The DOWNFORCE Thread!

[Imarvin240]

So I have been looking around on here trying to find proper info on wing angle, wing stand types, front splitters, diffusers, canard info, and other downforce aero related info...but didn't find much, if anything. I figured we should have a thread to post up questions/info/photos on our wing, splitter, canard, diffuser setups. I think this will help some of the future aspiring track guys on here.

Rules: Only post info, pictures, questions regarding downforce aero.



Here's mine to get it started.

It's a 70" Kognition Designs carbon fiber chassis mounted quick disconnect wing.





It's an extremely well made product and it's a well proven product on the track. The quick disconnect is just a few pins on each side that get pulled out to remove the wing, which then allows the hatch to open easily. The whole kit is super easy and simple to put together. The only tough part would be cutting the hatch in the correct spot lol. Touge Factory will be doing a full carbon fiber underbody diffuser, front splitter, and canards on the car, which I will post up later.


Looking forward to seeing some of the other setups on here and hopefully learning a few things as well.

[ehhhregartless]

[Bushido]

LOL

[Bushido]

[future]

That s15 8========D


as the rules say I need a question. So at what point is there too much Down force and just a bunch of drag?

[ehhhregartless]

I would think your times would get slower at peak downforce/drag limit. Then add power and adjust

[Sileighty_85]

So is this for the common track car, street car, or competition shop track car that 90% of us will never be at that level or have that much money to dump into aero to where this is just another wet dream pic thread?

[ehhhregartless]

I'm not sure what Marvin's personal goals are but I'd say all of the above. Plenty of people, including myself, are inspired but functional aspects. As long as its applied correctly, trickling down tech from the pros is what we all do in one form or another. Ultimately this isn't nissan road racing or nasa forum so if might not get that technical but looking at cool pics never hurts

[Bushido]

[ehhhregartless]

[tacotacotaco]

Small tips you guys can use to be more efficient.

1 front undertray even oem will help reduce air pressure in your engine bay. Creating down force on your hood. The lower the air pressure in your engine bay more down force.

2. Closing up any vents on your front end that are not necessary or ducting them so that they don't release into engine bay.

Using strakes or dams to cover leading edge of tires.

Not using any hood with vents into engine bay. All vents should be pulling air from engine bay.

All very basic easy to do tips just for making car more efficient

[Z_Spool]

Originally Posted by Bushido

I feel like this thread would be better suited to the technical discussion board, or else this is just doomed to be another pretty picture thread. That being said, hopefully we have some more engineering-minded members that can shed some insight into the aerodynamic properties to be discussed here. I do have a question for any with experience. I see fenders being modified like this more and more with basic cutting like on this S15 above and Yuta's Civic below as well as more hand crafted designs like the front wheel arches of the Bensopra GT-R. What exactly is the purpose of removing that portion of the body from the trailing edge of the tires?

[greddy2die]

I would assume to allow the air to disburse quicker & have less turbulent air getting caught in the fender behind the wheel / door area. However, that's just a guess! ha

[Def]

To make front downforce with a production car, you are trying to get as much air to flow under the splitter as possible.

The rear diffuser helps this by helping "pump" the air from the front to the rear. Same with small diffusers in front of the front wheels.

The venting of the rear of the front fender is trying to act somewhat like a rear diffuser - pumping more air out, which increases the mass flow of the air under the splitter, which drops its static pressure (Bernoulli's equation).

[xpinoyxmk]

Imarvin240, does that wing setup allow you to adjust to different positions, like the Scorch Racing S15?

Also, thought that red 180sx what built for show?

[Sleepy_Steve]

+1 you probably want to move this to the tech section.


The cowl area of the hood is a high pressure area, that turns it into an intake, and is why your vents flow some air at speed even with the climate control fan off.

The higher the flow over that part of the car, the better that place is for a vent as the lower pressure will make the vent move more air. Uras hood vent's normally look to be located reasonably well to evacuate air (and pressure) from the engine bay.

As Def (and someone else) said, even a front under-tray that doesn't go past the bumper will help smooth the airflow under the car and either improve down-force and / or eliminate lift.

Gurney flaps on the back of aero elements help kick the air up into the stream a bit more and allow a greater angle of attack for that element.

Dive canards are relatively inefficient on their own and are normally used to channel a vortex of air away from some drag heavy part of the car (ie; wheel wells)

The wheel wells are areas of high pressure, it's best to evacuate that high pressure outside the car rather than under it. See all the TT / time attack guys hacking the lower third of their fenders behind the front wheels, or spacing out the bottom of your fender about an inch and rolling the back lip flush like you do on the wheel arch.

When you have to vent air, top is best, then out the sides is ok, and lastly the bottom is the worst place to do it, you want nice fast smooth flow down there.

