Why upgrade?

The VW Fox comes with a single outlet exhaust manifold from the factory, but if you can hunt up an older VW with a dual outlet exhaust manifold, then you'll effectively double the exhaust capacity of your engine.  The bottom line is engine power.  Techtonics Tuning states, that with the dual outlet exhaust manifold, their dual downpipe and their tuned exhaust, the engine should gain 10+ HP!

• You will have to find the dual outlet exhaust manifold.  You can either go to a VW dealer [tremendously expensive - I was quoted $800 Canadian to import one from Germany!], or the better choice - to an Auto Recycling Yard [it cost me just under $100 with taxes and shipping].  The part you need is called a "dual outlet exhaust manifold", and it has to come from a 1979 or earlier Volkswagen Dasher or Audi Fox, with a GASOLINE engine.  No matter what the yard tells you, the cars only had one type of gasoline engine, and the transmission type does not matter - I inquired about this when I called Techtonics Tuning.  The exhaust manifold from a DIESEL Dasher / Audi Fox WILL NOT WORK!

Click here for a picture of the dual outlet exhaust manifold.
If you are having trouble finding one, please check Fast Forward Autobahn Sport Tuning.  Please tell David Marshall that I (Adam) sent you.
• In order to be able to connect the exhaust manifold to an exhaust system, you'll need a downpipe with dual inlets, referred to as a "dual downpipe".  Mine is ordered from Techtonics Tuning.  (Apparently a stock one from an Audi Fox / VW Dasher will fit, but finding one in good shape can be tough.  I am also not sure about the diameter of the stock pipes, or whether they're mandrel bent)  You can reconnect your stock exhaust system to this downpipe; but if you want the best performance, you best bet would be to get a tuned exhaust system.  Techtonics also makes these.
• The Techtonics Tuned exhaust for the Fox is a cat-back system, meaning it replaces everything from the catalytic converter back, and includes all the hardwarde you need to install it.  It also replaces the 1^st muffler with a resonator for improved flow.
• Another modification you can make, is to remove your catalytic converter.  This is illegal, but will improve your flow a bit, and I hear (no pun indended) it will give your Fox a more sportier, deep sound.  I have also heard that many VWs which have had the catalytic converter removed for performance purposes still pass emission tests.  It indeed does give you a deep, raspy, rally-style sound.  My setup does not include a tip, yet the exhaust sounds great!  (Update: I will be installing a high-flow catalytic converter soon in order to be environmentally-friendly, and to pass emissions test here in Ontario.)
• No, Techtonics Tuning didn't pay me to go on and on about them.  In fact, I don't think that they know about this page.

