Aerodynamics

[Initial-D]

I have a diffuser, big rear wing and a large front undertray! Lol!!
The difference is amazing!

[Jake]

I have a diffuser, big rear wing and a large front undertray! Lol!!
The difference is amazing!

Did you really notice a big difference after installing these?  Is it the sort of thing that you notice on the road or only on track?

[McCARTHY]

you will notice the effect on the road however they wont be quiet as effective on the really undulating A and B roads as they would be on track. Anything aerodynamic like this needs speed to work at its best... but you would certainly notice a difference over the stock handling

[fraser]

To add more confusion, the level of downforce generated by undertrays and other ground effect devices (i.e rear diffusers) varies exponentially with ride height, and to get any real noticeable effects you have to have a \'really low car\'.  For example in F1 when the FIA raised the ground clearance and implemented wooden undertrays (wear guides) to gauge this, in the nineties, the teams all reported that they were getting about 1/5 to 1/6th of the ground effect.  And they\'re talking in terms of a few millimeters rather than a few inches.   In reality it is impractical to get a road car to generate useful downforce from ground effect, and much easier to use wings, but remember that any downforce you generate at the rear will unsettle the overall handling and can cause a very light front end at high speeds which can be very disconcerting (the number of times you hear people saying that \'the front end started to slide so they lifted\' of at the start of a horror story crash)....

[Initial-D]

I run my car really low (too low really) I can just make a speed bump at a few mph only. Its true that the benefits of the items only work at higher speeds, I mainly find that stabilty is increased during high speed cornering, the rear feels more planted and less likely to slip out compared to running the car bald.