Mazda FE-DOHC engine
Encyclopedia
The Mazda FE-DOHC was the DOHC variant of the FE. The official Mazda engine codes are FE-DE and FE-ZE, depending on output level. It is still commonly called the FE3 because of its head castings. The FE-DOHC shares the same dimensions as the original FE-SOHC, including the square 86 mm bore × stroke and it has an ideal 1.74 rod/stroke ratio. The FE-DOHC is usually identified by a gold-coloured cam cover, however not always. There were at least five different FE-DOHC engines available with various compression ratio, camshaft and ECU tuning combinations, however none were fitted with a turbocharger from the factory. Despite this, the FE-DOHC is already built for turbo with large forged connecting rods, large journal dimensions, oil cooler, piston oilers, web-stiffened block with main girdles (and braceplate where equipped). This robust engine design is a favourite of tuners who are aware of its capability because it already has a high-power capacity perfect for custom turbo jobs. As much as 600 whp has been seen on a stock engine. The common FE-DOHC crankshaft is cast while the forged crankshaft is fitted to the aluminum sump engines with both the main bearing braces and the main bearing girdle plate. In European 10.0:1 compression, non-catalytic trim, the FE-DOHC produces 148 ps (108 kW) at 6000 rpm and 133 lb/ft (182 Nm) at 4000 rpm. The 9.2:1 compression, catalytic converter version produces 140 ps. The Japanese domestic market variants produce anywhere between 145 ps and 170 ps, with the late manual 4WD GV Wagon having 165 ps in certain years.
who built Mazdas under licence also fitted the FE-DOHC engine to the Mazda 323 from 1991 to 1994.
Alongside the sedan, hatch and coupe models the FE-DOHC was also being used in the GV wagon, which ran until 1997.
The rest of the world received the FE-DOHC in the 1995–2003 Kia Sportage
, built by Kia under license. Kia first introduced the engine in March 1992, when they installed it in the Kia Concord
, a license built version of the 1982 Mazda Capella
. The Sportage variant was reconfigured for rear-wheel drive configuration with long single-runner intake manifold, low-duration cams and exclusively in the low compression ratio of 9.2:1.
The F8K1 was the intake camshaft for the F8-DOHC, only listed due to family ties.
The combinations available:
system, short for Variable Inertia Control System, a variable intake setup to optimize runner length and resonance at different engine speeds. Much like Toyota's Acoustic Control Induction System
, it had two sets of intake runners, a long set for low-medium RPMs, and a short set for high RPMs. It was operated by a vacuum solenoid based on the engine's current speed, actuating a pair of butterflies inside the manifold to open or close the short runners past 5 400 RPM. This system has been used on many Mazda engines since including the BP. The K-series V6 engines used a different principle to the same effect dubbed VRIS.
Applications
The FE-DOHC was a European and Japanese market engine only (excluding use by Kia), and as such was only ever delivered in vehicles by Mazda to countries in those markets, with the exception of New Zealand who also received European market models. The engine was first fitted to the GD model 1988-1992 626 GT, 1987-1991 Capella and the 626 Coupe GT 2.0i/Capella C2 GT-X and GT-R. In South Africa, SamcorSamcor
The South African Motor Corporation, known more commonly as Samcor, was a South African car manufacturer created in 1985 through the merger of Ford's South African subsidiary and Anglo-American Motor Corporation, which produced Mazdas for the local market...
who built Mazdas under licence also fitted the FE-DOHC engine to the Mazda 323 from 1991 to 1994.
Alongside the sedan, hatch and coupe models the FE-DOHC was also being used in the GV wagon, which ran until 1997.
The rest of the world received the FE-DOHC in the 1995–2003 Kia Sportage
Kia Sportage
The Kia Sportage is a compact crossover SUV built by the Korean automaker Kia Motors since July 1993.- First generation :...
, built by Kia under license. Kia first introduced the engine in March 1992, when they installed it in the Kia Concord
Kia Concord
The Kia Concord is a four-door sedan produced by South Korea's Kia Motors from 1987. Its two foremost competitors were the Daewoo Royale and Hyundai Sonata. All versions used Mazda four cylinder engines. The Capital/Concord lineup underwent a series of facelifts, eventually becoming the "New...
, a license built version of the 1982 Mazda Capella
Mazda Capella
The second generation rear-wheel drive Capella was available between 1978 and 1982, in both sedan and coupe forms. It was known on export markets as the Mazda 626, with the exception of the United Kingdom, where it was called the Mazda Montrose, the name was changed to honour the local Mazda...
. The Sportage variant was reconfigured for rear-wheel drive configuration with long single-runner intake manifold, low-duration cams and exclusively in the low compression ratio of 9.2:1.
Head and valvetrain
The Mazda FE-DOHC uses a wide-angle, DOHC, belt-driven valvetrain configuration with flat-tappet 33 mm HLA bucket lifters. It is a non-interference design. There are two valve springs per valve and four valves per cylinder. While a dual valve spring configuration is used, the stock springs are fairly low-sprung. Low spring rates were chosen for increased valvetrain longevity and low friction with the dual valve springs for the reduction of harmonics and increased valve stability. It is advised to increase the spring rate for turbo and high-RPM applications.Camshafts
The Mazda FE-DOHC came with several different camshaft profiles from the factory. As such there were several camshaft combinations available.| Camshaft | Lift (mm) | Duration (deg) |
|---|---|---|
| FE5A | 8.855 | 245° |
| FE3N | 8.852 | 240° |
| FEAP | 8.650 | ? |
| KO13 | ? | ? |
| F8K1 | 6.800 | ? |
The F8K1 was the intake camshaft for the F8-DOHC, only listed due to family ties.
The combinations available:
| Intake | Exhaust |
|---|---|
| FE5A | FE5A |
| FE3N | FE3N |
| FEAP | FE3N |
| FE3N | KO13 |
| F8K1 | FE3N |
VICS
The FE-DOHC featured Mazda's VICSVICS
VICS or Vics may stand for:* Variable Inertia Charging System, a variant of variable length intake manifold* Vehicle Information and Communication System* Northwich Victoria F.C., nicknamed "The Vics"...
system, short for Variable Inertia Control System, a variable intake setup to optimize runner length and resonance at different engine speeds. Much like Toyota's Acoustic Control Induction System
Acoustic Control Induction System
Acoustic Control Induction System, or ACIS, is an implementation of a Variable Length Intake Manifold system designed by Toyota.Simply put, the ACIS system uses a single intake air control valve located in the intake to vary the length of the intake tract in order to optimize power and torque, as...
, it had two sets of intake runners, a long set for low-medium RPMs, and a short set for high RPMs. It was operated by a vacuum solenoid based on the engine's current speed, actuating a pair of butterflies inside the manifold to open or close the short runners past 5 400 RPM. This system has been used on many Mazda engines since including the BP. The K-series V6 engines used a different principle to the same effect dubbed VRIS.