Today if we were to keep developing the car, we would add fender vents to relieve pressure in the wheel wells, add more pressure reducing vents to the hood. add extensions to the side skirts to reduce air from spilling under the car. Make some improvements in underbody air flow. Lower the ride height and add some front to rear rake.
Any of the things we did here can be easily made in the home workshop and if you follow our guidelines will absolutely help, not cause excessive drag, possibly reduce it nor screw up your aerodynamic balance. Going more radical than this can mean some cut and try possibly going backward. Unless you have access to analytical tools like CFD or can hire an aerodynamicist with motorsports experience, our mods are safe and sure. Go ahead and try them on your car!
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You mentioned “racket mounted pins that slide into holes on the support bracket mounted on the frame. ” Any chance you have a part number or example link to go off of? Thanks!
The pins were just something we made.
Ive got A Z32 Race/Street setup. Still using the factory locations for the intercoolers (using US spec bumper). Would it be best to have the air exit out the bottom if front of each wheel or put vents in the wheel wells? Currently I am only using the factory exit out the bottom ( the version without the factory NACA duct).
Rear Diffusers in the back are challenging due to the dual exhaust. At this time I am not interested in a side exhaust. How much would it reduce in performance if you ” poke” the exhaust through or would I be better off making a smaller one that just goes between both exhaust pipes?
Last thought. It’s regarding air flow in the Engine bay. Currently I don’t have any holes in the hood, however I was thinking of taking off the molding that seals the hood near the windshield/wiper area. It would leave a 1″ gap along the entire width of the hood where the air could exit. I am unsure if that would help or hurt.
I would vent in the wheel well or better out the sides in front of the wheels. It is better to blow the exhaust over the top of the diffuser rather than in it. Removing the molding at the rear of the windshield is a bad idea, the base of the windshield is a big high-pressure zone, the flow would back into the engine compartment, the opposite of what you want.
By your comment of the high pressure zone in front of the windshield, would that also mean lifting the hood to vent hot air is a bad idea/ineffective?
Yes, looks cool, works bad. Look at static pressure contour from CFD on Google image search. Pretty obvious, it’s a bad spot to vent. You want to vent in LP zones, gurney flaps, and gills, can prevent flow reversion.
Those strakes on the diffuser are flow conditioners, not VG. The point of them is to reduce spanwise flow. They were heavily used on early swept wing aircraft.
Also, the point of producing a vortex, is to have an effect on a surface downstream, pointless to put VG on the rear, unless that vortex is directly making down force (which is unlikely, but not necessarily inconceivable.)
I disagree and so do other motorsport aero guys including the guy who helps me that has a PHD in fluids.