E30 Complete Engines
M20 Engines: A Brief History
The M20 engine group was introduced in the late 70's in 2.0L and 2.3L sizes in the European model BMW 320/6 and 323. A later 520 sedan combined the fuel economy of the small six with the convenience of a 4 door sedan.
With consumer demand for more power, engine size was increased to 2.5 L, and in then new E30 chassis, electronic fuel injection powered the 323 and 325 versions. In the shadow of another fuel shortage BMW developed the ingenious 2.7 L eta engine which came to the U.S. in the 1983 528e and '84 325e. The engine was designed for minimum friction loss, highest possible fuel efficiency and maximum low rpm torque. In comparison, the 2.7L eta produces 170 lb/ft of torque at 3250 rpm, whereas the 2.8L 528i produces the same amount of torque but at 4500 rpm.
The 2.5 and 2.7L engines were strong and successful. In 1986 a BMW 325iS prepared by Linder with support from BMW Motorsport won the European Group A Championship and in the United States the Korman Autoworks 325e won the 24 Hours of Watkins Glen and the 1986 IMSA Endurance Driver and Manufacturers Championships. The Director of BMW Motorsport GmbH, Munich, Wolfgang Peter Flohr, wired a message of congratulations saying "The headline,'Korman's BMW Wins 24 Hour Race' is for BMW Motorsports GmbH a highlight which we tried to achieve in the United States for years and which goes without saying to your account only."
Everyone says they want more torque but horsepower still sells. By popular demand the 325iS came to the U.S. It had less torque (164 lb/ft @ 4300 rpm) but and increase of 41 horsepower at an enthusiasts 5800 rpm. It quickly became much more of a favorite than the low revving but efficient eta model. The 325iS made its own racing mark. In 1989 a 325iS entered by Le Team with engine and suspension by Korman Autoworks scored another win in the Watkins Glen 24 Hour Race. The primary competition R&D program for Korman Autoworks in 1993 was to develop the BMW 325iS for the SCCA IT series. The new model was an immediate front runner, overturning the previous dominance of the Nissan Z cars. The BMW won all but one race of the season, breaking lap records everywhere, and ran away with the Mid Atlantic SCCA ITS Championship!
See related information under Rebuilding: Engines and Turbos
Korman offers 4 basic rebuilding configurations:
Korman Stock Rebuilds
2 year/24,000 mile warranty
Our stock rebuilds are assembled to BMW specifications by our experienced and dedicated technicians rather than off a mass production assembly line. Korman engines are assembled with meticulous craftsmanship, precise machining, and detailed blueprinting. All of our boring is done with a torque plate for exceptional bore roundness and long engine life. These hand built engines are available at prices comparable to a factory reman units which offer only 12 month/12,000 mile warranties.
318i P/N 11318010
325e P/N 11036100
325i P/N 11036200
Korman Stage 1 Competition Engines
2 year/24,000 mile warranty
Korman Stage 1 Competition Engine-318i
As above, but includes 2.0L conversion to provide the "punch" missing from the 1.8L engines. Headers are included (check local laws for legality). High compression pistons, special valve work, and Stage 1 head porting yield 140 horsepower.
P/N 110B3180
Korman Stage 1 Competition Engine-M20
Our Stage 1 rebuild will provide a moderate increase in power through the use of our proven performance techniques. Special valve and valve seat work, increased compression, Korman-Stahl Headers and Stage 1 cylinder head porting will net a gain of 12-25 HP depending on model. Performance computer chip suggested, not required.
325e P/N 11036410
325i P/N 11036510
Korman Stage 2 Competition Engine-M20
Our Stage 2 engines are designed for maximum performance without adversely affecting engine life or driveability. All Stage 2 Engines receive our flow testing porting and polishing, proven 3 angle valve seat work, back cut intake valves, dual valve springs, titanium retainers, Korman Rocker Arms, Korman-Stahl headers, and a Schrick 272 Camshaft (upgradable to a Schrick 288 on some models). M20 "i" engines receive our aluminum flywheel, while M20 "eta" engines receive our exchange lightweight flywheel. Korman performance computer chip suggested but not included.
