no spoiler look

[REMUS]

What do you reckon on this, most GTE's seem to have the spoilers still on. I think this is quite a nice style, what do you guys think?

http://i24.ebayimg.com/03/i/03/11/1b/1c_1_b.JPG
http://i7.ebayimg.com/03/i/03/11/3f/32_1_b.JPG

The Rear bumper isnt really to my taste but I do like the tail gate and the custom vauxhall lettering on the smoothed area, although the pic's are quite fuzzy.

[Sweeny]

id like da whole car if da bumper at the bakc didnt stick out so much from the tailgate!!!!

but yeah no spiler looks nice, but it makes me think of a bog standard astra

[_SBD16v]

my gte has no spoiler ;)

[REMUS]

yeah rear spoilers actually really screw aero-dynamics.

[DarrenH]

yeah rear spoilers actually really screw aero-dynamics.

for a good reason ! the mk2 is shaped like a big plane wing, the gte aerofoil "spoils" the airflow going over the back of the car to stop the rear end lifting at high speed !

i think i read somewhere that the only road going cars with big enough wings to create positive downforce are the sierra and escort cosworths. all the rest of the cars fitted with spoilers are there to prevent UPLIFT !

[REMUS]

Well I know the physic's in the operation of a performance rear spoiler.

A GTE spoiler isnt located in an area where is recieve's enough of an influx of high velocity air current to create a downforce in comparison to say the roof tip spoiler that is available or even better the whale tail even if it looks kinda funneh :p

[DarrenH]

but it doesnt create downforce, i already said that !

[REMUS]

and therefore it doesnt do anything worth taking into consideration... my point was that the spoiler only has one effect which is drag.

[Steve Heley]

Ran mine for a while without the spoiler, only difference i noticed was it didn't look as good as it does with it on :)

[dethstar]

apparently the air flow isn't fast enough for the spoiler to have any affect (if any at all), until you are doing at least 100.

[REMUS]

depends on the position, surface area and angle of the spoiler, some of the chav'ed up saxo's you see flapping around have pretty decent down force at 20 mph lol

[tomstickland]

A GTE spoiler isnt located in an area where is recieve's enough of an influx of high velocity air current to create a downforce in comparison to say the roof tip spoiler that is available or even better the whale tail even if it looks kinda funneh
There will be high speed air flow over the spoiler. It will flow down the back of the tailgate.

Anyway, the rear spoiler is what make a GTE look like a GTE.

[REMUS]

I'm afriad like all hatch backs this isnt true, the only air that reachs the spoiler is the disturbance created by the contours of the body steamline.

If you don't believe me all you need to do next time your at a rolling road when they set up the big fan, is stand behind the car. Nearly all the air is deflected away.

The GTE spoiler is purely cosmetic. I think the front and rear bumpers make a car look like a gte imo.

[tomstickland]

Nah, when the air flows over the top of car then it also flows back down the rear of the tailgate. There is a low pressure area behind the boot of the car sure. Lowering the drag coefficient is all about trying to make the front and the rear of the car streamlined so that the air flows above and below can match up.

[REMUS]

And thus my rather simple/blunt point "yeah rear spoilers actually really screw aero-dynamics."

A rear spoiler is not steamlined. A car will go faster without one.

[_SBD16v]

i dont care about speed i like the look without one

[REMUS]

i dont care about speed

*has a heart attack and faints*

[tomstickland]

And thus my rather simple/blunt point "yeah rear spoilers actually really screw aero-dynamics."

A rear spoiler is not steamlined. A car will go faster without one.

Yes, anything that increases downforce will increase drag too.
So it will go faster, but I think I'd prefer a bit more downforce on the back.

[Brett]

If you don't believe me all you need to do next time your at a rolling road when they set up the big fan, is stand behind the car. Nearly all the air is deflected away.

LMFAO very scientific. Why didnt all the people who designed the cars save a fortune on all that wind-tunnel techonlogy and just get a big fan for their garage?? A hatchback is actually a very aerodynampic shape, and the main flow of air will be down the rear window over the spolier, regardless of wether or not its cosmetic.

Put the spoiler on anyway. It wont slow you down at all, the noticon that it might do in any noticable way is laughable.

[REMUS]

It was the only real world application for tom to experiance. I don't exactly know what you are trying to say because you are making such a general comment.

For instance your comment "A hatch back is actually a very aero-dynamic design" what relivance does that have to anything?

1) we arn't talking about the car we are talking about the effects of the spoiler
2) it is the formation of the front of the car that has the most effect on it's coefficentcy rateing not its arse lol.
3) the main flow of air hits the windsheild/front bumper if you have ever studied wind tunnel research, i belive they did some promotional stunt for the calibra because that is still the most aero dynamic coupe out there atm i think? well it was at the time.

It isn't laughable that a rear spoiler has an impact, it just doesnt on a gte, it only creates a drag vortex at the back of the car which makes it handle better but slows it slightly.

Brett all of this has already been talked about. I don't want to hav to comment on the rest of your post but i will if you want?

[tomstickland]

The critical word being "slightly". I expect the spoiler to increase down force slightly and increase drag slightly.
I expect that with the GTE it was 50-50 aerodynamics and styling.

However, I think the rear of a car will have a much greater effect on drag than you seem to think.

[Brett]

It was the only real world application for tom to experiance. I don't exactly know what you are trying to say because you are making such a general comment.

