Behind the Scenes: The NASCAR Peak Antifreeze Series powered by iRacing.com – For the Alpha: the Omega, Part 2
July 8th, 2015 by JaimeB
Before we dive back into this, let’s review: We’re talking about how to be more efficient with your setup process, and spend less time trying 28 different setups every week that don’t work and spending more time in the fine-tuning stages. In the last article, I discussed how to approach the initial setup build, as well as forming a plan for how you’re going to wind up with what you want. If you missed it, you can check it out here: https://www.iracing.com/iracingnews/nascar-news/behind-the-scenes-the-nascar-peak-antifreeze-series-powered-by-iracing-com-for-the-alpha-the-omega-part-1
In that article, I focused primarily on the setup I built for the GFR cars in the Daytona race for the NASCAR PEAK Antifreeze Series. Nobody in their right mind would expect the setup built for Daytona to have a chance at Charlotte, or Iowa, even, but it was to illustrate the process to get to what we wound up with. That same process can be applied to everywhere, any track, or even any car. We’re starting to get more and more accurate with iRacing’s physics and dynamics simulations, and with each step forward the older methods (such as the awful “setup matrix”) will become less and less effective. When all is said and done, every vehicle that hits a race track is still a car, and all cars are dictated by the same rules of physics. While I speak mostly from working on the NASCAR PEAK Antifreeze Series cars, I still use the same process for working on my BMW Z4 GT3 car, the Aston Martin DBR9 (which is amazing, right??), and even the Late Models.
“We’re talking about how to be more efficient with your setup process . . .”
Something a lot of people don’t realize about racing (especially stock car racing) is how much setup parameters carry over from one race to the next. For instance, in the spring Bristol race a few years ago (2010 or 2011, if I remember correctly), one of the pit reporters was discussing how Paul Menard was doing very well in the race, closing the report by mentioning how crew chief Slugger Labbe used the same four springs at every track they visited. WHAT? Well, to further support that, an article in Circle Track Magazine in 2004 said that the Busch Series champion from “several years ago” used the same four springs at every track. That could have been a lot of drivers who are in Cup right now, but my guess is probably Kevin Harvick, when he took the crown in 2001. When I worked at US Legends, I got the chance to talk to a lot of mechanics, drivers, and crew members for Cup-level NASCAR teams. Something I always worked into conversations was how often springs get changed. David Ragan (who was in the #6 car at the time) told me they “rarely” change springs from week to week, and never change them at the track unless there’s a problem. Another friend of mine, who was one of the mechanics on the #48 car during their reign of terror also told me that they never changed front springs, but would change rears depending on the track characteristics (bumpy, smooth, minefield, etc.).
In the sim racing world, we suffer from a few limitations that make it impossible or at least impractical to do exactly the same thing as these guys. First, we don’t have shocks. Well, we have something, but their being labeled as “shocks” or “dampers” is arguable at best. This places a limit on how much we can actually carry from track to track. Yes, we could – and have – taken springs from Charlotte and run them at Kansas, but anything much bumpier than Charlotte (Michigan, for instance) will need a new spring package. The other thing, and the main reason why the Cup teams can do this, is that they can change their suspension geometry to get what they need. Let’s say the #48 had a front roll stiffness of 3500 lb/degree at Charlotte and the body rolled [this much] in the turns. They could take the same springs to Indianapolis, pair them some with different shocks, then move the roll center to get the roll stiffness back to where they need it for the track. Like I said in the last article: They know what they’re trying to get ahead of time and they adjust until they get that back. As for us, we can’t do that, so we either have to change the sway bar, or soften the front springs. Maybe someday though.
That said, we are getting closer and closer to running the same thing everywhere. While, during the 16-race schedule, I may have 8-12 different spring packages for the tracks, those can be further narrowed to four configurations: Smooth Intermediate, Bumpy Intermediate, Short Track, and Road. Believe it or not, the Smooth setup was actually derived from the Daytona car, albeit with a heavily modified rear end configuration. The Michigan car was developed from the Auto Club Speedway car, which went partly into the Pocono car, which has become the Kentucky car, and the Charlotte car will come back at Indianapolis and the final four races. Will they be the same? I wish! If we could build the shocks to what we wanted and move the suspension components (like we can in the V8 Supercar), then we could use the same springs.
