High-Value Proposition

In which we learn that building and racing a competitive autocross Corvette needn’t cost a fortune

Photo: High-Value Proposition 1
March 24, 2022

“Always racin’” is a handle that Scott Fraser applies to himself on occasion, and with good cause. That’s because he runs his 1989 C4 in just about every autocross event possible. And with great results, as he’s either won First Place or achieved a podium finish in a whole slew of events throughout the Southwest. What’s the secret of his success?

Well, to start with, his DNA runs deep in Corvettes, having previously owned an ’87 Z51. And his family are enthusiasts as well. “My parents had a bunch of 1963-1967 Corvettes in the ’70s,” he shares. “They would buy and sell them.”

As for the C4 shown here, there’s a thorny history to go with it, along with lots of make-it-work improvisations. “I bought and built the car specifically to autocross,” Fraser says. “I knew the 1989 models had the ZF six-speed transmission, an updated front suspension with zero scrub, and they were lighter-weight cars [compared with later versions of the C4]. Plus, I liked the looks of the earlier C4.” Why the preference for the ZF six-speed? On the ’87 model Fraser owned previously, he didn’t care for the overdrive button.

Fraser’s ’89 is far from stock, as he’s added a number of upgrades, some of them involving the hands-on “engine-uity” he developed as a mechanic for an Audi dealership, and also as a race driver in many types of high-performance cars. These included a Mazda Miata, a Porsche GT3, a Datsun 240, several BMWs, and an original ’66 Shelby Cobra (chassis number CSX3170) with an aluminum, 440-ci mill cranking out 820 hp at 8,200 rpm. But even with all of Fraser’s expertise, he’s modest about his competition accomplishments. “I have had some luck during the years,” he allows.

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There’s clearly more than luck at play here, as Fraser has a laundry list of autocrossing accolades to his name, including numerous SCCA championships and three Good Guys Autocrosser of the Year titles. An impressive background, to be sure, but what led him to running a C4 in autocross competition?

“In late 2017 [it emerged] that 1987-and-later cars would be allowed to run Good Guys events,” Fraser explains. “This reminded me of when I first started autocrossing nationally and how quick the C4s were. I looked over the specs and quickly realized this would be a good out-of-the-box car to run and modify.”

From the start, he was looking for an ’89 Z51 car. “I found one in Texas for $7,500 with an older Paxton supercharger. I knew I was going to do the LS swap, but figured it would make sense to get a clean car that was taken care of, and I could sell the supercharger to recoup a good part of my money.” A good plan in theory, but in practice it turned out otherwise.

Fraser leaned on a good friend, former autocross-car co-owner/-driver Tom Kubo, to fly out and drive the Corvette back to Norcal. When Kubo arrived in Dallas, he found that the owner had trailered the car a few hours to meet him, rather than driving it. Still, after giving the C4 a once-over, Kubo paid the guy and struck out for home.

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Not more than five miles down the road, the car overheated. The coolant leak was slow enough that Kubo managed to top it off at every fuel stop, limping it home over the next couple thousand miles. When he finally arrived home, he said he would never make the trip again with an older car that wasn’t checked out in advance. “Can’t blame him,” Fraser winces. “Digging into the car, I found the thermostat housing was installed incorrectly, not flush, and was leaking.”

For further history, he obtained a Carfax report and found out the C4 was local to the San Francisco Bay Area, but had somehow ended up in Texas. Even though the shop that did most of the work on the car was no longer in business, Fraser assumed everything was installed correctly. He was mostly correct.

“I found [that] the MSD [ignition unit] was disconnected and just left in the left-front area of the engine compartment,” he says. “Most of the wires were just bundled up, and the boost-timing knob tucked up under the dash.”

In addition, the engine had a second fuel pump under the throttle body, with fuel lines that were “very questionable.” To address this, Fraser removed the second pump and installed a larger one in the factory tank. The wiring harness had also seen better days, with lines cut, spliced, and then left loose. The jumbled wires caused unplanned alarm activations until Fraser ripped out the system. “Let’s just say I should have started with a stock car,” he admits.

