<center><img src="http://pictureposter.audiworld.com/124134/tubular_bells.jpg"></center><p>
...the effective (w)hole is greater than the $um of its' parts.

<u>Intro &amp; Overview:</u>

Regarding a '93 90Q, here are 21 maintenance &amp; mod. items which may collectively boost mileage &amp; torque. Or they may not!

I am going to illustrate some items that may not usually be considered part of the Intake System because I find them useful when considering the Intake as a whole system. Taking several simple steps towards amongst other things, "tubular bells" (see above). A more efficient &amp; low cost system is my goal.

I will attempt to expand each topic below in this thread as time permits. I invite you to check back here &amp; welcome your comments &amp; questions. I have questions of my own that perhaps you can help me with.

Certainly, many of these ideas are not new, nor mine, but I've included them as I like them. I'll finish as time permits.

Topics:

1. Grill;
2. Scoop;
3. Bucket;
4. Filter-box Mounts;
5. Bucket to Filter-box seal;
6. Filter-box Snorkel;
7. Filter-box Lid Clamps;
8. Filter-box Exit V-stack (Mance's Mk. I);
9. "Restrictor-Plate" MAF;
10. OEM Noise Damper;
11. New OEM Rubber Gasket &amp; Telephone Cord Fix;
12. Non-"S" T/B;
13. T/B to I/M OEM Gasket, Synthetic Seal;
14. Intake Manifold, why & how:
a.) what to do, in order of importance:
-1. Vacuum
see why: http://search.audiworld.com/showthread.php?t=2594448&highlight=over+again
see how: http://search.audiworld.com/showthread.php?t=2594462
-2. EGR Passage
-3. while your there, Valley Pan; & more...:
b.) VAP's I/M Workshop; see: http://www.12v.org/audi/imworkshop/
15. Injector Re-cycle;
16. Injector Spray;
17. Vac. Lines &amp; FPR; (see link re: "excessive fueling": [/url])http://www.interworldna.com/pico/automotive/pico-emissions-related%20_components_&_actuators.php
18. EGR Solenoid;
19. Cam Cover Vents &amp; Hoses;
20. O2 Sensors; &amp;
21. Odo/Tripmeter &amp; Trip Computer;

Organizing the Work: &amp;

Conclusion: I will tell you straight away that I am very satisfied with the results of all of this, as the car runs better (faster, smoother &amp; more economically) than I thought possible. More to follow.<ul><li><a href="http://tubular.net/covers/large/TubularBells.jpg">Tubular Bells</a></li></ul> (this is the music I'm reminded of by the noise generated when doing the port-work of the Intake Manifold Workshop with abrasive paper spinning on the end of a high-speed mandrel...)

Sorry, since "The Change" the topics I've completed no longer appear in numerical order.

<center><img src="http://pictureposter.audiworld.com/46176/2005-05-25_002.jpg"></center><p>
but it ran the best it ever has after doing these, mostly not engine performance modifications, and the phone cord was one. Before i did it i mind as well not had a gasket there, but that nice new snug fit with a snap even! It's that job well done feeling....

...then my brother hit a crub and i havent driven my car in years

b/c why, now 3 years ago, would i have put a stock tb back on when i had two others that were worked on? Hmmm...

<center><img src="http://pictureposter.audiworld.com/50038/plenum_to_tb.jpg"></center><p>
...fits into the "backside" of the OEM T/B Seal, shown above.

This fix allows the above seal to better ensure no un-metered air leak occurs between the OEM Noise Damper &amp; the T/B by enlarging the circumference of the seal. Ensure that the seal is in good condition. Over time, they degrade due to heat exposure &amp; will tear when you try to remove them from the T/B.

Get used to using the search function, alot. See also original write-up here:

http://forums.audiworld.com/a4/msgs/1560129.phtml

Please pay attention the the 45° angle Mance talks about in the thread below, as I want to use this same idea to do a fix on the Air Filter-box.<ul><li><a href="http://forums.audiworld.com/12v/msgs/3337.phtml">2nd paragraph here...</a></li></ul>

<center><img src="http://pictureposter.audiworld.com/124134/v_stack_6_trial_fit.jpg"></center><p>
...It was not without some trepidation that I did this mod, as at the time IIRC, Mance was not making any more. That may have since changed, or not? In order to do this, I had to hammer (a great deal) on one of Mance's lovely &amp; rare creations (Gasp!). That I was successful, I am relieved, but be warned, if you try this, you may not be! It also took a long time to do.

