New exhaust

You'd have to go to a good exhaust shop...all the other options would still take you to someone that welds and has a pipe bender.

How many Audi powered IM's are out there?

Phil, I'd recommend you find a header that will fit your engine and then find a shop that will build you an exhaust system to match your engine/header combination and fit in the engine bay.

A poorly designed/constructed header may not add any hp and in many cases actually lower hp and screw up the power curve.

Bill.  Only Henry knows for sure.  But not very many.  There are 2.0 naturally aspirated and there are also 1.8Ts out there.  People started demanding more power which lead to the Suby cars.  I know Henry bought a bunch of crate engines from VW/Audi a while back.  Mine is one of those.  Nice to know I've got an original 0 mile motor built by the pros.  Its the part of my car I worry about the least.  Of course now I'm trying to blow it up.

If that's the header that you have ,I agree that it may be restrictive. The design is correct (assuming you have a 1342 firing order) but way too short  (IMO) from your exhaust valve to the collector.  (the four into one part) The two center runners should come together further downstream and so should the two outer ones. Then those two runners should come together further down into the final one exhaust tube and on to the muffler.  I'm sure there are some engineering guys out here that could refine or better define what I'm suggesting. Your current 1.5" runners could maybe go up to 1.625"  Also, I think the bung for A/F ratio or O2  should be downstream more to read what the average is for all 4 cylinders.  There are a number of quality shops that can build you a nice header. You just have to find one in your area. Someone like A-1 ?

Anyway, that's my 2 cents........Bruce

I imagine it's not hard to find a well made header that will flow better than the stock unit (and weigh less).  I did a quick web-search and came up with dozens.  The problem might be getting it to fit in a speedster's engine compartment.

Yes Ron.  My exhaust manifold is on the driver side.  Exhaust manifold in Golf comes out the back of engine.  Most headers offered for this car are very long normally going to rear of car.  That's why I had to choose this very short one.  I think it will fit.  Found someone who can build system this winter.  Still thinking I might try to piece one together myself.  I worked in a gas station for 4 years when I was a kid.  We built some exhaust systems for muscle cars including my 67 mustang.  I might give it a try.  My current exhaust system is very large and heavy.  This will remove a lot of weight from the rear of the car.

Ok. Exhaust dropped out in one piece. This thing weighs a ton. And new header looks like it's going to work. I'm going to run a single exhaust with no cat. Probably a borla. My first question. There are 2 O2 sensors on old exhaust. There are actually 2 O2 sensor ports on the new header. One obviously needs to go to the header. Where should the other one go?

On your old setup, one O2 sensor is before the cat, and one after. Since the new one will have no cat, I'd put it where you'd like. You'll probably throw a code. 

Ooops, it was early and I mis-read the post. Comment deleted!

I'm never afraid to show my ignorance.  What does "throw a code" mean?  Will the car not run without a cat?  If it has to have one I'll place one.  Can I forget about the O2 sensor after the cat and just not hook it up?  Or can I hook it down stream from the header or like you say just anywhere?  Or am I completely screwed and I have to have the ECU reprogrammed?  I like to work on my car as a hobby but hey I'm a doctor not a mechanic.  I need all the help I can get.

Since your familiar with a code blue that is the same code for an O2 sensor that cries help, bad air quality . Mechanics code book.  not

Actually on my IM one O2 sensor was not put back in when the subie heAders were installed I only have one on the end 

Phil,

"Throwing a code" means that an engine problem will present itself with a text alarm, saying something like "error code 352" or the like, usually in the dashboard.  In your case, what you see or hear, if a code presents, depends on the installation of the engine, ecu, etc.. as to how the error/alarm shows.

And you won't pass a safety inspection...Spark plug Non foullers work sometimes

Throw a code= "check engine light." 

There are a couple things you can install to prevent this; the tuner boys have a whole lifestyle based around such tricks. Probably no need to bother in your case but it depends on what your ECU does with the second O2 read. If it looks heavy to the computer, the computer might try to lean you out to get a "proper" read from the sensor. Probably not, but maybe.

