Last time you lot got all up in arms because I cut my front bumper to make way for the RE-Amemiya intake. Well, you guys are really gonna hate this one. I just love the dirty look of a Wangan bumper.

there is no bumper...the bumper is an illusion

What's wangan bumper mean??
I keep hearing "wangan" something....

Hey dude its up to you man... Just dont expect to win alot of car show contests....

What's wangan bumper mean??
I keep hearing "wangan" something....

googled- japanese street racing thing.

http://www.examiner.com/sports-car-in-tampa-bay/what-is-wangan



manga/anime car racing thing-

http://en.wikipedia.org/wiki/Wangan_Midnight


wangan warriors

http://www.wanganwarriors.com/

Haha thank you zoom44 :)
I'm actually from japan and when we say wangan, it's a highway that connects Tokyo to Osaka and this highway has long ass tunnel that we can do topspeed runs.....
But I keep hearing like wangan bumper or wangan wing so I thought there was another meaning in the states....

Anyways thx tho!

to the OP.. at least you don't have to look at the POS rear of your car when you're driving :)

looks like shit, congrats I guess

It sure isnt fly...




...like a G6.
Like a G6.

A Geeesiksssss

Educating Shin on Japanese was pretty funny. How is cutting up the bumper supposed to help Wangan runners? Is that supposed to reduce drag?

Haha but zoom44 is right
There is a comic called wangan midnight also! :)
I just don't get the term "wangan bumper"
Hey but being different is kinda cool tho

Basically, the person who started this thread has no sense of aesthetic. Hence, he thinks that this bumper makes his car appear more like a Japanese :dragster:

lolz i dig it haters will hate all day do what ya feel man

That should help with your "time attack track monster" plans :uhh:

OP and the purpose of this is......?

I don't think it looks to bad with your exhaust maybe a different angle pic would help

any angle and it will still look bad. Just my take on it. Do what you want to do.

I kept seeing cars with cut rear bumpers in my Option and Option2 magazines and I just love the look, so I cut it. Also, I get to see my RE-Amemiya exhaust now.

I'm sure the original idea was to reduce drag to go faster on the Wangan expressway. But from what I've gathered, it's now more of a style thing.

looks like it would induce lift- which is not a good thing when doing highspeed runs in a tunnel on a highway in Japan

It shouldn't induce lift. If anything, it should increase downforce by allowing the escaping air to expand as it exits thus creating a low pressure spot. I highly doubt what I've done would create any quantifiable effect, but I'm sure that there are some cars that would benefit from it. As for the 8, I would suspect that for there to be any positive effect it would need a diffuser and/or an undertray to produce the desired downforce or less drag.

Maybe I should see about some fiberglass panels...

Im confused, whats the red thing that looks like it has a purple cog going through it used for?

Also, you're right on the idea that it would create some down force if the air would be moving at higher velocity out your bumper, but all those corners create way too much turbulence for the air to flow smoothly, so instead of creating downforce it just chops up the air. Thats why sleek and flat underbellies are attractive :P

That red thing is a tow hook.
The thing is our 8s are too slow that we don't need downforce lol
Wangan runners are living in 300km+ range that they need soooo much downforce to keep their cars on the road.
Your car's maybe good for corners on high speed track if you really putting downforce.
Do you track Interpol??

so instead of creating downforce it just chops up the air.

thats what i was postulating above- that by removing a bumper which was helping somewhat to keep the car down it may have inadvertently created more lift.

shin- the 8 will do 150mph and it gets a little lifty/loose at about 120-125 so yeah it doesnt hurt to have a little more downforce when doing a highspeed run.

Not feeling the looks. I agree it looks like it would induce lift. No lower rear bumper or diffuser will not keep air from coming off the back of the car and sweeping under the rear.

Are you the guy that got hit with the egg?

Ya that's why I was asking him if he tracks his car or not :)

Im guessing he just likes to, "Pop tha hood playa'".

Are you the guy that got hit with the egg?

I almost peed.

Shin, I did track the car, but this summer I was off with my school's Formula SAE team helping get the car, that I spent all year helping construct, to become one of the world's best. That left me penniless for racing my own car. Next season is looking slightly better if I don't go to Europe with them.


I KNOW that the changes I've made will minimally affect any downforce or drag made by it, but it will still change the airflow. I've seen what huge changes made to the diffuser on our formula car only make minute tenths of a percent changes in downforce and drag. Whereas not having the diffuser altogether cause sthe drag and downforce to both reduced by 15-20% and 60-70%. And this is on a 330 pound car that has a 0-60 of less than 4 seconds.

Our RX-8's, like most cars, are kind of wedge shaped with the pointy end first. At lower speeds, this causes a bit of downforce. However at high speeds the car will act like a wing, create some lift and give you that floaty feeling. The air traveling over the top is at a lower pressure than the bottom because it must travel faster. (Try it yourself with a small strip of paper. Hold one end at your bottom lip so you can blow over it. Blow and you'll see the strip of paper rise because the faster moving air is at a lower pressure.)