For instance your comment "A hatch back is actually a very aero-dynamic design" what relivance does that have to anything?

1) we arn't talking about the car we are talking about the effects of the spoiler
2) it is the formation of the front of the car that has the most effect on it's coefficentcy rateing not its arse lol.
3) the main flow of air hits the windsheild/front bumper if you have ever studied wind tunnel research, i belive they did some promotional stunt for the calibra because that is still the most aero dynamic coupe out there atm i think? well it was at the time.

It isn't laughable that a rear spoiler has an impact, it just doesnt on a gte, it only creates a drag vortex at the back of the car which makes it handle better but slows it slightly.

Brett all of this has already been talked about. I don't want to hav to comment on the rest of your post but i will if you want?


in response to 1) ealier in the therad you claimed the shape of the hatchback had a negative influence on the effects of the spolier. (in fact is a positive influence) Therefore what car the spoiler is on does matter - apparently. 2) wrong, the rear of any car is VITAL to aerodynamics, nbot only that but the arse of a Mk2 is very clever aerodynamically, its very high and very smooth, these charactheristics greatly reduce drag and thus improve aerodynamics. The result is smoother air flow over the car and, yes, the spoiler too. 3) back to point 2 really, it matters greatly what happens to the air after it hits the front of a car, how it gets channeled around the car. Its not all about the front. I belive (although Im no expert) that a teardrop is in fact a very aerodynamic design, the rear of the teardrop is cruical to that fact. It was precisly due to the shape of the BACK of the Calibra that it was such an aerodynamic design.

In short if I went out and took the spoiler of the back of my car, I would notice nouthing that was either an improvemnet or detrimental to my cars behaviour, vene though as tom says it would have an effect, but its so small its not noticable.

[REMUS]

1) Quote me where I said it then brett? I just read all my comments I did not say once that a hatch back isnt an aero dynamic design.

2) Show me somthing that proves that then? Or is it just say so?

3) "how it gets channeled around the car" I didnt say it didn't matter I said the windsheild and the front bumper where both the main area's, infact when calculateing a co-efficentcy rateing it only takes into account that surface area, because if you think about it logically it is the area that has to force its way through the static/moveing air produceing the most resistance.

The rear end of the car does nothing but channel the air. Do you seriously expect me to believe a mk2 golf's rear end does ANYTHING but round off the veichle, a mk2 astra isnt really much more scuplted.

Watch a slow mo bullet cut through the air and watch how the air currents are created, the main difference is the fact manufacturers have to take into consideration the turbulence created below a car.

[Brett]

I cant be arsed to argue with you. Ive made a point you disagree, Im not going to pretend I have a degree in physics and argue in any great depth about a subject in reality I know nouthing more than the basics about.

i'd only end up looking like a plonker.

You'd do well to think along the same lines.

[REMUS]

oh i already know i'm a plonker :D I do know a cpl of things about physics tho.... i think :p

[tomstickland]

3) "how it gets channeled around the car" I didnt say it didn't matter I said the windsheild and the front bumper where both the main area's, infact when calculateing a co-efficentcy rateing it only takes into account that surface area, because if you think about it logically it is the area that has to force its way through the static/moveing air produceing the most resistance.
The way the air meets back up at the rear of the vehicle is important. The more slab ended the shape is then the larger the low pressure area at the rear of the vehicle is with wasteful vortices. Hence more drag.

[DarrenH]

vauxhall astra gte brochure


the deep front spoiler and neat rear aerofoil drop the CD of the 8v from 0.32 to a sleek 0.30

[REMUS]

I think the front bumper has more to do with that than the rear spoiler, i'll go see if i can dig anything up on google about this topic.

[tomstickland]

If you have witnessed the Le Mans race cars, you will have seen how the tails of these cars tend to extend well back of the rear wheels, and narrow when viewed from the side or top. This extra bodywork allows the air molecules to converge back into the vaccum smoothly along the body into the hole left by the car's cockpit, and front area, instead of having to suddenly fill a large empty space.

The reason keeping flow attachment is so important is that the force created by the vacuum far exceeds that created by frontal pressure, and this can be attributed to the Turbulence created by the detachment.

http://www.gmecca.com/byorc/dtipsaerodynamics.html

[REMUS]

Well thats talking about the sculpture of the bodywork not the spoiler I did say before "The rear end of the car does nothing but channel the air."

I didn't know that the rear end has to cope with more pressure than the front but I suppose its the exact opposite, the front has to compensate for high pressure and the rear for low pressure.

*mind boggles*

[tomstickland]

Yes, and it can seem a bit non intuitive, but the rear is more important than the front because of the big vortex divving about.

[CraigGreen]

dont forget the drag created in & around the wheel arches.

Fitting aftermarket wheels would affect this i'm sure. Thats why the side skirts flare up at the rear to direct air past the (185)tyres isnt it?

Hate all things about the Red Astra at the top of the thread btw.........

[REMUS]

yeah it is very chav'ish I just used it as an exsample for the no spoiler look.

[Tom]

Looks wrong with out the spolier I reckon.

[caul pope]

Well done guys thats a pretty full on discussion thats panned out from the original question; "no spoiler look"! I've no lower spoiler but do have a very smooth roof spoiler (what happens to the aerodynamics now?) that I have never seen before. I like the look, but I would as its my car ;)