First off, I want to thank theswoleguy, 20aeman, gre9del and all of the helpful VWvortex vendors mentioned below. A lot of the ideas and instructions below are borrowed, and I wanted to give credit where it's due. Theswole guy has a great post with general information about E85, a 1.8T-specific FAQ, and details of his experiences using E85, which can be found here: http://forums.vwvortex.com/zerothread?id=3866545.
Below are detailed instructions for the 4 steps needed for E85 conversion: installing a Walbro 255lph inline fuel pump, swapping out the stock MAF for a 3" VR6/TT225 MAF, replacing the stock fuel injectors with 630cc ones, and tuning the whole thing. You will need all of parts listed below, most of the tools mentioned, and some mechanical aptitude. I assume no responsibility for you performing this procedure or the negative impact it may have on you or your car. *Proceed at your own risk!!
Parts Needed: (and recommended places to get them)
-Walbro 255lph inline fuel pump with basic install kit (Clay@CTSturbo has a great deal going on now, $320 shipped for 4 630s and the Walbro pump, http://www.ctsturbo.com/produc....html)
-Walbro/MK4 relay wiring harness (optional, if you would rather save money and assemble this yourself, I recommend just paying the $65 here: http://www.usrallyteam.com/ind...d=412)
-Siemens/Deka 630cc fuel injectors (recommend purchasing from CTS along with Walbro pump above)
-Fuel rail spacers and extended bolts for aftermarket injectors (CTSturbom, USRT, ECS and others carry this)
-VR6 or TT225 MAF housing
-VR6 or TT225 airbox, or an intake that can attach to the 3" MAF housing
-3" silicon coupler
-3/8" fuel line hose clamps (2 or 4, depending on..)
-3/8" fuel injection hose (optional, but makes installation easier)
-computer with an OBD2 cable and VAG-COM installed
-multi-meter or volt-meter
-Torx and Torx Plus/TS security bits ( http://www.amazon.com/Silverhi...r=1-5 )
-long reach allen keys
-assorted sockets and drivers
-telescoping magnet (optional, but helpful)
-pick/hook set (optional, but helpful)
STEP 1: Walbro Inline Pump Install
1) Make sure you have all the parts you ordered, and all the tools you’ll need, especially if you don’t have a backup vehicle to make a parts run. Pay close attention to the little nuts and washers that came with the pump, o-rings on the injectors, etc.
2) Inside the car, remove the 3 torx head screws securing the lower kick panel on the driver’s side. Two of these screw positions are shown in the picture above; the third is off to the left.
3) Remove the kick panel by pulling downwards on the front edge, and then pulling the whole panel towards the rear of the car and out of the white sandwich clips near the pedals.
4) On the right side of the relay panel, locate relay position “87F/Diesel,” this is where we will be tapping to switch the new inline pump relay on.
5) Using a multimeter or volt meter, confirm that when the key is switched to the on position, this relay goes hot (12V) for several seconds before returning to 0V. This can be tricky if you are working by yourself, but can be done.
6) Start the car up, and then pull fuse #28 from the panel on the end of the dash. Doing this will disable the stock fuel pump, causing the motor to stall and relieving the injection lines of most of their pressure.
7) Remove the key from the ignition, and disconnect the battery.
8) Locate a suitable place to mount the new pump relay. My car had an unused stud near the factory airbox.
9) Locate a nut and washer to be used on the stud from your collection. You’ll need a M6x1.0 nut and M6 washer if you use this location.
10) To make installing the relay easier (and since it will be coming out later anyways), remove the factory airbox. This is done by disconnecting the plug going to the MAF sensor, undoing the hose clamp on the MAF, disconnecting the SAI line going to the airbox, and removing the two allen head cap screws or bolts securing the airbox to the car.
11) With the airbox out of the way, you can now use a ratchet and deep socket to install the relay, washer and nut to the stud coming off the fender.
12) Remove the four Philips head screws holding the headlight covers in place, and remove both halves of the cover.
13) Begin routing the wiring harness over to the passenger side of the vehicle. Learn from my mistake and route the harness UNDER the hood release cable. Replace the inner headlight cover, and you will notice a conveniently located notch that allows the harness to pass through and holds it in place.
