🔧 BUILD Quest for improved 4th gen Fbody drivability

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I wanted to update this thread (June 2023) with a more detailed summary of the 14-year journey with my 1998 Trans Am. In my day job, I'm an automotive journalist, so I drive a lot of performance cars, and every winter when the TA is under the cover I’m tempted to buy something new after driving the latest and greatest all year, but then every spring I get back behind the wheel and regain enthusiasm to keep at it. My goal over the last couple of years was to give it as much updating as possible to build a well-rounded late-model muscle car that blurs the line between muscle car and sports car, just how the new Camaro and Mustang have evolved over the years. And to get there, I had to correct a lot of self-inflicted mistakes that ruined the car’s drivability without much gain. This is quite the write-up for an only mildly interesting car, but verboseness comes with the territory, so here we go:

I bought the car from my cousin’s husband in 2009 for $4,000 with 100,000 miles. Their priorities shifted and the car was in need a lot of maintenance; it ran poorly, had dry-rotted tires and was in barn storage so it came with a family of mice for no extra charge.

What I bought was a stock 98 Trans Am with 16-inch wheels, sleek beak hood and SLP loudmouth exhaust. I immediately added drag radials, addressed the maintenance items and went to the drag strip, hoping for high 12s, low 13s because that was my expectation after being on LS1Tech for 5 minutes. HA. Well, the fastest F-Bodies run those times in later build years with 3.23/3.42 gears, LS6 intakes and factory production tweaks to the cam/heads. In stock configuration with loudmouth exhaust, my 98 with 2.73 gears, LS1 intake and 853 heads ran anywhere between 13.6 and 14.0 seconds, which was slower than my (at-the-time) daily driver mildly modded Grand Prix GTP.

From there, I added a Yank SS3600 torque converter and rear tubular lower control arms, which knocked 8/10ths of a second off the quarter-mile time to run consistent 12.8s; sub-frame connectors also went on at this time and really helped clean up the rattles and looseness of how the car flexed over bumps.

And then I ruined the car for a few years with poor choices.

I put a lot of trust into a performance shop that picked an inappropriate cam and didn’t put the effort into tuning. The car wouldn’t start when hot, it inconsistently idled and the torque converter tuning would make the car lug and vibrate. It was really a couple of miserable years with a loud, annoying and slow car. The cam was 231/235 .617/.621 113+3 with stock heads and a really mismatched powerband for an auto car with 2.73 gears. The car also had an LS6 intake, 42-pound injectors, 1 3/4 headers, off-road Y-pipe and Magnaflow exhaust. From there, I found a new tuner who fixed all the drivability issues so it drove much nicer, and then added 3.73 gears.

I had it dyno’d a few times in this configuration. The initial shop’s dyno spit out 401 rwhp. On a Dynojet at Dean's Performance with the revised tune, numbers were 370/345 in third gear with the converter unlocked. And then I had it dyno tuned from Speed Inc where it made 380 rwhp and 355 rwtq on their Dynojet. But it I was still disappointed at the track, running a best 12.0 at 113 mph. Looking back, that initial shop’s first dyno was laughable considering the trap speed and how poorly the car drove.

During this time, I also played a lot with the exhaust, finally settling on a Kooks catted Y with true merge, versus the ugly T-merges from previous designs that created that awful hammering sound at part-throttle.

And then I decided to take a big swing at the car. Up to this point, I had been running QA1 shocks at the back with drag radials, while up front was stock shocks/springs and summer tires. I hated how the car drove with a clear imbalance between the front end’s tightness and rear end’s looseness. I also had a drag-oriented short torque arm. So off all that went and in come the final suspension setup: Koni shocks, Strano springs, Strano sway bars, UMI long torque arm, double-adjustable lower control arms, adjustable panhard bar and a few other things. Holy smokes. Besides the converter, it was probably one of the biggest changes to how the car drives. Tight, controlled, responsive. It was like driving a car 20 years newer, instead of a bucket of bolts like how it drove with the old suspension.

Under the hood, I had Pat G from LS1Tech spec out a combo that would give stock-like drivability but with 11-second potential. It consisted of a pair of 799 heads (Z06-equivalent) pulled from a junkyard, which I had cleaned up and checked out, and an EPS cam with the following specs: 222/226 .626”/.626” 115 LSA +3, as well as a refresh of the valve train with trunion upgrade on stock rockers instead of something fancy the other shop installed. With this milder cam and upgraded heads with more compression, the car saw a giant torque increase under the curve, and power was much more usable and better matched to the auto trans. Now, I was making 390/375 to the wheels on Speed Inc’s dyno, but with a lot more power and torque under the curve and stock-like drivability.

That resulted in 11.82 @ 115 mph, and it has trapped as high as 117 mph. I consider this very impressive because it drives like it did when stock and power is accessible all over the place. Since then, I’ve installed a chrs1313 A/C ram air and have a dedicated set of C5 17-inch wheels with Hoosier drag radials to try and hit 11.50s, but my last time to the track with the setup was a bust because (as I discovered afterward) the throttle blade wasn’t going WOT thanks to the throttle cable adjustment being unclipped.

