In the three decades it’s existed, the E30 BMW 3-Series went from yuppie mascot to irrelevant old coupe to bargain fun car to cult classic to the celebrated standard of practical performance that it is today. We’ve seen plenty of custom E30 builds, but nobody’s created an E30 V8 that really felt like it could have come out of the BMW factory. Until now.
(Full disclosure: Rob Dietz called me up and told me that the E30 project he’d been telling me about was done. I dropped groceries I was carrying across the street for an old lady and headed right over to Dietz Motorcraft to get behind the wheel.)
In its original form, Rob Dietz’s 1986 BMW 325e was just another E30 coupe with a modest efficiency-oriented engine under the hood. Perfectly respectable and enjoyable, beloved by millions of people. However, in its current form, the car is something else entirely. It is a vision realized, an example of what happens when there is an entire philosophy behind a build, not just a desire for more power. (MOAR POWER!)
Of course power is an important part of the equation, because where there was once an M20B27 straight-six is now a M60B40 V8 from a 1993 BMW 740i. And with that, more than double the car’s original output.
Dietz chose this particular motor because it’s period correct. Had some BMW engineer been very forward thinking, it could have feasibly made it into an E30 off the assembly line.
Put another way: this is the 1986 BMW 340i that never was.
The subtly of this particular build is what makes it special. It’s so close to what I imagine an E30 340i would have been that I’m not entirely convinced this car didn’t slip in here from an alternate timeline.
While plenty of engine swaps skip details to get the job done more easily, every accessory and amenity was retained (or relocated) to make this car feel complete and have every switch and system work as easily as if the car had just rolled off a dealer’s lot.
On top of that, lurid burnouts and powerslides are equally easy. Is it the perfect E30 variant that should have been made 20 years ago? Sure as hell makes a compelling case as to why it might be.
Dietz pulled the ideal bits from a variety of BMW models in order to keep the build faithful to his original vision of a factory style car. The parts add up to a car that is most certainly unique, but plain at the same time.
Under the hood the 7-Series V8 is pushed as far back as it can possibly go, resulting in all its weight resting in the right place. Are you paying attention, Audi? Over and behind the front wheels, that’s where you want it. Proper subframe to engine clearance was achieved by dropping the subframe slightly, as opposed to notching the oil pan which is also an option... but doesn’t line up the driveline as nicely.
From what Dietz shared with me, fitment was not as much of an issue as one might think. A factory “wrinkle” in the transmission tunnel received a couple love taps with a hammer to smooth it out, as did the front frame rails as they’re damn close to the alternator and AC compressor.
The tightest spot was at the rear of the upper intake to the firewall. Here the heater hoses, expansion tank hoses, fuel hoses, PCV system and an assortment of other little things needed to be crammed in. Some small bends and cutting of hoses allowed everything to fit neatly, but work on these things requires pulling the upper intake through.
Everything, and I mean everything, on the car was replaced with new-old-parts that make the car feel like a time machine. But it’s revisionist history where it counts: The M60 power steering pump was adapted specifically for the E30 chassis. A Z3M radiator was fitted to keep up with the massive new engine’s cooling needs.
Other highlights from the build sheet include a new OEM 540i dual mass flywheel, E36 M3 Stage 2 clutch and E34 530i 5-speed transmission. I was quickly enamored with the car because of the way this setup draws you in. The clutch is heavy-ish, landing in that just right range for daily driving in a city without being vague or having an oddly high engagement point. The dual mass flywheel helps with NVH reduction, which in turn contributes to that factory “autobahn cruiser” feel.
Finally, the five-speed transmission... since you may be wondering why a car intended to be a cruiser wasn’t given a sixth gear. But the truth of the matter is, the car simply doesn’t need it.
It’s geared tall and that suits the personality of the car. With an open diff 2.93 final drive ratio and a 6,500 RPM redline you get 36 mph in first, 62 mph in second, 92 mph in third, 124 mph in fourth and 155 mph in fifth. Oh, and the brains behind that would be an 540i ECU with manual chip and basic tune that yields an increase of 22 HP. All that in a car that weighed 2,789 pounds new and topped out at 117 mph.
It had been awhile since I got behind the wheel of a car and instantly understood it. I’m impressed by plenty of the vehicles I drive, I even like most of them. But understanding them at all, let alone immediately, that’s rare. As soon as I pulled onto the PCH and got running through the gears, I knew what this car was about. And no, it is not hot nasty badass speed.
That isn’t to say that it won’t blow your hair back, because it sure as shit will if you ask it to. What started as a simple cruise up the PCH at sunset turned into a run up one of the more aggressive canyon roads in Malibu at dusk. It was a spur of the moment decision, but one I’m glad I ended up making because the road was the perfect place to connect with the 340i. It hasn’t been particularly well cared for over the years, but the car rode smooth over the road’s imperfections.
The route gained elevation quickly though a series of corners, but because of the tall gearing I didn’t need to constantly be shifting. For the most part I was able to remain in second and had all the power on tap that I needed. Once or twice I got carried away and went up to third, but then I erased speed quickly to be confident the front end would stay right where I wanted it to be into turns.
Confidence in a 31-year-old two-door with a 24-year-old V8 under the hood, it’s a beautiful thing.
It all stems from proper attention being paid to the setup of the motor itself, the steering feel and perhaps most importantly, the brakes. There’s absolutely no point in giving a small car a big motor if you can’t stop the damn thing with ruthless efficiency.
Braided brake lines, custom CNC brake line plate, Hawk pads, drilled rotors... it’s not anything particularly special, it’s just solid. Dietz retained the ABS system but deleted the booster, which gives the pedal this really great feel that’s perhaps best explained as just being easy. When braking is as enjoyable an experience as accelerating, you know you’re driving something special.
The intention was to build a high-horsepower E30 that was the yin the feisty and lithe M3’s yang. A variant that was powerful, but didn’t need to be hammered on in order to get the most out of it. Whereas the E30 M3 is manic, Dietz’s 340i is calm. That calmness makes the strength of the motor far more enjoyable, even though it’s not an M powerplant.
It’s a quiet car. Reserved, even. You can roll along with the windows up in the middle of the rev range all damn day and forget there’s a V8 under the hood. Since the interior has been refreshed as well and the E30 cabin is one of the all-time greats, it’s not as though it’s a rough place to spend time either.
But then again, you can also drop down a gear, get your right foot into the skinny pedal and hustle the damn thing. I didn’t go at it super hard because, well, it’s not my car and it’s going up for sale. I got after it in the canyons a bit and may have exceeded the legal limit on the PCH once or twice, but I left it to Dietz to demonstrate the full capability of the 340i.
In a cloud of white smoke, ears full of glorious V8-rumble, eyes locked on the end of a square red hood and the asphalt just beyond it illuminated by yellow fog lamps, we took flight. That’s kind of moment we’re all looking for, the one that stretches seconds and makes everything outside the car disappear. This car brought me there and while I’m just grateful to have been, I’m already looking to go back.