14) While routing the harness across to the passenger sides, use zip-ties to keep everything pinned up above the radiator and away from hot and moving parts.
15) Once over near the passenger side headlight, I dropped the harness down to where the motor mount is, and then routed it up between the power steering and coolant overflow reservoirs to the fuel lines where the pump will be located.
16) Going back inside the car, use an Exacto knife to make a small slit in one of the grommets running through the firewall. If you already have a vacuum line for a boost gauge running through like I did, this step isn’t necessary. Using a straightened out coat hanger, poke through the opened grommet and into the engine bay. Working under the hood, route the yellow wire from the new relay harness beneath the airbox, hoses, and other wires in the engine bay, and attach it to the end of the hanger with some electrical tape. Back inside the car, slowly pull the hanger back through the grommet, hopefully with the yellow wire still attached.
17) Pull enough of the wire through so that it can be cleanly routed away from the pedal assembly. Attach a crimp-on ring connector to the end of the wire large enough to fit on the relay terminal stud. Remove the nut, and reinstall along with the yellow wire.
18) Back under the hood, remove the 10mm nuts on both the positive and negative battery cables, and attach the one red wire in the new harness to the positive terminal, and the two black wires to the negative terminal.
19) The inline fuse holder included with the new harness can be mounted to the top lid of the battery fuse box. Position the holder and mark where it will attach with a scratch awl or similar. Find a very short self tapping screw and a washer or two. With the screw installed, you want to make sure that it just barely goes through the lid and doesn’t come in contact with any of the fuses.
20) Begin preparing the Walbro inline pump for installation by installing the sound deadening sleeve onto the pump, and removing the red plastic caps on the inlet and outlet.
21) Install the included hose barbs onto the pump. The barbs themselves are 5/8”, and the pump is between ½” and 9/16”, which I didn’t have so I used an adjustable crescent wrench.
22a) *Option 1: if your fuel lines are newer and in good shape, you can try installing the pump onto your existing lines. Use an Exacto knife to cut the FEED line (this is the one with the black right angle connector, shown above, going to the fuel rail pipe with the stamped forward arrow). Your want to make your two cuts slight after each bend in the hose, allowing enough room for the length of the pump. Some fuel will come out when you make your first cut, so you’ll want to have a cup or rag beneath to catch.
22b) *Option 2: if your fuel lines have seen better days, or refuse to stretch over the new pump’s hose barbs, you’ll prefer this route. Remove the feed line completely from the car. At the rear end, remove the quick connect elbow by pressing in the little button and pulling upwards. To avoid breaking this extremely hard to find and very expensive connector like I did, I recommend removing the metal clamp with a pair of needle nose locking pliers, and then gently make a cut lengthwise in the hose so that it can be easily pulled up. The hose seems to bind over time to the connector, and twisting and pulling is NOT the way to go. At the fuel rail end, move the easier to work with spring clamp, and remove the hose from the pipe, using some curved jaw pliers to assist in twisting the hose free if needed.
23) You will want to replace the fuel line with 3/8” ID “Fuel Injection Hose.” The injection part is crucial, as regular fuel hose or vacuum hose is not reinforced and is not rated to the 100+ PSI working pressure needed. Goodyear and other reputable companies produce this hose in rolls, or sold on the shelves in 18” pre-cut lengths. You may need to go to a specialty auto parts store, as this is not always carried at Pep Boys and the like.
24) Using the 3/8” fuel line hose clamps, secure two lengths of the fuel hose to the barbs on the pump. Position the pump in the car, with the electric terminals facing the front of the car, and install the lines onto the fuel rail and the quick connect elbow using fuel line clamps.
25) Looking at the case of the pump, you will see a “+” and “-“ stamped in marking each terminal. Place the wire’s ring connectors onto the appropriate terminal, and using masterful manual dexterity, install the included star washers and 8mm nuts.
26) At this point, finish up the installation by re-installing the headlight cover, dash kick panel, and making sure all your new wiring is secure. If you plan on continuing the conversion later and would like to use your car in the meantime, install the stock airbox and the connectors and hoses going to it. Otherwise leave the airbox out. Reinstall fuse #28 and reconnect the battery. Use a combination of door openings and key switching to the on position to prime the fuel pumps several times. Check underhood for the smell of fuel, and look closely at all the hose/barb junctions for leaks.