F for Fast: Maximizing the GM F-Body


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Big wheels, big power, big thrills: Rear-drive, V8-powered domestics have become huge at today’s autocross events, and they’re welcomed by many different programs, including the Optima Invitational, Good Guys and SCCA CAM classes.

The rules place few restrictions on car type or prep, so the fields vary from one extreme to another: old-school rods and vintage muscle cars to the greatest hits of the ’80s and today’s latest pony cars.

A lot of these vehicles take more than a few bucks to build, prep and run, though. And then there’s the reality that most older cars were just not designed to accept today’s 11-inch-wide wheels.

One chassis seems to drive up the middle. It’s common, quick, inexpensive and served by a huge aftermarket. Yep, we’re talking about GM’s fourth-generation F-body platform, basis for the 1993–2002 Chevy Camaro Z28 and Pontiac Trans-Am.

At the time of their debut, the specs for these cars were quite impressive: 275 horsepower out of a Corvette-style LT1 fuel-injected V8 and the availability of a six-speed manual transmission. Automotive publications, as well as the enthusiast market, were driven into frenzies.

A new Camry might make more than 300 horsepower, but back then 275 out of a production V8 in a relatively affordable car was a big deal. Even the crew from Ford didn’t achieve that kind of power until a few years later.

Weekend track warriors and showroom stock racers were happy to find the fabled 1LE option still listed on the Camaro and Trans Am order sheets. For these cars, this mainly consisted of a suspension package offering heavy-duty springs, specially valved dampers, and thicker anti-roll bars. Cars so optioned were also devoid of creature comforts like leather, air conditioning and T-tops.

The fourth-generation F-body evolved a bit over its production cycle, with the now legendary LS1 arriving for the 1998 model year. Depending on the flavor of F-body ordered, output ranged from 305 to 325 horsepower–again, strong numbers for the day–and the LS1 could be paired with the excellent T56 six-speed manual.

Today there are many different ways to prep one of these F-body cars for autocross. Two great examples are Tony Povletich’s 1994 Camaro Z28 1LE and John and Rhonda Fehring’s 2000 Firebird Trans Am. Both regularly run with the SCCA in the CAM-C class.

Cool Camaro

Tony Povletich’s Camaro is exceedingly rare. It’s one of only 135 1LE-equipped cars built for the 1994 model year, and has a scant 26,000 miles on the odometer. Even more rare: His car was used from day one as a racer. In a time when limited production performance cars are often viewed as garage queens or collection centerpieces, here’s one that has been regularly flogged around the track. The prior owners of this car, Brian and Bea Reggaine, campaigned it to a national championship for Bea at the 2010 SCCA Solo Nationals.

Tony has owned more than his share of cool F-body cars over the years, including a 25th Anniversary Trans Am and a number of earlier cars. “This is definitely one of my favorites,” he reports. “The 1994 25th Anniversary TA I had before this one would be a very close second to it.”

While the newer LS engines get most of today’s glory, the slightly older LT1 can still make plenty of power when built properly. Tony’s LT1 has been upgraded to the more powerful LT4 specs by famed racer/builder Danny Popp and now makes 420 horsepower.

The Cherry Bomb muffler found out back was sourced from a Farm and Fleet. “Don’t laugh,” Tony says, “there’s a long story behind that one, but, hey, it works and puts me at the decibel limit for SCCA!”

The brakes came from a C5 Corvette, while a 3.42:1 final drive and six-speed manual box originally fitted to a 1993 Camaro Z28 have been installed. “It will do about 72 mph in second gear before hitting the rev limiter,” he says, “which is perfect for most autocross courses.”

Potent Pontiac

John and Rhonda Fehring’s 2000 Pontiac Firebird Trans Am, on the other hand, is not an ultra-rare 1LE-equipped model. It doesn’t even have the flared nostrils the WS6 Ram Air package would add.

This one started out as a base model, pedestrian Trans Am, but, like Tony’s, it’s been beefed up as well. The Fehrings own a company called Hoosier Performance Engineering. They cater to the track day crowd and offer all sorts of upgrades for late-model GM performance cars like the Corvette as well as the fourth-generation F-body. Their Trans Am serves as a test bed for new products.

Since the Fehrings’ Trans Am is a 2000 model, it came from the factory with the Gen III LSI, but that has since been replaced with a 6.2-liter LS3–proving that not even cars that came with LS engines are immune to LS swaps.

