 direct into the casting for the 3 x fixing bolts. Genuine BW hotsides have stainless inserts not just tapped into the castings.

my chinese hotsided CR hybrid also did this to me> K04-faulty-wastegate-new.3gp - YouTube

 

[badger5]

IF it is, it could be ported right??

yes it could

 

[classy]

I'm concerned at the similarities & genuinely not being able to think of other issues that could cause this.

How should the car run if the n75 is bypassed & you run a pipe off the charge pipe, direct to the actuator?

From what I remember when I sourced this turbo mid last year, from calling around 10+ different Turbo suppliers (trying to get a cheaper price) - that Midland Turbo had the only recon turbo left, at the best price as well... in the entire country so it seemed.

The arising problem I heard when trying to source a recon K04 was that the hot side castings were obsolete & nobody could get hold of any to re manufacture that side of the turbo, hence nobody had any in stock. New units were in abundance but at nearly 1/3 of the cost more.

I won't have time to get the turbo off for the next few weeks but the thought is now in my head that potentially they have used a Chinese hot side to re manufacture the turbo due to the lack of genuine hot side castings, the price being cheaper than the others is also a worrying factor.

Would it be the case when identifying the turbo, keeping in mind it has been manufactured that they use the same process as the Chinese to assemble the turbo? If they do, the only way I'll be able to identify it is to take the turbo off & look at the wastegate?

 

[badger5]

yes.
the one I have described, with actuator direct plumbed no n75 it should have run actuator pressure which was 8psi.. it ran away however.
when we undid the actuator off the wg arm completely and wired it wide open, exact same thing, it ran away with itself.. QED: wg port must be too small to bypass the flow, so no control. Boost Creep from hell

 

[classy]

Yesterday I had a little look into this..

I connected up a bike pump & some make shift pipe & tested the actuator, all moving freely & holding pressure. Then ran a pipe from the charge pipe outlet direct to the actuator. Test drove same as when N75 disconnected as expected, limp upto around 4000rpm then quickly crept up to 1.5 bar & full boost.

Had a look at how the hot side was mounted, sure enough - M10 bolts. Still not sure whether this the way they re-secure Manufactured turbos.

Then I found a little play in the wastegate linkage. When the actuator was fully pressurised & open - A bit like the video posted above but nowhere near as much. Should it have any play in it at all? I assume not seeing as the flap goes over the hole & any play in that joint would off centre the flap over the hole.


Here is a picture, using a mirror against the bulkhead showing the back of the turbo. Can see the actuator rod & the EGT sensor. Then what I'm guessing are 3 m10 bolts (of many) holding the hot side in place.

Then a little video of how much play was in the linkage:




I'm going to be ringing Midland Turbo monday to see what they have to say, looks to me as if it can't be anything else.. I don't want to move/play around with the actuator linkage adjustment for when the turbo does go back, then I can't be accused of messing around with it.

Looking at the receipt it's just over 2 months out of it's 1 year warranty but think this is largely irrelevant seeing the problem is down to how it's been manufactured. Disappointed a reputable company have potentially sold me a dud turbo if it does turn out to be the case.

Either way the next step looks like it'll have to be taken off.

 

[badger5]

looks like quite a lot of up down travel. if the wastegate penny was tight to its seat via preload it would'nt be as free to float up and down. At least the sleeve on this one does'nt look to allowing the up down travel like I suffered on a CR/chinese hotside.

have a look at the other post I made on copy hotside and the pictures posted of a k04 copy and its very small wastegate hole, which has severe boost creep like you describe

 

[classy]

In that video I had pressurised the actuator with a bike pump, so it would have been wide open. When in it's closed position it didn't have any play up & down so can assume it was tight to the seat.

The WG port hole in the other post looks tiny! I'll ring the supplier Monday, see if they can admit to anything & I'll have to take the turbo off during the week to confirm 100% that this is fault. Gutted really!

Thanks for your input, Bill - much appreciated.

 

[classy]

Spoke to Midland Turbo last Monday - they admitted they do on occasion use chinese supplies when they cannot source geniune hot sides. Didn't deny a possible fault with it either when referring to the port size being to small, apparently the head tech there had heard of a problem before. Obviously they want the turbo back to examine the unit & check it but would like it confirmed myself first.

Took it off today - A lovely job I may add.

See video/pictures below. Are there any dimensions I work to, to measure the size of the port hole on this as I'm not sure how big it's supposed to be. Under the penny flap, the hole is round & about 20/21mm - the size of the penny is actually 30mm. At the opposite end in the passage way, it's more like an ovulated slit & measures around 21mm each way, gets narrow in the middle - I can't put my middle finger all the way through..

Small video -

 

[badger5]

there's your problem deffo chinese hotside, no inserts for manifold mounting

they best get their carbide cutters out to open out the flow to that wg port then

 

[classy]

there's your problem deffo chinese hotside, no inserts for manifold mounting

they best get their carbide cutters out to open out the flow to that wg port then

Thanks for confirming Bill. Almost called to see if i could pop it down to confirm this week but if it's 100% saves me a trip :icon_thumright:

So I have some ammo to go into an envitable debate about this with Midland Turbo - do you have any comparitive specs?

