NASCAR SPRINT CUP SERIES
FIREKEEPERS CASINO 400
MICHIGAN INTERNATIONAL SPEEDWAY
SIX QUESTIONS
JUNE 8, 2016
SIX QUESTIONS WITH KEVIN BAYLESS, CHEVROLET RACING NASCAR CHASSIS AND AERODYNAMICS PROGRAM MANAGER
Aerodynamicist Works with Team Chevy to Continue Winning Legacy

CAN YOU TALK A LITTLE BIT ABOUT HOW YOU GOT INTO THE FIELD OF AERODYNAMICS?
“Straight out of college I started work for GM on production car stuff. I actually designed bumpers. They sent all of us new hires up to Detroit for like three days of seminars telling us about different parts of the company. Dick Amacher was there and talked for a few minutes about Chevy Race Shop. I had always been involved in racing growing up. My uncle’s owned sprint cars for years, drag cars, all that sort of stuff. I went up to Dick after he spoke and said ‘hey can I get a business card, because that is what I would like to do one of these days.’ He gave me his card. My wife was still in school at Purdue so I was still working close to Purdue. When she got ready to graduate was about the same time GM consolidated all of the racing divisions into one. I read about it in National Speed Sport News. I thought, okay they are putting all this stuff together, so I dug out Dick Amacher’s business card and called him up and asked if they were going to have openings. He said yes and I wound up with an offer to move to Michigan. My wife also ended up with a job offer in Michigan. So we moved up there in January of 1992 was when I started at GM Motorsports Technology Group is what it was then. I worked there from 1992-1996. Then wound up an illness in the family moved back to Indy where my family was all from. I worked for an IndyCar team for a couple of years, worked for the Trans-Am Series and then I got called back because they were looking for somebody to do chassis and aero work on the IndyCar program based in Indy. I started back with GM in 2001 and have been there ever since. I was a mechanical engineer in school, always wanted to do racecar design that was why I took mechanical engineering. I did a little bit of aero stuff in school, but basically wound up at the right place at the right time.”

TALK ABOUT YOUR ROLE AS AN AERODYNAMICIST:
“As an aerodynamicist the main thing is focusing on how to use the wind to increase vehicle performance. It really comes down to trying to maximize downforce and minimize drag. For a Cup car or a NASCAR vehicle that predominantly turns left, maximize sideforce. We use a variety of tool whether it’s wind tunnel testing, track testing, computational fluid dynamics (CFD) simulation. But it’s all about trying to manage the airflow around the vehicles to maximize performance.”

WHAT TYPES OF DATA CAN YOU PROVIDE CHEVROLET TEAMS TO ASSIST THEM AS THEY PREPARE THEIR RACECARS FOR A PARTICULAR RACE?
“As the OEM (original engine manufacturer) we do the initial development on the body and get it through the NASCAR submission process. During that process we are limited in what we can do because there are specific performance targets that NASCAR establishes. There is a minimum amount of drag and maximum amount of downforce and maximum amount of sideforce. So, we develop the body to try to take full advantage of those limitations. Beyond that then there are areas that are not part of that submission process, particularly the underbody and how some things are tuned on the car that we will work with the teams to try to help them develop the car after we give them the basic components. Honestly, a lot of what we do is we provide assistance on the tools that they use. We don’t walk in and tell the teams how to build their cars, but I will work with the teams aero engineers on how best to use CFD or the wind tunnels. Each of the different tools have particular areas they are best for. We will try to use each tool to the best of its ability and where there is something lacking in one tool we will look for another tool to fill that gap. We will help the teams know the best tools to use as they go through the processes and tools as opposed to specific details on where to set the right-rear quarter panel or something like that.”

HOW MUCH IS DONE ON RACE WEEKEND? HOW FAR OUT ARE YOU WORKING ON INTERMEDIATE TRACKS OR SHORT TRACKS? DO YOU DIVIDE IT LIKE THAT OR UPCOMING RACES?
“Most of it all done at the shop, but there is some tuning that is done at the track. From our standpoint we are working on the next generation of bodies. That is all primarily based on the production car cadence. If there is a new production model coming we will know we need to start working on that. Sometimes it’s based on what NASCAR dictates. The Gen-6 car that was all based on NASCAR’s timing regardless of what we had going on the production side. We are working sometimes several years down the road on those types of projects.