My 2nd-hand V-Stack (Mk 1?) came w/o instructions &amp; may have originally been designed for some other application, the A4 perhaps?

I thought I could improve the fit, the method of mounting &amp; its' function here as follows:

a.) Increase the base (outlet) outside diameter to permit a different way of re-mounting the stack directly into B4 MAF screen recess/counter-bore. This, in turn is going to allow a step-less transition from inside the stack into the main MAF I.D.);

b.) Curve the straight tapered walls such that they have a more parabolic profile; &amp;

c.) Reverse bell-curve the inlet.

The main purpose of all of the above is not just that, perhaps if only theoretically, these changes might each allow a little more flow. Emphasis on <i>might</i>, as I only hope so. Perhaps someone with the required equipment could measure any change? I'd love to know. I really did it to try to get <i>smoother</i> flow, which especially at low speeds, is what I want the sensor to "see"; and because this; was fun.

<u>1st photo:</u> The Before Shot.
An as delivered VAP V-stack installed (borrowed this shot from someone here, thanks BTW). IIRC Mance made a couple of versions, but this is how my 2nd hand one looked to start with.

Note:
- how there is a step between the stack outlet &amp; the MAF I.D.;
- the tapered walls are conical, not curved &amp; all the change from parallel walls to tapered walls occurs in one place; &amp;
- the inlet ring is flat/horizontal.

<u>2nd photo:</U> Partially Mod'd. V-stack Installed Trial Fit.
Almost but not quite step-less transition to MAF I.D. at this stage; curved walls; &amp; reverse curved belled inlet. This was just a trial fit &amp; much more hand work was required to take it from looking a bit like a 50's minature hammered ice bucket, back to something more presentable.

The outlet length of the stack is long enough; &amp; the I.D. of the air-box lid outlet is big enough, that the stack now passes clear through the lid &amp; nests perfectly into the MAF screens counter-bore. Eliminated from the air stream are the steps/transitions for the V-stack outlet; the cork gasket; the screen circ-lip groove; &amp; main MAF I.D. (I realized when I saw photo 1 that I had never mounted my V-stack as well as this one was; I put the wraps of tape on the very bottom of the stack &amp; fitted it into the lid, but not through! In STFA, I had found this thread: Posted by Hokie_90 on 2003-06-27 13:53:14 re: electrical tape: "I wrapped it around 5 times, ½ up from the bottom of the base". Ah-hah!

<u>3nd photo:</U> Where the stack now mounts:
If you where late to the MAF party like me, in STFA you may recall the phrase "leave the MAF screen lip in place". I have no idea why this was, but now I'm using that spot to mount the V-stack.
The stack base O.D. is now larger (approx. 3 &amp; 1/16") &amp; a tight interference fit into the OEM counter-bore cut for the discarded MAF screen &amp; butts up against the step itself. The stack clicks into place (a very satisfying sound!) with a little twist &amp; even with a tiny smear of anti-seize is held in very firmly (supporting the stack with just one finger under the lip, it hung &amp; held the weight of the air-box lid, MAF, flex hose, my trouble light &amp; the plenum w/vent hoses while I tried to take a picture!). No more 5 wraps of electrical tape!

<u>4th photo:</u> How to Curve the Walls.
Do this before the rim. Clean the pipe first. Note the wood under the pipe. Started with a 2 &amp; 3/8 O.D. pipe &amp; moved up to a 2 &amp; 7/8" when able. File &amp; polish your hammer-face. Check the fit frequently (you will need a few breaks!). The stack outer surface gets pretty ugly during this part but should remain pretty on the inside if you do this right, which is: only strike the stack where it is touching the pipe. It all cleans up v. nicely afterwards with a little hand sanding. Adjust the fit &amp; make the base circumference round &amp; the edge flat &amp; square (sand &amp; file) when you're done.

<u>5th photo:</u> "Rrroll Back the Rrrim" (don't ask, it's a Canuck thing).
Yes, I did get the idea to do this part from looking at the rim of my own Mk 1 V-stack, made from a large "Timmy's" paper coffee cup (it worked!). That I was able to de-screen w/only a modified paper coffe cup reminds me that I should mention I have the diminutive OEM MAF &amp; perhaps it is less sensitive than the larger ones to de-screening?

