Auto Spotlight: BMW M3 E30, Part 3: The Specs

Part 1 is here.

Part 2 is here.

     Let’s move on to the fun part: the numbers.  Ain’t no room for opinions here, it’s all hard numbers and tests.

     When M started development of the M3’s then unnamed engine, they decided to go with the high-revving 4 pot route instead of a lower-revving 6 cylinder.  They based the block on BMW’s 1.8 liter M10 engine which was powering the rest of the 3 series lineup at the time.  The head however, was based on the M88 engine (cut down to 4 cylinders of course) which powered the street version of the M1,the E28 M5, and even some second generation E34 M5s.

     The stock 2.0 liters of displacement wasn’t enough for M, so they decided to both bore and stroke it to 93.4 mm and 84.0 mm, an increase of 4.4 mm in bore diameter, and 7 mm in stroke length.  They then adapted the M88, which featured double overhead cams, onto their 2.3 liter block by machining both the intake and exhaust ports for better flow.  They added eight counterweights to the crankshaft to deal with the increased rev limit, and also added individual throttle bodies (ITBs) to help each cylinder breathe with maximum efficiency.  This combination gave the S14 around 200 horses (197 hp i believe ) in production form.  While being powerful and efficient all the way around, M also wanted their S14 to be seen as clean and fuel efficient as well.  Thus they added a catalyst converter, which when tuned with their engine management, would return over 30 miles per gallon.  While the inclusion of the catalyst converter would lower the maximum output, it only sapped around 5 ponies in all, leaving the final power output at 192 hp.  The more powerful special edition M3 EVO2 which arrived in 1990 sported a larger power unit, both bored and stroked again to 2.5 liters by increasing bore diameter to 95.5 mm and stroke length to 87 mm to produce 238 hp.

     The chassis was also modified to accompany the increased power figure.  Lightness and stiffness was the goal.  The chassis was stripped down to only its bare necessities and then some.  The front windscreen and rear window were bonded to the chassis for improved stability and handling.  The front and rear bumpers, sidesill, boot lid, and spoilers were built from plastic to reduce weight.  Brake disc sizes were increased, while the front disks were exchanged for ventilated ones.  Stiffer anti-roll bars and springs/dampers were also included.  At the end of the diet, the stock weight was around 1200 kilos, or 2646 pounds, giving the car an impressive 6.15 kg per hp.  (Keep in mind that the E46 M3, which ended production in 2006 sported a 5.50 kg per hp ratio.)

     In the area of aerodynamics, you can definately see the improvements.  A large front spoiler was installed to reduce front axle lift by one-half, and the loud rear wing reduced rear lift by two-thirds.  The larger wheel arches helped increase track length by a bit, and could hold larger wheels and tires for increased grip.  The rear C-pillar was shortened and widened to allow better airflow to the wing and the front windshield was raked back as well.  The coefficient of drag was a low 0.33, which probably attributed to its efficient fuel consumption and high speed.

     As for real world performance figures, zero to sixty was found in 6.5 seconds, and reaching the century mark was done in 19 seconds flat.  The top speed was an impressive 143 mph with the catalytic converter, and 146 without.  Remember that this car was released in 1982, and those numbers were very impressive at the time.  If they seem tame to you, we’ll take a look at the motorsport variants of the E30 M3, which featured increased power figures, and even more madness.  Stay tuned.


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December 2009
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© 2009 Rusi Li

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