Discussion
Desert Dragon said:
Porsche911R said:
I like downforce.
Downforce meaningless on road cars - on road you'd be better off with a bit of mass and 4wd 
the thing is, now we have quite big numbers on road cars, you actually get a good amount of downforce at 100mph.
as most of these cars hit 140 in a blink of an eye it's better to have downforce than lift.
4WD will offer you zero extra grip if you have lift and the front gone light !
Porsche911R said:
Desert Dragon said:
Porsche911R said:
I like downforce.
Downforce meaningless on road cars - on road you'd be better off with a bit of mass and 4wd the thing is, now we have quite big numbers on road cars, you actually get a good amount of downforce at 100mph.
as most of these cars hit 140 in a blink of an eye it's better to have downforce than lift.
4WD will offer you zero extra grip if you have lift and the front gone light !
Oh come off this BS about 'good amount of downforce at 100mph'. A GT3 will not even be producing 100kg of downforce at that speed. And downforce acts as a function of total car weight. For a 1500+kg car it's not in any way significant. A bit faster per the stopwatch (and really that's a bit only) but that's about it.
isaldiri said:
Oh come off this BS about 'good amount of downforce at 100mph'. A GT3 will not even be producing 100kg of downforce at that speed. And downforce acts as a function of total car weight. For a 1500+kg car it's not in any way significant. A bit faster per the stopwatch (and really that's a bit only) but that's about it.
you are probably correct about that, but at say 150mph in a corner my Scuderia feels a lot more stable than my dad's BMW (or for that matter my FF), so less weight and a little downforce (or less lift) probably has a positive effect overall. my GT2 on the other hand felt scary as soon as there were gusts from the side (I suspect that was the wing as the Audis around me seemed to have no such issues...)Edit: on the GT2 I meant even on a straight road
Desert Dragon said:
GT3 and 911 turbo latest gens are on road or lets say autobahn at 140mph on a bend. Explain how down force vs 4wd may be an advantage in real conditions please and how often which is perhaps more relevant? Its raining most of the time all year round. If you check your average speed on any 911's continuous computer it will show approx 30-33mph over its life.
you have lost me with that lot.it's not raining very often I find, so that's a pretty strange comment to make 1st off, . and while the ave speed is 30 ish as we spend a lot of time at lights etc, we do go to 140+ most trips out.
if you have lift in a 4WD car you have lift be it 4WD or not, so I just don't get your point the cars going to be unstable if it has lift at speed.
isaldiri said:
Oh come off this BS about 'good amount of downforce at 100mph'. A GT3 will not even be producing 100kg of downforce at that speed. And downforce acts as a function of total car weight. For a 1500+kg car it's not in any way significant. A bit faster per the stopwatch (and really that's a bit only) but that's about it.
I’ve been round the Milbrook bowl in mine...you can absolutely feel the effect of the aero as speeds increase. Can’t remember the speed but somewhere between 100 mph and 120 mph you can really feel the car sit down.Porsche911R said:
Desert Dragon said:
GT3 and 911 turbo latest gens are on road or lets say autobahn at 140mph on a bend. Explain how down force vs 4wd may be an advantage in real conditions please and how often which is perhaps more relevant? Its raining most of the time all year round. If you check your average speed on any 911's continuous computer it will show approx 30-33mph over its life.
you have lost me with that lot.it's not raining very often I find, so that's a pretty strange comment to make 1st off, . and while the ave speed is 30 ish as we spend a lot of time at lights etc, we do go to 140+ most trips out.
if you have lift in a 4WD car you have lift be it 4WD or not, so I just don't get your point the cars going to be unstable if it has lift at speed.
MDL111 said:
you are probably correct about that, but at say 150mph in a corner my Scuderia feels a lot more stable than my dad's BMW (or for that matter my FF), so less weight and a little downforce (or less lift) probably has a positive effect overall. my GT2 on the other hand felt scary as soon as there were gusts from the side (I suspect that was the wing as the Audis around me seemed to have no such issues...)
