I purchased a ’99 Trans Am with the optional WS6 package a few years back. It remained bone stock and completely original until about a week ago. Its LS1 ran well in stock form, but I’m always looking for stealthy ways to increase performance.
The SLP Blackwing air lid fits great, is highly durable, and promotes a stock under hood appearance. It rivals the performance of even the best aftermarket air lids.
Installing an LS6 intake manifold is a popular performance modification on ’97-00 LS1s, and I found an SLP-modified LS6 intake that allowed me to retain my ’99 Trans Am’s factory EGR plumbing while boosting output. Looking to measure its effect and have the computer tuned for maximum performance in process, I scheduled two dyno sessions at H.S. Motorsports in Omaha, Nebraska--one for base-lining and other for post-manifold-install pulls.
Another popular modification with F-car owners is the installation of an aftermarket air lid. The air lid takes the airflow passing through the rectangular air filter and directs it toward the MAF sensor and ultimately into the intake manifold. The factory air lid assembly on ’98-02 Firebirds and Camaros is equipped with a series of molded-in ribs and a large canceling chamber that serves reduce intake noise to comply with drive-by standards.
The stock LS1 air lid assembly includes molded ribbing and large noise canceling chambers for drive-by noise compliance. Aftermarket lids feature neither.
Almost immediately after the LS1-powered F-body was introduced, aftermarket companies began producing their own formed-plastic air lid assemblies, which contained no noise baffling and provided airflow with a straighter path into the MAF sensor. Reports of approximately 10 hp and/or quarter mile performance improvements of .1 and 1 mph were commonplace. My own experience with them mirrors that. Fitment of the aftermarket air lids can leave much to be desired, however.
The 5.7L LS1 V8 in my '99 Trans Am was completely stock and included its original air lid. I replaced the its original LS1 intake manifold with an LS6 unit to increase performance and measured the gains on a chassis dyno. That presented the perfect opportunity to dyno test the SLP Blackwing air lid.
To increase the potency of its 2002 Firehawk and Z28 SS, which were rated at 335 hp, SLP Performance Parts entered a joint venture with Donaldson Filtration Solutions to create the Blackwing air lid. Unlike common aftermarket air lids constructed of molded hard plastic, the SLP Blackwing lid was constructed of the same OE-quality material as the stock LS1 air lid and fit equally as well. As a “factory-installed” piece, it increased the LS1’s horsepower rating to 345 hp when combined with SLP’s high-flow exhaust system.
Being a sucker for factory high-performance components, I purchased an SLP Blackwing air on eBay for $250. It was used but in excellent condition and included the rare-but-necessary A.I.R. pump extension hose with rubber grommet and metal bracket that was specific to it. I was elated that I had a complete assembly, which not only allowed for installation just as SLP intended, I knew it would increase the marketability of my unit should I decide to sell it down the road. With the dyno test of my ’99 Trans Am planned, I wanted to use that opportunity to measure the effects that the Blackwing lid had on full-throttle performance on an otherwise stock LS1.
SLP developed the high-performance Blackwing air lid for the 2002 Firehawk and Camaro Z28 SS. It boasts aftermarket-lid-level power increases while fitting like the stock unit. The Blackwing air lid remains quite desirable.
The A.I.R. pump injects fresh air into the exhaust manifolds to promote a cleaner and more complete consumption of the unburned fuel in the exhaust stream at cold startup. Through 1999, the LS1’s air pump pulled ambient air from the wheel well. Beginning in 2000, GM added a secondary breather tube to the factory air lid to provide filtered air to the A.I.R. pump. That necessitated another port on the air lid box. When SLP codeveloped its Blackwing air lid for the 2002 F-car, it included a port (or hole) in the driver's side of the lid body to accommodate the A.I.R. pump hose.
Aftermarket air lids are void of the ribs and provide a smooth transition into the MAF sensor to promote maximum performance. The SLP Blackwing is an excellent piece all around.
While installation of the SLP Blackwing lid onto all ’00-02 Firebirds and Camaros is quite simple, the A.I.R. port must be plugged for use on ’98-99 F-cars. That meant I had to devise an easy and effective solution to seal the A.I.R. port on my Blackwing lid airtight for my dyno project. Since it was considered an aftermarket component, there was little chance of finding the exact grommet at my local GM dealer. I measured the original grommet and set out to find a generic plug that contained the same OD measurement of 0.9375-inch (or 15/16-inch).
Those efforts proved futile but a helpful counter worker at my local O’Reilly Auto Parts store pulled a wide array of Dorman PCV grommets they had in stock. After looking through a couple dozen samples, we finally found a grommet that fit perfectly—Dorman 42055—which retailed for $6. It contained an OD or 0.9375-inch and an ID of 0.75-inch. What’s its original application you might ask? You’ll likely be as surprised as I to learn that Dorman 42055 is its replacement for the valve cover breather tube grommet on our beloved Pontiac V8!
If you're installing an SLP Blackwing air lid on your '98-99 Firebird and need to plug the A.I.R port (or you're eliminating the A.I.R. setup from your '00-02 F-car), all you need Dorman number-42055 grommet and a typical black plastic plug measuring .75-inch diameter to seal it. It looks like it belongs there!
Once back home, I lightly lubricated the rubber grommet and easily slipped it into the A.I.R. port in the Blackwing lid. I then plugged the grommet using a black plastic hole plug in .75-inch. I found one produced by Hillman (number 881287) at my local Lowes store (Lowes item number 139472) for less than $1.50 for a two-pack. Together, the components provided an airtight seal and looked as if they were designed for that very purpose. And best of all it cost less than $8 to accomplish it.
If you're concerned with any unfiltered air slipping past the black plastic plug, a thin coat of black silicone sealer will eliminate any possible trace, no matter how minute.
If you own a SLP Blackwing air lid and intend to run it on your ’98-99 Firebird, or plan remove the A.I.R. pump from your ’00-02 F-car and need to plug the A.I.R. port in your Blackwing lid, look no further than Dorman number-42055 grommet and a .75-inch black plastic hole plug. It’s all you need!
P.S. If you are interested in the results of the LS1-to-LS6 intake manifold swap, and how the Blackwing affected performance, the details can be found on Car Craft's website.