“On the team side they will be working on getting cars ready to go to each particular event, but they will also be working on packages. They might be working on their next intermediate car package. They will target a particular race that they will say they want to have a new aero package for Indy. A lot of times the big races they will try to have a new package ready for that event. That kind of goes for the garage. Teams may have the All-Star race; teams will come in with something new because the rules are maybe a little bit more relaxed there. So, they will see what they can get away with and try something new for the All-Star race. If it doesn’t work it’s not the end of the world because it’s a non-points race. For the Chase everybody puts a lot of effort into getting stuff ready for Chicago and beyond for those Chase races. They divide things up sort of by function. There will be a particular race for say the intermediate tracks because you don’t need a lot of brake cooling and different things like that. Short tracks there is a completely different package because you need a lot more radiator cooling and also short tracks don’t use the right-side window. That affects the flow around the car. Road courses are different because you have a lot of brake cooling and things, plus you are turning left and right. That affects how you build the car and sideforce and some of that type of thing.”

HOW HAS THE AERODYNAMICS CHANGED WITH THE NEW LOWER DOWNFORCE PACKAGE?
“It’s about a 500 pound reduction in downforce and a reduction in drag to go along with that. Balance is pretty similar, but it’s a significant reduction in downforce.”

ARE YOU CONSTANTLY TRYING TO HELP THE TEAMS GET THE DOWNFORCE BACK?
“Absolutely. That is one of the reasons that it is always a moving target for NASCAR is because the teams are constantly clawing downforce back. If they leave the rules the same the downforce level is constantly growing because that is what teams get paid for is to develop the cars and they will find more downforce. In order to even try and maintain some level of performance NASCAR has got to eventually take some downforce away to get back to where they started.”

WITH THE NEW CHANGES THAT HAVE BEEN ANNOUNCED FOR MICHIGAN AND KENTUCKY HOW IS THAT GOING TO AFFECT THE CARS AND THE RACING?
“So it’s a combination. You are going to lose about 500 pounds of downforce. You are going to lose a significant amount of drag, as well as sideforce, both the smaller spoiler and the skew and toe changes. Definitely will slow the cars down mid-corner, it will likely and it will depend a little bit from track to track, top speeds will probably go up because of the reduced drag. It’s going to make for a much larger difference between straightaway speed and mid-corner speed, as well as the amount of off throttle time. Drivers are going to have to lift earlier going into the corner and wait longer before they can get back to full throttle which is really the idea behind the whole package. That should open up more passing opportunities with the off throttle time. The drivers tend to like that because that gives them more time where they feel like they are in control of the situation. With a high downforce package and the drivers just driving around with his right foot planted he really doesn’t do a whole lot. As soon as you open up that delta between mid-corner speed and top speed that puts the car back in their control.”

CAN YOU TALK ABOUT HOW AERODYNAMICS AND MECHANICAL GRIP WORK TOGETHER TO GIVE US THE RACING PRODUCT WE HAVE TODAY:
“As the aero comes off then it puts more of a premium on mechanical grip. It works a couple of ways. One of the reasons that NASCAR has looked over the last two or three years at taking downforce off is that opens up the potential for Goodyear to do some more things with tires. Go a little softer on the tire which gets back some of the speed on a sticker run, but then the speeds fall off more through the run as the tires wear. Which again, fits in with what the drivers like and what the fans tend to like because there is more opportunities for someone who is good at the beginning of a run and someone else who might be better at the end of a run and more passing opportunities. As the downforce level drops, it swings the importance equation more towards mechanical grip. Where with a high downforce car you tend to really compromise the mechanical set-up just to try to keep the aero platform fairly steady once you take downforce off then that harsh ride that you were using to keep the platform really steady now starts to hurt the tires more. So, you have to go back and you’ve got to rethink how you manage tire life at that low downforce level. Suspension set-up’s become different to try to maximize mechanical grip.”

HOW HAS AERODYNAMICS IN THE SPORT CHANGES OVER THE YEARS?
“The understanding of aerodynamics has changed dramatically. The tools that were available back 30 years ago, the amount of wind tunnel time was very limited and was mostly the teams going to use the wind tunnel that was owned by the manufacturer. Those tunnels were all based on developing passenger cars with high ride heights. They weren’t very sophisticated tunnels. Now the teams use Windshear and Aerodyn for specifically built as racing wind tunnels designed for low ground clearance and developing the underbody of the vehicle as much as the top surface. The tools have greatly expanded. 30 years ago we didn’t have CFD that is a whole new tool that has come into the mix in the last several years. The engineers, the crew chief’s, everybody involved really have a much greater understanding of the significance of aerodynamics as it relates to performance and how to generate performance through the shape of the body and the different components. The understanding is huge. The deal now is as the sanctioning bodies try to take downforce away that understanding doesn’t go away. The genie is out of the bottle so to speak, so you can’t just say ‘oh we are going to go back to the old style’ and not have aerodynamics be a factor because it is whether you like it or not. At 200 mph aero is important.”