I can see how what I've done, coupled with the pipey exhaust, could cause some more turbulence since there are not any venturis or even a flat undertray. But, giving the same amount of air more area to occupy and escape cannot create lift if its on the high pressure side. Air cannot curl under, this is because both sides curl towards the dead area right behind the trunk and that the air coming off the top is at a lower pressure than the bottom.

Lol. And no, I didn't get hit with an egg.

"Pop tha hood"?

Hope to see you next year at some tracks :)

And 0-60 in 4 seconds sounds fun :p

Are you the guy that got hit with the egg?

lol

^^2nd that ;)

Maybe make a custom diffuser to clean the look up a bit? Lol

Is it acceptable to rofl instead?

Yes

Maby I am Wangan

Maby I am Wangan

that mesh looks horrible lol, no offense.

diffrent strokes for diffrent folks

...if you want to look like a rolling accident :bootyshak and too broke to repair... hey whatever...you think it's 'in'....but IMHO it reflect poorly on the RX-8 community ... similar to slammed fart can ricers....just worse if that's possible.

^
Wow u must know me that is exactly what happend I was hit and run in a parking lot granted the car is no longer that way affter I saved money for a new bumper. I just dident want to roll around missing parts of my bumper for 2 months dick

..confused ...you aren't the OP...what happened to you was a tragedy...what the OP did voluntarily a travesty lol!

O my bad. fully agree

^ just looked at yours..didn't see the pic before...not so bad really..perhaps paint it black?

It started black but the mesh was to large and it looked like nothing was there

sorry i'm not in the wangan scene is the OP really what they do out there?

We already have plenty of threads all about Dick's. So why are we discussing wangs?

http://stancedesign.powweb.com/Stanceworks/HATERS.png

^
http://teddziuba.com/images/one-skill-all-junior-developers-lack-is-knowing-how-to-tell-your-boss-to-fuck-off.jpg

http://wind-warrior-lan-idieas-and-updates.3060367.n2.nabble.com/file/n3132127/demotivational-poster-kkk-rollin-hatin.jpg

David nice abs. All that down time with no car you must been running to work ;)

Shin, I did track the car, but this summer I was off with my school's Formula SAE team helping get the car, that I spent all year helping construct, to become one of the world's best. That left me penniless for racing my own car. Next season is looking slightly better if I don't go to Europe with them.


I KNOW that the changes I've made will minimally affect any downforce or drag made by it, but it will still change the airflow. I've seen what huge changes made to the diffuser on our formula car only make minute tenths of a percent changes in downforce and drag. Whereas not having the diffuser altogether cause sthe drag and downforce to both reduced by 15-20% and 60-70%. And this is on a 330 pound car that has a 0-60 of less than 4 seconds.

Our RX-8's, like most cars, are kind of wedge shaped with the pointy end first. At lower speeds, this causes a bit of downforce. However at high speeds the car will act like a wing, create some lift and give you that floaty feeling. The air traveling over the top is at a lower pressure than the bottom because it must travel faster. (Try it yourself with a small strip of paper. Hold one end at your bottom lip so you can blow over it. Blow and you'll see the strip of paper rise because the faster moving air is at a lower pressure.)

I can see how what I've done, coupled with the pipey exhaust, could cause some more turbulence since there are not any venturis or even a flat undertray. But, giving the same amount of air more area to occupy and escape cannot create lift if its on the high pressure side. Air cannot curl under, this is because both sides curl towards the dead area right behind the trunk and that the air coming off the top is at a lower pressure than the bottom.

Lol. And no, I didn't get hit with an egg.

"Pop tha hood"?

Why hello fellow FSAE guy. What school are you from?

I hope you realize you can't possibly compare open wheel aero to closed wheel full body aero. I hope the diffusers on your FSAE car are bordering on ridiculous because the speed you're going at in FSAE you need cartoonish aero bits just to make it work. That said, I've heard that in the last few years the gains in aero has shown the aero cars are starting to pull away from the non-aero cars in the autocross. I have also heard that those cars have gigantic front and rear multi element wings with end plates that look like the armor on the sides of a tank.

This thread actually made me break open a book yesterday, I'm not done yet, but you can't even begin to talk about diffuser effects unless you have a flat undertray. More cross section for the air to occupy = lower velocity = higher pressure. The whole point of a diffuser is to keep the air from going turbulent in order to keep the flow under a flat floor flowing. You got to keep the velocities under the flat part of a tray higher i.e. lower pressure.

I don't think you can prove anything just by looking at it on a street car without a flat floor, especially if you have no idea where the boundary layer is forming. Ground effect also seems to be a huge pain in the ass. The air could have gone turbulent and choked the flow off long before it even got to the tail where you chopped it all up. You just don't know unless you model it in CFD or you just take that variable out entirely by making a smooth undertray, then ramp in (feed nozzle) and then ramp out (diffuser).

I didn't really want to discuss this till I had a better understanding, this is just people thinking their eyes are as good as a wind tunnel of CFD. Which in my mind is absolutely ridiculous.

We already have plenty of threads all about Dick's. So why are we discussing wangs?

This is genius. I am going to open a Chinese drive in called Wang's. I'm going to open this on 45th.

