New Pics including Engine Bay below

I came to this forum a while ago with the intention of getting an S2000. However, something came up, and I was forced to change my plans

What came up was a car on ebay. A 2003 Z4 3.0i. Nice car, comparable to the S2000 (and I'm sure everyone on here feels the latter is the better of the two). However, there was something special about that Z4. A twin screw supercharger.

This Z4 puts down 323 to the wheels (around 390 at the crank assuming 15% loss). The other lovely thing about the engine/supercharger combo is that the torque curve is about as flat as your 5th grade crush's chest.

Long story short, I flew up to New York and picked it up (not after lots of talking, getting all the records and information on the car that I could, etc.).

Impressions: I test drove an S2000, so I'll try to compare it to that (since most people here will be able to relate).

Steering: Very similar to the S2000. Similar wheel diameter, similar point and go turn in. Really responsive to driver inputs. The biggest difference is that the steering gets heavier at speed, which makes handling bumps and corrections much easier.

Shifting: No doubt, the S2000 is better, but the Z4 is great, too. The shifts are a little bit longer and lack the heavenly smoothness of the S2000's gearbox, but it's not bad at all. It's the second best shifter I've ever used.

Throttle: Most BMWs of that time period use a drive by wire system that is designed for smoothness, not response. As a result, fuel input doesn't react much to minute changes in throttle postions, and there's a noticeable delay between throttle movement and a change in fuel input. The previous owner had this removed, and the throttle now reacts very similarly to what I experienced in the S2000 (with a much larger range of acceleration). In short, I'm very happy with it. I'd like some more resistance in the pedal, but that's a minor complaint.

Brakes: I never came anywhere near their potential on the drive home (car's running sticky Dunlop Direzza Sport Z1 Star Specs to boot), but the pedal is nice in linear.

Ergonomics: Telescopic steering wheel allows you to adjust it just how you like it. You sit REALLY low in the car. The car itself is about as low as the S2000, but the seating position is a couple inches lower. I don't particularly mind one way or the other (I'm young and my back works just fine). The ride home was surprisingly comfortable.

Handling: Car responds just like the S2000 (as you'd expect another short wheel base, 50:50 car), and the tires have far more lateral grip than I'd ever use on a public road. Bumps don't really upset the car as much as a lot of the reviews said. I suspect that's more an issue with the run-flat tires that came on the car and their super stiff sidewalls.

Acceleration: Wow. That's all. Not only does it have 323 hp and 291 torque at the wheels, it's got 3.46 gears (as opposed to 3.0x on the stock car). It's just stupid fun. Forget about traction anywhere in first gear. About halfway through 2nd it'll hook up and then it's just gone. It's really hard to explain the instant torque a positive displacement supercharger provides. It's something you have to experience. I'm guessing this is what an electric car feels like. Oh, and despite all this it, averaged 33 mpg on the way home (due most likely to the bypass valve). The car also has the limited slip differential from an E46 M3 to help with hook up. It works just like it should, and although I never pushed the car hard enough to test it in the turns, there is this spot in town that always has one tire hanging in the air for a bit and it always caused my 328i to get loose if I wasn't careful. The Z took it like a champ.

New Pics











Old Pics

Here are a couple of quick pictures I snapped on my droid:





Did I leave anything out?

 

Very nice car. I like the color and wheels.

BTW, 323 x 1.15 = ~371

J

 

Very nice! Love the wheels! A Z4 is a terrific car. Wow, that's probably a little beast with that kind of power, especially a PD type supercharger setup, it must have a _ton_ of low end.


Actually that's not correct either. You're adding 15%, and what you need to solve for is the original value of which 323 is 85% of (so to speak).

323 / 0.85 = 380

 

What an unassuming beast..

Any engine bay shots?

 

Great review, how much did you pay for it if you don't mind?

I looked up the specs, stock for stock it's a little heavier thhen s2000 with a little less hp, but I bet with that supercharger it's a monster

 

Love those Z4's! Congrats!

 

Assuming 380 HP and about 3000 lbs, it should be faster than the E90(2) M3, new 5.0, etc. Nice car!

 

nice. how much did you pay? my unicorn is still a z4m coupe

 

What engine mods does it have? That power figure is well over 100 more than stock (~250hp IIRC).

 

Unfortunately, no. Forgot to take any. I'm also 150 miles from the car at the moment. I'm doing a co-op in rural South Carolina, living in a house on the edge of a lake with no garage or anything. Thus, it's a bug-infested, constantly wet car hell. I'm not going to subject my new car to that. As a result, it's staying in a warm garage at my parent's house. I could probably get my brother to take a few shots under the hood.

About the horsepower, 390 was a quick guestimate doing some awkward math with 323*20/17 in my head. It turns out to be exactly 380. Not a big difference to me.

$11.5 and 56,000 miles. Unlike the guy who found the S600 on Craigslist, I found a deal and didn't tell anyone about it. It was originally listed for $15 on Ebay, some guy asked the lowest he was willing to take and the owner replied that he had it listed for $12.5 on Craigslist. I checked Craigslist and it had $15. Turns out his wife changed the Craigslist ad to match Ebay. So I offered 11.5 and he agreed.

It uses the ESS package. It's got a custom aluminum intake and intake manifold, larger injectors, cams, and is running 8.5 PSI. I could get more power of it if I used their headers, but I'm satisfied for now. They also offer a stage two that adds an liquid intercooler. Headers + intercooler is good for about 40-50 hp according to their dynos (which the previous owner's independent dynos matched up perfectly to). Basically, there's still room for growth. Torque's increased 56% over stock and 8.5 PSI corresponds to .58 atm, so assuming the intake and intake manifold freed up the engine a bit as is, that seems like a perfectly reasonable efficiency.