What I wanted to do here was encourage the air from the sides &amp; behind the entrance lip of the stack to get sucked in.

It was surprising how hard I could hit the thing (&amp; had to!) with a carefully polished ball-peen face hammer (and how long it took!). After reading of Mance's process here...

http://forums.audiworld.com/12v/msgs/64894.phtml

...I'm surprised it didn't split! Obviously I wouldn't recommend my process unless you could afford to ruin yours.

Do this sitting down. Note the wood underneath. Start by sanding the square edges on the outer lip round to help prevent any stress cracks from starting on the edge &amp; then start hammering carefully round &amp; round the rim.

<u>6th photo:</u> (shown above) Getting There.
This shows the fit into the counter-bore; the curved walls before sanding; the reverse curved bell-mouth; &amp; the almost smooth transition to the main MAF I.D.

<u>7th photo:</u> Purposely Installed w/Filter-box Flat Out of Position.
Very near the level of fit &amp; finish I wanted now.

I temporarily mounted the stack like this to show that I could here employ a stack that did not have the "flat" edge cut off its' perimeter. However, would I have been successful in rolling back the rim if there had been no flat? Perhaps not.

Lucky for me, my only regret is that during one of the trial fits, I broke a rib inside the lid w/my mallet tapping the still to tight fitting stack into place.

Cheers, David.

<center><img src="http://pictureposter.audiworld.com/124134/vs_1_stock_v-stack.jpg"></center><p>...although this is not my stack or photo, mine looked like this to begin with

<center><img src="http://pictureposter.audiworld.com/124134/vs_2_mods_to_mances_v-stack_2.jpg"></center><p>

<center><img src="http://pictureposter.audiworld.com/124134/vs_3_b4_maf_mod__screen_ridge.jpg"></center><p>

<center><img src="http://pictureposter.audiworld.com/124134/vs_4_mods_to_mances_v-stack_.jpg"></center><p>

<center><img src="http://pictureposter.audiworld.com/124134/vs_5_mods_to_mances_v-stack_.jpg"></center><p>

<center><img src="http://us1.webpublications.com.au/static/images/articles/i10/1023_9mg.jpg"></center><p>
... modification; this is one of the last things I did.

Re. Siting a CAI; an excerpt from AutoSpeed magazine, an interesting article:

"At the front there must be a point above which the air goes over the car, and below which the air goes under the car. This is called the stagnation point, and it is here that there will be the greatest pressure developed on the front of the car as it moves forward. This graphic of a Mercedes shows the high-pressure stagnation area in red, lesser high-pressure areas in green, and the low-pressure areas in blue. (They're low pressure areas cos the airflow is being accelerated around a curved surface at each of those spots.)

And hey, that's all very well and good - but how do you find where the stagnation point is on your own car? And what if it's impossible to site the intake for a cold air duct there anyway? How do you rank the quality of other potential sites?"

More to follow.<ul><li><a href="http://autospeed.com/cms/A_1023/article.html?popularArticle">The complete article at Auto Speed...</a></li></ul>

<center><img src="http://www.kisracing.net/mediac/400_0/media/DIR_6726/rrs4b.jpg"></center><p>
...here is a photo that appears to show the location of the CAI on the IMSA 90Q. It appears to be in the stock location. you can see a bigger version of this photo here:

http://www.cargurus.com/images/2009/04/06/15/24/pic-36728.jpeg

My question is: Was this location mandated by "the rules" or was it the free choice of the designer(s)?

Looking back at the Benz illustration (post above), it could perhaps be close to the very best spot.

determined to be ideal. Why spend money on his VS just to modify it?

Understood. However, there are few alternatives. Because his stack, Mk I or II, offered the best starting point for what I wanted to do.

I would have prefered a 2nd-hand Mk II, however, at the time, it was the only one on the market. You could look at it this way: at least I haven't "ruined" a Mk II.

This was much easier than starting from a raw piece of tubing. That would have been beyond what I could do.

At least the picture you showed is the S3 VS, and that's the only version I know of.

The new version, "XVS", hasn't been released yet...

...Check this out...<ul><li><a href="http://forums.audiworld.com/12v/msgs/18009.phtml">New Stage 3 velocity stack....</a></li></ul>

in your desire to modify it. But, to each their own.