I'm part of Oregon State University/DHBW Ravensburg's Global Formula Racing, the first collaborative team in the series. Our team won 3 events this year including the championship race in Michigan as well as taking first in design in at least 5 of the 6 events we attended.

My position on the team is within the composites and chassis team. We were responsible for designing and making the two carbon monocoques as well as the diffuser and many other miscellaneous parts.

I'm still learning fluid dynamics so I have good idea of how it works, but I'm no expert on this... yet. I will be making a model of the RX-8 and running some CFD simultion as one of my projects this year in my classes. When I'm finished I'll post the results of what cutting my bumper actually does to the airflow. I was using the formula car's aero as an example to show that even large changes on such a small car yield in very minute results whereas similar changes done to our cars would yield in even smaller returns.

Your front bumper and undertray matter more than your rear, if you are serious about high speed (and please stop quoting the GFR cars, they are open wheel and completely different), then you want a nearly sealed front end and flat under tray, why? Coanda effect and angle of attack.

You're goal is a net force towards the ground, seal up the bottom, and have a rear diffuser with a final path that points around 10 degrees for a race car and 30 degrees for road cars. If you watch a proper race car in the rain (le mans car for example) you'll witness a vortex behind the car. For example you stand on the left side of a road facing the road, the car passing from your right to your left, you will witness (in the rain) a visible vortex behind the car about 4-5 feet off the ground spinning counter clockwise (and if you are on the right side of the road, car passing left to right, the vortex will spin clockwise to you), that vortex is due to the rear diffuser's angle and the bottom of the car's "control" of the passing air.

http://www.revozport.com/webpics/FERRARI/F430/Diffuser%20Fins/F430_press-rear.jpg

Faster the air moves under the car the lower the static pressure, the diffuser then alters the momentum slowing the air in addition to adding a y -axis (front of car to back - x axis, back of car then skyward - y axis.) Simple terms, air goes up, car goes down.

But your stock front bumper, stock under tray, stock wheel wells, and missing rear bumper will yield nothing, i repeat, nothing, its all in your head (or in this case, your following of a trend within the car culture.)


Sincerely,

Hater

I didn't really want to discuss this till I had a better understanding, this is just people thinking their eyes are as good as a wind tunnel of CFD. Which in my mind is absolutely ridiculous.

oh I like him- he gets to stay.:beer05:

If anyone wants to do some learning...you could do worse than start with these papers

...by Volvo’s Dr Simone Sebben http://papers.sae.org/2004-01-1307

...also a GM paper http://papers.sae.org/900317

... but it'll cost you ;)

I'm part of Oregon State University/DHBW Ravensburg's Global Formula Racing, the first collaborative team in the series. Our team won 3 events this year including the championship race in Michigan as well as taking first in design in at least 5 of the 6 events we attended.

My position on the team is within the composites and chassis team. We were responsible for designing and making the two carbon monocoques as well as the diffuser and many other miscellaneous parts.

I'm still learning fluid dynamics so I have good idea of how it works, but I'm no expert on this... yet. I will be making a model of the RX-8 and running some CFD simultion as one of my projects this year in my classes. When I'm finished I'll post the results of what cutting my bumper actually does to the airflow. I was using the formula car's aero as an example to show that even large changes on such a small car yield in very minute results whereas similar changes done to our cars would yield in even smaller returns.

Very cool. I was on the the WWU team that made V38. You are probably more familiar with the car that came after mine V43 (*cough* which you guys copied and modified by putting a single in it. *cough*, jp jp).

I would be interested in seeing the results of your CFD simulations. How do you plan on creating an accurate model of the RX-8? When do you plan on having them done?

If anyone wants to do some learning...you could do worse than start with these papers

...by Volvo’s Dr Simone Sebben http://papers.sae.org/2004-01-1307

...also a GM paper http://papers.sae.org/900317

... but it'll cost you ;)

I'm sure there's better SAE papers than two that covers mild street car applications for what we're discussing. If anyone is going to school in a University in Michigan or any with a legitimate automotive engineering program, those papers are probably free while on the intranet at the school. Anyone?

The Joseph Katz book and some easy reading from the Simon McBeath book is what I'm referencing right now.

The CFD simulations will be done by Christmas probably. I'm planning on using my car and a tape measure to get any measurements I can't find elsewhere. But mostly it'll be just a lot of time behind the computer. I'll likely be using Solidworks but could be using Katia instead. It won't be a perfect simulation, but it'll be accurate enough to have a good idea of whats going on around the car.

The CFD simulations will be done by Christmas probably. I'm planning on using my car and a tape measure to get any measurements I can't find elsewhere. But mostly it'll be just a lot of time behind the computer. I'll likely be using Solidworks but could be using CATIA instead. It won't be a perfect simulation, but it'll be accurate enough to have a good idea of whats going on around the car.

Will be a big deal if you ever put it in your resume. It is an acronym, so yes... all caps... and yes, I am OCD, as others on this forum will attest.

Nerders gonna nerd .... :cwm27:

Lol, I haven't actually gotten to use CATIA yet. I'm supposed to be learning it this term, gotta actually design parts for this years car.