In 1987 GM started a program centered around the GM Tech center. The concept was to give racers access to engineering resources from multiple GM companies. Communication between the teams and engineers was challenged at best. After meeting with both sides, I was tasked with identifying and solving problems on a team-by-team basis. Teams identified an issue, GM provided paths to solutions through the tech team. The first adventure proved the value of multi-level engineering. Most of the factory supported teams received body panels, some engine parts/ blocks, a set amount of time in the wind tunnel, a win could mean more time and parts. I had ties with a few Oldsmobile teams and a deal with Pontiac. I had been to the wind tunnel in Marietta, GA as support fabricator with a couple Oldsmobile teams. The Pontiac deal was a body deal, teams paid $3500 to hang a body, Pontiac paid $6500 to put the body in primer w/ crush panels, cowls, and spoilers. Total $10000. The wind tunnel was a crazy deal Pontiacs tested in Detroit, engineer Gary Eaker, the Olds group tested in Marietta, GA, Louis Duncan an independent aero consultant, Buick was divided by the two. A lot of the aero characteristics were common in G bodied GM cars until 1987. Monte Carlo Aero coupes, Gran Prix 2+2, Cutlass, Regal rolled over for 1987, with 1988 coming the Gran Prix, H body Olds Delta 88 and Buick LeSabres meant body changes. The 1981-1987 G bodies were the first generation of NASCAR cars that received an abundance of wind tunnel time. Flying bricks. The wind tunnel moved our train of thought, but our worst enemy was a concept the English called your mind’s eye. This theory tasked redneck racers; they were seeing things that challenged their minds. The aero process broadens the knowledge of the prototype, creating 3 D models by physically measuring with Faro Arms, confirming frontal area, establishing points of contact, identifying dead spots. GM tech center was ahead of the game, Olds, Buick, and Ford used wind tunnels that were not automotive centered, the ability to generate support data on site was limited. Racer imagination pushed the call for different but associated data and eliminated all false targets. Pitot tubes were commonly used in the aircraft industry, aviation familiar crew chiefs by the mid 80’s used the tubes to establish patterns of air pressure on the racetrack. Teams also started using wind speed indicators to manage air flow. All the racetrack data had to correlate to wind tunnel information to complement the process. A good example was cowl pressure, we knew that higher cowl pressure meant more rear wheel HP. Any air management task affected down force, drag, flow pressures. This included but was not limited to, increased, or decreased frontal area, grill opening size, cowl configuration, A, B, C pilar shape, side skirts, air dams, pressure inside the cock pit, chassis rake. The irony of the aero dance was the teams were looking for an edge, NASCAR was trying to take advantage of leaks in the teams to keep the field even. GM was trying to beat Ford. From an engineering standpoint, the NASCAR world changed drastically from 1980 to 1990, in the mid 80’s a wave of new racers hit the ground, they appreciated the data based/ engineering approach to racing, NASCAR moved from winning crew chiefs being just great assemblers, folks that knew how to get a car to the last 50 laps of a race, pit crews stumbling around like a blind hogs looking for acorns. The Herb Nabs, Jake Elders, David Iffts, Dale Inmans, Robert Gees, Boobie Harrington’s and disciples were losing ground to engineers, Gary Nelson, Harold Elliott, Robert Yates, Jack Roush, Ray Evernham, Alan Kulwicki, Dan/ Bill/ Ernie. One of the GM Tech Team projects addressed and matured design perimeters for cooling NASCAR stockcars, the concepts challenged by what racers thought they knew. Teams used the same cooling system designed from the mid 1970’s. The racing radiators of the time were based off diesel truck designs, it was a given that copper dissipates heat more efficiently than aluminum, but in comparing cooling equivalencies vs weight the aluminum radiator is ½ the dry weight. In the mid 70’s Modine addressed the racing aluminum radiator need with two choices a four and six core designed to set on top of the rear steer front crossmember. 22”x 27”x 5” and 22”x 27”x 7”. The new focus on aero identified multiple givens, first, was the downforce/ drag associated with grill opening size, second, included the airbox/ ductwork in front of radiator, third, was the radiator core design, and forth was exiting the air from under the hood. The Tech Team approach gave the teams an opportunity to declare opinions and address their wind tunnel/ track data results independently without sharing proprietary data. The consensus was to challenge the grill size vs cooling ability, engine builders across the board saw engine temperature challenges with small grill openings, the Chevy crowd was non-committal, the Olds, Pontiac, Buick crowd all confirmed that temperatures increased from the 1985 models that had larger grill intakes. Buick had some testing scheduled using a DEPAC system known as Oscar. One of the Tech Team engineers was involved in an Oscar test on a trans am car and identified wind speed differences in brake cooling ducts, these differences indicated that the stainless mesh size effected flow. After reviewing the trans am data the Tech Team asked the Buick team to include wind speed channels that picked speeds in front of the grill, behind the grill, and behind the radiator, six sensors total. We asked to start with 2- 8”x 10” grill openings (standard size)
1st run grill taped to 2- 6”x 10”, 6 laps @ operating temps,
2nd run grill opened to full size 8”x10”, 6 laps @ operating temps,
3rd run grill closed to 4”x 8”, 6 laps @ operating temps,
4th run grill opened with fine mesh, 6 laps@ operating temp.
