Richie's '91 20vt Avant

[loxxrider]

My former Cayenne has made me immune to high brake costs. Each rotor for one of those was a minimum of $700 LOL

[uberaudi]

My power steering belt got shredded at the track but I still managed to make the two hour trip home with it flipped and slipping. I got a box of parts in today so I pulled the 20v into the garage and went ahead and replaced it. Everything else seemed good, (except the stripped tensioner bolt!) so I topped off the fluid, started it up, and proceeded to witness a waterfall of Pentosin start to accumulate on my floor....damn x plug had lost it's o-ring. Great, looks like I'll be doing my vac conversion sooner than I thought. At least the booster is in the mail.

I also replaced my plugs as I was starting to break up in the higher rpm's at the track. They were some old Bosch Platinum's (F5DPOR) that looked liked they had been in there a while...but were burning nice and even over all 5 cylinders.

Not much left of them!

I went ahead and threw in some F6DTC's, which I understand is the recommended plug for the 3B and also replaced the hissing coolant overflow cap. I was hoping to drive it this week but there's always next week right? Or the week after...

[uberaudi]

Haven't done much with the 20vt for a while because I've been getting my winter beater/commuter/rally pig ready for the deep stuff:




'88 5k with a QLCC chip/spring with strapped intercooler on stock unknown mileage MC1, bpv, Urs6 springs (giving about .75" lift), Bilstein HD rear, Boge Turbo's up front, LED fogs with foot switch on deer slayer bumper, broken door handles, a dimpled hood, and a desire to be a menace on the road. Total investment: just shy of 200 bucks. She ain't pretty, but man is she fun! hahaha

Alright back to the 20vt... I found a little time tonight and threw in a better stereo in the 20vt to replace the hideous old ass silver Pioneer. Craigslist find for 50 bucks. A Kenwood KDX-697. Not anything special, but it's mostly black with variable color display and sounds quite a bit better. Check it out!

[loxxrider]

That's pretty similar to what I have in mind and isn't bad at all. I'm not sure if that one has dsp functionality, but if it does, it's a great one.

[uberaudi]

Dsp? Not sure if it has it, but probably not.

[ringbearer]

Love the beater!

Paint the rubstrip/beltline area black down the sides of the car and it would look stealth from the sides and MadMax from the front

[uberaudi]

Hadn't thought of that but I like it! I was also considering some Swedish snow camo, cause you know, it's snowing! 14" on the ground with 6-8 on the plowed road, only a couple in the driveway. It drug the entire couple miles up but the diff locks kept the wheels spinning.

[WOMBAT]

Dang. 14" already! Snow tank ftw. That avant is awesome!

[ringbearer]

Damn that looks like fun. I tire of the perpetual Sumer here in ca.

[uberaudi]

Since one of my x plug o-rings on my power steering pump took a shit, I decided to just go ahead and convert over to the B3 vacuum booster to try improve my brake feel as well as eliminate more leakage from my system. I got all my parts together and started the process according to loxxrider and a-talk's writeups.

B3 9" booster - this one happened to be: 893612105E
OEM Grommet for booster - VW 357-611-817
OEM square o-ring for booster to master seal - VW 357-611-243
BMW 90 degree check valve - 34331161300

Power Steering Pump Seal Kit for leaky x-plugs - CRP 026198049B
M10x1.0x8mm with crush washer to block off accumulator line
Drag Link Socket modified to fit x-plug - NAPA SDL3822

Everything came apart fairly easily and after pulling the master it was pretty clear it was a good time to dive into this project:

Kind of hard to see, but there is a pool of green gold lurking in the shadows!

Power steering pump with the two outermost pistons removed, new seals and paint:


While everything was apart and other things easier accessed, I dove a little deeper to try and resolve any future leaks. The return line for the rack was pretty wet looking so I cut the crimp collar off revealing the factory barb fitting, and slipped on some 10mm ID (3/8") power steering hose with a nice quality ABA 15mm fuel injection clamp. This is a quick and simple solution for a non-pressure line. I don't even want to know how much the factory return line is anymore, if it's even available.


After cleaning a bit more I went forward with the conversion. I installed the booster (which was a super tight fit) and bolted everything else up with new seals. I had to bend the fuel lines quite a bit, but they managed to fit just barely to the side of the booster.


As for the vacuum source, I used some sili-bronze and brazed on a random 90 degree fitting to the ISV elbow. It was even .5" diameter, the same as the check valve in the booster which made selecting the correct hose only a small task for the FLAPS.


Now that everything was hooked up, I fired her up, only to realize the brake pedal is hard and I don't have any brake assist.

