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Old 06-24-2020, 10:02 PM   #6 (permalink)
Join Date: Mar 2020
Location: Quebec Qc Canada
Posts: 52

AcuraMatata - '99 Acura EL Base
90 day: 39.45 mpg (US)

Le Vehicle - '12 Dodge Gran Caravan SE
90 day: 22.35 mpg (US)
Thanks: 10
Thanked 40 Times in 26 Posts
Phase 5: 1999 Acura EL and Civic EX sedan

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)

Last edited by ACEL; 06-27-2020 at 12:37 PM.. Reason: To complete
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