325i P/N 11036350
325e P/N 11036370
Korman High Performance Clean Air Engines
2 year/24,000 mile warranty
Stage 1 High Performance Clean Air Engine-M20
In our Stage 1 Clean Air Engines we apply our high performance techniques to extract maximum power from stock parts while making no changes that affect Federal or State emissions laws. Our flow tested porting, polishing, valve and valve seat work promote smoother, more efficient air/fuel flow keeping the mixture better suspended for cleaner burning. Valve spring pressure is increased for a higher max rev limit of 7000 rpm. To reduce reciprocating weight and improve acceleration we lighten and balance the connecting rods, fit stronger light weight piston pins, and lighten the flywheel. These techniques produce a 10-15% power increase and an engine which revs much more quickly. Korman Performance computer chip suggested, not required.
325e P/N 110364C0
325i P/N 110365C0
Korman Stage 2 Clean Air Engines
These engines receive our Stage 2 competition-type engine treatment for maximum emissions legal performance. Porting and polishing are more extensive than in our Stage 1 Clean Air Engine, and all valves are swirl polished. Also included are our titanium valve spring retainers, dual valve springs, Korman Rocker Arms, light weight steel alloy connecting rods, light weight piston pins and our lightened steel or aluminum flywheel (depending on model). Ceramic thermal barrier coating for the exhaust manifold and our special engine oiling system modifications are also provided. Special computer chip required.
325i P/N 11036650
Korman 2.7 Liter Stroker Engines
The 2.7L 325 eta engine is the ultimate in smooth, very high torque, ultra efficient performance. But the light nodular iron cast crankshaft and light valve spring pressure limit this pleasure to about 4850 rpm. Our special conversions include a high performance 2.7L crankshaft and improved valve springs which allow safe revs to 6900 rpm. This conversion is available on all of our M20 Stock, Stage 1 and 2 Competition and Stage 1 and 2 Clean Air Engines. Call one of our staff for suggestions and pricing for any applications not listed.
Korman Race Engines
Whatever your series, whatever your specifications, Korman can build you a dependable, long lasting engine engineered for maximum power. Whether you need a reliable engine for BMW CCA Club Racing, or a 325 HP "conservative" race engine, call us first!
Korman Cylinder Heads
Korman cylinder heads are available prepared to the same specifications as described in our engine packages. If your engine is of moderate mileage and the bottom end is in good condition, then bolting on a Korman prepared cylinder head is a very economical and effective way of improving your engines' performance. Your cylinder head will be prepared by the same race engine technicians that build our winning race engines.
All Korman Cylinder heads are chemically cleaned, peened and inspected for flaws and warpage. No traces of old gasket material are left to spoil the sealing surfaces. New rocker shafts, rocker shaft clips and rocker arms are included, as are a cylinder head gasket set and Bosch spark plugs.
Korman M20 eta Cylinder Head Rebuilds
325e Stock Cylinder Head Rebuild-P/N 11122006
325i Stock Cylinder Head Rebuild-P/N 11122036
If your eta engine was manufactured before Dec. '86, it has small valves, 40mm intake and 34mm exhaust. Our Stage 1 and 2 Cylinder Heads include larger valves, 42mm and 36mm, respectively.
325e Stage 1 Clean Air Cylinder Head Rebuild-Parts as noted above, includes labor to modify cylinder head to accept larger valves. P/N 11122106
325e Stage 2 Clean Air Cylinder Head Rebuild-Stage 2 porting and polishing, parts as noted above. P/N 1122206
325e Stage 2 Competition Cylinder Head Rebuild-As our Stage 2 above, plus a Schrick 272º Performance Camshaft. P/N 11122306
Korman M20 "i" Cylinder Head Rebuilds
325i Stock Cylinder Head Rebuild-P/N 11122036
325i Stage 1 Clean Air Cylinder Head Rebuild-Stage 1 porting, includes replacement exhaust valves and parts as listed above. P/N 11122136
325i Stage 2 Clean Air Cylinder Head Rebuild-Stage 2 porting, includes replacement exhaust valves and parts as listed above. P/N 11122236
325i Stage 2 Competition Cylinder Head Rebuild-As the Stage 2 above, also includes a Schrick 272 camshaft. P/N 11122336
Extrude Honed Intakes
The perfect compliment to your new cylinder head! The ExtrudeHone process accomplishes porting and polishing throughout the complex BMW intake manifolds which are inaccessible by hand tools.
ALL 4 and 6 Cylinder P/N 13EXTRUDE01
© Korman Autoworks, Inc. 1997, 1998