A-Pillar aerodynamic modifications / fairings

[ademonrower]

Please read disclaimer at bottom.

Cars with prominent gutters on the A-pillars clearly have an aerodynamic disadvantage in comparison with (more modern) cars with concealed gutters, or no gutters. Without ruining the "look" of a (older) car, I've discovered quite a lot that can be done to make the gutter almost disappear. I've done the modification on a Volvo 245 (wagon / estate / break), without invasive measures or damaging any of the bodywork or shiny trim: I can take the modification off easily, and the car is exactly as it was before.

The modification is basically a hard-PVC slat made from the curved corner of some air-duct shaft, with some small lugs positioned on the trailing edge to locate it flush with the gutter trim, and two small brackets underneath - one top, one bottom - with a screw through them into the rubber of the windshield trim. I used a hot-air-gun to soften the PVC to modify the curvature of the end-parts. That was very easy. I primed the PVC and painted it the colour of my car.

I've driven 1,000s of km on motorways with the modification, and it has never come loose. On the antenna side, I additionally used the antenna screw-hole to affix it. Yes: antenna: additional advantage: I took the external A-pillar-mounted antenna off, and simply re-routed an antenna wire inside the slat: perfect radio reception, perfect solution for that annoying radio antenna :-) which also caused bad air-flow :-(

The "forward-facing" mod of the A-pillar is, of course, only half of the story, because to minimize turbulence AFTER the A-pillar (where there is a step-inwards towards the window) one should also fit a "fairing spoiler" to lead the flow in smoothly to the window glas. However, I haven't done it yet, and I also need to be careful not to obscure view out of that window :-) A small fairing made from perspex or similar, cut to shape, and heat-formed, could be quite easy to make... perhaps also quite easy to fit, but I haven't got that far yet...

DISCLAIMER: I take no responsibility for damage to life or limb if you make a similar modification on the basis of my modification described herein. I take no responsibility for damage to life or limb that may occur whilst driving with this modification fitted to your car. Use your common sense, do tests, and don't take any unnecessary risks. If anything falls off your car whilst driving, it can seriously injure, or even lead to the death of, another driver/rider or pedestrian etc.

[freebeard]

Does it help with wind noise?

[ademonrower]

Good question. Sorry, I can't tell you. I only did it in the **hope** that it would reduce drag. Even there, I have to admit that I didn't test it. Still, if someone has the desire to do a proper analysis of the situation with the Volvo 240 A-pillar, that would be interesting, and the I would have a fairing already made to fit :-) I should really have attached flow-threads, driven and photographed. Perhaps I'll do that now... they worked well in my sailing days :-)

[freebeard]

Volvo 240 A-pillar

Four cylinder, zero doors?

NHV (noise harshness ands vibration) is separable from low drag. The contribution to drag will be small, but the differnce in NHV could be significant, given the proximity to the driver's ears.

I don't think the trailing edge is as big a problem, it might facilitate reattachment or act as a boxed cavity.

[ademonrower]

Thank you: good to know. Perhaps I have then gained more in cabin comfort than in reduced drag :-) I've just made what I call a tailgate flow-extender. I don't know what it's really called. Perhaps you can help me there. pics attached. Basically just to see how it looks/works in preparation for something more "proper". Made from transparent PET heat-formed, and attached with a curl-over to the upper rim of the tailgate.

[aerohead]

Originally Posted by ademonrower

Thank you: good to know. Perhaps I have then gained more in cabin comfort than in reduced drag :-) I've just made what I call a tailgate flow-extender. I don't know what it's really called. Perhaps you can help me there. pics attached. Basically just to see how it looks/works in preparation for something more "proper". Made from transparent PET heat-formed, and attached with a curl-over to the upper rim of the tailgate.

Lucid's lead designer for the upcoming Lucid Gravity SUV, Derek Jenkins, refers to them as a ' rear wing', which on the Gravity, will have 'massive rear overhang', helping to make it the 'most aerodynamic SUV ever'.
Some designers combine them with boat-tailed burst-edges down the sides of the rear glass, creating a shallow, hollow tail on this angled rear to allow for a little additional pressure recovery.

[freebeard]

Jargon on this website would have it a 'Kammback'.

[C4Evermore]

Welcome! Nice work. Looks factory painted like that. I've been wanting to do something on the leading edge of the front doors on my SUV. At high speeds with a crosswind the noise is horrendous. Definitely creating some drag.

[ademonrower]

Thank you to all for comments/compliments! Very much appreciated, as I get into the eco-modding business for the first time. A very worthwhile pursuit, because I've always thought that having a car is a very large responsibility, and that there's a massive space between the kind of materialism that leads many simply to "use" a car as a mere disposable, and the materialism that means "caring" about the material stuff you have, optimizing it, and making it last... thereby reducing it's negative environmental impact. I suppose we're the "lucky ones" who have the interest, have acquired the skills, and have some time to do this. Are there eco-modding barter schemes? i.e. you mend my wooden cupboard, or bake me a cake, and I'll do something to reduce gas consumption of your car? Are there community schemes for teaching people the techniques of hypermiling? When I know enough about this myself, I think I might start one... :-) I really like this forum, by the way! Glad I joined!