The Trans Am has served as the shop’s own skunkworks test lab for products like their own heavy-duty hubs. These hubs replace the original ball bearings with stronger Timken tapered bearings. The spindle and flange are custom forged units from Strange. “The hub is completely rebuildable, re-packable, and it retains the ABS wheel speed sensor function,” John explains.

The shop also totally re-engineered the suspension, although they followed GM’s lead. “I’m a big believer of separate load paths for shock and spring inputs, like the factory designed,” John explains. “Coil-overs drive all that loading through a single mount, and I feel it negatively impacts vehicle ride quality.”

Actually, the car does have coil-over springs at the rear–kind of. “I could not get the desired rear spring rate high enough and still have a spring that wouldn’t fall out at full droop,” he explains, “so I used a small coil-over spring on the shock and a 5-inch Afco spring on the axle mount. So the car has six springs in it.”

Pick a Platform

In SCCA CAM autocross action, these fourth-generation F-bodies face off against newer machines–cars featuring more technology, more stock power and more advanced suspensions.

Still, the older cars hold their own. At this spring’s SCCA CAM Invitational, J.J. Mallrich had the top-placing fourth-generation F-body after wheeling his 1999 Camaro Z28 to a fifth-place finish–just about a second and a half behind the winner, 2015 Mustang GT driver Dennis Healy.

Now, though, with fourth-generation F-body prices about as low as they can ever possibly go, our two feature cars show the potential for making one of these into a true world-class racing machine.

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Comments
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Will
Will UltraDork
2/6/18 5:47 p.m.

Just my opinion, and I'm not unbiased, but I think the 4th-gen is a good balance compared to other cars it typically competes against. In ESP trim, mine is 3,240 pounds and has 344 RWHP. All other things being equal, anything with more power is probably going to be heavier. Anything lighter is probably going to have less power.

 

Mark_42
Mark_42 New Reader
2/7/18 2:26 p.m.

Just an FYI on a finer point...  It'd be Psalm 100:1 (not Psalms 100:1)
The entire book is a book of Psalms, each chapter being an individual Psalm.

If you substitute the word Song for Psalm, it's easier to see the proper use.

Sorry for being a "Grammar Nazi", but it's something I think is worth knowing.

StuntmanMike
StuntmanMike New Reader
5/7/18 11:08 a.m.

Lets just be honest, the engines were underrated. The LT1 was the same as the Corvette's engine rated at 330 and the LS1 was the same as the 350 rating. I've had my 4th gen SS Camaro for almost 10 years and I love it. Its a great balance of power and cheap parts. I started modding from day one so I've always run in SM for auto which is okay when its other modded street cars but for any class prepped SM car I don't stand a chance. On the track I pass my fair share of new Mustangs and Camaros in my run group as well as Porsches, FRSs, etc, and of course give my fair share of point bys. Either way its no slouch and can keep up with any reasonable modern car. As much as I'd love to get a Corvette, I love the unassuming attitude of a clean 4th gen that I still get compliments on.

MotorsportsGordon
MotorsportsGordon Reader
5/7/18 11:33 a.m.
StuntmanMike said:

Lets just be honest, the engines were underrated. The LT1 was the same as the Corvette's engine rated at 330 and the LS1 was the same as the 350 rating. I've had my 4th gen SS Camaro for almost 10 years and I love it. Its a great balance of power and cheap parts. I started modding from day one so I've always run in SM for auto which is okay when its other modded street cars but for any class prepped SM car I don't stand a chance. On the track I pass my fair share of new Mustangs and Camaros in my run group as well as Porsches, FRSs, etc, and of course give my fair share of point bys. Either way its no slouch and can keep up with any reasonable modern car. As much as I'd love to get a Corvette, I love the unassuming attitude of a clean 4th gen that I still get compliments on.

The lt1 was 300 hp the 330 hp engine was the lt4. Then there was the iron head lt1 that was in the impala ss,roadmaster,fleetwood,and caprice-260hp.

te72
te72 Reader
5/7/18 11:57 p.m.

Had a lot of fun in my 01 SS 6M. The only thing louder than the exhaust (open headers, because youth) was the stereo playing Journey (volume turned up to hear over the exhaust, because blown, quality GM oem speakers, and youth). The only thing louder than the exhaust AND the music? The two idiots driving around in this black beast of a car.