• If you have access to a dyno, so that before and after tests could be done, I'd love to see some actual results!
• Locate and order the parts.  Audi Foxes and VW Dashers are becoming quite rare, so you may have a bit of trouble locaing the manifolds.  Here's a tip I was given - try calling around the smaller yards which may be out in the countryside, because they often have huge lots and are able to keep old cars.  And these yards may not always be in the Yellow Pages or connected to satellite searches from other yards.
• Prepare the Manifold
• I decided to paint my new manifold, thus I had it sandblasted clean of the rust.  The inside was also cleaned out of the stuff that was burned on.
• You really should have the "in" side [the 4 intake ports which bolt onto the engine] machined, to ensure proper seals with the engine.  This cost me $20, and took all of about 30 seconds for the shop to do.  The manifold was in excellent condition, though, so it didn't take long.
• Scrape off any left over bits of gasket on the "out" end of the manifold.
• Re-thread the studs if necessary.
• I bought some "High Temperature Engine Manifold Paint" from Canadian Tire, cleaned the manifold with Acetone, let it dry, and gave it a few coats of the Manifold Paint.  Be extra careful when masking the manifold so that the studs don't get painted over, and that you don't get paint inside it also.
• Prepare the Car
• [When I was performing this upgrade, I was also painting the Valve Cover and Timing Belt Cover, so I had a few extra parts removed, which helped with access to the components.]
• The rest of the procedure is done easiest at a shop with the proper equipment
• Air-powered tools
• A high quality car hoist
• A real mechanic :)
• When the car is still on the ground, ensure any tapes/CDs are out of your audio equipment, and that you know what to do with your alarm after the battery is disconnected for a while, if applicable.
• Disconnect the battery.
• Remove the entire air cleaner assembly.  I took off everything up to the rubber air intake duct which connects the air cleaner assembly to the throttle body.
• Hoist the car up, and remove the exhaust up to the catalytic converter
• The screws holding the back exhaust to the catalytic converter could be very rusty.  Take care when unscrewing them, but you'll most likely want to get new ones as the ones on your car will probably be very rusty.
• Remove the catalytic converter from the downpipe, also taking care with the screws.
• Remove the downpipe.  This is a little tricky, as access to the screws may require to lower the car and get at them from the top.  This is best done with two people - one unscrewing, the other holding the downpipe.
• Remove the exhaust manifold.  Very tricky, and shouldn't be attempted by a non-mechanic.  When unscrewing the nuts which hold the manifold in place, be sure not to use excessive torque as this car break the studs.  In my case, 5 studs unscrwed with the nuts and luckily none of them broke.
• When removing the manifold, be sure to take the Oxygen Sensor off as well!
• With the manifold off, it might be a good idea to just check out the engine in detail for this you might not usually see.  In my car's case, the 4^th cylinder [the one closest to the passenger compartment] was slightly leaking.  There was a black carbon deposit around the exhaust port.  [Note: This was a source of the "VW Engine Clicking", or "Lifter Noise".  Usually the noise is attributed to noisy valve lifters, but in my case it was the sound of the exhaust gases leaking through a tiny  hole on the connection between the engine block and exhaust manifold.]
• Clean the exhaust ports to be free of charred black crabon deposits, etc..
• Install the Manifold
• If any of the studs broke during the removal of the single outlet manifold, replace them.  This is extremely tricky, and I really feel for anyone unfortunate enough to have this happen to them
• If any studs unscrewed during uninstallation, buy some new studs and install them.  Not too difficult a procedure, but they have to be torqued enough to hold the manifold in place.
• Depending on what kind of manifold and downpipe you get, the Oxygen Sensor might go in a different place.  My 1979 Audi Fox manifold had the Oxygen Sensor hole plugged, and my Techtonics dual downpipe has a hole for the Oxygen sensor.
• You can leave the oxygen sensor as one of the last things you put on before putting back the air cleaner assembly, so that the wires don't get in your way.
• Install the manifold.  As simple as that :)  Well, aside from the 2 inner top studs, you'll have pretty good access to them.  The torque on these is very, very important, so have a professional do this; or if you must do it yourself, have the proper tools and skills.
• Install the Dual Downpipe
• Optional.  I used the same Manifold Paint to paint my entire exhaust from the exhaust manifold back.  I have been told that the pipes Techtonics uses are aluminized, but I figured that some extra paint won't matter, especially if it can withstand the heat.  So, I used Acetone to clean the pipes, painted them with a few coats of the paint, and let them dry, hanging under the hoisted car.
• If the dual downpipe was painted, be careful when moving it into position, so you don't scrape too much of the paint off.  Once you've got it in position, have one person hold it in place, and then the other screw on the nuts and tighten them.  Torquing here is also important - but also follow the instructions, if any, that came with your downpipe and exhaust.  Techtonics suggests tightening all of them fairly tight, letting the engine run and get warm, then letting it cool off totally, and then retightening them to ensure the best contact.
• Note: the stock single downpipe has a bracket welded to it which attaches to a second bracket on the underside of the car.  The Techtonics dual downpipe does not have any mounting brackets, hooks, etc..  Mine was also slightly off centre compared to where the stock one rested.
• Installing the Catalytic Converter / Test Pipe
• Now decide whether you want a catalytic converter back on, or whether you'll have a custom-made test pipe replacing it.  This should be decided at the beginning so you can have the pipe made and painted at this step.
• Basically line this up and connect, ensuring the gaskets have good seals.
• If you want to use a test pipe, the easiest way is to go to a local muffler shop, and have them make it.  It might be good if you know someone who works there, because they may be reluctant to make one for you since it's illegal to drive without a catalytic converter.  Just take your catalytic converter along to have the proper length, and know the size of your exhaust pipes, so you can get the same diameter test pipe.
• I have recently found out that a test pipe compared to a high-flow catalytic converter (like the one Techtonics sells) is virtually identical in the flow it provides.  I will soon upgrade to a catalytic converter.
• Installing the Cat-Back Exhaust
• If you have painted the pipes, then put together the exhaust and hang it in place.  This will allow you to fine-tune the location the pipes are to take, exact locations of clamps, etc..
• My Dynomax Super Turbo muffler is positioned diagonally to the ground, because that allowed to the most centred tailpipe and the most clearance around it.
• After you've got it positioned, tighten everything.
• Installing a Chrome Tip
• I can't help here.  My Fox has the pipe from the muffler back painted blue, and that's all that sticks out.  The sound without a catalytic converter, and with the 2" pipes is a great rally-style (but not annoyingly loud), and I see no need to make it even louder.
• Finishing Up
• Install the Oxygen sensor.  I had to move the bracket holding the plug by 90^o by the airbox, because the sensor itself is much lower than it is stock.  The wires still reach and aren't excessively stretched.
• Re-install the air cleaner assembly, ensuring to plug all the plugs back in.
• Plug your ears when reconnecting the battery, as your alarm will probably go off if you have one.
• After everything is back to the way it was [well, except the new manifold, downpipe, and exhaust], run the engine until it gets warm.  Let it cool off, and re-tighten everything.
• Driving
• If all went well, the first thing you should notice is a great rally-style sound.  Mine is a deep, raspy, slightly airy sound.  An .MP3 sound file is coming eventually...
• The biggest difference is heard between 2000-3000 rpm when accelerating moderately and heavily.
• If you drive as you did before, switching gears at around 3500-4500 rpm the only difference you'll hear in sound is right between switching gears - a low, deep puff of air.
• If you drive a bit more sporty than "normal driving", you'll get some amazing sounds! :)  No more need for your audio system - open up the windows and drive!  It's as though you were in a GT class GTI... it's great!
• Highway noise is only a bit louder, but not at all deafening or annoying.  Compared to an Acura Integra with a 100% free-flow exhaust I got driven in on a highway, the Fox is very quiet.
• Performance
• I have taken my Fox on a Dynamometer [Dynojet Model 248C].  I will eventually post the graphs here.
• 89.3 HP @ 5400 RPM [Road HP]
• 93.7 ft-lb torque @ 3350 RPM
• 122.3 HP [Flywheel HP]
• 0-60 km/h is better, but nothing mind-blowing.
• 80-140 km/h is a huge improvement.  I have a 4-speed transmission, so at speeds over 125 km/h there's no point in downshifting.  With this new setup you simply step on the gas at 80 km/h and you can feel a great improvement over stock, not to mention great overall acceleration!
• Top speed - anything over 100 km/h is illegal, so I <ahem> don't know.  Figures and pictures eventually coming.
• .
• I am finished the upgrade and driving my car.  This web page will be completed as soon I find some free time to accurately write this up.