Diffusers work by making the air stream slow down and expand. You must do this gradually to avoid flow separation (stall) over the element. Because that takes space to do the expansion gradually, the sooner you can start that expansion the better. Because they work better w/ smooth flow, best results are found with a flat bottom and splitter or front under-tray already being used.

You want a good front to rear balance of down-force just like you would mechanical grip. You can use one to band-aid the other but that changes the balance based on speed and makes the car difficult to drive.

Down-force generates drag. If you have too much drag at the front, it can make the car unstable in a straight line.

Sealing up gaps between an air dam and a splitter can make large improvements.

Your rear wing's angle of attack is found by drawing a straight line from the leading edge to the trailing edge and measuring the resulting angle.


That's all I know on the topic. I was a business major in school. I just read a bunch of race car books / magazines.
All of that crap I just typed up assumed that the car is moving forward through the air at a not full-lock slip angle.

[ehhhregartless]

^Looks like we're off to a good start.

Originally Posted by xpinoyxmk

Also, thought that red 180sx what built for show?

"The highly modified SR20, built by Toshitake, puts out an adequate 593 horsepower; more than enough to get him sideways on track. Actually, that’s pretty much more than enough for anything you’d want to do with the car. Seki chooses to drift ~"

[Wheel Lounge]

Originally Posted by Bushido

Ready for take-off..

[crzsteveo]

I also hope I can absorb some info on aerodynamics from this thread. I would like to improve the aerodynamics of my car and track it soon.

http://www.worldtimeattack.com/index...-aerodynamics/

[Sleepy_Steve]

Originally Posted by crzsteveo

I also hope I can absorb some info on aerodynamics from this thread. I would like to improve the aerodynamics of my car and track it soon.

http://www.worldtimeattack.com/index...-aerodynamics/

Dude, just come hang out one weekend when I'm wrenching on my car. I'll learn you some aero shit. Maybe even lend you a book on it.

Opener at VIR is on March 20th's weekend, lots of race cars to look at if you want to swing by.

[shmoo]

happy festivus, because race car.





_because race car.

y, i know she's not a two four tay, but, come on, i wet sand one.

but, y'all are getting down for real. are all of these diffusers/ splitters/ canards custom? how about these spoilers?.. i'm considering a big country labs one, or an apr gtc 500 one. i've researched some voltex and a couple others, but i'm just not sure. where are y'all working from?

turkey

[zeitgeist]

What do those pictures have to do with this thread..............

[turbo2nr]

Originally Posted by shmoo

happy festivus, because race car.

_because race car.

Y, i know she's not a two four tay, but, come on, i wet sand one.

But, y'all are getting down for real. Are all of these diffusers/ splitters/ canards custom? How about these spoilers?.. I'm considering a big country labs one, or an apr gtc 500 one. I've researched some voltex and a couple others, but i'm just not sure. Where are y'all working from?

Turkey

kill yourself.

[LockOn!]

Originally Posted by shmoo

happy festivus, because race car.


turkey

Troll? I really hope troll.


on topic:

[1Badhatch]

Originally Posted by ehhhregartless

I'm not sure what Marvin's personal goals are but I'd say all of the above. Plenty of people, including myself, are inspired but functional aspects. As long as its applied correctly, trickling down tech from the pros is what we all do in one form or another. Ultimately this isn't nissan road racing or nasa forum so if might not get that technical but looking at cool pics never hurts

What is the name of this kit or specifically the front canards and bumper

[DJDANGER24]

^^ Garage Mak

[turbo2nr]

Garage mak makes the aero, IIRC that is seki motorsports s13

http://thenaritadogfight.com/2014/12...or-sports-s13/

[shmoo]

how's it going y'all sorry to barge in here again.. i did so a couple years ago.

it's kinda weird, the 3s guys don't/ aren't really taking to the downforce thing, however y'all are. they all just kind of go big ass turbos, and no real phun.

we're in the process of putting together a two forty, just whatever

^^y thanks for the info.

_isiah

[crzsteveo]

Originally Posted by Sleepy_Steve

Dude, just come hang out one weekend when I'm wrenching on my car. I'll learn you some aero shit. Maybe even lend you a book on it.

Opener at VIR is on March 20th's weekend, lots of race cars to look at if you want to swing by.

ill have to take you on that offer. Ive been doing a lot of reading on front splitters with positive and negative pressures and how it affects lift and down force on the front of the car. Very interesting stuff for sure.

[shmoo]

Originally Posted by crzsteveo

ill have to take you on that offer. Ive been doing a lot of reading on front splitters with positive and negative pressures and how it affects lift and down force on the front of the car. Very interesting stuff for sure.

would you mind posting up some information on that? or, some links to this negative/positive downforce?.

I've rocked the front splitter for a a while, I'm a little on the fence about the big wing thing though. I'm not sure if it's because I believe or because I want to believe.

_isiah