pablo_ottawa

Hey guys and gals,

Got a 2002 A4 1.8T QM and I'm wondering is it's possible to clean the N75 valve. If-so, HOW????


Anyone know?

Audictd

You could try but in the end its an easy and inexpensive part to replace.

pablo_ottawa

That's a lot of help.....

I'm not sure what your definition of inexpensive is but where I come from 100+ for a "servo" (because that's basically what it is) is EXPENSIVE. If all it needs ia a cleaning to get it running like new then I'll opt for that...

Thanks for answering my question.

Audictd

Try a little gasoline

johnny quattro

There are cleaning instructions available.

Let me know if you need a link?

pablo_ottawa

Hey Jonny,

thanks for the reply. I read both your edited and unedited posts and if you could provide links to both procedures that would be great.

So let me get this straight. Now you have bypassed the n75 entirely??? Is your car a project car or is it your daily driver? What about issues? Have you had any by running a direct and unregulated boost?

Your mod sounds interesting. I'd love to know more.

Cheers and thanks.

johnny quattro

Hi! Pablo,

My A4 is my regular vehicle.

First of all, regarding the N75 cleaning.

The link below explains how to test your N75 (couldn’t find the link for cleaning):

https://www.audiforum.ca/performance...hipped-a6.html

read N75 information in reply #4

Second, trying to make a long story short, I had an oil leak.

I traced the leak to a cracked crankcase breather elbow (common problem with the 4 cyl 1.8T). See pic # 1.

This connects to the PCV (See pic # 2) followed by a mess of check valves and hoses.

Instead of replacing the elbow, (knowing it probably would crack sometime again), I substituted an aluminum block breather Adapter (See pic # 3) with a ¾” NTP fitting (from 034 Motorsport) so that I could make the PCV, and vacuum lines simpler and more robust, plus I wanted less turbo lag from my DV.

I then read an article on the forum about getting rid of check valves and simplifying the vacuum system.

Read from link:

In - Line Check Valves

When I modified my crankcase ventilation and vacuum system (replaced crankcase rubber breather with aluminum fitting, removed and eliminated the pressure regulator pancake valve, eliminated the jet pump and 2 unnecessary check valves, looped the N245 and connected the DV direct to intake manifold), I also added atmospheric venting through a catch pot.

The end result is less check valves to fail, a much simplified vacuum system, what feels like instant turbo, and no more crap and volatiles being recirculated into my intake manifold! Total cost was maybe $60 and about 4 hours loving care, lol!

Please study my revised vacuum diagram in pic # 4 below, and compare it to the stock A4 AMB vacuum diagram, and you will see the differences.

I saw a catch pot (precision engineered) retail at $225!

I don't have the coinage for a precision built catch pot, but found an excellent, inexpensive alternative.

Consists of an black ABS pot (from a water filter system) 2 nylon reducing elbows, and a home fashioned mounting bracket.

Total cost of parts $15.00, Princess Auto.

Pics # 5 & 6 attached showing installed pot, and you should see the volatile crap now dumped into the pot, that was previously being routed through my intake manifold.

The pot has a screw top fitting, and all I have to do is twist and pour away the crap once a month.

I hope all of the above makes sense and sorry if I have been a bit too long winded.

Let me know if you need any more detailed information.

Quangvan

Hey guys just read this thread, I just installed new motor mounts and am pretty sure I strutted or cracked a check valve giving my a leak a heavy throttle if that makes sense. I'm interested in doing this simplification of the vacuum system. It deletes the PVC and a lot of check valves but since this is my daily will it still pass emissions? ESP the new new computer hooked up e test.

pablo_ottawa

That's a great question... Johnny, how did your etest go?