Eric's '90 80QT: rustic bits

[savagerocco]

I had one but I sold it to Nick at least I thought I sold it.... still haven't gotten money. I'll see if he ended up using it. I got a buddy in Scotland who could apo one for us since shipping is usually the big part.

Sent from my SAMSUNG-SM-N900A using Tapatalk

[pkw]

having used this turbo, i think you need to get tuning with it, what injectors are you running? SEVERAL members on this forum rode or drove my car with the volvo turbo, and all of those guys have also had stock k24 20vt cars, and know the difference. Any of them could tell you that there certainly was a "night and day" difference with the volvo turbo.

Well, I know a lot of people like to use huge injectors and the ones I'm running are only 33 lb. But my AFRs are fine (13.0-13.5 at 15 PSI boost, a little richer at higher boost) and haven't seen the duty cycle go above 85% yet. Although I realize it's close to where I probably should be looking into something larger.

Personally I would like to see it a little richer than that. that is a good ratio for up to 6 psi. I would like to see 12-12.5 by 15 psi and like to see 11-11.7 by the time you get around 30 psi. I would guess that for that amount of difference a simple raising rate FPR would supplement you just fine and be tunable to a degree.
*that is assuming that your WBO2 is reading accurately.

[elaw]

Well... I finally broke down and did it... I ordered an S2 ABY airbox from a guy in the UK! Soon it'll be "bye-bye" to my hoky intake setup:

This will be a major milestone: it'll be the first time since I started screwing with turbo'ed Audis that I have an intake with no PVC pipe in it!

Only downside is I'll probably still have to mod the airbox as most likely my MAF sensor is larger than the opening.

[Golden91CQ]

Only downside is I'll probably still have to mod the airbox as most likely my MAF sensor is larger than the opening.

A piece of PVC should do the trick

[elaw]

[elaw]

Well it looks like I will in fact be replacing my PVC (polyvinyl chloride) intake setup with another PVC. Except in this case PVC means "pricey vehicle component"! Aaah... I crack myself up!

Anyhow, for those that like photos here it is:

It doesn't seem to do much now, but I'm confident that when I move it from the basement floor into the car it will work well.

One thing I'm pleasantly surprised by is that my MAF sensor may be somewhere near fitting! I'm running a pretty large sensor (about 3" diameter), and I had assumed I was going to have to hack up the new airbox to accommodate it. But it looks like the existing opening is about the right size which makes me a very happy camper.

Speaking of new toys, this:

So what's a "this", you ask? Well I'm glad you asked!

The executive summary is that's a replacement for an N75 valve. It has 4 ports: one connected to boost, one to atmosphere, and the other two go to the top & bottom chambers of the wastegate (yes, both of them).

When the valve is not energized, it routes boost to the bottom WG chamber and atmosphere to the top. In that way it's just like an N75 that's not energized - full boost is applied to the WG in the usual way and it'll regulate boost to whatever level the spring is calibrated for.

Now here's the fun part: when you energize this valve, it applies boost to the *top* of the wastegate and atmosphere to the bottom. Yes that's right it uses boost to force the wastegate *shut*!!

That of course sounds crazy but there's actually some method to the madness. First, as you might imagine it causes the boost to rise as fast as possible since the WG gets held shut harder as boost rises. And second, it solves a problem. If you're like me and running a small turbine housing, at high boost and RPM the flow through the exhaust is very high. Due to the restriction from the small housing, that means pressure in the exhaust manifold is also very high. Since that pressure is applied to the poppet valve in the WG, if high enough it can actually force the wastegate open against the spring pressure, even if no boost is applied to the WG diaphragm. That can cause difficulty getting high boost at high RPM.

Basically what it comes down to is I want to have my cake and eat it too. I want a small turbine housing for fast spool, but high boost at high RPM. And I want a soft WG spring so I can control the boost to a lower level at part throttle for driveability (a stiffer spring in the WG would reduce the problem).

Anyhow (didn't mean to write an essay here...), this valve will allow that to happen. Most of the time it'll function like an N75 valve, metering boost to the lower WG chamber. But up top when I want a little extra "oomph", I can go to a higher PWM value on the valve and route boost to the upper WG chamber, to counteract the exhaust pressure trying to force the wastegate valve open. Here's another way of looking at it: this one goes to 11!

[savagerocco]

DIYAUTOTUNE.COM?

[elaw]

Nah, the one they sell is a 3-port valve. I got it from these guys: http://circuitse7en.net/fantcube/index. ... oductId=23

[elaw]

Word to the wise if anyone else is trying this: this valve is definitely not made for use in harsh environmental conditions, say like you might find under the hood of a car. For example the spot where the wires connect isn't sealed at all.

I tossed some RTV on there to deal with that particular issue, but I may try to find a way to give it some additional protection, like mount it in a box or something.

