Audi 80 Avant

[A80Avant]

Right a small update:

after fitting the tank and fumoto valve to drain to the sump, i realise that even with that being done, there is still a hell of a lot of blowby going to the airfilter and turbo, making all N75 hoses, lower wastegate chamber, mushroom filter and turbo full of oil. It is clear then that the tank alone wont work. As an alternative i must try the provent tank instead, so ill order one from efiexpress.

I cannot be bothered having 2 tanks one emptying to the other etc at least not at the moment, so for the time being the tank will vent to the atmosphere through a filter and keep everything clean hopefully.

I may end up needing 2 provent tanks, who knows! but i can say that i have had enough with all this oil residue and spill.

Brake servo is going for round 2 and probably willl be fitting one from an S2 while i send the new which turns out to be faulty back to germany for either a replacement or a refund. More to come after easter.

Finally, im not sure, but can all the oil blowby if going into the N75 valve and hoses cause boost fluctuations and such? I went out the last couple of days for some boost checking and this is what i get. Lag increasing by anything between 50-140rpm and today boost not reaching target by 0.1bar at least occasionally!.

tried 2 N75 valves(mac units) and they were doing the same. One of them, was oily in the exits,from all the blow by.

[Rocco]

Right a small update:

after fitting the tank and fumoto valve to drain to the sump, i realise that even with that being done, there is still a hell of a lot of blowby going to the airfilter and turbo, making all N75 hoses, lower wastegate chamber, mushroom filter and turbo full of oil. It is clear then that the tank alone wont work. As an alternative i must try the provent tank instead, so ill order one from efiexpress.

I cannot be bothered having 2 tanks one emptying to the other etc at least not at the moment, so for the time being the tank will vent to the atmosphere through a filter and keep everything clean hopefully.

I may end up needing 2 provent tanks, who knows! but i can say that i have had enough with all this oil residue and spill.

Brake servo is going for round 2 and probably willl be fitting one from an S2 while i send the new which turns out to be faulty back to germany for either a replacement or a refund. More to come after easter.

Finally, im not sure, but can all the oil blowby if going into the N75 valve and hoses cause boost fluctuations and such? I went out the last couple of days for some boost checking and this is what i get. Lag increasing by anything between 50-140rpm and today boost not reaching target by 0.1bar at least occasionally!.

tried 2 N75 valves(mac units) and they were doing the same. One of them, was oily in the exits,from all the blow by.

please pictures

i have a strange outlet in my sump too... with a oil line it seems. it has to be more or less just return oil line

[jade]

Right a small update:

after fitting the tank and fumoto valve to drain to the sump, i realise that even with that being done, there is still a hell of a lot of blowby going to the airfilter and turbo, making all N75 hoses, lower wastegate chamber, mushroom filter and turbo full of oil. It is clear then that the tank alone wont work. As an alternative i must try the provent tank instead, so ill order one from efiexpress.

I cannot be bothered having 2 tanks one emptying to the other etc at least not at the moment, so for the time being the tank will vent to the atmosphere through a filter and keep everything clean hopefully.

I may end up needing 2 provent tanks, who knows! but i can say that i have had enough with all this oil residue and spill.

Brake servo is going for round 2 and probably willl be fitting one from an S2 while i send the new which turns out to be faulty back to germany for either a replacement or a refund. More to come after easter.

Finally, im not sure, but can all the oil blowby if going into the N75 valve and hoses cause boost fluctuations and such? I went out the last couple of days for some boost checking and this is what i get. Lag increasing by anything between 50-140rpm and today boost not reaching target by 0.1bar at least occasionally!.

tried 2 N75 valves(mac units) and they were doing the same. One of them, was oily in the exits,from all the blow by.

Hi

My systems dry, Try using a check value on the return, I can give you details if you wish, but no signs of from breather system in my air intake, before I fitted the check valve to the return it was filling the separater tank with oil

Regards

W

[A80Avant]

when you say return line, which one do you mean excactly?

