Extra down force on track

[Bender Unit]

Just wondering if anyone on here has used a GT wing to give them some more downforce on track?

Just wondering how effective thy actually are in increasing rear end grip and cornering speeds?

Havent had any experience of them myself so iterested to know others views.

Cheers

James

[MartG]

Don't forget that if you increase the downforce at the rear you also need to do it at the front too to maintain the balance of the car

[dave5526]

A wing will only increase downforce at high speeds, and probably not enough to offset the extra drag and weight it will give to the car. Going totally spoilerless would probably be the best improvement you could make in that department!

Having said that, due to my above opinion, I've never actually fitted one to try it out - someone who has may prove me wrong!

[kaiowas]

Don't forget that if you increase the downforce at the rear you also need to do it at the front too to maintain the balance of the car

Depends on what the car is currently like and what you're trying to achieve.

Have been thinking of adding a GT style wing myself as our car is pretty pointy which is ideal through the tight slow stuff as you can really hustle it through the corners but long high speed sweepers can get a bit hairy and the added rear end grip at speed would be pretty useful to help settle things down.

Like the OP I'm a little unsure about what sort of speeds you need to be doing for such a wing to be effective though.

[aw11rally]

Have you already got a fully flat undertray and functional rear diffuser? If not this would be the best place to start as it speeds up the airflow under the car thus creating negative pressure. I'd guess it would also reduce drag and could be done in a way that would add very little weight, and can be done cheaply.

[John145]

As aw11rally says, ensuring your flat floor is flat is the best place to start. All cars naturally produce lift and a flat floor attempts to reduce this effect by speeding up the air under the car reducing the pressure.

An aggressive method of improving rear end grip is to hang the middle flat floor so it is scraping on the floor, this will reduce the amount of air that can get to the rear of the car, reducing air pressure further.

Putting a skirt on the front and sides of the car is another cheap method to improve downforce but to get it effective it'll need to scrape across the floor, not ideal for road use.

Also these methods make the car's aerodynamic drag worse so don't use these modifications on a road car or your mpg will drop a bit.

Generally you will only notice these improvements in fast corners, 60mph or more. Big wing on the back is an inefficient method of improving downforce, but you will also induce understeer in fast corners as the balance of the car is shifted.

[kaiowas]

Although aware of the benefits I've not considered adding a flat floor as yet as I was under the impression that it would be a lot of work and add a reasonable amount of weight to the car for little real benefit, particularly as our car doesn't run much lower than stock yet (coilovers are on the way though).

Maybe I need to reconsider this. What material would be best used for the floor? I'm guessing ally sheet for areas where there are plenty of mounting points available and plywood for areas where greater stiffness would be required. Any thoughts on suitable material thicknesses? I don't really have any idea of the magnitude of forces that will be acting on the underside of the car.

[LimeyMk1]

I'd think 1mm sheet would be alright for the underside Phil, I've used some 0.5mm for an exhaust heat shield and it's reasonably rigid when bolted in place.

[John145]

Doesn't need any particular strength, they aren't load bearing and can be mounted to various parts underneath. A flat floor will be more beneficial than a big wing and cheaper

[Shmed]

I have one of my engine undertrays missing, will that be detrimental to my downforce? The one that goes by the gearbox is not there.

[MartG]

The OEM undertrays are intended more to keep road muck off the underside than to reduce lift, htough they may have a very minor effect on the smoothness of the undercar airflow

[squariel]

what about airflow to the engine if you fit a flat floorpan.
would a set of nascar style vents work ok.

[MartG]

The sidescoop should provide enough airflow to keep the engine cool