Instead, we need to apply the process I mentioned in the last article. We need to know the attitude of the car that will give us the best performance and the numbers to produce that. So, let’s say we know that at Texas the most downforce was produced when the front was at 3.0″ and the rear was at 5.7.” When we take it to Charlotte, where it’s smoother and loads are higher, we need to adjust the car so it’s doing that again. Whether it’s stiffer springs or simply changing the ride height, we can at least do that much right now. Changing the springs would require a new track bar angle and height, the alignment settings are basically dictated by the track configuration, and the only thing really left to adjust is the front sway bar. Suddenly, something a professor in college told me makes sense: “Tune aero with the springs and shocks, tune the handling with sway bars and weight.”
Something to keep in mind with this is the ever-growing prevalence of aerodynamics. Like it or not, the days of completely mechanical, low-drag cars are gone. Even my go-kart has a small diffuser under the front bumper, and my friend’s oval kart has a rear diffuser, so there you go. If you’re going to try to push a brick through the air, you have to make it work as best as it can. If you don’t, someone else will, and then they’ll be walking away from you.
“To lessen the complexity of your setup building process, stick with a front end configuration once you have found something you like.”
Ideally, the front end of the car is the first thing that will see any air. I say “ideally” because I won’t make assumptions about anybody, but that’s how most cars work. If it’s the first thing to hit the air, the way it hits the air will dictate EVERYTHING behind it. That’s why you hear Formula 1 Engineers say things like “We redesigned the nose of the car and got more rear downforce.” In the same way that the center section of a Formula 1 car’s front wing winds up feeding air to the rear diffuser, the front end of a stock car will ultimately dictate how the air flows over the entire car. Aerodynamic dependence dictates a very stiff setup and, for the most part, a stiff front end will behave the same way at almost every track. Usually some small adjustments to the shim stack and the shock springs will bring the nose back into where it needs to be. So, if you want to lessen the complexity of your setup building process, stick with a front end configuration once you have found something you like. It may not produce winning stuff each and every week when you start, but once you’ve gotten to where you can reproduce things week-by-week, you can then start tuning the front end to get the little extra you may be missing.
This simplification of the setup process does two things. First, it will definitely keep your setup folder cleaner, and give you a much better starting point each week, since you know what went wrong the week before and can adjust to fix that. If I had a dollar for every time we started practice for a race and Nick (Ottinger) told me, “I GOT 17 SETUPS FOR THIS TRACK BUD,” I could retire . . . even at this age. Keep your choices limited, and you’ll eventually have no problem having something really good for the race. Another major plus is what we’re now facing in the NASCAR PEAK Antifreeze Series races starting with Kentucky: Variable weather.
Yep, the race in just over one week will be the first where we’ll have changing weather conditions during the race. In previous years, we didn’t make a bunch of adjustments during the race unless there was a major problem. Now it’ll be a little different, and we need to be able to compensate for changes. Maybe the track will get a little bit warmer and we need to tighten-up the car; or the wind might change and suddenly the car’s incredibly loose going into one of the turns. Sticking to one style of setup, and one that has been developed for the weeks and months prior, gives us a gigantic backlog of notes on how to adjust it.
“Sticking to one style of setup, and one that has been developed for the weeks and months prior, gives us a gigantic backlog of notes on how to adjust it.”
That said, there have been races in the past where adjustments made in back-to-back races produced different results. In fact, in the race last month at Dover, I reduced the pressure in the left-rear tire of Nick’s car by 1.0psi because he was tight on turn-in and to the center. In the race before, at Charlotte, he reported the exact same problem in Turn 1, which has a similar banking shape as Dover, along with the same bank angle and vertical loads. At Charlotte, it fixed the car completely. At Dover, it sent it to the back. They were two completely different setups and responded in the opposite way, so after the adjustment at Dover failed, we had no way to know what would fix the car. Imagine now we have both variable weather and the newly-demonstrated dynamic track surfaces and you imagine see the challenges.
I don’t want to suggest that setting-up a car is easy; it’s far from it and, with the direction iRacing is heading, it’s going to become more and more complex. The good news is that, with each update that makes the chassis more realistic and requires less “sim-world” thinking and more real-world thinking, the final steps once the setup is built will become more and more simple. What was built at Charlotte will work as an excellent baseline at Kansas, and that will carry over to Chicago. Some minor changes will take it to Texas, then Atlanta . . . and the list goes on. Someday we’ll get to the point where we can actually run a single setup for the entire season and have it work very well and predictably. While it used to take an entire week to get a car configured for a race, it could take an hour or two in the future. It is, at least, a year or so away before it will work completely, but it still works now, so why not take advantage of it?