I would love to hear from some engineers and flyers on this question: Why is the 308 rear spoiler angle opposite to every other spoiler/wing I have ever seen on a car? The angle of attack should be to provide downward thrust on the car. It seems looking at ours that it would cause lift. To demostrate I have included some pictures below. So, what's up with this? Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
I have always assumed that they were for style more than anything else just like on most cars. Remember that when they started putting those on the 308 body was 8 yrs old and due for style updating.
As far as I know, the "generally admitted" story goes that the spoiler was a necessity on the 365 (512) Berlinetta Boxer for extracting hot air from the engine compartment. The aerodynamics of that car created a sort of "cushion of air" which stagnated just behind the sharp rear window and over the engine louvers (what in aviation you would, in a way, call a "boundary layer") preventing the hot air from the engine compartment exiting through the engine louvers; there were fears that the hot air stagnating in the engine compartment could damage the engine in the long run, through insufficient cooling. So the rear roof spoiler was introduced to energise a flow of air onto this place, just behind the rear cabin window; to blow that cushion of air stagnating over the louvers, and allow extraction of hot air from the engine compartment. This is the reason why the rear lid of the spoiler is pointing downwards: the spoiler is forcing outside air over the engine louvers. It is said that it worked... On the 308, and to my knowledge, the spoiler has no other function whatsoever as aesthetics, and creating a family resemblance to the 365/512BB. In Europe at least, the roof spoiler somewhat fell "out of fashion" with the end of the 328 line; most late European 328 GTBs have no roof spoiler, returning to the purity of lines of the original "Vetroresina" (= the glass 308) Best
Just a guess, but I would assume the top mounted spoiler is used to limit turbulence over the engine vents, increase heat dissipation from the engine compartment, and reduce detachment of laminar flow over the rear of the car rather than directly increase down force on the rear of the car. The shape of the engine compartment of a 308 reminds me of a pickup truck airflow wise, and those trucks tend to loose the laminar flow of the stream of air over the bed and circulate air that is in the bed. And when that stream of air separates from the tail of the car, it makes the rear lip less effective. DISCLAIMER: I did have ONE class in aero engineering in college and I have stayed in a Holiday Inn Express recently. Best Regards, John M
I beleive this was to aid more hot air extraction from the rear deck. if you look at older 308's ( pre QV ) a lot of them just had two slots of louvers ( euro cars ) they moved to all cars having the extra long rows of louvers with the injected cars and all QV's and the spoilers.
Well from the responses (thank you) it seems that the correct name for this device should be a "heat reduction fin" and not the common spoiler.
Happy to oblige: my two babies in April 2011, both 1989; the black "S" has the roof spoiler, the red "B" do not... I can testify that the engine temperatures are exactly the same on both car, een if I tend to push the "B" harder. Best Image Unavailable, Please Login
I just looked at mine and it seems to me like if you cut it in half and looked at the profile the bottom might have a subtle curve while the top is flat. The implication is that air flowing around this thing would speed up as it flows over the bottom curve creating down force at the top (an airplane wing turned upside down). I don't think its angle of attack would be an issue in creating down force, though to my eye it doesn't really appear to have the shape of a true NACA airfoil. The profile would need to be measured for chord and camber to know for sure...
If that is the case then perhaps it reduces engine compartment temp? We know that engine temp is regulated by the thermostat right.
The critical technical element here are the micro-eddies in the laminar flow region caused by the faux leather finish. GMAB guys...iIt's not an air-cooled engine. The lip on the deck edge is somewhat functional...the spoiler is pure cosmetic 70s "look" and the one thing on the car I'd like to remove. IMO its a cheesy flaw in one of the all-time great auto styles.
Sad to think that a car designed by an aerodynamics expert with a low cd would incorporate a useless spoiler for form without function...
I don't think you could call the 308 a form-follows-function vehicle. It is not. The styling may have been aided by an air tunnel but the shapes and details are clearly driven first and foremost by aesthetics and not pure function. And I like the spoiler. Don't mind the car without, but also don't hate it with.
Dennis, Having a "S" with the roof spoiler, and a "B" without, I usually spend some time looking at both cars and trying to make my mind a find a definite answer; as for myself, I do indeed like the "S" with the roof spoiler and the "B" without...so I am fine with my cars as they are! I do know that I still think the "S" looks better with the roof spoiler...but, on the other hand, my "S" being black, it is a bit different, as every detail is integrated in an overall color. On a red car, I think the black spoiler compliments nicely the windows louvres. For a "B", you know that the roof spoiler could also be ordered body color should you wish it to be so, and this does not appeal to me. But definitely, it is true that the later "B"s ('88 and '89) were mainly ordered here without the spoiler, which seems to confirm a change of taste, a "back to the original 308" trend...
Ferrari 308 Quattrovalvole Road Test - Aug 1983 Regarding differences between the 308 QV over the previous 2-valve model: "A basket-handle airfoil spans the gap between the roof sail panels, apparently for no reason other than the American sales department's thinking it makes a nice decoration."
Hi, Sorry to hijack this thread but I've always wondered why some cars come with a "textured" finish to the spoiler matching the GTS roof and some had a smooth finish. My USA 1983 GTS has a smooth texture. Any comments.
My 82 had the rough texture. My 85 has smooth. I had metal on the 82 and 85 but I understand some where fiberglass?
Well, the power windows, mirrors and air conditioning were concessions to "luxury" but is there any documentation suggesting that the spoiler was bolted on for purely cosmetic reasons? And I don't think the looks of the spoiler hurt the car either...