<center><img src="http://pictureposter.audiworld.com/124134/vs1.jpg"></center><p>...Compare this with "photo 1: The before shot..." above.<ul><li><a href="http://pictureposter.audiworld.com/124134/vs_1_stock_v-stack.jpg">http://pictureposter.audiworld.com/124134/vs_1_stock_v-stack.jpg</a</li></ul>

<center><img src="http://5cylinder.com/images/90_IMSA_6.jpg"></center><p>
...fixed this annoying &amp; hazardous problem (the "before" photo at bottom, see also the "after" at link below).

The rear spoiler was now able to be trimmed back (it was eventually replaced by a much cleaner aerodynamically, bi-element wing), &amp; consequently both top speed &amp; fuel milage where improved.

Yes, it was all quite embarrassing for Audi Gmbh, Ingolstadt had an image problem. Even though the fans loved it, the quattros where prancing around, not on four wheels but <i>su due</i> &amp; to make matters worse, they where in effect; RWD!

How could they expect to sell Quattros, let alone FWD sedans Monday to Friday, if they where clearly racing RWD on the week-ends?

It had to be stopped &amp; it was. The cars were eventually banned; the photos remain, but few details where ever revealed.
But now you know the rest of the story of...

...Unintended Levitation.<ul><li><a href="http://alex62.typepad.com/imsablog/images/2007/11/18/audiwreck89.jpg">after photo...</a></li></ul>

<center><img src="http://pictureposter.audiworld.com/124134/b4_grill_1.jpg"></center><p>
Grill opening just in front of the air-scoop.

1. Outboard Side: Flashing removed from the trailing edge of the "sawtooth" area. This is right where the horizontal slats attach to the curved profile of the perimeter frame of black plastic.

I'm curious to know why this was made in this fashion, was it for strength; is it a vortex generator, maybe it helps the air through the narrow opening behind the headlight; or does it just make noise to help mask engine intake noise? Otherwise, it certainly looks to be made more complicated than it needs to be. It's quite different from the B3 grill, but very similar to the A4.

What I wanted to do was allow the air to leave the grill in a little cleaner fashion, so I removed the flashing with a little riffler file.

2. Horizontal Slats: here again, removed the flashing on the top sides (only) of the slats, the bottom side was found nicely rounded.

(photo to follow)

Scoop Extension:

This curved piece of aluminum fastens to the back of the grill, using the two outboard grill mounting screws.

Its' purpose is to try and guide a little more air into the scoop. My scoop is worn, cracked &amp; actually bent outboard, right where it contacts the back of the grill.

This piece, when the hood is closed, connects the scoop face to the grill, over to the first vertical post. Previously, my scoop only reached about half way there (to the edge of the "q" on the "quattro" badge).

(photo to follow)

Scoop Mount:

My scoop was being held slightly closed, &amp; being bent by, a bracket for the A/C condensor (non-OEM?), behind the scoop. Bent the bracket out of the way of the scoop, loosened the top front scoop mounting screw, adjusted scoop &amp; re-tightened.

Not that this really made the scoop much larger, but more importantly in my view, was that it also widened the narrow gap behind the headlight housing &amp; the rear wall of the scoop/bucket.

(photo to follow)

<center><img src="http://pictureposter.audiworld.com/124134/b4_bucket_.jpg"></center><p>
Headlight Bucket:

Sealed all the openings as per one of Mance's old CAI threads (see below). I used a temporary weather-stripping caulking (wear gloves!), tape &amp; some plastic plugs, all available locally.

The above photo shows why you best use gloves. Have a look inside the snorkel &amp; noise damper also; no their not painted grey.

Compare this with all the gaps to be seen in the photo at "5. Filter-box/Bucket Seal:" two threads down.<ul><li><a href="http://forums.audiworld.com/12v/msgs/8454.phtml">http://forums.audiworld.com/12v/msgs/8454.phtml</a</li></ul>

These are the 2 rubber grommets in the fender-well that receive the Filter-box mounting pins.

If they are missing, the Filter-box to Bucket seal cannot be properly maintained. I suspect these are lost during Filter-box installation, as all 3 Audi's I've owned had one missing.

Use "Simple Green" liquid detergent on the grommets' face &amp; bore, then mounting the box is a little easier &amp; the grommets are not pushed through into who knows where?

<center><img src="http://pictureposter.audiworld.com/124134/b4_airbox_entry.jpg"></center><p>
This is the Seal that sits around the Snorkel &amp; is held between the Bucket &amp; the Filter-box.

