[Silvey01]

I’ve got an eco mod and a performance mod for people with a Cavalier/Sunfire (J-body). Other people can benefit from this too. The steps will be different, but the benefit will be the same.

I remembered that the J-body has an air box or intake muffler in the driver’s side fender. Eliminating this air box frees up the restrictive catacombs that the incoming air has to go through to enter your engine. I did this mod in under 70 minutes including jacking up the car and with the help of pneumatic tools.

How is this an eco/performance mod? This air box is kind of like you running marathon breathing through a straw. If you get rid of the restriction then your car can breathe better and more efficiently. This translates to you not needing to press the accelerator pedal down more than you need to to get going. Less pedal means less gas injected into the engine saving you fuel. And your engine will thank you for it. Just keep you foot out of the pedal because less restriction means your car will be a lot more rev happy.

All you need for this is a jack and jack stands, ratchet set, screwdriver flathead and phillips, pliers, Optional tools, a sawsall and a long blade (if you don’t have one read the article for alternative), compressor, air ratchet, impact wrench and sockets, hammer and punch

On to the mod!

Jack the car up, place jack stands under the car as required (I put them under the lower control arm). If you don’t know where your car’s jacking points are look in your owner’s manual. Take off the driver’s front wheel. It’s a lot easier that way. In the engine compartment, if you have a strut tower bar go ahead and unbolt the driver’s side of the bar with a 13mm ratchet. There is a fuse box that you’ll need to remove that is right over the filter box. All you need to remove that is pliers. Take out the center plug of the fastener, and then you can pull the rest of the fastener out. The other side is only held in by a tab. Lift the front where the fastener was and pull the fuse box up. You don’t need to disconnect any wires you’re doing this just to have room to pull the filter box up.

Unscrew the 4 bolts of the filter box with a flathead or Phillips screwdriver whatever your preference. Unscrew the band clamp closest to the engine/throttle body. Take the plastic ducting along with the top of the filter box and air filter and set it aside. The only thing holding the bottom of the air filter box on the car is a tab next to the firewall. You just need to bend that tab back a little to get the filter box off. If you can’t bend the tab with your fingers then you’ll need a small pry bar or big flathead screwdriver. Be sure to wrap the pry bar/screwdriver in a paper towel so as to not scratch the paint. After the tab is bent take the bottom of the air filter box out. You’ll see the ducting of the box connects to the air muffler in the fender. You can press out one more fastener. It’s the plastic nipple that holds the air intake of the air muffler to the body of the car. It’s down from the plastic fastener from the fuse box that you took off. If you can’t locate it you can just tug it out when the air muffler is free. If you did find it press it out with a hammer and the proper sized punch.

Get down on a creeper (or the floor), take a 7mm ratchet and unbolt 3 bolts that hold the underside plastic on, then unbolt the 2 bolts in the outside wheel well. There are 2 more bolts on the inside wheel well only loosen those. The plastic of the wheel well will still be attached by 2 plastic fasteners at the top, taking these out is unnecessary (and they usually break just enough so you have to buy more from the dealership $2 or 3 each). The plastic will be pliable enough to do what you need to do.

Unbolt the upper bolt (10mm or 13mm depends which year) with the metal tab on the backside of the air muffler. Discard it/recycle it. You won’t use it again. If you already pressed out the air intake of the air muffler in the engine bay you only have one bolt left, but you have to unbolt the windshield washer fluid reservoir. (Thanks GM engineers for making something easy harder to do!) I didn’t do that… I got out my sawsall, put a long blade in it, and cut the backside of the bottom box of the air muffler half way through. ONLY CUT HALF WAY THROUGH! THERE ARE WIRES ON THE FRONT SIDE! Then cut the front of the bottom box. Once that comes off the air muffler comes right out. Button everything back up, clean up and take a test drive.

If you don’t have a sawsall there are coupons in many magazines and even some Sunday papers for Harbor Freight that have sawsalls for around $20. If you don’t have that coupon then I think regular price is $40. That’s good price for any saw. These are good cheap tools, not bad cheaply made tools. If you don’t have a sawsall or don’t have a Harbor Freight store or the like in your area you’re stuck with draining the washer fluid reservoir, and unbolting it to get to that last bolt.

Since doing this I’ve noticed that I don’t have to rev the engine as much to get started. Even starting in 2nd gear isn’t a chore. The engine revs easier. The car doesn’t hesitate when going around a corner in 3rd gear or going up hill in a numerically higher gear. My car is happy and I’m happy because it’s easier to drive.

As soon as the test drive was over I filled up and it’s time to do a mileage test.