EDITOR’S NOTE

WINTER PROJECTS

Seven months ago, I did a thing; a thing that surprised a few of my friends: I picked up a used BMW 335D. (Hey, at least it’s diesel!) I had watched a few people in the industry having so much fun with theirs that I had to see what it was all about.

When I got it, I promised myself I’d leave it stock for at least a few months so I could really get a good feel for the car before tearing it apart. Well, seven months later, it’s still stock. But that ends now.

I just ordered an intake, exhaust, PVC catch can (these have blow-by like a Duramax), intercooler, a tune and a bunch of other things to remedy known problems these cars have (think killer dowel pin in 12-valves or the oil cooler in 6.0Ls).

Before tearing it apart, I spent some time getting some before “numbers.” The first thing that went on the car was a data logger in the form of a Banks Super Gauge. I gotta say, this gauge is the greatest thing I’ve seen to come out of the industry for a long time. It’s a little, round gauge just like you’d find on the pillar of so many trucks, but it can display hundreds of parameters and can also log them at the push of a button. On the 335D, there are more than 100 different things you can view. Oh—and it reads codes and can clear them, as well, plus so much more. I’m not even close to understanding everything this little gauge does; there’s just so much there.

So, from the data logs I did, I now have peak EGT in a number of situations. I have air density numbers (great to test the intercooler with), air temps, boost, trans temp, oil temp, fuel pressure and about a dozen others. While data-logging, I dyno’d the car last week: slightly more than 230 hp at the wheels—which almost perfectly matches what it’s done at the drag strip. It spins off the line, so I know it’ll do a little better with some good tires (and the high trap speed makes me think so as well). However, so far, 9.14 is its best in the eighth-mile. I didn’t measure torque, but it should be a little less than 500 lb-ft. So, the base numbers are 230 hp, 9.14 in the eighth-mile, EGTS that rarely crest 800 degrees and 34 mpg.

Now, to tear it apart!

Tearing into this car really does make me nervous. German engineering can be tricky (and expensive if I screw it up). I know how a Duramax, Cummins and Power Stroke work like the back of my hand, but this BMW is new to me.

First up: vacuum lines. This engine is controlled very heavily by vacuum. Like in an old Toyota, there are vacuum lines everywhere. And, they start to crack at around 60k miles— which is right where mine is. I’ve fixed a few leaks that caused check-engine lights, but because so much of the car is coming apart, I’ll be replacing all the lines with new and better ones.

Then, it’s on to the decarbonization of the intake and head. This is something that everyone with a newer vehicle needs to know about, and if you wrench on your own car, you should know how to do the procedure. It’s pretty expensive to have someone else do this, and it needs to be done every few years. Basically, the EGR introduces sooty exhaust into the intake, combined with blow-by from the crank case, and you end up with a thick, black film lining the entire intake tract. This restricts flow to the engine, hurting performance and mpg. In some instances, it can do serious damage to the engine, itself, necessitating a full rebuild.

So, I picked up a cheap media-blasting tool from Harbor Freight and some brake line to adapt the spray nozzle to fit into the different intake tracts. A few adaptors for my shop vac should get all the media out of the way before finishing the job.

While the intake is off, I’ll be deleting the swirl valves (tiny, little flaps that change airflow for efficiency purposes). I don’t really want to remove these, but they have the reputation of falling off and getting into the valves, wreaking havoc. So, they’re out.

Next is all the fun stuff—intake, tune, intercooler and exhaust. I’ll actually be doing the intercooler at a different time so we can learn what it does on its own (I have high expectations for this one!).

I’ve been told that with what I just listed, these cars can easily make much more than 400 hp at the wheels. That’s a diesel car that does 11-second quartermiles and still gets 30-plus mpg.

I can’t wait. Stay tuned.