Wing vs spoiler vs none on an X

[Janis]

Love to move my hand up and down through the air, in big arching curves as I'm driving. Feels like I'm flying. Then I make sounds like.....(ooops I've said too much).

Hahah I do same even at 30kmh
Without sounds, yet.

 

[carl]

And you have some baby boomer behind you trying to figure out why you can't make up your mind about turning left or right using hand signals.

 

[Dr.Jeff]

Well, if it's a baby-boomer behind then don't worry about it. He's had his turn signal on for the last four blocks and no intention of making any turns.

 

[Fiataccompli]

Well , I can't really answer the original question (but I AM considering ditching the factory wing that someone put on my 85, maybe in favor of a duck tail spoiler). I can say that ever since getting serious about bicycle racing a a while ago I have re-thought those (ref the comments about autoX discounting aero) old preconceptions about the power of air flow. Yeah, makes a difference at pretty low speeds....where you feel that & where it makes a difference with our cars & their HP I don't know.

 

[Steve Hoelscher]

Yep. I lived in St. Augustine Florida for several years, just across the street from the beach. I road my bicycle on the beach nearly every day. I always chose the windward direction for the outbound leg so I would be returning with a tailwind. A 5 mph head wind at 20 mph on my bicycle was big.

 

[Fiataccompli]

You are living better than me...when I'm at the beach (riding a bit inland...used to regularly ride Neptune Beach-St Augustine/back when we would go to Neptune quarterly) I am pretty sure that I managed to have a headwind both directions.

I realized that I am not psychologically suited to ride on the beach and a beach cruiser when I found myself within a few minutes of taking off on the beach tucked in to a low aero position holding the bars a few inches from the stem...yeah, it was actually pretty efficient, but I'm pretty sure I was not doing "beach cruiser "right!

When you're downhill or coasting in a paceline (where you DO NOT brake) the amount you can modulate speed by your position on the bike really brings the point home. Strategy/physics/mechanical fun/competition....hard for me to resist the lure (and I'm sure it's the same with stuff with ICE motors) of racing!

 

[Dr.Jeff]

Spent most of my life living on the beaches of Southern Calif. Enjoyed riding the boardwalks several times a week, typically a 12 mile loop. But only the casual 'beach-cruiser' type of riding, with frequent stops at friends' places, bars, where-ever it was fun to hang out. So doesn't really count much as exercise. And yes, somehow it seemed I'd always being riding against the wind, both ways. Felt like you had a tire go flat.

I think the point about vehicle aerodynamics making a difference, and at what speed that happens, is typically more concerned with things like downforce vs drag. Although I also agree that air resistance is a valid aspect, especially with a low power vehicle like the X.

 

[Steve Hoelscher]

I started out riding down A1A from St. Augustine, south, typically to Matanzas Inlet or Marineland, and back. St. Augustine Beach is a drive-on beach (fairly hard packed) and typically not busy during the week and practically deserted south of St. Augustine Beach until you get to Ft. Matanzas. One of my neighbors had a couple of cheap 10 speed "mountain bikes" that he put in his yard sale and I bought both of them for $40. Now I had bikes that I could ride on the beach without ruining my nice road bike. So I would ride these at a fairly brisk pace, for a cheap bike on hard packed sand with a head wind, until the sea water began to ruin the mechanicals. Once a bike was done I would take it to the dump and roll out another I had bought at area yard sales. I did this for most of the 10 years I lived there.

 

[Dr.Jeff]

Good times.

 

[Kevin Cozzo]

My car won’t go fast enough to generate downforce from an aero aid That or its driver can’t drive it fast enough to take advantage of the downforce from an aero aid...

yeah, but you'll look so cool! lol

 

[Fiataccompli]

Good man, keeping the road bike off the beach!

My reference to air flow & cycling was only that its "there" more than we sometimes assume. Don't need downforce on a bicycle & aero may or may not be a big issue for our cars (it was, however, rather fascinating watching how the MPG varied on my TDi wagon based on combinations of speed & how much stuff was attached to the car...nothing/roof rack/hitch rack/combinations thereof/etc).

But all this does lead me to ask whether anyone has any data on if the duck tail does function well as a spoiler.

 

[Dr.Jeff]

I agree air resistance plays a role. I remember waaay back when full-sized American vans were all the rage. They customized the heck out of them. About the same time the "energy crisis" hit and gas prices soared. So one of the magazines wanted to see what could be done to improve the fuel mileage of a van (I know). Bottom line was one of the biggest improvements they found was to remove the side-view mirrors. That reduced the air resistance enough to make a noticable difference.

So I didn't mean to discount air resistance earlier. I was merely saying that in most automotive discussions that I've seen when "aerodynamic effect" is the topic, it seemed to focus more on downforce for some reason. Likely more of a track related thing, to gain traction/grip.

But for a street car air resistance is probably more relevant.

 

[Janis]

Got a wasp somehow in the car now and tried to get it out without stopping. Had to open a door at 60kmh. There is enough force..

