Upgrades to Improve the Performance of the Pontiac Fiero!

      Many times I get asked, "How can I improve the performance of my Pontiac Fiero without spending a lot of money?" While there are a number of simple and fairly inexpensive ways to improve the engine performance of your Fiero, you are ultimately limited to 190 horsepower with the stock intake plenum. If you want more power than this, then I recommend saving your money for a turbo or engine swap. In any case, there are several cost-effective ways to improve the performance of your Fiero. This list below makes the assumption that your Fiero is already running in good tune and that you have a V6. Unfortunately, while there was significant aftermarket support for the Iron Duke in 1984, (headers, larger throttle bodies, etc), very little of that is attainable today. This list will focus primarily on the V6 Fiero: (NOTE: Some links will direct to a new page)

  - Air Intake: Improving the air intake and filter
  - Throttle Body: Increasing to a larger throttle body
  - Port Matching: Improving the flow of the intake components

  - Ignition Coils: Higher voltage ignition coil (MSD / Accel)
  - Spark Plugs: Installing quality spark plugs
  - Distributor: Installing Upgraded/Revised V6/60 Distributor

  - Rocker Arms: Installing roller tipped rocker arms
  - Underdrive Pullies: Installing accessory underdrive pullies
  - Belt Tension: Improving the factory tension to eliminate slippage

  - Manifolds: Upgrading or improving the stock exhaust manifolds
  - Y-Pipe: Improving the factory Y-Pipe
  - Catalytic Converter: Upgrade or Removal
  - Cat-Back Exhaust: Replacing the factory exhaust system


- Air Intake: Improving the air intake and filter

The factory air intake (drivers side panel) is more than acceptable to provide enough air-flow for an otherwise totally stock Fiero 2.8 V6/60. Several dyno tests have shown no perceivable difference between an aftermarket cold air intake kit, and the stock intake system. However, the stock intake can be further improved slightly by eliminating some of the restrictive baffles through the intake process. Rodney Dickman, an aftermarket parts designer/reseller, has developed a simple replacement air intake kit that allows the replacement of the stock water separator. The images below show the before and after, as well as what is included in the kit. In addition to this kit, it is also recommended

- Throttle Body: Increasing to a larger throttle body

The Fiero's stock throttle body, made by Holley, has an interior throttle body diameter of 54mm. This is more than sufficient for the 2.8, and realistically for anything up to 245 horsepower. In an effort to improve airflow to the throttle body and provide more volume to the engine intake Darrell Morse, a Fiero enthusiast and member of the Minnesota Fieros Club, offered a series of upgrades for the Fiero's V6. The improvements offered was a machine / boring package for the Fiero's stock throttle body. This upgrade increased the size of the stock throttle body by 3mm, to a total of 57mm. Other services offered including matching the new bore of the throttle body to the intake. The original prices from the Fiero Club were as follows:

•Stock # 1517 Complete Refinishing of your unit sent in......$218.90
•Shipping and handling.........................................................$  38.50
•Core charge if you cannot supply a unit..............................$137.50

I opted to have the throttle body bored and port-matched to the intake plenum. The improvement was nominal of course since the engine was still mostly stock at the time, but I did notice a slight improvement in throttle response, though it could be a plecebo effect. At the very least, it should provide more volume to the intake when the engine's camshaft and head porting is able to take more advantage of it. Below is the comparison between the stock and bored size, as well as a picture of what the throttle body looked like when it arrived from Darrell Morse.

- Port Matching: Improving the flow of the intake components

The Fiero's intake is made up primarily of three components: the intake plenum, the intake runners, and the intake manifold. Matching between the plenum and the runners is actually pretty good and all that it really needs is gasket-matching. Gasket-matching is the grinding of material on the intake so that it reaches the limits of the interior area of the exposed intake. This is to ensure optimal flow from one component to the next where it will not be impeded by imperfections. Port-matching on the other hand, is the process of grinding away material from the intake components to ensure proper alignment between the exit and entrance ports. This is where the Fiero picks up some considerable improvement in the mid-to-upper rpm range. The alignment of the ports between the intake runners and the intake manifold are horrendous. The ports on any one side are off by as much as a third of an inch. When you consider that there is misalignment on both sides of the intake, this can result in 1/2 to 3/4ths of an inch restriction between the components.

