Does anyone have any technical data on or experience of the effects of fitting these, what speeds do they start to have an effect etc. Am trying to decide if it's worth spending / losing the ground clearance, any opinions welcome

 

Rear diffuser without full flat floor is pointless and just cosmetic addition.On some cars(Rally cars,Race cars etc.) is full flat floor which create positive downforce(something like suction effect),best way(for relative lower price,than full flat floor) how get bigger downforce is APR rear spoiler(fully adjustable and which is tested in aero tunnel).I'm not sure but these diffuser(HT Autos) are not tested in aero tunnel,if you are looking for aero tested and mostly used out are APR(which are tested in aero tunnel)
Full benefit from just diffuser,is not possible due you don't have as above i say Full flat floor....
A diffuser takes the airflow from under the car and channels it out into the low pressure area behind the car. The shape and design of the diffuser will determine how much (if any) downforce is produced. A full flat underbody will work the best with a diffuser, like the picture of the Enzo .
On a car without a flat underbody, the bottom of the body panels and rear bumper is usually lower than the bottom of the actual chassis of the car. A diffuser will help keep the airflow smoother when flowing into the area behind the car.

 

And this link will help you decide,if its worth or no
http://forums.evolutionm.net/evo-x-g...unctional.html


Jura

 

also, when flat bottom has been fitted, the lower the car to the ground, the better the downforce effect.

 

no i think you've answered that one thanks , how about front lip spoilers, purely cosmetic? am sure i've seen one advertised somewhere as actually lowering drag but am more interested in front grip...?

 

Answer on your question will be this APR Front Carbon Wind Splitter

or form CarbonMods


These from Ht Autos are purely for cosmetic purpose,for full potential of these splitters above you will need again flat floor.On standard car these above splitters will create positive downforce which is positive grip,but i think this will be just at higher speeds no at lower speeds.

Jura

 

nice one mate thanks for that, found them here
http://www.invo-tec.com/products/bod...subaru/impreza
they pretty massive... as you said a (small section of ) flat floor, so the things that sit below the lip of your front bumper (about same depth) are cosmetic then.....shame more grip at speed to counter the spoiler would be good but don't want to go mad




and i am once again at peace with my scooby... thank you

 

Hi there these splitters are effective at some speeds,at lower speed you will need adjustable rear spoiler like is APR GT-300 with front splitter like is above APR or Carbon Mods,and car must be lowered for better flow with good diffuser

Voltex Diffuser




Jura