* about bicycles- had a treck bike supposed for sprint disciplines with low drop handlebar- pleasure to ride against wind

 

[GregS]

My version of a spoiler. I fitted a temporary small boot lip spoiler as a trial to see if it has any effect on aero or grip, I didn’t want anything large enough to cause drag on the straights, it is only 22mm high and 30 degrees from horizontal, a bit like the ones on some modern sedans. I also shot some video on the way to the track with the car on the trailer at up to 120kph (tow car and trailer may have had some effect on aero) with 4 short bits of string/wool taped to the boot lid to see what happens with the air flow. As expected, it’s very turbulent back there, mostly the string was blown forward and did almost nothing, the most active one was attached to the trailing edge of the engine lid, it occasionally rotated and lifted vertically (see still shots). Comparing lap times with and without the spoiler, my conclusion is that it had no effect, and I would have to make something taller and/or elevated above the boot lid to have any effect, but I don’t want to create any extra drag.

 

[fastx19]

In my experience, I have to agree with Steve on his points from the actual benefits and use of a wing. However, if you are going for the "Look" more than the application, then you can will probably want something a bit different. As a teen in the very early 80's, I had the Lamborghini on the wall with its big ass wing on the back. Aerodynamically it did 0 for the car, in fact I think it made it slower. (Don't even get me started about the wing on the hood!) Anyways, even though performance wise it did nothing, for looks it was awesome. I think Road and Track had an article where they showed some bimbo posing with one and a saxophone on the wing (it was the 80's people) and their comment was the only use of the wing was to hold the sax.

Later in life, I had the chance to build up a race car and stuck a big ass wing on it (as you can see in my thumbnail) but in order for it to really work on the X you need to be up pretty high so the air coming over the car actually gets to it. However, as is it with all things in life, once you put the wing on, then you will suddenly find yourself needing a lot more down force on the front. We did the same thing on the front of our car with a big ass splitter. Looked interesting but it worked. Sometimes fast is not pretty...

 

[Cratecruncher]

In the early 70's of aerodynamic devices in F1, Colin Chapman was constantly pushing the rulebooks and the laws of physics. One story I heard was about the huge wing on the back of the Lotus 72D. It was mounted with very hard durometer rubber grommets because the rules said the inclination of all wings must be fixed. When the judges pushed on the back of it the thing was rigid. But at least one driver behind the 72D noticed the Lotus driver's helmet pop into view on every straightaway. Apparently that wing could generate a LOT more force than some whimpy 200 pound official.

An airfoil produces net negative pressure in proportion to the square of speed and to the angle of inclination. Unfortunately the pressure is perpendicular to the wing's surface meaning there is always a small component facing the opposite direction that you are going and that's a drag. Airfoils with a thicker cross section tend to generate more lift at lower speeds. There are libraries full of airfoil shapes and billions spent gathering empirical data on them. If you just want the looks, go for a flat plate parallel with the ground similar to the stock wing thingy. If you want a low speed downforce generator you'll want a big fat asymmetric wing section kicked up in the back out in unobstructed airflow but adjustable so you can flatten it out for the ride home.

 

[stingray250]

Wing?!?!?!? What wing.......

I took s cheap ricer spoiler and made some new euro lookin side skirts, spaced the blades out a bit...

Works for me.

 

[JimD]

It is really a matter of personal preference. I have never had a huge wing or duck tail. I have had 4 Xs with plain trunk lids, two lids with chrome luggage racks and one late model with "stock wing" on the lid. Obviously, I can't decide. I have a late model wing on the shelf in case I change my mind... again.

I couldn't find pictures of some of the cars. I only own the first 2 cars pictured.

 

[Steve Hoelscher]

I liked the look of the lip spoiler on X1/9s, assuming they have a more aggressive overall look. Wider wheels/tires, slightly lowered, etc...

I like the wing if the car has a very aggressive look. FAZA flares, front spoiler, Very wide wheels/tires. Its all very much a package. A big wing on an otherwise mostly stock car looks out of place. And then the VERY FAZA styling cues look like something was forgotten without the wing.

Incidentally; there is a reason Dallara mounted the wing at the height of the roof in his original design. The air flowing over the roof will tumble badly behind the rear window over the engine and rear trunk. A low mounted wing is very inefficient as the air flow is very dirty there. The higher wing works much better in a cleaner flow.

 

[darwoodious]

My version of a spoiler. I fitted a temporary small boot lip spoiler as a trial to see if it has any effect on aero or grip, I didn’t want anything large enough to cause drag on the straights, it is only 22mm high and 30 degrees from horizontal, a bit like the ones on some modern sedans. I also shot some video on the way to the track with the car on the trailer at up to 120kph (tow car and trailer may have had some effect on aero) with 4 short bits of string/wool taped to the boot lid to see what happens with the air flow. As expected, it’s very turbulent back there, mostly the string was blown forward and did almost nothing, the most active one was attached to the trailing edge of the engine lid, it occasionally rotated and lifted vertically (see still shots). Comparing lap times with and without the spoiler, my conclusion is that it had no effect, and I would have to make something taller and/or elevated above the boot lid to have any effect, but I don’t want to create any extra drag.

GregS - I love the look of your engine cover here. Definitely not stock... looks like bare metal that was clear coated? Clearly a custom rear cover with the elongated vents. Quite nice.

Please do give details. Thanks.