FastLapSim5 Racecar Sim Cuts Lap Times Without Turning A Wrench

The promise seems almost too good to be true. Be able to test changes to your racecar on your laptop to determine their impact on laptimes without leaving the comfort of your living room. That’s what the FastLapSim5 racing simulation promised, so we put it to the test. We collect plenty of data on our NASA Honda Challenge 4 Integra and have a solid understanding of how the race car responds to changes in suspension alignment and aero. With that basis, we feed all the data the program requested into our laptop and here’s the result.

As a racer, you’re always working to go faster and are constantly looking for the next component or tweak that will make you a winner. Would changing the spring rates make the car corner faster? Would a different gear ratio drop a few tenths of second per lap? Testing these types of things can be extremely expensive and time consuming. You have to buy new parts and then install them. You have to tow to a racetrack and attend a track day to test. After all of that money and time there is no guarantee any of these new parts or settings will produce faster lap times. That’s where FastLapSim5 comes in.

The FastLapSim5 software from CompCams/ProSim Software is only $69.95 and includes an enormous amount of computing power when it comes to trying different setups on a racecar. Just the ability to change the final drive on a car and simulate it around a known track was worth the money to me.

Replaces So Many Outside Functions

Instead of an alignment shop, a spring dyno, and three different sets of tires all you need to test a racecar is a Windows laptop with a CD-ROM and the FastLapSim5 software (which will set you back $69.95 available online). The program loads up easily and doesn’t require an engineering degree to understand. Simply choose a car from the drop down menu, or design your own, and pick out a track to test it on.

There are an enormous amount of parameters that can be adjusted to simulate your vehicle accurately including: Wheelbase, Weight, Aero Properties, Front/Rear Track Width, Center of Gravity Location, Front and/or Rear Wing (length, width, angle), Engine Power Curve, Rev Limiter, 1 to 6 Speed Transmission, Manual or Automatic Transmission, Gears or Axle Ratios, Front or Rear-Wheel Drive, Spring Rate, Damper, Tires, Brakes, Brake Bias Adjustable Front/Rear, A-Arms, Struts, Swing or Custom Suspension Specs, Front and Rear Anti-Roll Bar Rates, Driving Styles, Driver Error Considerations/Limitations, Driver Steering Response Time, Shift Time, Temperature, Humidity, Wind, and Elevation. I found the simulation program immensely inclusive.

FastLapSim5 has a 1997 Acura Integra in its database which was a great place to start for my Honda Challenge 4 car (a 1993 Acura Integra). My next steps were to go through the different vehicle parameters in the program and input data from my own racecar.

To play with the FastLapSim5 software I chose a 1997 Acura Integra from the vehicle list and began to modify the car to match my National Auto Sport Association (NASA) Honda Challenge 4 Acura Integra racecar. The differences between the 90-93 DA Integra and the 94-01 DC Integra are minor, however the racing version of this car that DNN Motorsports built is quite a bit different. Regardless, the FastLapSim5 software let me make the adjustments to the existing vehicle to match my own race car as closely as possible.

Because my team has data from tuning our race cars on a chassis dyno I was able to use the information from our latest pulls to enter it into the simulation program.

The cool part about the FastLapSim5 software was that it was asking for specific information about my race car – that I actually possess. To input the power curve data to replicate engine power I simply used the information from the last time we took our car to Performance In-Frame Tuning for a dyno pull.

Both horsepower and torque numbers are utilized when inputting data into the horsepower/torque curve in the FastLapSim5 software. The more accurate the data you put in, the more accurate the simulation will be.

Pulling up the power curve data entry window in the FastLapSim5 software I used the printout from the dyno to enter the values for both horsepower and torque. In the engine section of the program it was also immensely important to enter the accurate rev limiter for the engine computer so the simulation knows when to shift gears. This rev limiter data entry could also be changed during back-to-back runs to see if a higher RPM produces better results.

Using our Proform wireless vehicle scales we were able to measure each wheel weight accurately with the driver in the car. To input this information into the FastLapSim5 software we just took the numbers directly off of the Proform scale display and plugged them into the program.

