'97 Passat TDI Build
 

I think I have enough posts now to post up pictures.

To recap; I have had this Passat TDI wagon since about '07. I bought it with 224k miles on it. It was a daily driver for about 5 years until I replaced it with a crown vic when I switched jobs, had a shorter commute, gas was cheaper, and I got fed up with fixing all the broken sh.t on the passat.

The B4 Passat chassis and vehicle is infamous for its poor design of simple, but numerous plastic parts failing requiring constant upkeep. Have four working windows and doors is a rarity in these cars. The 1.9 L TDI drivetrain is great though. I did put a 0.685 to 1 5th gear in when my original 5th gear went toast on a low tranny oil situation after I bought the car. It does have a performance chip from a reputable vendor from the TDI Forum and 0.205 nozzles (110 hp). It has great power, but I never hit the 50 mpg mark as others did but I knew its potential.

I kept the Passat, just incase gas/diesel took another huge jump and I had to commute long distances again. It sat next to my house for years, and was fired up about every other month.
It had diesel stabilizer in it. Well the inevitable happened in 2022, gas through the roof and I had a 42 mile round trip commute.

I parked the crown vic and fired up the Passat, which still ran, but was moldy inside, and had two broken rear doors that wouldn't open. Only two front windows worked.

My previous best tank when I commuted and vacationed was 42 mpg. I drove from 70-75 mph and normal driving.

Once I started commuting, I needed new tires for sure, had cracked sidewalls and tread on two. I slowed down to 65 mph max, did my gas mileage and got 45.7 mpg. Best ever. Now, I have a 26 gallon tank, but I am refilling every 8 to 10 gallons or so, so I don't have to wait so long to determine if aero mods help or not. My tank is vented so to get 26 gallons in, you have to fill it until you see the diesel in the neck, otherwise it first shuts off at 21 gallons.

https://forums.tdiclub.com/index.php...-1-jpg.148228/

I joined and starting reading through this forum and wanted to do the aeromods, but not go too crazy. I originally kept this car, because it is rare, TDI passat wagons were made in Germany, so only about 1,000 or so were imported. They didn't sell well in US. I thought this car would increase in value, but it never really did since they were lemons and being a mechanic or mechanically inclined was mandatory for owning one.
So, I have no problems with modifying it, as least it will be getting used and saving me money.

First- Roof rack delete and passenger mirror delete. The car had four antennas or bases, original owner was an archeologist and had 3 or 4 GPS antennas. These cause drag.

https://forums.tdiclub.com/index.php...-4-jpg.148230/

Next, I bought a Scan Gauge II. Now I knew where my poor gas mileage was coming from. Me.

Next mod was rear wheel skirts.
These were made using metal sheet rock corners, which are cut to curve into the wheel opening. They form the frame to bolt the skirt covers to.

https://forums.tdiclub.com/index.php...-1-jpg.148787/

Then I taped the curved frames with gorilla tape to hold the arch, then screwed to the inside wheel arch. Then the covers are cut out of coroplast then screwed to the metal corner frame. These are very secure. I use a piece of sheet rock corner on the bottom folded over both sides of the coroplast, which is bent so the tire doesn't rub. When screwed on, its very secure, no flopping. The bottom edge is held to the wheel well by hooks so the whole thing will swing down if the side screws are removed.

https://forums.tdiclub.com/index.php...03-jpg.148458/

Not sure why none of my pictures will post?

PM the mods?

Rear skirt

https://ecomodder.com/forum/attachme...7&d=1658445870

https://ecomodder.com/forum/attachme...8&d=1658445895

https://ecomodder.com/forum/attachme...9&d=1658445913

Skirts added
 

The paint don't match, but it is better than white coroplast. They are very stable though and don't rub, but tire clearance is only about 1/2". I need some pizza pan covers :).

https://ecomodder.com/forum/attachme...0&d=1658446145

https://ecomodder.com/forum/attachme...1&d=1658446168

Does it have EGR?

For a moment I thought you were reducing th opening of the front wheel well.

I probably will reduce the openings on the front wheels, they are large. I will try to find some 1/8" ABS sheet for the front wheels since its stiffer and more durable.

If I have the time this summer, I was going to repaint the entire car and will paint match the skirts. They will look much better.

Rear Diffuser
 

My next mod was to start the rear diffuser. I will be having a full undertray of coroplast but I need to transition the undertray to the rear diffuser so I had to add a support bar. The bar was aligned so the undertray will curve up and hit the diffuser. Should provide a bit of downforce too :).

https://ecomodder.com/forum/attachme...1&d=1658509989

The muffler is going away but that will be another step.

So the steps are:

1. support bar to screw the diffuser and undertray to.
2. Passenger side diffuser in plastic
3. Remove two mufflers (one is a resonator I believe). Make a new 2" cat back exhaust and install.
4. Driver side diffuser out of sheet metal, with exhaust terminating at surface.
5. Make undertray for the rear bumper at both sides of the diffuse to get rid of the parachute, I have now.

Diffuser part 2
 

So I built a diffuser out of an old Sears rooftop carrier. It was plastic and had a curve I could use, and it was going in the trash anyway. I did build some strakes, mostly for support. These are riveted on to provide strength. Looks a little like tuner bling but they add a bunch of strength and kept a good curve in it for transition.

https://ecomodder.com/forum/attachme...1&d=1658510441
https://ecomodder.com/forum/attachme...1&d=1658510441

I had to cut the rear bumper, which bothered me at first, but it was a parachute really. I cut nothing but plastic, so its integrity is not compromised.

https://ecomodder.com/forum/attachme...1&d=1658510441

The bumper is cut flush to the steel support beam. The diffuser angle is a little steep, probably 15 degrees or so, but I can flatten it by adding a fill in piece at the bumper. I will do some tuff testing once the full undertray is in to determine the proper angle.