Replacing my old seal did several things:

a.) when car is moving, any ram air I might have, is not lost here (<u>see the cresent of daylight just above the Snorkel O.D. in the photo above</u>) (thanks to whomever for this photo);
b.) when car is stationary, no warm engine compartment air is sucked in here;
c.) when driving, the engine is definately quieter!

What I used was a black closed cell foam seal for a toilet bowl, 3/4' thick. Because its' I.D. was too large, I cut out a section in the same fashion as the "Phone-Cord Fix" such that in place, the seal is maintained because, cut on an angle, the gap is held closed.

A single long tie-wrap, or two in series, lightly fitted around the Seal's' circumference keeps it in place during installation. The new seals profile is not rectangular, I put the relieved side towards the box.

This new seal is thicker than the original, so installation is slightly slower, but it also prevents the snorkel seal forward flange from rubbing on the back of the bucket.

(more photos to follow)

put the photo to follow in this post using HTML code as I showed you.


You can do it!!!!

<center><img src="http://pictureposter.audiworld.com/124134/b4_grill_2.jpg"></center><p>
...I simply made smooth, by de-flashing, all the little "C" shapes along the left-hand side (see above), right where the air leaves the "funnel" shapes.

...One of the things I like best about forums like this, is that I get to consider &amp; build on (or choose not to, or to take a different route to) that which others have done &amp; written about without necessarily having to repeat what they have done.

The alternative is that I'd be working by myself, &amp; having to work a lot harder to get to the same spot. Later on I hope to show some examples of this, for instance, how I picked &amp; chose items off Mance's I/M Workshop Menu like I was ordering dinner, &amp; asking the waitress for substitutions (thanks very much, BTW, for facilitating access to the above (see below); &amp; some mistakes I made along the way.

"I took the road less travelled &amp; that has made all the difference."<ul><li><a href="http://edsaudi12v.com/audi/imworkshop/">EDIGREG's thoughtful link to the I/M Workshop &amp; more...</a></li></ul>

<center><img src="http://pictureposter.audiworld.com/124134/b4_snorkel.jpg"></center><p>
I'll divide the Snorkel into two parts:

a.) The short, convergent "front half" bell-mouth.

De-glazing the surface finish:

I simply de-flashed &amp; contour sanded the front half. As found, the O.D. has two square edges that that are not condusive to good flow. The removal of those two edges is the only change to the shape I will make. I took particular care to ensure that the O.D. edge of the bell-mouth was carefully rounded to form one continous decreasing-radius curve, right around to it's back.

What I am trying to do here is, encourage as much air as possible, to enter the the snorkel from the sides &amp; behind the bell-mouth O.D. The bell-mouth, when installed, protrudes proud of the bucket back wall to best admit clean, dry air. Hopefully, this attention will yield a little more flow from the sides &amp; behind, than would otherwise enter.

See also the link to Mance's notes below. Make it dull; use a grit that is not to rough so that there are no threads or even fuzz raised off the plastic surface, note (photo above) how it almost turns white when you do this.

Note also my old crumbling Bucket to Filter-box Seal, yours may be similar; &amp;

b.) The long, divergent "rear half" reverse megaphone (or cone).

Perhaps the reason why the stock snorkel is so quiet, is this part of it. It may also help to keep water off the filter, as I imagine the air slows down again here and any moisture can fall out.

Cone wall straightening:

I used the rounded back side of a wide straight hand file to first remove all the waviness out of the cone wall, this took the greatest amount of time of all the work here. You will immediately start to see the low spots as you begin; continue until they are all gone. To best do this, sit down in a comfortable chair &amp; spend some quality time, just you &amp; the whole lower half of the Filter-box. Ensure the trailing edge of the cone is de-flashed when you're through.

Then I used the file to just blend into the narrowest section of the cone where it joins the "front half". Note that this work can enlarge the the I.D. of the duct, if only fractionally.

Last, I used my long I/M tool &amp; some sandpaper, to reach in with the die-grinder &amp; again, give it that dull finish, such that all the file marks where removed.<ul><li><a href="http://forums.audiworld.com/12v/msgs/6668.phtml">from</a></li></ul>

...(the wire ones).

I just made sure the loose ones where providing about the same clamping pressure as the tighter ones by re-bending the wire just a little. They should all take about the same amount of force to close.

