Original front bumper accessory, is it worth it?
 

https://zapodaj.net/images/671e0d0ec5a13.jpg
I marked in the picture and is it worth it to mount a spoiler on the front bumper? does it help reduce fuel consumption?

'Spoiler' would be upright at the rear. What you circled is nominally a 'splitter'. Functionally, it lowers the stagnation point, forcing air up or to the sides instead of underneath.

So it depends on the relative merits of the streamlining the underbody as opposed to over the top.

If it were vertical it would be an air dam. Splitters are used to produce downforce at the front.

Thanks, I know the spoiler is in the back, they write on the manufacturer's website as aerodynamic parts. So it's not worth it? I have air dams fitted to the front wheels. Because it wasn't factory.

You're starting with a vehicle that is already optimized, i.e., not much 'low hanging fruit'.

This is why A-B testing is necessary. Not something you want to hear without the part in hand, I know.

I understand, because this overlay to the bumper needs to be glued and screwed, and used is not cheap because it costs a minimum of $ 110 and plus varnishing. thx

Are there existing attachment points?

Because a flat sheet of Coroplast [cheap] or Polymetal [durable] cut to shape could serve as a test article.

from what I know that you need to drill holes from under the bumper and there are marked places for screwing the screws.

according to the catalog it is called "Front styling kit",,.

'styling'
 

I looked at pages of aftermarket add-on 'aerodynamic' goodies for the Megane II GT online.
There were no drag benefit claims offered for any of, what I'm going to call 'chin spoilers' listed.
It appears that these products are 'ornamental', 'decorative,' with no attribution to enhanced aerodynamic performance.
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Your car is reported at Cd 0.35.
The 1989 Renault Megane concept car reported to be Cd 0.21 by Renault. It had no 'airdam' of any kind.
The 1987 Renault Vesta-II concept was reported by Renault to be Cd 0.186. It had no front airdam.
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None of the really low-drag concept cars, century-old low-drag research models, or land speed record cars had 'airdams.'
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'Airdams', while they 'can' be associated with drag reduction, do not necessarily appear to be a prerequisite 'for' drag reduction, if the 'nose' of the car has already directed the leading edge flow where it is deemed best to go.
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Published airdam test results show quite a spread in performance:
* The 1983 GM-Pontiac Firebird Trans Am airdam, with wrap-around sides contributed a Cd 0.036 drag reduction.
* My 1984 Honda Civic CRX modified nose over-fascia airdam indicated a delta Cd 0.0157 drag reduction, from it's top speed.
* The 2013 GM-Chevrolet Malibu's drag reduction due to it's airdam was published at Cd 0.005.
* The 2015 GM- Buick Excelle GT airdam was credited at Cd 0.0064.
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I haven't been in Poland since 1997, and I don't know what the laws are like now, with respect to owner modifications.
Personally, I'd be hard-pressed to drop up to, 153-Euros ( like I've seen for some airdam extensions ) without some guaranteed level of performance.
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If you aren't running the risk of breaking some law, perhaps to could cobble together a cardboard and duct tape facsimile of an add-on chin spoiler, and see if it produces a 'visible' result at the fuel pump.

Hmm...I'll see. In Poland, the law prohibits the use of illegal LEDs and Chinese xenons. And in addition, the wheels must not protrude behind the fender.
The Ibiza V has no Cx listed. But the Ibiza IV had 0.33 Cx and the areo version 0.30 Cx, i.e. rear spoiler, rear wheel spoiler, full front grill and special wheel covers.

https://i.ibb.co/K05ym6s/pobrane.jpghttps://i.ibb.co/x5qsbHg/IMG-20230612-191504.png

Aerodynamic shields are marked in green in the picture. And unfortunately, many cars do not have these certain covers. I marked in red which I installed the original and cost little. But I have a plan to mount a heat shield marked in blue.