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Fraser had some success initially with the stock L98 engine, along with aggressive alignment settings and some used tires. But he wanted an aluminum block for more rear-weight bias, and an LS engine seemed like the perfect way to start. These powerplants remain a hot commodity, however, so it took some finagling and Internet searches to find one.

“A few years before getting the C4, I was planning on building an LS-swappped Miata,” he says. “I had been cruising Facebook and saw longtime Corvette autocrosser Jeff Glorioso was at Able Chevrolet, where my friend and racer Rich Willhoff is the parts and service director. [Glorioso] posted [that] his 2003 Z06 was getting a ‘heart transplant.’

“I immediately messaged him, asking what he was doing with the old engine,” Fraser says. “He gave me the option that if I would like to buy it for the core charge, the engine was mine.”

The price was obviously a no-brainer, so Fraser sent his father Jim (who sadly passed away last fall) to pick up the LS6 in Rio Vista, California, about 120 miles away. Then Fraser called another longtime friend and engine builder, Mike Broadwell, to check it out. Broadwell noted that the cylinders needed to be bored out, which meant a full rebuild. Fraser wanted to keep the engine in drivable form, so he asked for a few modest, but meaningful, improvements along the way.

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New 6.125-inch rods and pistons were among the more notable changes, as were some strategic upgrades to the valvetrain. “I was planning on leaving the stock cam, and to change it later, but friends helped push me over that cliff,” Fraser says. “I spoke to the guys at Comp Cams [and] said I wanted a cam with minimal chop [that could] stretch to 7,000 revs.” He ended up with the company’s Stage 2 Turbo grind.

The heads were going to be left stock at first as well, but Fraser spotted a sale on CNC porting from Katech and did that, too. A trunnion kit, LS7 lifters, a new oil pump, and a stock “batwing” oil pan with Improved Racing baffles and a windage tray were also added, thanks to yet another friend. (There’s obviously a recurring theme here about having good racing buddies.)

One friend in particular who Fraser mentions is Keaten Schuster, who not only helped with work on the C4, but also lent a differential out of his own project car. Additionally, he installed a set of Van Steel solid differential bushings while Fraser was stuck at work during a last-minute race-prep session. Schuster even went the literal “extra mile” to break in the engine. “[He was] pretty much a lifesaver,” Fraser says.

Yet another pal provided much-needed assistance on the intake side of the engine. “I had a friend, Jason Isley, who was writing an article about building a CAM-S car for autocross, and it had an older-version FAST intake manifold,” he relates. “I reached out to him and bought [the intake] with the throttle body and injectors. Of course the only thing that would work for me was the intake manifold.”

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It turned out that the throttle body was for an early setup with two connectors, while the setup Fraser uses only has one. The injectors were also far too big, at 80 pounds, since the intake, throttle body, and injectors had call come from a twin-turbo C5. The exhaust posed some challenges as well.

“I searched high and low for headers. I didn’t want long-tubes because the L98 had cheap long-tubes [on it] and they bottomed out,” Fraser explains. “The biggest struggle was trying to find headers that would clear the C5 pan in the C4 chassis. I went through three different sets and ended up getting a pair of takeoff headers from Curt Hill of Hill’s Rod and Custom.” Interestingly, Hill had removed them from a Corvette chassis that is now under the ’72 Blazer he races. 

As for the bellhousing, Fraser wanted to run the factory-style unit but would have needed a $500 Tilton starter to do so. He chose a more affordable option instead. “I wanted to be able to replace the starter at the local auto parts store if it ever failed,” he explains. “It might be one of the things to get changed out later, though.”

In the meantime, Fraser went with a used QuickTime bellhousing from a fellow C4 owner in Texas, who also helped him choose a clutch slave. For the clutch master cylinder, Fraser used an After Dark Speed kit with a travel limiter, with a custom hose to adapt to the new slave. The clutch itself is a McLeod twin-disc unit with an Exedy aluminum flywheel. A B&M short-throw shifter stirs the gears.

