Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Aerodynamics for Cooling Systems of Turbo Car

wildman10 · 05-12-2016, 12:55 PM

I'm heavily involved in adding a turbo to a normally-aspirated car and have been designing the cooling systems from scratch, with particular emphasis on aerodynamics. Although the car, a Mazda RX8, is not noted for ecomodding I've tried to use its principles in my work.

Write-Up on cooling system aerodynamics

I wrote the write-up here to explain my thoughts on cooling system aerodynamics. If you have any feedback on my write-up then please comment away.

Exhausting Air Flows Into Wheel Wells

I've started to look again at the grey area that is the effect of exhausting cooling air into wheel wells, particularly those at the front, as I may be adding a gearbox oil cooler where ducting cooling air into a front wheel well is an option (from the lack of any alternative I'm already retaining the oil coolers ahead of the front wheel wells and exhausting cooling air into them).

I think the issue is very important as the wheels are supposedly responsible for up to 33% of drag, most notably at higher speeds, from generating a complex series of vortices and turbulent flows.

I've found very little on air flows within wheel wells in general in several hours of searches let alone on adding air from cooling flows. From what I knew and have found out, air flow in and around wheel wells is very complex, depends on many factors and is very hard to model. Furthermore, some unexpected factors such as the groove between tyre tread and sidewall has significant impact. In general, air in the wheel wells have a negative Cp (AFAIK talk of 'higher' pressures in the wheel well to explain fender/wing vents refers to their values relative to those above the fender/wing not pressures in absolute terms) that would help pull air through a radiator and adding more air to be exhausted from the wells will create more drag in many forms.

My gut feeling is that I should avoid dumping more air into the front wells as that will create more drag than dumping that air underneath the body.

Does anyone have anything to help educate me here?

05-12-2016, 12:55 PM	#1 (permalink)
wildman10 EcoModding Lurker Join Date: Feb 2015 Location: London, UK Posts: 15 Thanks: 0 Thanked 8 Times in 6 Posts	Aerodynamics for Cooling Systems of Turbo Car I'm heavily involved in adding a turbo to a normally-aspirated car and have been designing the cooling systems from scratch, with particular emphasis on aerodynamics. Although the car, a Mazda RX8, is not noted for ecomodding I've tried to use its principles in my work. Write-Up on cooling system aerodynamics I wrote the write-up here to explain my thoughts on cooling system aerodynamics. If you have any feedback on my write-up then please comment away. Exhausting Air Flows Into Wheel Wells I've started to look again at the grey area that is the effect of exhausting cooling air into wheel wells, particularly those at the front, as I may be adding a gearbox oil cooler where ducting cooling air into a front wheel well is an option (from the lack of any alternative I'm already retaining the oil coolers ahead of the front wheel wells and exhausting cooling air into them). I think the issue is very important as the wheels are supposedly responsible for up to 33% of drag, most notably at higher speeds, from generating a complex series of vortices and turbulent flows. I've found very little on air flows within wheel wells in general in several hours of searches let alone on adding air from cooling flows. From what I knew and have found out, air flow in and around wheel wells is very complex, depends on many factors and is very hard to model. Furthermore, some unexpected factors such as the groove between tyre tread and sidewall has significant impact. In general, air in the wheel wells have a negative Cp (AFAIK talk of 'higher' pressures in the wheel well to explain fender/wing vents refers to their values relative to those above the fender/wing not pressures in absolute terms) that would help pull air through a radiator and adding more air to be exhausted from the wells will create more drag in many forms. My gut feeling is that I should avoid dumping more air into the front wells as that will create more drag than dumping that air underneath the body. Does anyone have anything to help educate me here? Attached Thumbnails __________________ Old age and experience will always beat youth and enthusiasm. Failing that, older people know more tricks and can afford better lawyers. 3 projects: Designing systems for turbo-charged engine in Mazda RX8 and aerodynamic modding for mpg on road and performance on track Mazda RX8 R3 for improved mpg (currently 17 mpUSg) 2001 Honda Accord 2.3 for improved mpg (currently 29 mpUSg in sedate driving)