5. Aerodynamics mods supported by trials and monitoring data
Finally, I am getting there. Driving behavior and mechanical mods brought some good results. Time to add some improvement in the aerodynamics field.
For starter and since the beginning of 2019, I read a lot of scientific papers on the web. What works. What works better? What is the most recent knowledge about a particular road car aero topic?
I also purchased Julian Edgar, 2018, Modifying the aerodynamics of your road car, SpeedPro Series, Veloce Publishing, England : Step-by-Step instructions to improve the aerodynamics of road cars.
Secondly, modifications monitoring methods and tools
Fuel log: from the first fill of this car in 1999, I log every fuel fill and distance covered to compute mileage and check on car maintenance need.
Digital dashboard: standard car dashboard is so weak on information that I use an ELM 327 Bluetooth OBD2 adapter and Android phone or tablet app TorquePro or RealDash: both apps allow real time engine monitoring and datalogging of parameters, direct from car ECU (Engine Control Unit), like coolant temperature, gps speed, RPM, throttle % opening, intake air temperature, instant and long time mileage and else: mileage can be calibrated. OBD2 adapter cost less than 20 US$, each app pro version costed below 10 US$ (free version of apps log less parameters but are still usefull).
Digital differential manometer to measure air pressures on the car body in various points: allowed to relocate the air intake mouth in the front “dead zone” of higher air pressure: also useful to evaluate the air intake tract components, from mouth to throttle body, to reduce restriction and improve the flow of air to engine.
Tufts test: assistant required for pictures or small movies using a smartphone: observations of tuft movements and positions frame by frame with some movie viewing app or movie editing app better done on larger computer screen. I use an Apple MacBook and Quicktime player to review frame by frame and extract interesting frames with a screen capture for further examination.
Dust test: to better see actual vortex deposited dust areas on car panels and choose correction, e.g. separation edges
“Throttle stop” method to evaluate modifications according to Julian Edgar on Youtube 2020 :
Drag improvement speed difference computation proposed by Julian Edgar on Youtube in 2020:
Fuel tank filled to the brim, every fill in 2020: no two fuel pumps are the same and will stop at the same filling level thus introducing errors in mileage. From this 2020 spring, I fill the fuel tank to the mouth. I stop when I see fuel about to pour out. That way I am sure the difference between fills is minimum and get accurate mileage measurements.
Test facing low or no headwind on flat straight road when possible
. It seems that testing with tail wind and gusts "steals" air from the engine thus results are not as good as when facing low wind speeds. I will have to check on that with the manometer.
Now, modification, testing, measuring, data logging, approving or disproving modification, next modification and loop…
(Continued with some actual results)