Last week Tim and I went to Cosworth in Torrance, CA to setup and being tuning on the Singer Vehicle Design Porsche 911 motor, using Pectel Engine Management. It was a great project, and we got to work with a lot of really smart people. These days chassis dynos are so common people seem to forget the value of a proper engine dyno. Last week was a good reminder.
Chassis dynos have always been much better tuning tools than they are for fine power measurement. I find it entertaining when people make evaluations based on small changes in chassis dyno reported horsepower. Here are several of their shortcomings:
- Thereís a whole power delivery system between the flywheel and the driven wheels that absorb energy at different rates. These include transmissions, differentials, tires and clutch components. They all have different amounts of drag at different loads and RPMs, and they all heat up and cool separately.
- Its harder to control the environment. Chassis dynos offer mathematical corrections for air density, but that canít effect how coolers reject heat, etc.
- You generally donít control for humidity. Water displaces air, period.
- You canít always run as consistently as you want. Good dyno installations have closed-loop water and oil temperature control so this doesnít play a factor.
- You canít always control the throttle as accurately on a chassis dyno.
- You canít hit all the load sites you want.
- They are less safe, and engine failures can hurt the entire driveline or even chassis.
One great thing about this project is the brain power involved. Everyone had their expertise and the group gelled incredibly well. Our team consisted of:
- Maz Fawaz, our fearless leader from Singer Vehicle Design, who stayed calm and made sure we were properly fed and watered.
- Eric Hsu from Cosworth, our dyno operator and an excellent tuner in his own right.
- Tim Gergorio, the General Manager at Singer whoís also responsible for a lot of the mechanical parts that go into this.
- Tim Whitteridge from Apex, who handled the entire electronics system design and wiring harness build.
- Jae Lee from Mirage International, expert on all things air-cooled Porsche.
- Lyon Kaplansky from Cosworth, the Indycar & F1 veteran engine builder whoís contribution in terms of technical experience and knowledge is immeasurable.
- Tyler Hara from Cosworth, helping with dyno setup duties.
Its not often you get to work with a team as good as this. Special thanks to Ken Anderson and Jeremy Sundt from Cosworth for making this happen, and Rob Dickinson from Singer for his vision.