Bored Performance By David Gunsul

An engine is basically a large air pump; the more air you can get in and out, the more horsepower you will make. A good way to get more air into you engine is to bore out your throttle body. With the help of Paul Vargyas, I was able to find someone that bores out Fiero throttle bodies named Darrell Morse. Darrell can be reached at: 21411 Concord Street NW, Elk River, MN 55330, 763-441-5679, email: For just $150, Darrell not only bores out your throttle body, but even takes care of any broken bolts or screws that may have become a permanent part of your throttle body or intake plenum. The same cost also covers the return shipping as well.

It takes about two weeks to get your parts back from Darrell. To avoid downtime on my Fiero, I purchased a used throttle body and upper plenum from Paul Vargyas (this means I now have an extra intake plenum and throttle body if you are interested in purchasing them). When you get your parts back, you will notice that Darrell’s machine work is absolutely top notch. Although Darrell only bores the parts 4 millimeters over, the size difference is immediately noticeable.  Darrell also sends you a larger throttle body gasket as part of his service. You will not receive the plenum gaskets, however. If your old plenum gaskets are in good shape, you can reuse them. If they are not, I would suggest you buy a new set at the local auto parts store.

While your parts are still off the car, be sure to clean out your intake plenum to be certain there is nothing in there that can fall into your engine. This is also a good time to repaint your plenum or do any other cleaning or prepping you might want to do. In my case, I had the plenum “Jet-Hot Coated” and then I hand polished my new throttle body (hand polishing the throttle body was A LOT of work!).

If you did not think the price was a bargain for the money, just wait until you bolt on your parts. We are not talking about a supercharger or an oversize cam here, but the throttle response was notably improved. Ahhh, happiness is a Fiero with more horsepower! Horsepower gains will vary depending on the condition of your engine and other modifications you have already done to it.

I highly recommend this modification. It not only provided a nice power increase, but it also looks good too. If you have any questions you can reach me at my pager at 630-374-0479, I will be happy to help another Fiero owner gain some more horses!