September 3, 2020 admin

HMA in Motorsports: Behind the Scenes

HMA in Motorsports: Behind the Scenes

Our hobbies and interests are often the rubber band that absorbs the free time and energy that ebbs and flows relative to the higher priorities that we all have.  This has been the situation in our racing program.  The pace of business and family needs combined with the uniqueness of 2020 have caused us to modify our motorsports plan.

To recap, the Sports Car Club of America (SCCA) requires a certain level of participation to qualify for the “Runoffs” which is the national road racing championship race.  With numerous events cancelled in the Spring, the SCCA has waived the participation requirement.

This created an opportunity to deploy resources more smartly as well as allow for greater focus on other priorities.  We have decided to skip two race weekends and spend the effort normally consumed by normal car prep, travel, and race weekends on preparing the very best car possible for the Runoffs.

So, what is the new plan?

We have used the months of July and August to do several things that we’ve always had on the list, but never had the time to do.  We are rethinking every aspect of the car to both maximize the performance and finely tune it for Road America, the racetrack where the Runoffs will be held in 2020.

For 2020, we are fortunate in two regards.  First, Road America is our home racetrack.  I have been attending races there since I was 6 months old.  I spent countless summers at our house 2 miles away, and the race shop is only 90 minutes away.  I probably have 10,000 laps of the 4 mile race track. Secondly, our car was developed specifically to perform on high speed tracks like Road America.

The challenge is that setting up a car is about managing the gain versus the loss.  You can fly down the straights, but you will likely have no grip in the corners.  Tons of grip means tons of friction that reduces your top speed.  Managing the compromise is critical.

Suspension: We had a major suspension update prior to our last Runoffs in 2017 which we won at the Indianapolis Motor Speedway.  IMS is very different from Road America.  IMS is a tight track with slow speed corners where the ability to quickly shift weight laterally is key.  Road America has very long, fast, and well-spaced corners where the ability to balance the car on the edge for several seconds is important.  In our car, the slowest corner is 60mph and there are 5 corners over 95mph.

We will be looking at spring rates, alignment, caster, camber, steering angles, corner weights, and sway bar settings primarily.  These settings will help balance the car in long corners, raising our mid corner and exit speeds.  Just one incremental 1 mph exiting a corner can result in a 3-4mph gain at the end of the straight that follows.

Transmission: Our gearing is well optimized for Road America.  There are subtle changes and small gains, but we rarely make significant changes.  There’s a lot of super-secret philosophy to gearing.  Gearing is not just about top speed, but how you gain and preserve speed.  For every improvement in one area, you’re likely compromising elsewhere.

Aerodynamics: Our rules allow for much greater aerodynamic optimization.  We can run a rear wing and a front splitter, basically a sophisticated front spoiler.  We have avoided these, choosing to focus on maximizing mechanical grip through the suspension and tires.  However, we can get more sophisticated when it comes to managing airflow.  We do not want to add drag, which slows the car at higher speeds, but we want to be more efficient.  In the past, we have borrowed ideas from aviation including taping body seams and making the body as smooth as possible.

Is a wing and splitter a smart improvement or will it cost us too much time in drag?  Will a wing and splitter force us to make a spring rate change that destroys the balance we currently enjoy?  Perhaps this is an area of opportunity, perhaps not.

Engine: The engine is the most challenging part of development.  Our class is required to limit air into the engine by a Single Inlet Air Restrictor (SIR).  Think of the SIR as NASCAR’s restrictor plate.  All engine air must pass through a 23.5mm opening.  Functionally this limits the RPMs which limits horsepower and torque.  The engine simply runs out of oxygen.  The benefit is that it increases engine life and makes writing rules easier.  However, a restricted engine requires unique, custom made components to achieve maximum output which adds cost.  It is very difficult to find performance.  The last new engine we built took over a year, involved engineers from multiple countries and only found THREE horsepower.  I am done building new engines.

How do we know what works and what doesn’t?  We will test all these changes in a private test day.  The testing process is very simple.  We run the car as-is and set a benchmark lap time.  It won’t necessarily be the absolute limit with maximum risk, but a competitive, and repeatable lap time.  We will make each incremental change and measure against both the baseline lap time, but also the driver “feel.”  Good changes will be kept, bad changes will be discarded.

We also record data from the car.  This is the lie detector for the driver.  We will take a week to analyze the subjective “feel” from the driver and the lap time against the raw data of MPH, corner force, braking force, steering angle, and shock compression.  This will minimize the impact of the fluctuation in the driver’s performance.

From this, we will create the map of changes that should deliver maximum performance for the Runoffs.  Once we have the plan, the car will be taken completely apart and rebuilt to the new Runoffs spec.  Every bolt, hose, fitting, and rod end will be checked.  Anything questionable gets replaced.  Every weld in the chassis will be inspected and new brakes will be fitted.  The engine will be refreshed with new bearings and run on a dyno to break it in.  Runoffs prep will take all of the three weeks between the test and the race week.

We have traded track time for prep time.  We’ll know if it was a good decision when the checkered flag falls on the 2020 season on October 11.

 

To watch our recent past Runoffs Races, please click the links below:

2017: Indianapolis Motor Speedway

2016: Mid Ohio Sports Car Course

2013: Road America