Edit: on the GT2 I meant even on a straight road
Iirc, sportauto supertest had the 997 gt2 producing more downforce front and rear than the scuderia. In fact the scud I think produced hardly anything (small amount at the rear only).Edit: on the GT2 I meant even on a straight road
Cheib said:
I’ve been round the Milbrook bowl in mine...you can absolutely feel the effect of the aero as speeds increase. Can’t remember the speed but somewhere between 100 mph and 120 mph you can really feel the car sit down.
But is it really aero you are feeling or more an issue of general vehicle tuning to feel more stable at speed? I find some cars a bit of a pain on poor surfaces at low speeds but once moving at a decent click it's much less of an issue for example. Proper downforce ime (in say radical not piddly amounts in a road car) is a bit of a blind faith test - you chuck the car into a corner faster than you think is sensible and rely on the extra grip to get you through and personally don't/can't feel the aero. The numbers involved for a gt3 to me anyway simply don't suggest a big difference.
Desert Dragon said:
You do not get any meaningful lift in a 911 turbo on autobahn at 140mph. Turbo has extra weight right over the front axle and and this keeps them completely planted. If you'd like to meet up I'd be delighted to show you. Like doing 70mph in an ordinary car and its effortless and comfortable as a Lexus so not sure what you're on about with down force. Do you think it helps you on road other than as a styling cue?
nothing to do with 4WD, the turbo has that electronic front air dam which comes into action !isaldiri said:
But is it really aero you are feeling or more an issue of general vehicle tuning to feel more stable at speed? I find some cars a bit of a pain on poor surfaces at low speeds but once moving at a decent click it's much less of an issue for example.
Proper downforce ime (in say radical not piddly amounts in a road car) is a bit of a blind faith test - you chuck the car into a corner faster than you think is sensible and rely on the extra grip to get you through and personally don't/can't feel the aero. The numbers involved for a gt3 to me anyway simply don't suggest a big difference.
Don’t know and I know sweet FA about suspension systems but I don’t know how a car through tuning can “sit down” at that speed. It’s a pretty noticeable effect. And let’s face it that spoiler will at some point start producing downforce...it doesn’t just do nothing. Proper downforce ime (in say radical not piddly amounts in a road car) is a bit of a blind faith test - you chuck the car into a corner faster than you think is sensible and rely on the extra grip to get you through and personally don't/can't feel the aero. The numbers involved for a gt3 to me anyway simply don't suggest a big difference.
Cheib said:
Don’t know and I know sweet FA about suspension systems but I don’t know how a car through tuning can “sit down” at that speed. It’s a pretty noticeable effect. And let’s face it that spoiler will at some point start producing downforce...it doesn’t just do nothing.
do you really think something like 70-80kg is going to make the car 'sit down' as you say? the average passenger probably weighs that, I presume you don't particularly feel that effect with a passenger vs without....isaldiri said:
do you really think something like 70-80kg is going to make the car 'sit down' as you say? the average passenger probably weighs that, I presume you don't particularly feel that effect with a passenger vs without....
80kg of passenger is very different to 80kg downforce..As you know downforce is as it says ie an invisible downwards force not subject to the laws of centrifugal forces..A passenger increases centrifugal force more than it contributes to downforce,,However i agree with you that 80kg of downforce is pretty insignificant on a 1500kg GT3 when compared to the 900kg of the same force on a 900kg Radical;;Interestingly as downforce increases exponentially with speed and a GT3 Touring produces 50% of the winged GT3 at all speeds so on balance i also believe Cheib when he says he feels his GT3's downforce at 120mph on the oval Millbrook bowl..If he owned a Touring i'd be more sceptical..
isaldiri said:
Cheib said:
Don’t know and I know sweet FA about suspension systems but I don’t know how a car through tuning can “sit down” at that speed. It’s a pretty noticeable effect. And let’s face it that spoiler will at some point start producing downforce...it doesn’t just do nothing.
do you really think something like 70-80kg is going to make the car 'sit down' as you say? the average passenger probably weighs that, I presume you don't particularly feel that effect with a passenger vs without....All I did was try and make a constructive comment as part of a discussion. Unfortunately because it doesn’t suit your opinion you have to try and belittle it.