The results established a train of thought that discounted what racers had put stock in for 50 years,
1st run was a baseline the exterior speed was 170 mph, duct speed fluctuated from 168 mph to 128 mph back to 166 mph, behind the radiator never broke 128 mph water temp @6 laps was 215*
2nd run was exterior 170 mph, duct speed 140 mph max down to a stall speed no air flow to 120 mph, 120 mph to 0 flow behind radiator water temp@ 6 laps was 220* 240* spike
3rd run was exterior 170 mph, duct speed 128 mph steady, behind radiator steady speed at 128 mph water temp @ 6 laps was 192* steady 8 * below desired operating
4th run, was exterior 170 mph, duct speed 168 down to 150 mph to stall, 120 to 0 behind radiator water temp@ 6 laps was 230*
1st take: the radiator flows 128 mph
2nd take: the ductwork, airbox volume packs with air only to be evacuated as radiator allows flow (ductwork was similar to filling a glass with a pin hole in it, fills, overflow, then takes water as pin hole evacuates glass)
3rd take: grill size/ mesh size flow above radiator flow capability stalls air flow until radiator flow catches up
4th take there is a sweet spot, a restrictive size that dictates a steady flow, note this allows air 170 mph wind to create downforce above and beyond the 128 mph steady flow
5th take: based on test runs water temperatures on test 3 stayed steady while test 1, 2, 4, water temperatures fluctuated and rose above optimum, note based on aero the random loss/gain of downforce could affect handling tire adhesion/ braking
The Tech Team passed the information on to 6 engine builders and crew chiefs, each was asked what information the engineers from GM could help them with. As a collective of the Tech Team, we felt that the radiator needed to be more efficient, dissipate more heat. At first the group approached the issue saying the radiator needed to flow more air. The GM’s Frigidaire and Harrisons group looked at the Modine core, Harrison was in a partnership to develop an aluminum core that included high flow fin configuration with narrow cores, wide tubes for better dissipation of heat. This would allow engine builders to run more compression, aggressive timing, allow crew chiefs to tape up front ends for more downforce. In the process of designing a better configuration, GM engineers suggested an oil cooler/ radiator combination, Harrison engineers were working on a series of heavy-duty diesel radiators that used high pressure caps to raise boiling points of water and pushed teams to head that direction with 32 psi systems, distilled water, and a surfactant that decrease the surface tension in water. The concept of the GM Tech Team was strong, but the protectionist DNA of crew chiefs and engine builders didn’t trust any engineers that were not employed by the team. As desert storm rattled the world GM pulled back, on more than one occasion GM engineers had their feelings hurt by an old school crew chief challenging their family heritage. Harold Elliott, one of the best engineers in NASCAR, a championship engine builder told me that the information in the GM Tech Team system was valuable, but GM is married to NASCAR and NASCAR was socialist in nature, everybody should be equal! He went on to question GM’s sponsor programs, he knew as a Tech Team member we were directed to pass information on to all teams in a generic form, and that many of the teams discounted the premise of any research. Harold always said in Mr. Frances world you are only supposed to be as smart as NASCAR, they have an agreement with the manufacturers that allows you to step outside what they give you but only when they know! What you find without them is yours until NASCAR makes you pay for it. More times than not somebody rats you out.