The next step was to input the vehicle’s weight and weight distribution. Just like our dyno data, we had this information too as we had recently corner weighted our car using Proform’s wireless vehicle scales. To ensure our simulation was as accurate as possible we entered each individual wheel weight into the CG Calculator data entry window. The information from our Proform scale readout matched the information in the FastLapSim5 perfectly. The minimum weight for Honda Challenge 4 is 2,500 pounds with the driver in the car at the end of the race. Filled with fuel our car weighed in at 2,524 pounds knowing we would burn approximately three gallons of gas during a qualifying session and still hit the scales above 2,500 during scrutineering.

We know exactly what our Eibach spring rates are because Eibach labels each spring (and they verified them with a spring dyno for us). Entering the dampening information from our Motion Control Suspension shocks was a little trickier (especially because they are double adjustable with 18 different rebound settings and 14 different compression settings).

We dialed in the suspension on our simulated racecar by entering the exact spring rates from Eibach Springs. We had the opportunity to really nerd out during this process as Eibach kindly put our springs on a spring dyno and we had the exact values. One of our 700 pound springs measured 701 inch pounds while the other measured 703 inch pounds. We felt confident in our data entry as we knew exactly what our car had on it. We used the race shock setting in the software to try and match our Motion Control Suspension (MCS) double adjustable shocks. We also adjusted our track length and wheelbase (as we use wheel spacers to make the car wider).

The wing size and angle is a parameter that can be entered and adjusted in the FastLapSim5 software. We measured our rear wing and angle. Then we made small angle adjustments in the software to see if lap times would get better or worse.

The Ability To Add Wings

The program even includes aerodynamic drag and allows you to add wings to the front and rear of the car and enter each wings’ individual length, width and angle. We measured our rear wing size and angle and entered it into the system. Once the wing was set we moved onto the drive-train and entered the gear ratios for our Synchrotech Transmission Honda 5-speed transmission and inputted the final drive we were currently using. We had all of this data because we have changed the final drive multiple times in an attempt to find the perfect final gear ratio for certain tracks.

Once we had the car essentially built in the program it was time to pick out a race track to test the car on. I was hoping for the Circuit of the Americas because we had just run the 2018 NASA National Championships there in September and had lots of data from that track. Unfortunately, that track wasn’t available in the pull down list in the program. However, they did have Mid-Ohio Sports Car Course which is where the 2019 NASA National Championships will be held so we decided to start simulating our car on that track.

Here is a list of cars and tracks that are available to play with or modify with FastLapSim5. There is a De Lorean on the list, but I recommend you do not simulate 88 miles per hour or you may end up doing some Back to the Future shenanigans.

The existing cars and tracks in the FastLapSim5 software are interesting to peruse. Some of the cars listed in the program are a bit mind boggling. A 1990 Dodge Avenger? Why? Other cars are a perfect match for many road racers like the 1993 BMW M3, the 1997 Porsche 911, or the 1984 Honda CRX. Surprisingly, Mazda Miata is not on the list, but oddly a Mazda B200 pickup truck is. Regardless of no Miata availability, any car can be custom built in the program’s editor. But any track can be created in the track editor, including autocross courses.

I spoke with Kevin Martin from CompCams and inquired about an update or the ability to upload more tracks to the program. Kevin said currently there are no further tracks to upload, but to always check for updates to the program as cars and tracks are added. In regards to creating and then sharing tracks and vehicles, this is what Kevin had to say: “FastLapSim track and vehicle files can be shared by navigating to the FastLapSim5 folder found in the program files directory of your hard drive. Most users will find these files in the “C: Drive” folder under “C:FastLapSim5TrackFiles (.TK)” for track files or “C:FastLapSim5VehicleFiles (.FLP)” for vehicle files.”

He explained that FastLapSim5 provides a comprehensive step-by-step analysis of the interrelated physics performed during every increment of vehicle motion (this is done 1,000 times per second). The program allows you to change any component in a few moments and then run back-to-back tests to “hone in” on the ultimate setup for any vehicle on any track.