And a very god point from Taffy about centrifugal force....clearly a man with an engineering background !
Edited by Cheib on Sunday 2nd February 19:09
Taffy66 said:
A passenger increases centrifugal force more than it contributes to downforce,,
At risk of being a pedant, downforce increases the force available to the tyre without increasing inertia through higher mass. Similar idea but not quite the same as the above.Cheib said:
Not had many passengers get in the car at 100 mph to make that comparison have you ? And last time I checked the spoiler puts its force down on the rear of the car and not in the middle... which probably makes quite a difference.
All I did was try and make a constructive comment as part of a discussion. Unfortunately because it doesn’t suit your opinion you have to try and belittle it.
Ok I might have been a bit abrupt in my response but I (genuinely) wasn't trying to belittle it but trying to put some absolute figures on the discussion as an illustration. Believe that as you want. I'll try again anyway.All I did was try and make a constructive comment as part of a discussion. Unfortunately because it doesn’t suit your opinion you have to try and belittle it.
My point was that if you felt the car 'sit down' at speed, it should do something pretty similar at rest or low speeds with a passenger. That's irrespective of whether you're cornering where inertia comes into play where higher mass will have an effect on absolute cornering ability as noted above. The downforce numbers involved in my opinion anyway are not great enough to be solely responsible for the difference in feel or performance that are being ascribed to 'aero'.
Also, a spoiler doesn't act in isolation but in context of what it does to the overall car. While the wing obviously is at the rear of the car, the important part of what it does is apart from an absolute amount of downforce produced is how much it affects the aero center of pressure (front/rear balance namely) and therefore the forces generated on the car's contact patches which after all is what generates tyre grip.
isaldiri said:
Ok I might have been a bit abrupt in my response but I (genuinely) wasn't trying to belittle it but trying to put some absolute figures on the discussion as an illustration. Believe that as you want. I'll try again anyway.
My point was that if you felt the car 'sit down' at speed, it should do something pretty similar at rest or low speeds with a passenger. That's irrespective of whether you're cornering where inertia comes into play where higher mass will have an effect on absolute cornering ability as noted above. The downforce numbers involved in my opinion anyway are not great enough to be solely responsible for the difference in feel or performance that are being ascribed to 'aero'.
Also, a spoiler doesn't act in isolation but in context of what it does to the overall car. While the wing obviously is at the rear of the car, the important part of what it does is apart from an absolute amount of downforce produced is how much it affects the aero center of pressure (front/rear balance namely) and therefore the forces generated on the car's contact patches which after all is what generates tyre grip.
I am waiting for a another lol moment why you say a 1800kg cars stops the same as a 1400 kg car.My point was that if you felt the car 'sit down' at speed, it should do something pretty similar at rest or low speeds with a passenger. That's irrespective of whether you're cornering where inertia comes into play where higher mass will have an effect on absolute cornering ability as noted above. The downforce numbers involved in my opinion anyway are not great enough to be solely responsible for the difference in feel or performance that are being ascribed to 'aero'.
Also, a spoiler doesn't act in isolation but in context of what it does to the overall car. While the wing obviously is at the rear of the car, the important part of what it does is apart from an absolute amount of downforce produced is how much it affects the aero center of pressure (front/rear balance namely) and therefore the forces generated on the car's contact patches which after all is what generates tyre grip.
or you can lock up your brakes at 160mph
and now Audi have no clue when they had to add that tiny spoiler to the TT to stop it spinning under brakes.
take that massive wing off your GT3 and do craner at 125mph, report back ;-)
Porsche911R said:
take that massive wing off your GT3 and do craner at 125mph, report back ;-)
You couldn't do craner at 125mph in your gt3 with or without a wing. Feel free to do so and prove me wrong. Oh but you don't track your gt3 either anyway so a moot point.maybe you can on your sim I suppose....
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