How big should the port be?

They have already admitted they use a chinese hot side on when required so I'll need a bit more to go at them with.

 

[badger5]

port it, and it will work ok

 

[classy]

Spoke to Midland Turbo's head technician yesterday.

Told him about the problem, said he'd not heard of it before with their turbos but agreed it couldn't be much else causing the problem. Asked him to measure the port hole for a reference of a geniune turbo & another remanufactured one & they got 26mm diameter. So about a 5mm difference in size as mine measures 21mm!

They've collected same day as the call, going to fit a new hotside & renew the warranty, hopefully it'll be back Monday.

 

[badger5]

scarey how many other customers are having excessive boost and creep but are unaware! until BANG occurs

 

[classy]

scarey how many other customers are having excessive boost and creep but are unaware! until BANG occurs

It's scary how big the difference is & how on earth this slipped through the visual inspection, let alone when they tested it is beyond me.

Got it back Monday - some credit where due the turnaround has been very quick. I've received no documentation about the repair though so I'll be phoning them to see what they intend to do in terms of any goodwill offering seeing as this thing could of done some serious damage.

Here are some pictures just for anyones future reference on how it's supposed to look. They've replaced the housings, the port hole size as stated above is 5-6mm bigger than the previous one. Not only that whereas before I could just about squeeze my middle finger in there, in the new unit there is loads of room, can almost get two in there!

Seeing as the cars off the road for a bit, I figure I'll change the valve stem seals as seem to be burning quite a lot of smoke for the first couple of minutes when cold. Do the stems where much themselves on these engines typically?

 

[badger5]

its a chinese hotside still... no inserts on manifold fixing.
I would be tempted if that were mine to tak weld the wg sleeve into the housing as these have come loose after heat cycles, dropping the wg penny down and jamming it.
I cant resist porting them beyond what you have either.. Some carbide action if it were mine to ease flow into the wg port
but thats just me maybe

 

[BoostHard]

Sorry to revive an old thread but I have been having the exact same issue and the Turbo is a recon unit from Midland Turbo.
I have spoke with them but since the turbo is out side their warranty they are not being very helpful.

I am waiting for their head tech to call me back, They are saying this issue was sorted way before my turbo was purchased which was early 2012.

Bill I have spoke with you on SCN about this and you have been very helpful, But I would like Midland turbo to take it back and sort the problem.


Classy can I ask what date you bought your turbo from them?
Really need to get this sorted as its driving me nuts.

Also, is there a guide anywhere which shows how to remove the K04?

 

[classy]

Sorry to revive an old thread but I have been having the exact same issue and the Turbo is a recon unit from Midland Turbo.
I have spoke with them but since the turbo is out side their warranty they are not being very helpful.

I am waiting for their head tech to call me back, They are saying this issue was sorted way before my turbo was purchased which was early 2012.

Bill I have spoke with you on SCN about this and you have been very helpful, But I would like Midland turbo to take it back and sort the problem.


Classy can I ask what date you bought your turbo from them?
Really need to get this sorted as its driving me nuts.

Also, is there a guide anywhere which shows how to remove the K04?

Ideally you need to remove the turbo & measure the port hole up to confirm that's the fault.

Initially I called them to ask what size the port hole should be after measuring my own, when he came back to me (or I rang them another 3 times) & the difference in size was apparent I was then very direct in pinpointing the blame entirely onto them giving them nowhere to go.

My turbo was 4 months out of the 1year warranty I think. They picked it up next day & I had it back in 2. Albeit never got reference number or invoice this time round, it was all kept quiet, I did plan on getting them to warrant the turbo for another year but just never got around to it.

If they play hard, let them know that this is a problem from re-con k04 turbos that are coming from them, as they are having there chinese suppliers make up the Hot side casts for the K04's, obviously with the wrong specs. Maybe even reference a portion of this thread.

I would recommend if/when they replace the hot side of the turbo still taking it to Bill, as he'll tack the wastegate lever sleeve & do some additional porting of the wastegate port hole.

 

[BoostHard]

Thanks for the fast response. Are you able to measure the port hole with the Turbo on the car?

How easy is it to get the Turbo off the car?

I removed a K03 from a Mk4 gti and that was a pain.



Also when did you buy your turbo, I would like to confirm weather mine was purchased before or after yours.

 

[classy]

Wouldn't say it's impossible but it wouldn't be a nice job, just isn't the space for it or visual angle. I measured mine with a paper clip marking the diameter with a sharpy & then measuring the difference.

Though thinking about it now if you could remove the exhaust, wedge the wastegate open & stick a big chunk of bluetac over the hole so it indented the tac, carefully peel it back off & measure it could work? Just thinking out loud mind....

Took me just over an hour to get my K04 off the mk2, on the driveway. (Tech by day however). Getting it back ons a bigger challenge.

Without going through a sh!t load of reciepts I couldn't tell you fella I'm pretty sure it was Dec 11 thou as it says in my post above in feb it's 2 months out of date.