We use a Racpak IQ3 data logger which provides an incredible amount of vehicle telemetry, similar to that which is captured in FastLapSim5. I look forward to the day when I can compare my simulations from the program with the telemetry from my data acquisition (once I run a race track that is already in the FastLapSim5 program).

Kevin Martin explained that FastLapSim5 provides a comprehensive step-by-step analysis of the interrelated physics performed during every increment of vehicle motion (this is done 1,000 times per second). The program allows you to change any component in a few moments and then run back-to-back tests to “hone in” on the ultimate setup for any vehicle on any track.Once we had our car built, modeled after our Honda Challenge 4 racecar, and a track to play with, Mid-Ohio (the location for the 2019 NASA Nationals), I was ready to start adjusting different parameters to see if I could make the car faster. Here is a list of changes I tinkered around with and the resultant lap times:

LAP TIME CHANGES (Faster/Slower)
1:43.516 Baseline run
1:44.902 Added soft front sway bar (slower)
1:43.423 Took out front sway bar, put rear wing at 1% (faster)
1:42.968 Changed final drive from 4.92 to 4.71 (faster)
1:43.227 Changed rear sway bar from race stiff to race medium (slower)
1:43.990 Put rear sway bar back, lowered spring rates 100 inch pounds (slower)
1:41.192 Put spring rates back, adjusted redline from 6,500 to 6,800 (faster)
1:41.875 Widened front track 0.5 inches (slower)
1:41.052 Put track width back, put rear wing at 2% (faster)
1:40.998 Increased rear brake bias to 50/50 (faster)
1:40.756 Put rear wing at 3% (faster)
1:40.881 Put rear wing at 4% (slower)
1:40.660 Best run and broke the Mid-Ohio NASA Honda Challenge 4 track record

I was able to make the car three seconds of a lap quicker (only using parameters I knew I could change on my car in real life) and I never purchased a speed part or busted a knuckle changing the setup on the car. The simulation program did all of the work for me.

The official National Auto Sport Association Honda Challenge 4 track record around Mid-Ohio Sports Car Course is 1:41:449. Using FastLapSim5 with my Honda Challenge 4 car’s specifications and by making small adjustments to the wing and final drive I was able to simulate a 1:40:660 lap around the same track.

Running the simulations only takes a few moments and making changes in the program (spring rate or wing angle, etc.) is super easy. If you compare how much money, time and track access it would take to run through the thirteen different setups I tried around Mid-Ohio using the simulation then this program is worth its weight in gold. And since I was so careful and specific in the building of my car, I found my laps times around a track I had never been to were right in line with published track records for my same class of racecar. I think that is pretty impressive. Somebody put a lot of work into this simulation program.

A Real Time Overview Of The Car On Track

During the simulations there is a Track Window that provides an “overhead” view of real-time vehicle movement (you see understeer, oversteer, and all driver corrections) as the car traverses the track. As you make changes to the car you can see where the car performs better or worse on the course. You can compare top miles per hour or lap times and the program will provide you a slick little “Timing Slip” to show the vehicle’s performance after a simulation is completed. You can pause the simulation and look at the data to see what gear you are in at what portion of the track. I found that you can sit around and play with this program for hours and hours trying different combinations.

We got a lot out of using the FastLapSim5 software and think it will help us tremendously as we try to find the extra tenth of a second or two to help keep our team at the top of the podium.

Over the years I have tried to map out tracks and build Excel spreadsheets to determine the right gear ratio for a certain track. FastLapSim5 solved all of that for me in an easy to use and inexpensive format. This will certainly be a continued part of our vehicle development at DNN Motorsports and I look forward to tinkering on my car to make it faster (all while sitting on my couch not getting my hands greasy).

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About the author

Rob Krider

Rob Krider’s mantra is “Race Anything, Win Everything” and is a multi-champion driver who currently competes in the NASA Honda Challenge series.
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