I immediately thought bad booster which would totally suck balls since it's the first piece of this whole conversion that gets installed. I pulled the check valve out of the booster and fitted a blow through elbow in it's place and connected it to my Mity-Vac. It held a nice 30 in Hg for a good time:


I then pointed the vac gauge towards the steering wheel and watch it drop then hold vac as I depressed and held the brake pedal. I think the booster is good...I think.

Is my vac source sufficient? Could I not be getting strong enough vacuum to open the check valve or something? What gives?! Anyone been down this road?

And just a friendly reminder...if you're the first one to work, make sure and bring some doughnuts.

[LeafBox]

Speaking of the afterrun system. (last page)
Does anyone know the simplest way to get that to work on a car that never had it?

I'm debating if it's worth getting it working on my MC-swapped B3...

Regarding vac booster.
It's not quiet the same, but in my car I'm just using an open port on the intake to the stock NG vac-booster.
I'm also using the 100 turbo dual-piston caliper and it felt fine during my testdrive so I'm assuming it's a sufficent vacumsource.

[yodasfro]

I think your problem may be related to the source of vacuum. I think you want it to be post throttle body off the intake manifold. I can only imagine that T'ing into the the ISV elbow may cause idling issue too?
Now if you T'd in at the elbow coming off the manifold for the ISV that may work better at least according to any DIY for the urs4/6. Having a separate fitting dedicated to the vacuum line for the booster would be best but I understand you may not want to drill a hole in the intake manifold for such purpose.

[Berserker]

I agree with Austin, post TB for the vacuum source. Pre-TB never really sees much vacuum, since it's basically open to atmosphere minus the turbo compressor wheel and air filter.

[uberaudi]

Of course! That makes a lot of sense...I'll try and tee it into the intake somewhere and report back. Thanks!

[loxxrider]

That assessment sounds about right. I guess I should add that to the DIY after you report back that the issue has been fixed.

[PRY4SNO]

I feel like I'm on crazy pills or something... what am I missing?

You added a b3 brake master cylinder, but where's the vacuum booster? Usually that's a diaphragm that goes on the firewall side of the MC, no?

[ringbearer]

it's back in there, hard to see how deep that area is.

There is also a "venturi" fitting that if left out makes the pedal effort more than it should. This part increases the vac to make the booster more powerful. I read about it on QW UrS forum, don't have a link to the post or the part. Hopefully moving the vac source will do it.

[uberaudi]

Venturi fitting? Where would that go?

I'll take better pics of the booster when I try and tackle the vacuum issue this weekend. It's hard to capture a black booster in a dark cave.

[uberaudi]

Pulling vacuum from the intake manifold was the ticket, my booster is functioning as it should be now. Thanks everyone!

Once I pulled the ISV, it was obvious where I needed to tee for the booster, but there is very little space to work with. So I googled some shit and found this: http://forums.quattroworld.com/s4s6/msgs/151941.phtml

He used a factory Audi hose from a 1.8T B6. Part number 06B 103 221P. I ordered one off ebay for 11 bucks just to see what I'd be working with, not knowing if it was actually going to work. Here's the new hose, vs the old 90 degree:


So after some trial fitting and lots of trimming, I came up with this:

I used a 1/2" NPT male to female elbow, then a 1/2" male hose barb. This seemed to do the trick once I filed the threads down a hair on the elbow so it wouldn't cut up the junction.

It was the classic backache Audi wrench session reaching behind the engine from the front, as I trimmed, then fitted, then trimmed, then fitted the new hose junction. In the end it turned out great. It bumped the ISV up probably 1/8" now but I'll worry about that later. Down the road I might invest in a silicone piece which I assume will be much easier to work with.

Another shot from the backside:


And one of the booster and vac hose routing (the one just left of the power steering reservoir):


Now I just need a replacement for the steel elbow I botched with a brazed on fitting!

[uberaudi]

I recently lost my factory key which I was super bummed about especially since the spare is just a boring blank. Well today I made my boring blank a little less boring, ala porsche 917...


That's it. That's my only update with this car

[vt10vt]

I recently lost my factory key which I was super bummed about especially since the spare is just a boring blank. Well today I made my boring blank a little less boring, ala porsche 917...


That's it. That's my only update with this car

Hahaha you should do a write-up on the P-car forums. A lot of those guys would think you're a DIY god

[loxxrider]

That's badass! Now just be careful that that pot metal key doesn't break off when you try to turn your locks lol

[uberaudi]

Ahah thanks! It's an ilco key so it should be alright...pretty minimal material removal

[PW200-20VT]

What is the point/benefit from "drilling out" your stock air-box?

People do this with the s2000's stock air-box but it is purely for "sounds".

Is this the same scenario here?

[PRY4SNO]

People do it for sound, but it turns a very well functioning cold air box into a hot air box. Most people avoid doing so.