Once the upgrade is comlpete, I'll have the complete run-down of all the costs associated with it here.  Here's what I've got so far:  [All prices in Canadian dollars, unless specified "US"]
 

Part	Prices	Final Cost
1979 Audi Fox dual outlet exhaust manifold	$65.00 + $4.55 tax + $30.09 shipping	$99.64
Machining of the manifold	$20.00	$20.00
Ordered directly from Techtonics:    - dual downpipe    - tuned exhaust from cat. back	$135.00 US + $160.00 US  + $32.00 US shipping = $327.00 US	~$400.00
2x High Temperature Engine Manifold Paint [from Canadian Tire]	~$5.00 / can	$10.00
6 studs and nuts		$
"Test pipe"	Mine was free	$0.00
Catalytic Converter gasket		$
New heat shields (mine were rusted through)		$
	TOTAL:	> $600.00

• Air Cleaner Assembly - The entire assembly around the air filter.
• Air Intake Duct - the big flexy rubber hose which comes out of the air cleaner and connects to the throttle body.
• Catalytic Converter ("cat.") - This is meant to reduce harmful emissions from the exhaust.  The exhaust gases flow through a honeycomb lined with a catalyst which neutralizes many harmful gases.
• Downpipe - This is the pipe which connects the out end of the exhaust manifold to the rest of the exhaust.
• Single Downpipe - Stock on the Fox.  Has 1 inlet and 1 outlet.
• Dual Downpipe - Has 2 inlets which merge into 1 outlet.
• Engine Block - This is the part within which the cylinders move.  The exhaust manifold bolts directly onto it.
• Exhaust manifold - This is what collects the exhaust from your engine.  It is bolted directly to the engine block.
• Single Outlet Exhaust Manifold - This is what the Fox has from the factory.  The exhaust from the 4 cylinders merges into 1 outlet.
• Dual Outlet Exhaust Manifold - This is what you get from an Audi Fox/VW Dasher.  The exhaust from the 4 cylinders merges into to 2 outlets.
• Studs - These looks like screws without heads - one end goes into the engine block, and a nut goes on the other to hold tha exhaust manifold in place.
• Throttle Body - This is what controls how much of the air/fuel mixture gets to your engine.  You gas cable attaches to it.