Any 1.8t experts in the Reading / Maidenhead area?

You may be able to use Ptfe tape to seal up injectors.

Thats not a good way to test the system a bit hit and miss.

 

Might give the PTFE a go.

Can you elaborate on the test issue please? Remember there's no PCV valve here.

 

you need to pressurise from the turbo outlet into the system. You shouldn't have to block off n75. This may be your problem as i'm sure it should be normally closed. Wastegate shouldn't be affected.

You need to include breathers in the test but just not them to vent back to inlet as the system is open to atmosphere. These are a big cause of boost leaks.

Look on youtube for 1.8T boost leak test. It may help.

 

Thanks again, learning lots here.
think this through I'm just trying to think this through.

I only blocked the the pipe from the N75 that goes to atmosphere. It was leaking first time as it was getting air from the intake. Which I thought at the time was ok but I'm beginning to wonder now.

Sorry I don't quite follow what you mean with the breathers although I do suspect my system a bit. Something doesn't quite feel right about it. I'll do some digging on that one too.

I'll try again but I'll pressurise from the turbo outlet as you say but I'm not sure on the breathers yet.

 

[video=youtube;s29Q77hK-i4]http://www.youtube.com/watch?v=s29Q77hK-i4&feature=youtube_gdata_player[/video]

This might help

 

You can test for leaks from turbo compressor inlet or outlet

Anything down stream should be leak free. N75 should not leak under pressure if it is unplugged as the path goes through the valve and into wastegate actuator which also should not leak. There should be no air passing into atmosphere port unles valve is pluged in energised for whatever reason!

If you pressurise system to about 0.5 bar this will show up any leaks if there are any

Have you tried to go for a drive with N75 uplugged? If it is plumbed in correctly and you have no leaks you should see 5-8 psi of boost if your actuator is standard

 

http://forums.vwvortex.com/showthre...-pressure-should-valve-hold-b-t-signal-and-wg

Also in link below read Bills(Badger5) post, he explained it well

http://www.seatcupra.net/forums/showthread.php?t=237956

 

I think that may be part of the problem. N75 shouldn't be venting when in an off state. Should be operating wastegate it seems though.

Is it plumbed like this ?

Or this

 

I think that makes sense. Cheers again. The fact that this is far from a stock set up is making my life harder than it should not being clued up on the 1.8t.

The N75 is plumbed so that the bottom connection is connected to the turbo outlet pipe. When I blow through it air comes out the one on the right (labelled wastegate). This is connected to the turbo actuator. The other (intake piping) is left open. Yesterday I was finding that as soon as the pressure built up a little it was bleeding off to atmosphere. I couldn't get anywhere near 10psi in the system. So I blocked it and found the actuator was moving and then I was able to hold pressure long enough to find some leaks.

Now I think this is partly right. The N75 bleeds off keeping the actuator closed until it's told otherwise. By blocking it I fooled the N75 into thinking that we were running at high boost and it opened the actuator. Question is, it was completely open at less than 10psi. I don't know if doing it this way is correct or will achieve that.

I'll try again by taking the pipe off the turbo outlet and connecting the compressor from there. But I suspect the same thing will happen with the N75. It will leak to atmosphere so I can't achieve pressure.

Secondly I'm still trying to figure out if my breather system is right. It's a bit naughty going to atmosphere without a catch tank (which I'll sort) but both hoses from the valve on teh front of the block do that at the moment.

I'll try and get some pictures up too.

Cheers

 

It must be set in the map for 10 psi if this is happening. Can you see the boost control map?

Are you pressurising system with ignition off ie no power to the N75. If it is off, it should only pass to wastegate and not vent at all. You may have a duff valve.

Not sure if that is right. I know breathers can be cause of leaks and they are part of the the boost network usually. Don't know what you have done.

Pics will help.

 

Hi Thanks again for the reply. It's helping a lot.

Yes and it's flat out on the high boost map. There's very little difference when driving on either the low boost and high boost maps so I'm convinced it isn't that.

I think you're right. I retested the system yesterday and got the same result with the iginition on and off. I did nothing with the breathers this time. As soon as pressure hit 5psi it started to leak from the N75. It eventually got to 10psi and while it was leaking from the N75 I could also hear it coming from injector No. 1. The actuator also moved. I took the N75 off again and while blowing through the bottom connection I noticed air coming out of both side ports. So that looks a bit duff I think. How I didn't pick up on that earlier I don't know

Here's the N75


N75 connection to turbo outlet


And the test in place

On the breather system, can someone please tell me where pipe no. 10 connects to on a stock AGU or similar.



I'll look at getting a replacement N75 and somehow deal with the leak around the injector. The PTFE sounds a good idea as an interim measure.

I also want to sort the breather system out into something a little more reasonable.
Has anyone fitted one of these and what are peoples thoughts? Are there alternatives? I like the idea of being able to recirculate the oil but not 100% convinced that it would seperate from the damp air etc.

http://www.034motorsport.com/engine-components-18t-catch-can-breather-kit-mk4-18t-p-19167.html

 

The oil sperator is incorporated in the large fitting on the block. This should be more than enough for what you require.
Pipe 10 connects to the intake plenum. It is the part load beather circuit. During full load, where the engine is boosted, vacuum for scavenging the crankcase is sourced from the compressor inducer, and there is a valve that stops manifold pressure from leaking back into the crankcase (item 6).

 

Bingo! I knew something wasn't right and is probably another part of the problem. It had dropped off the pipe connection and there was probably a boost leak there from day 1 as well. I'm crossing fingers that we've managed to diagnose everything now.

I still think a tidy up of the system will help. I'll sort this and it will be functional but just not quite to my liking. I'm getting fussy now.

 

If the pipe from the plenum dropped off before the "bleed valve" 6 then yes, you will loose boost pressure and struggle to idle. Check the valve and reconnect. Check the leaky injector and replace the seals.
Hopefully your response should be much quicker, with target boost achieved by 2000rpm. From here the cal would need tweaking.

 

It fell off from the underside of the inlet manifold and I suspect it was loose / leaking from there beforehand. Having resecured my dump valve to that point that Vac leak was dealt with and the issue didn't show up on the pressure test. The hose had been left open to atmosphere as I simply had no idea where it went. It makes sense how boost leaks can effect the breather now.

 

Looks like you're on your way with finding the problems. Shows how important a boost leak test on turbo cars is.

 

yes I hope so. Still have that horrible feeling that tere's going to be more to it but at least I have things to go at now rather than chasing my tail as I was. I'll work my way through these issues and report back on how its gone.

Can's thank you guys enough! Cheers

 

Lets hope you got it sorted mate

 

Many thanks Sambo. It's been doing my nut I can tell you. It's got to be up for an award for the most frustrating conversion ever. It's fought me every single step of the way.

I managed to sort that pipe on the breather last night. Definitely crisper on the throttle now. I still seem to lose a cylinder on very light throttle but that's no susprise. New N75 ordered so hopefully that will be here today / tomorrow and I can take another step forward.

I still have a sneaky suspicion with the injectors on light throttle but I'll sort everything else first.

 

You'll probably find that the map will be over fuelling if it has been mapped with pipes off the inlet. Before any more adjustments are done, make sure all leaks are sorted.

Its a shame you went to emerald with it in that state.

Conversions can be easy, but I suppose you chose an uncommon one, a bit like my own with their own unique quirks.