[jade]

when you say return line, which one do you mean excactly?

Oil return to sump

[A80Avant]

my return hose is a 19mm large hose which should always drain. Why would a check valve be required to that hose? Does the sump get pressurised under boost? is that the reason?

[Billman]

my return hose is a 19mm large hose which should always drain. Why would a check valve be required to that hose? Does the sump get pressurised under boost? is that the reason?

the crank is pressurized through the blow by. during boost the crankcase-sump is pressurizedand is ventilated through the big PCV valve.

[A80Avant]

well then that means that the tank gets pressurised as well, and therefore more oil is going towards the vaccum during boost, hence the need of a check valve?

will the check valve work on off boost though allowing the oil to drain to the sump normaly, if i fit one there?

[A80Avant]

if i get the cam cover drain to which i have now connected through a T piece to that catch tank, and instead of getting that through the tank, i connect it directly to the drain of the tank (return to sump) will that make a difference?

i seem to think that most of the oil going to the tank comes from that hose rather than the OEM return (larger hose at the back) anyway...

[epic]

Perhaps you should do the twin system. Cyclone ( drain to sump ) and catch tank. This is what I'm running and very little pull through past the catch tank. The catch tank only collects about a 1/4 of a tank after about 4000 miles. This is a set up designed by JP with the catchtank drawn up by Rusty. Clearly for left hand drive you'd need to place the catch tank in a different location but I'm sure perfectly possible.

[A80Avant]

I'll probably endup doing something similar indeed. I have ordered a provent tank which does the same job and ill see if I can use it in conjunction to the current tank or use 2 provent together

[Jamo]

The Provent is good but the yanks seem to think it's not good for power cars and you need two of them.

I have a JP / Rusty system to go on mine, not the same as Epics a little bit different

[epic]

What's the difference Jamo?

[A80Avant]

i see, i may order 2 provents anyway. I just want to see if one + the tank i have will work equally to the system that JP has done.

I will take the whole metal plumbing off tomorrow to check for blockages again, as the valves are ok.

[A80Avant]

So out for some more tests today and i think i found the problem...

With my recent drain to sump solution, and the fumoto valve open, i went for a pull with the tank now venting to atmosphere. So i give it the full beens, it goes nicely, then boost drops as rpms climb, and what do you know? White smoke all over at the back!

i stop, look into the engine bay and the KN tank filter had been overwhelmed with oil blowby, a quantity of which was falling on the exhaust and thus giving the white smoke!.

So next test was turning the fumoto valve OFF. Out again and the white smoke was gone! Also the boost was much higher now and it only dropped to 1.9 at the redline whereas previously it had gone to 1.6bar!!

Am i right to assume then that my sump gets pressurised by loss of piston ring seal to 100% and therefore oil is going on a backwards direction during boost?
Although the drain is located at the lowest point of the sump, i didnt believe that it could go upwards.
However im now wondering if the way the system is setup is bound go cause some issues...

here are the photos of the current setup.
the circled bit is the T junction from the 13mm hose that drains the cam cover. This ends up in the block BUT on the OEM position which is way higher than the oil level of the sump itself.








So under boost, if this is seeing pressure, then oil from the cam cover is not finding it easy to drain downwards and hence goes into the catch tank through the T junction there. SO if the tank is getting pressurised as well with the fumoto valve on the ON position, then this is why im getting so much blowby to either the KN filter or the return to the turbo as i had it previously.

Once the fumoto is closed, then the tank will be getting full, and the original method of draining goes bust, unless i use a check valve as Jade suggested. This will be the next step, as getting a setup of 2 tanks will still cause issues if my sump is seeing positive pressure.

Ideally i would want to have that fixed, ie new piston rings etc, but even so im seeing some pressure at the sump, the oil loss is minimal, so im wondering if this is just something to expect when running 2+bar boost...

your thoughts?