I still enjoy driving the car. I debate what to do with it (sell or keep) because I also feel a sense of stewardship to keep this car on the road looking and driving as good as I can make it. All the kids in the neighborhood turn around and give it a thumbs up when I drive past, and my kids (2 and 5 years old) call it “Dad’s Trans Am.” They pretend work on their cozy coupe (like dad’s car). I know it’s superficial, but I don’t think I’d get that kind of engagement in a CTS-V or newer car. Or maybe I would, because they could actually ride in a car that properly fit child safety seats … the debate continues.

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Shawn1112

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And while I was at it, I figured let’s throw in a sub and let the front components take a break. I’ve had this cubby-enclosure subwoofer hanging around for over 10 years after buying it in camaro greasy greasy was parting out. I bought an amplifier from Goodwill for $40 that will be here soon and we will see how this goes.

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Whats your plan of attack for RCA signal on that amp? I'm assuming your still running the stock head unit, if not then disregard
 

Bru

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Whats your plan of attack for RCA signal on that amp? I'm assuming your still running the stock head unit, if not then disregard
I have a Pioneer head unit. This guy:

 
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Bru

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Nice to see the ole Bird getting some love
I often find myself browsing marketplaces looking for a project car. Then I was like, dumbass, you have one. I reached a point where anything to make it faster would be expensive and more work than I want to do, so these have been fun projects to enhance the usability and appearance of the car and make it overall more pleasant to drive.
 

The Beast

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I often find myself browsing marketplaces looking for a project car. Then I was like, dumbass, you have one. I reached a point where anything to make it faster would be expensive and more work than I want to do, so these have been fun projects to enhance the usability and appearance of the car and make it overall more pleasant to drive.

Yep, I too browse marketplace for f bodies.
I would love to own a classic but I can only drive 1 vehicle at a time.
After the T56 debacle, I gave the car some much needed attention in 2021.
 
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The Beast

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On the sound system side, I’ve been diagnosing distortion even with the aftermarket head unit and decent replacement speaker package (Kee Audio Level 2) all around. I took out all the speakers and double checked the wiring, and saw that one of the tweeters fell out of the front speakers. I don’t think this was my source of distortion, but I then recognized how awfully insulated the door panels and sail panels are. Which means there is no insulation. So I bought a cheap-o dynamat material from Amazon, covered the whole inside of the door panel, sail panel and it made a massive difference. I don’t have to play the music as loudly anymore and it’s has much more clarity and bass response. It sounds like a real car stereo now.

KILMAT 80 mil 36 sqft Car Sound Deadening Mat, Butyl Automotive Sound Deadener, Audio Noise Insulation and dampening https://a.co/d/7S03NDs

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My 02 keeps blowing the speakers by the passenger seats, I like what u did with the sound deadened. I have to swap my speakers out and while I’m at it I’ll do the hatch ones. Wish I could throw the boom box back there but I have a 10-12 cd changer from delco lol
 

The Beast

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I’ve been having fun this year continuing the modernization of the old heap. Two areas of focus are improving the lighting and sound system. For lighting, I’m going LED for marker lights and fog lights, including new Morimoto LED projector fogs. And I have a new set of replacement, updated headlight housings for the brights and lows; I plan to explore LED headlights once I can take some measurements.

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I changed all the exterior marker lights (turn signal, corner marker, brakes, daytime running lights) to LED, which required more care in picking parts than I imagined. I found a brand with similar physical size to the original equipment as well as a top lens for projection, matched the bulb color with the lens color and then had to get third brake light LED bulbs with resistors so the cruise control works. Also, replaced the hazard and turn signal flashers with no load LED flashers so those still work.

Brand is iBrightstar on Amazon https://www.amazon.com/s?k=iBrightstar&ref=bl_dp_s_mw_0

Overall, it was a massive improvement because the bulbs that were in there were toast. It’s wild how hot the stock incandescent stuff runs, and how nasty the bulbs and sockets were from heat. The new stuff is extremely bright even in daylight, which is what I wanted. View attachment 163551
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Where did u get your headlights from? I did the fog lights last year and that’s all I use to drive now since I haven’t done the headlights.
 

Bru

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Where did u get your headlights from? I did the fog lights last year and that’s all I use to drive now since I haven’t done the headlights.
LMC Truck lights.

IMG_5069.jpeg
 

Bru

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My 02 keeps blowing the speakers by the passenger seats, I like what u did with the sound deadened. I have to swap my speakers out and while I’m at it I’ll do the hatch ones. Wish I could throw the boom box back there but I have a 10-12 cd changer from delco lol
I think what was happening was that the doors and sails are such horrible speaker enclosures that I had to blast them so loud to hear music over the exhaust/road noise that the mid-level speakers I have just couldn’t take it. But now with the deadening, I don’t have to turn the volume up as high. And then with a sub hopefully that takes it down another notch.

I also bought the next-step deadening mat, but am happy with what I have now so might take a breather. It sucked!
 
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Turbocharged400sbc

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I often find myself browsing marketplaces looking for a project car. Then I was like, dumbass, you have one. I reached a point where anything to make it faster would be expensive and more work than I want to do, so these have been fun projects to enhance the usability and appearance of the car and make it overall more pleasant to drive.
 

sktchy

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If anybody wants one of the 12 disc changers I have one with the magazine sitting in a corner collecting dust.

I did two of those 10 inch sub boxes with a cheap 1000 watt amp and my car pounds pretty hard and still has room to stick the t tops in the holders correctly. Had to cut up the plastics and take the spare out of it to fit them right but totally worth it. I started with just the one side and never felt like it was enough for the car.