Quad-4 Fiero Conversion

The Quad-4 is a double overhead cam, sixteen valve four cylinder designed by Oldsmobile. Released to the driving public in the 1987 model year, the Quad-4 has been in cars such as the Olds Cutlass Ciera, 442, and Achieva, the Pontiac Grand Am and Sunfire, the Chevrolet Beretta and some other cars that I can't think of at the moment. The Quad-4 has come in several "versions" ranging from 120 horsepower to an awesome 190 horspower! Some of the differences between the Quad-4 versions include intake and exhaust manifolds, high compression pistons, cam shafts, valves, and a different PROM. Recently, the 2.3 liter Quad-4 has had some minor changes inlcuding an enlarged displacement to 2.4 liters and renamed the "Twin Cam."

Most people, including me, would suggest at least a 1990 Quad-4 and if it isn't the highly acclaimed High Output version, rebuild it to those specs. Some things you will need from the donor car: the engine, the computer, the wire harness, the transaxle, the motor mounts and brackets, the accessories (A/C, alternator, etc.), and, depending on your kit, some other stuff.

My Quad-4 is the HO version from a 1990 Beretta GTZ and is only slightly faster than an Iron Duke until you hit 3000 rpm, where the real fun begins! Due to this particular power curve, the Quad-4 doesn't perform well at all with an automatic transaxle, in my opinion.

Some things that you will be faced with in putting a Quad-4 in a Fiero is rerouting the coolant lines, rerouting the A/C lines, replacing the fuel pump with one from a V-6 Fiero, redoing the air cleaner and its plumbing, an entirely new exhaust system, and the biggy: the electrical rewiring.

After you finish your Quad-4 kit, you can expect to get 24 mpg with REALLY heavy-footed city driving, and around 38 mpg on the highway. Expect another 15 to 20 horsepower out of your Quad-4 over the donor car's numbers if you have a free-flowing intake and exhaust systems, removal of power steering pump, and other little things like good spark plugs.

The following specs are estimates based on my setup:
Displacement 2260cc
Location Mid-engine
Aspiration Normal
Horsepower 200 bhp @ 6200 rpm
Torque 165 lb-ft @ 5200 rpm
Compression 10.0:1
Redline 6750 rpm
Transaxle 5-speed (3.50, 2.19, 1.38, 1.03, 0.81 -- 3.61)
Test Weight 2900 lb
F/R Weight 44%/56%
Tires 205/60-15
Drag 0.36
The following was obtained from a Car Acceleration Simulator with the above information:
0-30 mph 2.3 sec
0-40 3.8
0-50 5.2
0-60 6.5
0-70 9.4
0-80 11.9
0-90 14.5
0-100 17.6
1/4 mile 15.3 sec @ 93.0 mph
Top Speed 138 mph
Actual times will vary depending on test conditions and I have left many cars in the dust that boast better numbers than those.
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