This will improve &amp; maintain the filter &amp; air-box seal; &amp; help prevent warping of the lid (see Mance's notes in the 1st paragraph below).<ul><li><a href="http://forums.audiworld.com/12v/msgs/21954.phtml">lid warp...</a></li></ul>

...This method may also accomplish the following:

a.) By eliminating the transition(s) from V-stack I.D. to MAF Housing I.D., it is hoped that more laminar flow will be delivered to the sensor; &amp;

b.) By moving the V-stack closer to the sensor (without physically cutting it shorter), it is hoped that the V-stack's positive effect will be enhanced.

You may also gather from reading below that what Mance may have been aiming for with his selection of aluminum tubing diameter for his eventual A4 V-stack was "matching I.D.s". It never did fit as well in the larger "90" airbox lid.

What I am aiming for, is hopefully at least as good a fit &amp; funtion as when one of Mance's originals is used in an "A4", but in a "90" instead, right through it's filter-box lid &amp; the modified velocity stack's O.D. fitted directly into the MAF housing's screen groove I.D., providing as seamless as possible, a stepless air passage-way from V-stack inlet to MAF outlet.<ul><li><a href="http://forums.audiworld.com/12v/msgs/346.phtml">To both deliver more laminar flow to ; &amp; shorten V-stack distance to, the sensor...</a></li></ul>

...so much in my case.

I should also concede that the lack of issues I've experienced with this mod may be in part due to the apparent fact that, with my stock medium mouth MAF, it is rather less sensitive to screen removal to begin with. This may also help explain my previous success with V-stacks made from paper coffee cups &amp; plastic wood-fill containers! Your experience may differ.<ul><li><a href="http://forums.audiworld.com/12v/msgs/58121.phtml">"...small bore MAFs dont suffer as badly from CELs..."</a></li></ul>

...you don't always see every velocity stack following the same identical set of proportions. Even amongst VAG, they are not identical.<ul><li><a href="http://forums.audiworld.com/12v/msgs/377.phtml">http://forums.audiworld.com/12v/msgs/377.phtml</a</li></ul>

<center><img src="http://pictureposter.audiworld.com/124134/b4_maf_mod_1.jpg"></center><p>
It has been said that this MAF may not be worth modifying, however I disagree. As the MAF housing may be the single most restrictive point in the entire system, in only makes sense to do some work towards easing that restriction.

No post removal or boring here, just simple smoothing of the interior surfaces. Used just hand files to:

a.) blend the two main interior cone shapes (which form the largest part of housings interior surface) at their intersection such that they then form one long curve;
b.) eliminate the flat front face of the entry to the sampling tube by increasing the radiuus of the inside &amp; outside curved edges;
c.) round off the flat front faces of the screw bosses on the centre-post;
d.) taper the sides of the centre-post in towards the centre, making it narrower towards the trailing edge (this also eliminates any transition between the centre-post &amp; it's backing-plate);
e.) reduce the profile of both the cast screw bosses &amp; the backing-plate that surround the screw heads to just the diameter of those heads; &amp;
f.) improve the filleting everywhere the sampling tube attaches to the housing I.D by blending them together, making the fillets as generous as possible.

The above certainly results in a slightly larger effective diameter due to the enlargment of the two main "D" shaped holes on either side of the centre-post; &amp; perhaps some increased flow due to reduced friction as well.

You may see the front end of my MAF at photo 3. of #8., the V-stack mod; above. You will there see how the leading face of the screw bosses on the sides of the centre post have been faired off.

<center><img src="http://pictureposter.audiworld.com/124134/b4_maf_mod_2.jpg"></center><p>

<center><img src="http://pictureposter.audiworld.com/124134/b4_oem_noise_damper_outlet.jpg"></center><p>
I suspect that for a lot of us, this piece like many others, is more than adequate &amp; can be made to provide yeoman service especially after some careful attention.

Purpose here:

a.) De-glaze the inside surface as per the Snorkel, previously;

b.) Remove the sharp lip which exists all around the I.D. at the downstream end of where the metal re-inforcing ring is driven into the inlet (where the accordian hose clamps onto);

c.) Remove moulding flash &amp; stepped surfaces on the interior glued joints (see one of these running from 8 to 2 o'clock across the rear wall of the outlet, photo above);

d.) Smooth the "duct floor" on the short side where it transitions from round to oval, leading down to, in front of the throttle-body (reach up there with your finger &amp; you will find what needs to be smoothed out); &amp;

e.) Pay attention to up-stream edge of the ear-shaped seal flange (see photo above) which guides air to the T/B's inlet. I found it is instructful to put the Damper to T/B Rubber Gasket in place here; then see &amp; feel the air path; &amp; ensure the requisite edges are all rounded &amp; smooth, no sharp edges for the airflow to catch on.