[elaw]

So... uh... an S2 airbox is actually supposed to fit in a B3, right?

I began installing the thing last night and it's not going well. There are significant clearance issues in a couple of places.

The first is between the side of the airbox and the turbo compressor:

There's only about 1/8" clearance there, and that's *after* I cut away a chunk of the heatshield - otherwise the heatshield was resting on the turbo. I know the Volvo compressor is larger than the AAN but I didn't think it was *that* much larger!

The next issue I don't think can be blamed on the Volvo turbo, and is what puzzles me the most. Bolted in place, the airbox can still rock back and forth a little. And when rocked forward, the heat shield actually hits the banjo bolt on the wastegate! The problem is a little hard to capture in a photo but this shows it sort of:


I wonder if both of these things could be related to the issue I discussed about 300 posts ago ( ) where seemingly the engine is sitting a little too far to the passenger's side of the car. I never was able to figure out the cause of that issue, or of course correct it.

[DE80q]

My MC1 seems to be sitting too fat to the right side as well. I was told to just loosen up the motor mounts and "push" it over.

[elaw]

Yeah I've already done that. If I hadn't the engine would be 1/2" farther over the wrong way!

It's a real puzzler... I had the same problem with both the MC and AAN engines in my 4Kq. But one common denominator I think is I've used the same engine-mounting brackets each time. Are you using the ones that came with the car or the ones that came with the engine? I've seen a lot of indications they're the same but I wonder if that's actually the case.

[DE80q]

I'm using the ones from the car. They are slightly different. I wish I would have measured them before putting them on.

[mrmotorhead13]

On your airbox... weren't early CQ S2's B3 based and the later ones B4 based... maybe you have the B4 version and there's some small differences?

[elaw]

That's definitely possible... I do have the later version airbox. It does seem to fit into the car okay, for what that's worth... as in, there don't seem to be any interference issues with the body.

[ur20v]

On your airbox... weren't early CQ S2's B3 based and the later ones B4 based... maybe you have the B4 version and there's some small differences?

No... All coupes/S2 are B3 chassis... S2 sedan and RS2 is B4.

So, is everything else you're using factory ABY? Exhaust manifold, downpipe, et al?

[elaw]

Well it's close!

Manifold is RS2 (but it puts the turbo in the same place as an AAN or 3B), downpipe is one of Hank's 3" ones. Thankfully the downpipe clearance is fiine, although the O2 sensor cable needs to be bent fairly sharply to clear the heatshield on the airbox.

[my2000apb DrBeastCar]

On your airbox... weren't early CQ S2's B3 based and the later ones B4 based... maybe you have the B4 version and there's some small differences?

No... All coupes/S2 are B3 chassis... S2 sedan and RS2 is B4.

So, is everything else you're using factory ABY? Exhaust manifold, downpipe, et al?

how does that work?!!?! I swear there are b4 based s2's

the aby's got b4 rear ends and suspension right?

[ur20v]

There are B4 based S2s... But they're all sedans

B4 rear diff and suspension would require revision of the unibody to facilitate it, making it a B4. But that never happened. As far as the ratios are concerned, maybe, I just don't know off the top of my head.

[mrmotorhead13]

On your airbox... weren't early CQ S2's B3 based and the later ones B4 based... maybe you have the B4 version and there's some small differences?

No... All coupes/S2 are B3 chassis... S2 sedan and RS2 is B4.

Pretty much what I said, except I didn't put "sedan" in... earlier S2 coupes were B3, later S2 (sedans) were B4.

[elaw]

Well the strangest thing happened earlier today...

I had always heard car salespeople say you can get ABS "just by checking a box" - but I never thought it could be that easy.

So today I get home from work and there's a box on my front doorstep. I bring it into the house... check it... and...

...I have ABS!

And in theory, I should have EDL too as this system came from a late UrS6 with no diff lock. Of course the system will probably be more effective once I install it in the car, but that will come with time.

Huge thanks to Kuma85 who, apparently with much difficulty, did an awesome job of extracting these bits from his parts car! :thanks:

[DE80q]

Very nice. The only problem I see with the EDL is the non syncronized locking ring used in the older style locking rear diffs. I can only imagine the noises that is could make trying to engauge at speed.

[elaw]

Uh... I think you may be misunderstanding how EDL works? That, or I am!

As I understand it, EDL (at least this version) doesn't actually lock the diff(s) at all. It just applies braking to a wheel that's detected slipping (presumably by the fact it's turning faster than the other wheels). As far as I know, the later UrS6s (like the car this system came off of) had a torsen center diff and open ones at the front and rear.

[DE80q]

Ok, that makes more sense. It wont actually lock the diff, just bring the slipping wheel's speed back down to the speed of the wheels not slipping.

[elaw]

Yeah, it's what every other car company calls "traction control" but Audi had to be different...