downforce...?
09 July 2005, 07:31 PM
#1
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downforce...?
just out of interest i was wondering what amount of downforce, if any, is provided by the average rear spoiler, and specifically the impreza high and low rear spoilers...?
09 July 2005, 07:41 PM
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Originally Posted by brihoppy
just out of interest i was wondering what amount of downforce, if any, is provided by the average rear spoiler, and specifically the impreza high and low rear spoilers...?
). I can't see the STi high level achieving anything like that as most of the force it generates is lost in flex (have you ever watched one at motorway speeds 
). The WRX ironing board is surely just trim. As opposed to "creating downforce", it may reduce lift a little by upsetting the airflow, but not by much.Big wings do look good though
09 July 2005, 09:31 PM
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been on a couple of driver instructor day thingies on a track and they've both told me that the spolier will do nothing, if you look at the spoliers on the back of racing cars - of varying descriptions - they tend to be more vertical than flat.
09 July 2005, 09:45 PM
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Leave your boot unlatched and speed along the road and see what happens. Generally cosmetic spoilers will cause the boot to lift, suggesting they actually cause lift rather than downforce, if anything!
09 July 2005, 10:26 PM
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Davy
When petter's spoiler "went missing"
it made a dramatic difference to the handling.
In general, road car wings make a difference, but not much.
The actual shape / profile of the wing is what's most important. Theoretically you want a nice flat top and an underside which is thicker at the front and tapered up to a point at the back (a classic aerofoil inverted).
The boot lifting at speed is due to the lift created by the actual shape of the boot. Unless the wing is really crap it will at least create some level of isolated downforce.. but of course, in the majority of cases, the rear of the car will still be in lift.. just perhaps a little less lift than without the wing.
In short.. in very high speed aggressive cornering, you'd generally miss the wing if it wasn't there.. but how often do we take corners aggressively at over 100mph on the road?
A more effective way to reduce lift is to lower the car / add skirts, but then of course you can't go over speed bumps
Cheers
Simon
When petter's spoiler "went missing"
it made a dramatic difference to the handling.In general, road car wings make a difference, but not much.
The actual shape / profile of the wing is what's most important. Theoretically you want a nice flat top and an underside which is thicker at the front and tapered up to a point at the back (a classic aerofoil inverted).
The boot lifting at speed is due to the lift created by the actual shape of the boot. Unless the wing is really crap it will at least create some level of isolated downforce.. but of course, in the majority of cases, the rear of the car will still be in lift.. just perhaps a little less lift than without the wing.
In short.. in very high speed aggressive cornering, you'd generally miss the wing if it wasn't there.. but how often do we take corners aggressively at over 100mph on the road?
A more effective way to reduce lift is to lower the car / add skirts, but then of course you can't go over speed bumps
Cheers
Simon
09 July 2005, 11:15 PM
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....I would need to see the stage times again, but I am sure I said to myself at the time that he could not have gone faster. Didn't he get 2nd without it on one stage?
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10 July 2005, 12:43 AM
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He made 2nd fastest on stage 3, but it was a weird stage.
Hirvonen was actually fastest, seb was way out of the top 10, and there were at least 3 or 4 P2's in the top 10.
Petter commented on the handling being less than ideal, but it was a slow stage so the disadvantage would have been slightly reduced. Either way, he did a cracking job on that stage, but unfortunately was way down the field for most of the rally after that
cheers
Simon
Hirvonen was actually fastest, seb was way out of the top 10, and there were at least 3 or 4 P2's in the top 10.
Petter commented on the handling being less than ideal, but it was a slow stage so the disadvantage would have been slightly reduced. Either way, he did a cracking job on that stage, but unfortunately was way down the field for most of the rally after that
cheers
Simon
10 July 2005, 11:06 AM
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Tests in Sport Auto
Lift in kg at 200 km/h: (negative numbers mean downforce)
1. Lotus Exige -58
2. Porsche Carrera GT -40
3. Lotus Esprit Sport 350 -39
4. Mercedes SLR McLaren -35
5. Lotus Exige (2004) -26
6. Porsche GT3 RS -25
7. Porsche 911 GT3 Cup -19
8. Mitsubishi Carisma GT Evo VI -14
9. Mercedes CLK DTM AMG -12
Subaru Impreza WRX STi -12
The old shape MY00 had 11 kg lift in comparison.
Lift in kg at 200 km/h: (negative numbers mean downforce)
1. Lotus Exige -58
2. Porsche Carrera GT -40
3. Lotus Esprit Sport 350 -39
4. Mercedes SLR McLaren -35
5. Lotus Exige (2004) -26
6. Porsche GT3 RS -25
7. Porsche 911 GT3 Cup -19
8. Mitsubishi Carisma GT Evo VI -14
9. Mercedes CLK DTM AMG -12
Subaru Impreza WRX STi -12
The old shape MY00 had 11 kg lift in comparison.