This is a sturdy piece, &amp; its generous wall thickness allows for the fair amount of material removal required in acheiving the above. I spent a good amount of time on this piece, more than I spent on the Filter-box Snorkel. However unlike the Snorkel, no real hand-file work here, just hand sanding &amp; the deep reaching rotary sanding I/M tools.

Note: I have skipped over the Accordian Hose as other than ensuring it is crack free; &amp; use a little grease inside either end to ensure it is mounted fully seated &amp; secured; I left it otherwise alone.

Note also: Missing in the photo above are the two rubber post mounts. I glued mine in place in the above empty mount sockets. This will save you losing yours.

Please also go back &amp; see <i>inside</i> the Damper at the photos for:
#3. Bucket (see smoothed inlet "ring" of Damper between Bucket &amp; V-stack; &amp;
#6. Filter-box Snorkel (see end of "duct floor" here) &amp;
also compare with the photo above.<ul><li><a href="http://forums.audiworld.com/12v/msgs/917.phtml">"The 2.8 airbox/plenum is well suited for all but..."(in the 1st paragraph)</a></li></ul>

<center><img src="http://pictureposter.audiworld.com/33772/s2fsm.jpg"></center><p>
Mind the Gap (between bumper &amp; hood!)

Mine isn't quite as bad as this, but almost. You get the idea &amp; this is much more interesting to look at than my stock set-up.

After reading the post below, I filled this space with black foam weatherstrip because, whether there is air bleeding in here or being sucked out, it is not helping to get more pressure to the grill &amp; the Cold Air Intake, I'm hoping that this will help to improve that.<ul><li><a href="http://forums.audiworld.com/12v/msgs/65472.phtml">"Air comes over the top of the front bumper like..."</a></li></ul>

Send your OEM injectors away for this:

Russ Collin's "RC Engineering" injector service:

http://forums.audiworld.com/showthread.php?t=2594340&highlight=RC

One interesting detail of this purely maintenance item is the accompanying print-out you receive back with your injectors. You can see that after cleaning, all six injectors flow more closely, the same amount of fuel. The rest of your systems will have an easier time delivering the required fuel with these.

As some folks here have had good success WRT improving both performance and economy by replacing the OEM's with slightly <i>smaller</i> than the OEM rated injectors on their cars, this standard servicing of the OEM's (as opposed to trying to fit <i>larger</i> injectors) is a very cost effective maintenance example of how less; is more.

you dug this up from the grave :-)
you know, this article http://autospeed.com/cms/A_1023/article.html?popularArticle got me thinking on, how affective is our intake setup from VAP? i know its better then stock, but dose it provide positive boost at all? i wish i head my car running, i would be testing it this as soon as i could find the equipment :-(

the wealth of this forum lies, hidden like flakes of gold in a river-bed, waiting for worthy miners to find them.

You may discover that VAP has answered your questions; if you do some digging.

Turn your questions into search terms, you may just find the mother-lode.

no argument that thats where the wealth is hidden :-) i dont think there was a question asked here in the last year that was not answered before by someone.:-)
ill do some digging ;)

still waiting for those scoop photos ;)

It was not very dramatic I'm afraid. By "scoop", I simply meant the inboard OEM extension of the headlight bucket which reaches over behind the grill opening. It has some rubber trim on it, usually worn and that was the impetus for my scoop extension.

I have seen it once, but can not remember what it looks like.

I am thinking of making one of my own.

I re-write this entire post first, as it is now <i>most</i> irritating to try to read.

(Perhaps you meant scoop-extension photo. I'm afraid I don't have one right at the moment. I attached the scoop-extension to two of the grill mounting screws. It is just an aluminum deflector that widens the front opening of the OEM scoop; slightly (expands it inboard, over to the first vertical grill member IIRC). Very simple to make. It may be helpful to make one out of card-board first. The metal gauge I used was very light. It is taller than it is wide, and is bent curved to blend carefully into the OEM scoop when the hood is closed; without damaging the plastic of the OEM scoop.)