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The C4’s wheels are Flow One units measuring 18×10.5 inches. These lightweight and budget-friendly rims were recommended to Fraser by Sam Strano, another longtime autocrosser and Corvette driver who also owns Strano Performance Parts.

The Z06 front brake calipers and rotors were takeoff parts sourced from yet another pair of Corvette autocrossers, Bryan Stewart and Sean Breese. Two more racing buddies had won gift certificates for Hawk pads, allowing Fraser to obtain front and rear units for the build.

Finally, Fraser is keen to highlight the contributions of RideTech, the company that put us onto his C4 project in the first place. The firm supplied boxes of suspension parts—including a set of coil-over shocks—for the car near the end of the initial build in March of 2021. These were especially important to Fraser, as he wanted to be able to change spring rates and not be limited to the options offered by aftermarket leaf springs.

“I am not saying the leaf springs are bad,” he notes. “Just that the ease of changing out the coil springs for different rates and ride heights is much easier in the front suspension. In [some] events I have changed the spring rates, ride heights, and, of course, shock adjustments.”

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Specifically, with varying weather conditions and road surfaces, Fraser has sometimes needed to soften the ride to maximize traction. “There is a balance of how the car will build grip,” he explains. “I have adjusted [the shocks] so soft that they ride smoother than if the car was in stock form. With adjusting the knobs I can get the ride to autocross specs [easily]. This is crucial for how the car will handle, and the last thing you need is to be hunting for tools.”

As general advice on chassis tuning, Fraser recommends getting an alignment that’s specifically geared toward what you want to do, since autocross alignment settings can be very different from one car to another. Then, set the shocks to their middle position and try changing every setting. Testing is key.

“I take a different approach than most people,” he admits. “When I hear, ‘I did this’ or ‘I did that,’ I look the other way. The car does what I ask, and if I want something different, I will adjust the car to do [it]. You just need to make sure it wasn’t induced by poor driving.” 

Fraser also suggests having more experienced drivers either ride with you or drive your car. Ask for their opinion about not only your driving, but also how the car feels. It’s possible that you’ve unwittingly changed your driving approach to compensate for an issue with the car. Someone with a fresh perspective may be able to identify that issue, giving you something to fix.

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As for Fraser’s C4, there isn’t much that still needs to be addressed, though he does have a few plans for the future. “I would like to install aftermarket seats, steering wheel, and brakes. Plus Le Mans–style headlights, and [to] move the battery to the right rear,” he muses. “I could use more horsepower. The list keeps growing.” 

Of course, it’s not just the mechanicals of the car that make the difference. It also takes a skilled driver to make things happen on the track. But despite Fraser’s considerable autocrossing experience, his first run in the car didn’t go all that smoothly. “In the first corner, with my son Cameron in the car, we spun! When the car stopped, we were both laughing.”

Looking back on his string of victories, Fraser feels some of his success has come from driving a bunch of different vehicles. From that, he knows what a car should do and what you need to change to make that happen. “I change things almost every run to maximize performance,” he notes. “Every week there was not a race, the car would be apart [to allow for] making a change or testing. Nothing was ever the same.”

His advice to autocrossing novices? “I believe one of the best tips for a beginner is to just get out there and start to run. You will have fun and learn from the very beginning. Go for rides and ask experienced people to ride and comment.”

After a couple events, Fraser recommends attending an autocross class with a group such as the Evolution Performance Driving School or SCCA. His advice, all told? “Quick and easy without going crazy,” he says. “The softest, lowest car will create the highest peak g [forces] as long as you don’t bottom out. The downside with being so soft is that transition time takes longer—most everything is a tradeoff.”

Also from Issue 153

  • Top Flight ’63 Coupe
  • C4 Market Report
  • 450-hp Silver Anniversary ’78
  • History: Birth of the Cheetah
  • Tech: Inside the LT6
  • Barris Kustoms ’58
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