Here's a bad thing I'm going to say, and maybe it's wrong, but anyway: I think the exhaust header you are about to throw away is better than the one you're fixing to install. It appears to be a true "Tri-Y" design and is properly sized to the engine. You have one too many mufflers on it—an easy thing to remedy—but even then you probably won't get more power with the new setup, cat or not. Come at me, exhaust experts. 

Maybe I should just keep the cat, remove the 2 big mufflers and place a Borla and be done with it.  It would be really easy.  Just have the exhaust come out on the right instead of the left.  That way my ECU and O2 sensors are unaltered.

edsnova posted:

 

Here's a bad thing I'm going to say, and maybe it's wrong, but anyway: I think the exhaust header you are about to throw away is better than the one you're fixing to install. It appears to be a true "Tri-Y" design and is properly sized to the engine. You have one too many mufflers on it—an easy thing to remedy—but even then you probably won't get more power with the new setup, cat or not. Come at me, exhaust experts. 

I agree with this. What Phil has is a long-tube tri-Y header, which I'd love to have. The short-tube aftermarket header would be tuned (if it's tuned at all) for 5000 RPM and up. There may be a better aftermarket Tri-Y (I'm not sure what's going in the middle of that one), but short-tube headers aren't generally a good idea on the street.

Honestly, I think I'd try leaving the manifold and cat (O2 sensors in place), and sticking a straight-pipe on that to see how it sounds. I wouldn't buy a Borla, as they are a Cherry-Bomb for rich guys-- a simple glasspack would cost about $15 and do the same thing.

Ed's tapped into the tuner thing, and he's correct-- somebody out there knows how to make pretty much anything you'll want to do work. But that "somebody" isn't likely to be here. Henry works hard to keep the stock ECU intact, and then build from there. I think I'd do the same, if it were me.

Phil,

Sometimes we are forced to be engineers, and sometimes we can take advantage of work others have already done.  You may want to consider phoning/visiting an Audi/VW tuner near you to find out the accepted exhaust wisdom by those who routinely pump up the HP in engines like yours.

Stan is right Henry likes to keep the ECU stock to facilitate servicing .... Actually proven technology is the only way to be able to hop in turn the key amd drive away. 

What is the max horsepower increase a better header exhaust setup can achieve?

I am not sure

Sage advice guys.  Think I'll just add a new muffler and be done with it.  I think I'm searching for performance that just isn't there.  I can at least make it sound faster.

Phil, my car has a Dynomax 17747 muffler if that helps you at all.

Phil IM356D posted:

Sage advice guys.  Think I'll just add a new muffler and be done with it.  I think I'm searching for performance that just isn't there.  I can at least make it sound faster.

I think you're on the right track.  As far as mufflers go, Magnaflows are nice.  To keep the noise down get the biggest that will fit.

Too bad you couldn't get a long tube header that would fit.

Phil, just go with one of these and you have quiet cruising and more noise on acceleration. http://www.dynomax.com/mufflers/dynomax-vt-mufflers

Marty Grzynkowicz posted:

Phil, just go with one of these and you have quiet cruising and more noise on acceleration. http://www.dynomax.com/mufflers/dynomax-vt-mufflers

 

I have been reading reviews on this muffler.  Most report it to be quiet at idle and with a nice sound during acceleration.  But there are many comments about a clanking sound at idle.  Dynomax sates that this occurs due to negative pressure at idle in big V8 cars with large cams.  I have a 4 banger with a mild cam but this still makes me a little nervous having these mechanical bits in a muffler. 

I'm really leaning toward this.  $93 and a million mile warranty.  All reviews I have read are perfect.  Great sound no drone.  Many of the reviews are from VW owners with my engine.

This is a vw Jetta with a 2.0 AEG engine like mine with a 270 degree hydrocam and a borla muffler.  I've got the 260 degree hydrocam (a little milder).  I think this sounds pretty awesome.  Maybe too awesome.

https://www.youtube.com/watch?v=rVGvxaI-c3U

Phil, I get your reservations with the potential  clankng sound.  The Borla sounds pretty......................loud

I used to have TWO in line mufflers on my 2110 from IM... I wonder if it is worth experimenting with only one muffler Phil... it couldn't hurt if you can do it with the existing muffler . 

