My car so far

[bobert50]

Common sense suggests your right (and others) on the huge wing being pretty much cosmetic purposes only.

Common sense also suggests a 3ltr straight six would have a higher top speed than an ATR too, sometimes you'll never manage to talk any sense into people though

 

[Demon]

The wing on an ATR does NOT provide downforce. Fact.

What it may do is reduce lift.

As for whomever said "You can tell that it works because it flexes at high speeds", if I mount some cellophane on a coathanger it will flex at 70+mph.

The wing on an ATR does provide downforce, FACT... i.e. it provides a force acting downwards...

Sure it in all probability it comes no where near the upward force the rest of the car's aerodynamics generate, but if you are going to be pedantic, at least offer a little explanation..

And as for the cellophane comment, well the spoiler isn't cellophane, it's a rigid structure, which takes more force to deflect then cellophane.. I agree the observation was originally misplaced, but just explain why he's wrong, not get all pedantic and condescending...

AFAIK these type of spoilers are the old skool way of reducing lift by 'spoiling' the airflowing over them, if designed correctly this would produce some downward force that acts against the cars 'lift' which is generated because of the overall cars aerodynamics having the opposite effect.. the downside is the by adding something that is deliberately 'spoiling' the air, this creates drag and has an impact on top speed/high speed acceleration.

My old Astra GTE had a small aerofoil style spoiler from the factory that was claimed to reduce the overall lift by 25% at 100MPH, which is significant, but it knocked approx 7-10MPH off the top speed as reported by people taking them off..


AFAIK, The trend now is to simply reduce the amount of lift the car generates in the first place, this is mainly done by reducing the air disruption/spoiling under the car, this not only reduces lift, like the net effect a spoiler has, but also reducing drag considerably, thus, if anything aids top speed/high speed acceleration..

At the end of the day the entire car can be seen as a wing, for downforce, the air pressure above the car needs to be higher then the air pressuce under the car, since air disruption/distance to travel etc all contribute to a higher pressure (in general this is), if you have a particularly poor design that is causing too much air pressure under the car, you have to offset this with a spoiler..

The above is not a scientific factual statement, more just what I've picked up on the subject coupled with some physics/common sense..

 

[Kappa]

well in aerodynamics if you have an object which reduces upward lift, that object DOES indeed provide downforce, to counteract it.

A question to people who know more about spoilers and stuff, is an f1 style diffuser more effective than a huge spoiler?

 

[Demon]

well in aerodynamics if you have an object which reduces upward lift, that object DOES indeed provide downforce, to counteract it.

A question to people who know more about spoilers and stuff, is an f1 style diffuser more effective than a huge spoiler?

The diffuser allows a more controlled exit of the air under the car, so I believe, and that should increase the airflow under the car, reducing pressure and therefore reducing lift.. I suspect that it's effect is twice as good as a huge spoiler, since it's reducing the lift without 'spoiling' the air, hence drag will be reduced for the same net gain, so higher top speed..

Be interesting if we had any aerodynamisists to give us the more indepth low-down...

 

[Bleek]

There's little point diffusing air at one point on the car, it's a considered approach and hence called an aero 'package'.

My car is slowly turning in to a race car (BTCC S2000 spec on a budget) and the approach is to get the car as close to the ground as possible, remove as much drag under the car whilst forcing air up around and over. In my case things like diffusers, cannards, spoliers and the like will make a significant difference.

Like I said before, the ATR spoiler on track does make a difference and does stabilise the car at speed.

I'm tired of all this 'Internet theory' of how quick the car is or how it doesn't do this, doesn't need that. Debate is healthy, but factual information if required to solidify a statement and there's plenty lacking in this thread.

Please don't think me patronising in that comment, whilst I enjoy theorizing I also like hard facts and evidence to credit those theories.

 

[Enfield]

Just read a bit more of this thread about the spoiler...I reckon it probably is just a cosmetic thing.

