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Batteries : MG4 SE SR versus Trophy LR
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gary333
Established Member
If you think for a second that all car manufacturers are designing cars based on optimal engineering principles then you are living in cuckoo land unfortunately.
Plenty of detailed articles going back decades showing that many car rear spoilers are not reducing drag but quite the opposite. Plenty of manufacturers publish this data in their Tech sheets themselves.
No.
Not sure who is living in cloud cuckoo land here Gary. But it doesn't sound as if you know much about modern car engineering. Today, it's all about optimal engineering. And yes indeed, I was someone that actually part wrote the manuals for car & motorcycle manufacturers so I know about the spec side of things. I cannot speak for all manufacturers of old but trust me, no manufacturers over the last 20yrs fits a spoiler if it's just for show. If it's an aesthetic enhancement it always has to have a cd benefit too. It's actually a rule of engineering. Getting more efficiency/range is critically important, with manufacturers going to quite extreme measures to achieve this, some even breaking the law to get what they want (VW). It has to have a cd benefit. Everything is all about getting best range whether it's ice or EV. Aero-dynamics is particularly important.
I'd be very interested to know where you are seeing this plentiful evidence about car rear spoilers NOT reducing drag & actually increasing it. There are differences in spoilers of course, some fitted to aid braking, some for anti lift while others are for aesthetics. But all have to have some amount of cd reduction. Some spoilers are purely for cd reduction.
Anyway, nice to hear your opinions Gary. Bye for now.
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Bam Bam
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I'm not an engineer, but always thought that rear spoilers were to add downforce and improve grip, which would reduce efficiency.
I noticed that if you look at the most efficient EVs they don't tend to have rear spoilers and instead are very curved.
The Tesla 3 has a sort of spoiler-y thing I suppose, but it is nothing like the one on the MG4, which I was led to believe (perhaps wrongly) was aesthetic and did not improve efficiency.
I noticed that if you look at the most efficient EVs they don't tend to have rear spoilers and instead are very curved.
The Tesla 3 has a sort of spoiler-y thing I suppose, but it is nothing like the one on the MG4, which I was led to believe (perhaps wrongly) was aesthetic and did not improve efficiency.
Hi Bam Bam, yes it's all very interesting this spoiler thing. Spoilers are used for a number of reasons but primarily (in most cases) to improve efficiency especially of vehicles with less than ideal aerodynamics. My own ZS EV has a spoiler above the rear window. It's sole purpose is to reduce drag by improving the cd figure. My car is essentially brick shaped so the spoiler helps somewhat. It has no other real purpose. It certainly doesn't shield the rear screen from road spray & dirt but it may help a little. And that is the same for the majority of cars on the roads. It doesn't necessarily need to be a big 'wing' type as on the MG4 & thus can melt into the car design almost unnoticed. The MG4 spoiler is designed to stand out & help efficiency at the same time. How much extra efficiency it provides is the question.
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Roger001
Standard Member
That is the point of adding a spoiler to the more brick-shaped cars (such as the MG4). Its job is to improve the air flow over the back.
The thing is that the low air pressure zone found at the back does not just cause one effect. Instead, it causes drag and lift, so any added spoiler added is designed to do the best it can to reduce one or both issues. If the spoiler is providing downforce, this just means it was designed to overcompensate for lift.
Everest
Prominent Member
My 2p worth would be that different manufacturers / models use them for different reasons. On performance vehicles they are required to add downforce, especially at higher speeds, despite efficiency reductions. On slower and more energy critical vehicles, such as EV's they will be primarily to reduce drag.
Whilst not wanting to add a flame to the touchpaper of this thread, I have to disagree with our honourable member who claims to know all about the 'spec side of things' saying "all have to have some amount of cd reduction". If that were the case then a) Audi would have added a spoiler to the original TT, rather than adding it as a recall because the vehicles were found to be unstable at high speed; and b) our 996 and 997's were equipped with motorised spoilers which only raised at 75mph and back down at about 55mph. I'd suggest that the engineers at Porsche wouldn't have added the complexity and weight of the motors if said spoilers had a beneficial improvement of cd, rather than just downforce at high speed.
Yes, without getting over complicated, you are perfectly correct in that different cars use spoilers for different purposes just as I eluded to in one of my earlier posts. Based upon your above comments you perhaps are not understanding why spoilers are fitted. But you are not adding flame to the touch paper either. Down force & braking spoilers often retract partially or fully dependant on purpose as they only get used for the purpose intended. However an aero dynamic advantage is often still available when only partially retracted & of course no aero advantage is required when a spoiler is deployed for braking other than sometimes some down force. But that in its self is an aero dynamic advantage by increasing cd, not reducing it.
I also have here & in other threads eluded to the fact I was a tech & engine design engineer for years working with the folks that actually design cars. That was imperative that we worked together on parts of the project. Aero dynamics affects the engines so the whole car is developed as one piece so everything works together, if you see what I mean. Therefore I learned a considerable amount about aeros, including spoilers. I wrote the manuals on engines & transmissions for the products we made. I never said I was an expert on aeros but I know a thing or two from wind tunnel testing that we did on countless cars. I can repeat, respectfully most folks don't understand how spoilers work or why they are there. And that's ok, why would they! The reasons can be multiple. But folks can of course believe what they wish to believe. That's all fine.
I also have here & in other threads eluded to the fact I was a tech & engine design engineer for years working with the folks that actually design cars. That was imperative that we worked together on parts of the project. Aero dynamics affects the engines so the whole car is developed as one piece so everything works together, if you see what I mean. Therefore I learned a considerable amount about aeros, including spoilers. I wrote the manuals on engines & transmissions for the products we made. I never said I was an expert on aeros but I know a thing or two from wind tunnel testing that we did on countless cars. I can repeat, respectfully most folks don't understand how spoilers work or why they are there. And that's ok, why would they! The reasons can be multiple. But folks can of course believe what they wish to believe. That's all fine.
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OriginalBigAl
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I reckon the spoilers are there for kerb appeal and as a extra inducement to part with more money for the higher spec model. An instantly visible ,recognisable addition which raises your social status.
Like the old L, GL, GLS badges.
Like the old L, GL, GLS badges.
MG Clive
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Ahh yes, the picnic table, lol Picnic Tables, Aerodynamics and the Girl | ViaRETRO
Everest
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They don't make them like the used to, do they... the cars, not the girls, that is 
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