1993ka24det

no, I left the middle of the middle of the trunk were it is until i order a fuel cell

njn63

iTrader: (4)

Very nice. I have the rear "flaps" cut out but I haven't cut the jack recess yet. Why not cut the flange and take that weight out?
No aerodynamic reason to. The jack recess is in the tire wake while the center of the trunk shouldn't be in the stream of air due to the diffuser.

1993ka24det

Which part?? Happy New Year

njn63

iTrader: (4)

The flange with 2 holes on the top of this picture:


I'm just trying to make sure there isn't a function for it I missed. Happy New Year

sixshooter

iTrader: (12)

And the trunk's belly is a structural rigidity element that shouldn't be removed unless something else structural is added.

1993ka24det

I don't know why I left the flange there, I guess just to add flair

True, I was thinking of linking the two rear roll bar mounts. Sorry to get off topic of Aero. Hey Six I will be in Tampa soon

chpmnsws6

iTrader: (12)

The section 1993ka24det cut out is also a rust point. I cut mine out when I did the swap for that simple reason.

Ski_Lover

I've seen the trunk resessed area replaced with thin light material on race cars at TC Design Fab, Tony knows what he's doing over there, I'm guessing his cages take care of any rigidity issues. (They tie into the rear shock towers)

Dlaitini

pointy is for airplanes that go past the speed of sound.. they NEED pointy to make the shockwave break where the designers want to.

below that speed, look more at cargo planes, with their curves for air funneling.

A ton of people have this misconception that sharp and ponty means "faster"

When F1 teams back in the day hired some Boeing aero engineer to help them, the engineer told them "you dont need me, you want the guys that built the WW2 planes, aero works different when you go past the speed of sound"


You put anything in the airflow that is moving air to the side or up or down, it will cause drag. The splitter is just sperating the air, and then directing up and over, or to the sides, creating high pressure on that side(s) (gross oversimplifaction I know)

now question i have, people that run with canards, depending on if you run a clockwise or counter clockwise track, can you test running one side or the other.. see if raising pressure on one side of the car could help? I know oval cars are set up on the extreme end for that kind of stuff

Handy Man

Yep. If you want low drag at sub-sonic speeds you should be thinking tear drop, not arrow.

mx5-kiwi

Good picture, but isn't the shape and the resultant cd more to do with the back of the object and the air seperation /turbulance?

I mean what if the first pointy example was pointy at the back too? Not a dome as shown....I suspect then it would have a pretty good CD again...

Hence why F1 and all high end race car designers focus so heavily on the rear end.

As do the yacht hull and keel designers, wing keels were designed to minimise drag not provide lift and so on....Boeing with the vertical wing tip extensions...

Which leads me back to the MX5....undertrays and diffusers etc....It would be great to know how much of an effect they could potentially have on our little cars.

Then we could decide on whether it is cost effective to focus on that area or not...I mean if "theoretically" the best diffuser gained 1 MPH and 1 KG of downforce I can see many other areas to focus on...

If on the other hand it was theoretical to see a gain of 15MPH and/or 40Kg downforce, it might be higher up the priority list.....

Some experienced designers must be able to give us a ball park.....

jacob300zx

Lets keep this thread on topic and avoid the engineering student discussion on who's brain is bigger to another forum. This is more of a rocket city rednecks aero thread.

Handy Man

Very Nice! Is that a one-off or a production piece?

emilio700

iTrader: (3)

If you are referring to the white NB in Jake's post, no. OTS from Autokonexion. Something I designed but never had built for myself. Mike liked it and put into production. Good race or street nose, covers 9's, low drag, room for brake ducts and oil cooler without hacking more holes in the nose. In the end we went with the ABS sheet set up instead.

Handy Man

Exactly what I was thinking. Nice job! Now only if it were for an NA

doward

...and fit to stock fenders instead of flares.

Mobius

iTrader: (2)

They make a fairly similar NA bumper as well

ThePass

iTrader: (3)

^ definitely not as good aerodynamically.

Supe

For you V8/LS1 guys, how big are your radiator openings in your air dam? Mine is measuring 6" tall by exactly the width of the radiator core including end takes, but I can't help but feel that I'll be choking off the radiator somehow, and am terrified of having overheating issues. I'm using an ABS inlet box with a venturi shape that seals to the radiator which is laid forward at an angle (with a mother thumper SPAL puller fan on the engine side), so all air would have to be drawn in through the inlet box.

Handy Man

Sounds about right. A rule of thumb is that you want the inlet to be 33% the area of the heat exchanger.