In that video with the M3, M5, Euro ATR, 330i, etc the Euro ATR didn't have a spoiler. Why is that?

The Police have used the ATR as an unmarked car and have removed the spoiler. Also wasn't it an option to have it removed at the factory?

 

[Bleek]

Ok, I don't like posting this image because it's not something I condone on the public highway it's also willy waving rubbish. This was a top speed test in a controlled environment (airstrip).

Now, ignoring the fact the speedo is reading nearly 160mph the rev limiter is being hit. Like I said before, the maths of 7,800 rpm, 215/45 R17 a 4.266FD and 5th gear of 0.787 equates to 154MPH. FACT.

You can't disprove the basic maths and engineering at play here, that is what the gear rations allow at that engine speed on that size rolling radius. End of story.

edit: sorry for the awful pic quality, this was taken 2 years ago with the 'state of the art' P910i PDA phone.

 

[Bleek]

Just read a bit more of this thread about the spoiler...I reckon it probably is just a cosmetic thing.

In that video with the M3, M5, Euro ATR, 330i, etc the Euro ATR didn't have a spoiler. Why is that?

Because it's a Japanese Euro R, different body panels/style to the UK but there was an optional spoiler.

But clearly your not listening to reason here, I've had FIRST HAND real world experience of spoiler ON spoiler OFF around a track.

 

[Bleek]

The Police have used the ATR as an unmarked car and have removed the spoiler. Also wasn't it an option to have it removed at the factory?

The police removed ALL 'Type R' marks including the twin exhaust, not for performance but for stealth.

There was indeed a factory option to remove the spoiler of fit a low level one.

 

[Enfield]

Because it's a Japanese Euro R, different body panels/style to the UK but there was an optional spoiler.

But clearly your not listening to reason here, I've had FIRST HAND real world experience of spoiler ON spoiler OFF around a track.

Ok, like I said though, I haven't read ALL of the thread yet.

Either way, I couldn't care less.

 

[Bleek]

Fair enough.

 

[[TW]Fox]

Now, ignoring the fact the speedo is reading nearly 160mph the rev limiter is being hit. Like I said before, the maths of 7,800 rpm, 215/45 R17 a 4.266FD and 5th gear of 0.787 equates to 154MPH. FACT

Thats fine but it still doesn't need a big wing to keep it on the road at that speed. If it did, then other similar cars would also need one. And they don't have one.

It is a styling aid - a small wing is all thats required to disrupt the airflow enough to provide a bit of downforce. Anything more is for cosmetic purposes.

I'm sure you do feel a difference witH NO spoiler, but I'd wager you WOULDNT feel a difference if you swapped it for, say, a lip spoiler.

 

[[TW]Fox]

The police removed ALL 'Type R' marks including the twin exhaust, not for performance but for stealth.

Err no, they did not remove them for 'stealth'. Unmarked Mondeo ST's retained their twin pipes and unmarked Vectra GSi's also kept their 'uprated' exhuast systems.

 

[danza]

You can't disprove the basic maths and engineering at play here, that is what the gear rations allow at that engine speed on that size rolling radius. End of story.

Whilst it can't be disproven, you can say that it's doubtful the rolling radius is as given on the tyre due to compression.

 

[Bleek]

Err no, they did not remove them for 'stealth'. Unmarked Mondeo ST's retained their twin pipes and unmarked Vectra GSi's also kept their 'uprated' exhuast systems.

Err yes.

Every single Police ATR that has come up for sale has had some form of stealthing, all of them have had the 'Type R' badges removed and if I recall right the boot spoiler too.

Both the Midlands and Manchester Police force remove the badges, the rear spolier and changed the front grill to 'stock' Accord.

 

[Bleek]

I'm sure you do feel a difference witH NO spoiler, but I'd wager you WOULDNT feel a difference if you swapped it for, say, a lip spoiler.

True. I'm only human after all!

The different could be calculated and modeled but I agree the difference would be hard to recognise.