 

Fun times indeed, although I am sure my hearing took a hit because of that car. Worth it, I'd say, for the memories and the stories. Plus, I got the desire to own one out of my system early. Surprisingly capable cars, it really is a shame that the material quality wasn't up to the level of the engineering, these would be $25k cars if the interiors weren't the obvious result of cost cutting...

landstuhltaylor
landstuhltaylor New Reader
5/9/18 7:12 a.m.
Will said:

Just my opinion, and I'm not unbiased, but I think the 4th-gen is a good balance compared to other cars it typically competes against. In ESP trim, mine is 3,240 pounds and has 344 RWHP. All other things being equal, anything with more power is probably going to be heavier. Anything lighter is probably going to have less power.

 

So you're about 100 lbs overweight and 50whp down from where an ESP 4th gen should be. cheeky

Will
Will UltraDork
5/9/18 6:21 p.m.
landstuhltaylor said:
Will said:

Just my opinion, and I'm not unbiased, but I think the 4th-gen is a good balance compared to other cars it typically competes against. In ESP trim, mine is 3,240 pounds and has 344 RWHP. All other things being equal, anything with more power is probably going to be heavier. Anything lighter is probably going to have less power.

 

So you're about 100 lbs overweight and 50whp down from where an ESP 4th gen should be. cheeky

I have a hard time believing you're getting an LS1 with stock displacement, stock heads and stock cam to 394 at the wheels. If you can prove me wrong, I'm happy to follow the recipe.

As for the weight: Sure, I could cut some more weight from the car. It still has AC and the stereo. You want to do a lighter exhaust, 2-piece rotors, etc., the money starts adding up, though.

te72
te72 Reader
5/9/18 10:38 p.m.
Will said:As for the weight: Sure, I could cut some more weight from the car. It still has AC and the stereo. You want to do a lighter exhaust, 2-piece rotors, etc., the money starts adding up, though.

Not familiar with class rules here, but it would be pretty quick to drop 100 lbs, at a reasonable cost, if you were to replace just the battery with a litium, or even something like an Oddysey, as well as a change in wheels. Again, not familiar with class rules in this case. Replacing the hood and perhaps the hatch glass with lighter materials would give some good returns I suspect, they are both quite large.

kb58
kb58 SuperDork
5/9/18 11:10 p.m.

Meh, I had one of these from new. Engine was awesome, gearbox was awesome, suspension was great...

... and it was the most unreliable car I've ever owned. Thankfully the warrantee took most of the hit, at somewhere around $6000 worth of trouble in the first several years. Also, it was a heavy beast; one afternoon autocross practice cost me $500 in tire wear just for that single event. No thanks.

Will
Will UltraDork
5/10/18 5:55 a.m.

In reply to te72 :

I already have a sub-2 pound battery and CCW wheels. Hood/hatch must remain stock.

pushrod36
pushrod36 Reader
5/10/18 7:02 a.m.

I owned a 2001 Trans-Am about about a year ago.  It was the car I lusted after in high school.  Besides going fast, making beautiful noises, and looking good parked in my driveway it may be the worst car I ever owned.  The doors were a mile long, but ingress/egress was marginal.  The interiors are kind of crummy.  I couldn't fit a helmet in the car (I'm 5'10") without removing the t-top interior cover panel.  I couldn't fit my daughter's child seat behind me.  There was almost no usable trunk space, and if the tops were stowed there really was no trunk space.

For me it was a validation of the phrase "never meet your heroes."

te72
te72 Reader
5/10/18 10:22 p.m.

In reply to kb58 :

Heh, I picked one up that was pretty well used, about 110k on it if I recall. Quite clean though, looked to be a one owner, well cared for car, at first inspection we thought a grandma must have owned it... until driving down the road one day, hit a slight bump in the road and the music followed suit with a rather startling BOOM from the 10" JL that was in a very well integrated box that I discovered was there. Turns out "grandma" must have really liked her music haha.

 

I think I drove mine for about 6 months in my time in Arizona, had a lot of fun with it, was the most powerful car I'd ever driven up to that point. Also in that time, fried the differential, the alternator crapped out on me, and the power steering never was quite right. Was a tad problematic, and that's just what I remember of it.

te72
te72 Reader
5/10/18 10:28 p.m.
Will said:

In reply to te72 :

I already have a sub-2 pound battery and CCW wheels. Hood/hatch must remain stock.

