The fiero is a popular car to modify. Many owners and kit car enthusiasts alike would like to have a little more power out of these vehicles. There are fiero performance upgrades out there but when people are not aware of them or want a lot of power they install larger engines. The fiero came with two engines, the 2.5 liter “iron duke” or “tech four” four cylinder engine was the base engine. The performance engine was the 2.8 liter v-6 engine found in the gt cars. The 2.5 liter engine made 105 horsepower and 135 ft/lbs of torque stock. The 2.5 l engine has been used in the nascar touring car series and was known as the “super duty” engine. The 2.5 liter has access to special high port aluminum heads which also needs a special intake manifold and the use of a carburetor instead of the stock throttle body fuel injection. There is also a cosworth produced 16 valve head which could produce a great deal of power. Both of these are costly alternatives and may cause problems if you live in an area where emissions tests need to be taken.
A fuel injected option is through pontiac motorsports. They produce an engine with keith black pistons, chevy LT-I connecting rods and some other fine tuning which will produce 145 horsepower and 250 ft/lbs of torque. This is still a costly option and only produces the power of the stock v-6. There are still options for people wanting a little more power at a reasonable cost. Simple bolt on parts include k&n air filters which let more air in expect a few hp. A free flowing exhaust should have about the same affect with a few hp gain. Larger ratio roller rockers from crane cams should provide a reasonable increase in power. The 1.6 ratio roller rockers act as if it has a larger lift camshaft. The roller rocker tip also slows wear and creates less friction, using less power. A camshaft makes more power but requires a little more work than the rocker arms. A fairly simple bolt is to change your accessory pullies with underdriven pulleys. If your car needs a lot of power for a powerful stereo or another high power need, I wouldn’t suggest it. If not they can sometimes show descent gains in power. An custom exhaust header would be a great upgrade although I’ve yet to see any sold in the aftermarket. Most performance enthusiasts purchase the 2.8l v-6 engine powered gt. The 2.8 liter makes 140 horsepower stock. Most of the v-6 upgrades are focused toward the street performance crowd. Many people change the engine to a 3.1 liter engine, or for a reasonable cost can rebuild the 2.8 liter with a cheap stroker kit making it a 3.1 liter. Roller rockers can be used alone or with a camshaft to make reasonable gains. The 3.1 liter engine with a slightly more aggressive cam and a little added fuel can make 165+ horsepower. Blueprinting a stock 2.8 engine during a rebuild can net a 15 hp gain. A free flowing air filter (k&n) and a better flowing muffler should produce 5 or 6 hp gain. There are a fair amount of cams to select from through crane cams. A high lift cam with not a lot of duration change can produce gains up to 15 hp. The stock exhaust manifolds are a very rough casting. With some work smoothing out the rough spots in the manifold can produce gains up to 8 hp in the higher rpm range. Underdriven pulleys can produce reasonable gains in power, if not a lot of battery power is needed to power special accessories. The intake setup and the ecu chip are supposed to be very good from the factory and aftermarket parts show little gain in power. Some people would rather make their power with a turbocharger. A turbo on a 2.8 or 3.1 can produce results above 200+ horsepower. Extreme turbo systems with a highly built 3.4 liter engine can make upwards of 300 horsepower. All engines can gain a good amount of power with a reputable porting job and a good multi angle valve job. So there is hope for out there for everyone that doesn’t want to swap a larger engine into their fiero.