As shown in the image below, it is necessary to grind away where the ports do not properly meet. Because the Fiero has an exhaust gas recirculation (EGR) system, the parts of the intake exposed to the internal process should be heavily stained. This will work in your favor as it will provide you with the appropriate template for grinding. Make sure that the components you are port-matching came together. Port matching differs from Fiero to Fiero, so it's important to ensure the runners and intake manifold came together at the factory if you intend to use this method. Grind away at the stained areas of the intake ensuring that you do not go beyond the clean metal that was originally protected by the gasket material. You will want to grind away the metal on both sides (intake runners and intake manifold). Use a sanding wheel to smooth out the insides if you have time, this will optimize the effort.


- Ignition Coils: Higher voltage ignition coil (MSD / Accel)

One of the big improvements of the V6 Fiero was the introduction of the computer controlled ignition timing. With this new system came the 30,000 volt high energy ingition coil. Unfortunately, the factory ignition coil is limited in it's ability to properly provide power to the engine at certain higher RPMs. While it's arguably one of the more reliable components on the Fiero, it falls short of being able to provide adequate power to the ignition system above 4,000 rpms. Misfires and a dull spark can lead to fouled plugs and limited performance. Many aftermarket coils are now available from a variety of manufacturers. Most of these coils all provide a significantly higher voltage than the stock coil and are able to keep up with an increased rpm range. Users who switch to these coils have found slightly improved emissions, a smoother idle, and improved performance in the upper rpm range (above 4,000). Here are just a few of the more commonly offered ignition coils for the Fiero, most of them can be purchased either through the Fiero Store or Summit Racing:

- ACCEL High Output SUPER COIL #51063 - 48,000
- MSD Blaster High Output Igntiion Coil #51065 - 45,000
- Summit Racing® High Output Ignition Coils SUM-850012 - 40,000
- PerTronix Flame-Thrower HEI and TFI Ignition Coils D3002 - 50,000
- Mallory High Performance Replacement Coils 29210 - 30,000
- Davis Unified Ignition Screamin' Demon Coil 31723 - 45,000
- Moroso ProCoil F Ignition Coils 72358 - 32,093
- Crane PS91 Performance Ignition Coils 730-0491 - 40,000

- Spark Plugs: Installing quality spark plugs

Although I generally recommend the use of original OEM AC DELCO steel tipped spark plugs, the quality of these plugs has decreased since most manufacturing of these now occurs in China. There are a number of aftemarket spark plugs that can suite your needs depending on what those may be. Generally, steel tipped plugs provide a greater transfer of power (hotter spark) from the ignition to the combustion chamber while platinum tipped spark plugs provide more reliability and are longer lasting but provide less power transfer. What this means is that the platinum plugs fire at a lower voltage which translates into a less intense spark (less efficient). Other spark plugs offer improvements in the spark transfer which include design changes at the tip to ensure a more complete spark. Another improvement that can be made to the performance is increasing the gap of the spark plug to .060 from the stock .045. This can improve low-end torque and engine response at all rpms. In the words of Ray Paulk, "Ideally, you want a spark plug with low conductivity combined with a coil large enough to fire it over a relatively wide gap." Below is a list of plugs available for our engine.

[Platinum] - Greatest life-span / Least spark transfer
[Steel] - Average life-span / High spark transfer
[Copper] - Short life-span / Highest spark transfer

- E3 Spark Plugs E3-40
- Bosch Platinum+4 Spark Plugs 4449
- NGK V-Power Spark Plugs 2771
- ACDelco RAPIDFIRE Performance Platinum Spark Plugs
- ACCEL U-Groove Performance Spark Plugs 0274
- Champion Copper Plus Spark Plugs 18
- Autolite Racing Spark Plugs AR23
- Pilot Automotive Nitrode Spark Plugs SP-NP22C

- Distributor: Installing Upgraded/Revised V6/60 Distributor

There is now a "factory" upgrade available for the Pontiac Fiero V6's ignition. The original Fiero V6 distributor consisted of a stator made up of a series of prongs. Over time, these prongs can bend and / or rust causing a poor connection. There exists a revised distributor which replaces this archaic design with a pointed "cog" wheel, if you will. (Shown in the picture below) The revised distributor design is built off the same distributor stamping so it appears to be 100% identical to the factory distributor when assembled. All existing Fiero electronics can be swapped to the new style distributor. As it stands, most new replacements ordered for the Fiero will be of this design. If you still have an original distributor and are looking for improved performance (engine smoothness / misfire reduction), consider getting a new distributor rather than rebuilding your old one. I would recommend keeping the old distributor for the next owner. You never know when the OEM piece might be valuable.

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