Well suggestions at this point can get a bit more expensive and / or less comfortable for a street car... I'm sure you've considered replacing the seat and removing the passenger seat? I don't recall the rear seats being heavy enough to even worry about, plus it's more weight over the rear axle, so I'd leave them anyway.

 

Second suggestion is one that I did on my Supra. Replaced the stock two piece steel shaft, with the often-failed center carrier bearing, with a single piece carbon shaft. Carbon weighed 11.8 lbs, compared to stock at somewhere around 30, 35 lbs? It was a substantial weight loss for relatively reasonable cost. Plus, less rotating weight, always good! =)

 

Then again, if you're in a competitive class, there's probably a formula for this chassis and not much point in trying to get too creative, right?

te72
te72 Reader
5/10/18 10:33 p.m.
pushrod36 said:

I owned a 2001 Trans-Am about about a year ago.  It was the car I lusted after in high school.  Besides going fast, making beautiful noises, and looking good parked in my driveway it may be the worst car I ever owned.  The doors were a mile long, but ingress/egress was marginal.  The interiors are kind of crummy.  I couldn't fit a helmet in the car (I'm 5'10") without removing the t-top interior cover panel.  I couldn't fit my daughter's child seat behind me.  There was almost no usable trunk space, and if the tops were stowed there really was no trunk space.

For me it was a validation of the phrase "never meet your heroes."

This sums up my experience pretty well too. High school dream, they were the fast new car then. They really should have put the gas filler door on the passenger side, can't tell you how many times I had to either find an outside lane to fill up at, or just take up more room between pumps... or just climb out the often open t-top haha. Didn't wanna bang up the doors man...

 

Interiors definitely not up to the level of the rest of the car. Never tried the helmet thing back then. No kids, but I did stuff a few passengers in it, it was alright for shorter drives? Trunk, I have to disagree with you on, I found it to be cavernous, but I had just come from owning an NA and then an NB Miata, so take that for what it's worth.

 

Definitely one of those "hero" cars, unfortunately.

81cpcamaro
81cpcamaro Dork
5/10/18 11:02 p.m.

I have more helmet room in my 1999 Camaro (T-tops) than I did with the 2012 Camaro SS (no sunroof). Slightly better helmet room than the 2nd gen CP car I had as well.

4th gens do have good potential and there is plenty of ways to improve them. Since a lot of people have modded them, no guessing on what works.

Will
Will UltraDork
5/11/18 6:01 a.m.

In reply to te72 :

I've got a Sparco driver seat, Kirkey passenger seat, and Racecraft seat mounts. The rear seats and driveshaft can't be altered.

I've also replaced steel coil brackets and oil pan baffle with aluminum, lightweight crank pulley, etc.

As I said, there's weight to be found, but overall, this is a well-prepared car for the class.

I still want to know how to get 400 to the wheels from an ESP-legal LS1.

Furious_E
Furious_E SuperDork
5/11/18 7:49 a.m.

Driveshaft is aluminum on all the LS powered 4th gens anyways, so it's already pretty light. 

I autocrossed and DDed my 98 for around 2.5 years and while it certainly had its shortcomings, they're really hard to beat on a performance per dollar basis. I too thought the trunk was pretty huge and helmet clearance was never an issue since I always ran with the T tops off. Actually, the Camaro was by far the most accommodating sporty car I've had (I'm 6'3".) 

te72
te72 Reader
5/11/18 10:45 p.m.

In reply to Will :

I'm guessing any other ideas I might have are probably either addressed in your case, or illegal for the class... Building my Supra to just have fun on track, class or rulebook be damned, so my ideas for modifications might not work in most classes, for better or worse. Better, because they would likely cause a bit of an arms race, or worse because they sometimes work out REALLY well but fall into that "that will never work" category that discourages innovation...

 

As for getting 400whp out of an ESP LS1, could it be that some cars are dyno'd closer to sea level than you are? Where I live, it's 6500' elevation. That same 400whp at sea level is only about 320whp here. Is ESP one of those classes where internal mods are illegal? If not, lighter components, porting can go a long way... If you're not limited on fuel systems or ecu tuning, running a car on ethanol could easily net 400whp on an LS1. Longer intake runners, ceramic coated manifolds and other creative heat management methods, oil selection... all small gains, but adds up!

 

If nothing else, some of those higher powered cars might be just living on borrowed time too. I've played with a few cars over the years that were stupid fast, but I knew I'd outrun them as soon as they blew up...

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