Street Car smooth underbody?

[Kambu]

It is a diffuser, but its there for styling purposes only.
If you look up pictures of a normal ferrari 430 or any other, and the racing counterpart (GT2). You will notice, that on the racing car the angle of the diffuser is way smaller. The original diffuser is there for mainly styling purposes.

[AlpineF1]

ah thanks personally i think its a silly idea but oh well

[superdread]

A bit offtopic, but whats the reason for raising the front of the underbody on the prototype car?
Isnt it "The lower the better". Is it just regulations, or is there another reason for it? Maintaining grip when going sideways?
I wouldnt really worry about achieving too much downforce on the mr2, I just dont see it happening.

There is a minimum height difference between the sides and the middle of the splitter in the regulations, but in recent years the teams have gone for higher ones to get more air under the floor, to create more front downforce with the front diffuser. They need that because they switched to wide front tires (more load to keep them warm).

[marcush.]

A bit offtopic, but whats the reason for raising the front of the underbody on the prototype car?

it´s in the regs -mandatory-
the idea is to stop the splitter get so close to the ground that it starves the underbody from air getting under it.
Flat bottom cars tend to porpoise-they increase downforce with diminishing rideheight so the ssystem converges towards zero rideheight quite quickly ,when the flow starves the downforce disappears quickly and the rideheight comes back to normal...this can get very nasty.

[superdread]

A bit offtopic, but whats the reason for raising the front of the underbody on the prototype car?

it´s in the regs -mandatory-
the idea is to stop the splitter get so close to the ground that it starves the underbody from air getting under it.
Flat bottom cars tend to porpoise-they increase downforce with diminishing rideheight so the ssystem converges towards zero rideheight quite quickly ,when the flow starves the downforce disappears quickly and the rideheight comes back to normal...this can get very nasty.

Also when one edge is raised there is a funnel effect (pressure buildup) and as the the front gets almost all of its DF from the floor, the pressure buildup results in flying hilarity (as some Mercedes CLR and a Porsche GT1 can attest).

Mark Webber's double backwards flip at Le Mans is one of the best crashes of all times (together with "Rally Car hits Horse").

[aussiegman]

As the original question was on a road/track car, I suppose the question is how much work are you prepared to put into the car to prep it for the track and them return it for road use??

I have a car which see's street and track time. One the street it has the flat floor (aluminum panels) on all of the time as the height difference is very small and it is a hassle to take on and off quickly.

To run on the track, we install (as well as various ducts for brakes etc) a carbon/kevlar front splitter (which is two levels and has diffusers for front wheels), lower the suspension to 60mm ride height from 100mm at the front (measured at the outside level of the splitter) via adjustable coilovers, install a 5 element rear diffuser with deep fences (still approx 60mm ride height so lower than the floor) and install new deeper side skirts that maintain 60mm road clearance along the length of the car with approx 7 degree rake. It takes probably well over 2 to 3 hours to install and set the suspension up either the day before or if needs be at the track in the morning which is less than ideal.

The difference these extras made on the track was huge and definitely worth the effort, but (and its a big but!!), you need to be prepared to switch the gear on and off the car. It's usefulness on the road, aside for a decent flat floor that doesn't reduce ride heights stupidly, is questionable at best and a painfully expensive exercise at worst.

I was lazy once and drove to get fuel, it ended up like a certain credit card advertisement:

Driving on the road with all you aero and r-compound tyres on the car - Fun but kind of embarrassing
Needing to dodge everything you can see and those you can't - Really annoying and tiring
Smashing the front splitter you spent 3 months designing, building and installing - Expensive and priceless for those around you watching.

I am still yet to live it down more than a year later!! The latest is Hulk smash splitter. I am just waiting impatiently for someone else to have their turn and do something stupid.

[Cam]

Aussie, how long in real time does it take to install all that and remove it each time?

Oh: great story btw. It's nice to learn form other people's f/ups.

[aussiegman]

If you ignore jacking, wheels changes, changing suspension heights/settings and the re-alignment, probably:

1: Remove front bumper and guard liners - 5 minutes (standard fittings)
2: Remove rear bumper and guard liners - 5 minutes (standard fittings)
3: Remove and store side skirts - 5 minutes (standard fittings and Dzus fasterners)
4: Install race front bumper & splitter hangers - 10 minutes
5: Install splitter - 15 minutes (have to install the brake ducts & floor panel from the firewall forward as well)
6: Install race front bumper - 1 minute (using Dzus fasteners)
7: Install rear diffuser with hangers - 15 minutes (this one is a pain and we're working on a way to make it easier)
8: Install rear bumper - 1 minutes (using Dzus fasteners)
9: Install side skirts - 10 minutes

So just over an hour to remove and replace. Can do faster if you have too but prefer not to rush it and have it align properly and store the removed parts properly. Changing suspension and alignment are also time consuming....