Phil, the guys that told you to keep the original header were right. That shorty is just a poorly designed manifold. If you don't like the rusty original, get it Jet Hot coated. Borlas  sound better than Flowmasters which sound hollow. The Dynomax mufflers are a lot like Borla only cheaper.

Fpcopo VS posted:

Phil, the guys that told you to keep the original header were right. That shorty is just a poorly designed manifold. If you don't like the rusty original, get it Jet Hot coated. Borlas  sound better than Flowmasters which sound hollow. The Dynomax mufflers are a lot like Borla only cheaper.

Magna-Flows sound really good. I always thought Dynomax's sounded hollow as well. 

Phil IM356D posted:

This is a vw Jetta with a 2.0 AEG engine like mine with a 270 degree hydrocam and a borla muffler.  I've got the 260 degree hydrocam (a little milder).  I think this sounds pretty awesome.  Maybe too awesome.

https://www.youtube.com/watch?v=rVGvxaI-c3U

Loud mufflers....fun for a while. 

Okay with the top down.  Very annoying with the top up.

I really like the idea of ceramic coating my headers and down pipe (stock ones).  The guys who powder coated my wheels do a lot of exhaust ceramic coating.  Still working on picking a muffler.  I'm going to at least initially put the exhaust together without the cat.  I'll see how it runs without the cat.  I can always put it back on.  In Virginia real top down driving season begins at the end of October.  I should be able to have it back together by then.

Stan

I've started looking at the Magnaflow mufflers.  What is the difference between the straight through mufflers (MF) and the multi-chambered mufflers (XL)?  There not too much info out there.

Henry used the Dynomax 17748 super turbo on my car.  I have know idea how this muffler would sound on a N/A VW-Audi motor but it quite at cruising speeds and sounds nice on my Suby turbo.  Losing the Cat will also raise the noise level so don't go crazy with a loud muffler. 

From the picture Marty, I guess your O2 sensor is just before the muffler in that hole.

Looks like I have two sensors.  Phill may just have one.

I have 2 O2 sensors, at header and just past the cat.  Its really amazing looking at these exhaust systems.  Everything on the water cooled systems are completely custom.  Nothing held together with clamps.  Everything is perfectly measured and welded.  Perfectly air tight.  I'm sure that's why most people advise not messing with perfection.  I think I may initially put mine together with U clamps and then drop out of car and take everything to a shop and have it welded.  And maybe then have the whole thing ceramic coated.

I've built half a dozen exhausts. If you've got a welder (even a cheap one), you can buy mandrel bends (J-bends) in various sizes from Summit Racing or your local speed shop. You can generally make everything you need with a hacksaw (or porta-band) and these J-bends. I tack everything and build as I go, without committing to full welds until I know what I've got will work.

If you try to get stuff with slip-joints, you are seriously limiting your choices as far as bends, radii, etc. If you have a muffler shop bend one up, it won't be mandrel bent, and the turns will be reduced in size (if that matters to you). This is why the builders do it like they do. 

As far as the muffler (chambered or straight-through), a chambered muffler is generally better for "tuning" the exhaust (not for sound, for performance)-- but that's what makes them sound "hollow". That's why I like Magna-Flow-- they wrap the whole thing in heat absorbing material even with a chambered muffler.

I've used both-- I think what you want all depends on how aggressive you'd like it to sound.

As far as the muffler (chambered or straight-through), a chambered muffler is generally better for "tuning" the exhaust (not for sound, for performance)-- but that's what makes them sound "hollow". That's why I like Magna-Flow-- they wrap the whole thing in heat absorbing material even with a chambered muffler.

So the straight through mufflers in your opinion "sound" better??  At this point I just want the car to sound better.

Marty Grzynkowicz posted:

Henry used the Dynomax 17748 super turbo on my car.  I have know idea how this muffler would sound on a N/A VW-Audi motor but it quite at cruising speeds and sounds nice on my Suby turbo.  Losing the Cat will also raise the noise level so don't go crazy with a loud muffler. 

The neat thing about Marty's exhaust header is that it is completely symmetrical from left to right and therefore it can be installed backwards. I did that with an earlier version of my Soob conversion and just bolted a straight thru Cherry Bomb pointing straight out the back and it was all over.