Exactly my thoughts. I wanted to comment on the bottomless, sideless NACA duct, but I thought that would be too nerdy. So I'm glad to not be alone in that observation.

Great idea and throw some strain gauges on your springs to measure the downforce

And when is the GB on the lip spacers :)

There is certainly optimization that can be done on a flat bottom car, but when you are speaking of the affects of multiple surfaces and channels you are actually into the realm of a ground effects bottom car which I agree is a much more complex model.

That is why I separate out the venturi/diffuser in my post above (ground effects).

I too saw that the area behind the front wheel arches could be changed up to get air more smoothly down over the flat bottom, but air trapped above the flat bottom tray does have obstructed flow and minimal outlets and so will stagnate and the high velocity air flows over and around the stagnant air.

This flat bottom is more complete than many OEM flat bottoms such as the Nissan GTR which to its credit manages to eliminate lift with no wings/drag.

https://www.gtrlife.com/forums/uploa...1366989007.jpg

A flat bottom FD project is for people who want to feel like they are optimizing their car set-up by emulating real race cars and for the odd track day guy or time attack guy to experiment with.

Any one that actually races knows the class structure where a unibody FD is going to have a chance of being competitive will not allow a flat bottom let alone ground affect venturis/diffusers.

https://cimg8.ibsrv.net/gimg/www.rx7...ce3040d8d4.jpg
I'm planning to add the part as shown in the figure that connects the wheelhouse inner surface to undertray seam-less.
https://cimg3.ibsrv.net/gimg/www.rx7...c7484e35b5.jpg
NACA duct is attached like this. And appreciate for many comments.

Mic. Fucking. Drop. Good on you, sir.

Me gusta

Have you guys ever seen the PW:JDM Honda S2000 panel?

http://www.gotuning.com/images/produ...stalled_02.jpg
http://www.gotuning.com/images/produ...stalled_07.jpg
http://www.gotuning.com/images/produ...stalled_08.jpg

I always thought this was the most amazing and ambitious kit out there.

^ Nice.....exhaust/muffler shrouding.

The FD bottom is, actually, pretty flat, even by today's standards! If you look at a stock FD bottom, with all of the plastics in place, you'll see that Mazda did a pretty good job filling in the open spaces for most of it. They did the wind tunnel leg work (not sure how available CFD modeling was then), and improvements like these would be marginal at best. Is there room for improvement? Always! I think the cheaper alternative would be to first start with designs from privateer racing teams that have done some of this type of stuff and labored throught the trial-and-error.
Looks cool, but I'm afraid that's its only value.

Me wants! :drool1:

I really don't understand all the hating in this thread. The man has made a pretty cool setup and some of you have to just shit on it. Where are all the custom parts you've made? Where is your engineering degree that justifies the doubt?

Regardless of whether it really works or not, it looks cool. Sometimes that is all that matters. Do you think all these "street diffusers" were really wind tunnel tested?

The point I'm really trying to make is, the man has obvious skill to produce these parts that look very professional in fit and finish. He's even taken the time to measure and model the underside in CAD.

It's not like he's putting neon lights on it and ruin the car.

Vince

It wasn't actually so long ago that even top level professional race teams developed their cars without CFD, and without wind tunnels, and they managed (with greater margin for error of course) to create modifications and make race cars better. I'm certain the poster welcome constructive feedback, but there's no reason to be so disdainful just because its the internet.

+ 1 million.

Nobody gets all upset when people put crappy carbon door sills on their car for purely aesthetic reasons.

This guy never even tried to push claims of benefits on us and has not been salesy. He showed what he created. And this type of thing has been talked about for years without ever seeing something come to fruition, so naturally some people are eager to see it become available as a product.

If one of the vendors came out with this, many of the critics never would have been so harsh and quick to dismiss.

Thread Recap
 

OP seems to be coping fine, and intended to gather commentary and opinions. If you're into product design or iterative engineering (or the internet), this is how it actually works. If you wanna get in your feelings about it, that's cool too.

want!

As a moderator you should be encouraging a better and more respectful and inclusive approach. Lead by example. No one is crying here. It's a cool concept and it was refreshing this guy didn't go full out sales mode trying to claim benefits. The opposite of that guy trying to sell magic twin turbos.

I was crying and I don't appreciate anyone trying to shame me for it.

Haha. Now I'm crying too. Internet is too mean hahaha

I don't see anyone shitting on this thread or project? People have questioned it's effectiveness, it's design and it's testing methods. But that's not shitting on someone - that's conversing with them.

No one said "this is a waste" or "this will never work" or "this is stupid". The harshest thing I've read is "it would be good to see some CFD" and if this is already it CAD - should be doable. Questions on the NACA ducts were addressed by the creator and he showed us how they were connected along with an appreciation for the question.

No one has to take sides. Let's just see how it progresses - we all want cool, new and effective stuff for our cars. :peace:

One guy said the design is "suspect at best", that naca ducts are more than just fancy wholes, and that one needs engineering skills to do this. Being condescending and inferring that the creator was basically an idiot.

The OP wipes out some CAD models and the attitude instantly changes.

I'm not picking sides. I'm saying that we could have started off positive first and then gotten critical after asking questions. Saying the design is "suspect at best" is shitting on it.

Jin-74 my offer still stands if you change your mind. I do run a factory with laser/press brakes/powder coating etc in NJ so i can do them and even offer them with variations in exhaust cutouts etc.

It is awesome; and any aero product with no testing, no analysis, and no justification is suspect. Welcome back to reality.

Try not to be so thin skinned. There's plenty of room for improvement/iteration/analysis and the rush/push to productize and sell without a second thought (not from OP, btw) is embarrassing.

OP has already given some improvement/explanation and I'm looking forward to v1.1 or whatever the next iteration is.

Be honest man, re-read your posts and tell me you weren't being shitty with most of your comments/a bit of a keyboard cowboy with a straight face :P

This thread needed some tiger mom to balance out all the fainting school girls.

Medium-low sorry if I'm kindof a dick. But, I'm not here to cradle snowflakes or create a safe space. Picture JimLab in your mind and realize this isn't so bad. At least I brought memes and a modicum of introspection.

Back to the actual topic:
* Still out to lunch on the diffuser integration - actually needs cfd or pro-level opinion to be more sure
* Interested in detail shots of transmission cooling area, which way is air going, is it even necessary?
* Believe *new* front fender well interface could be improved further by smaller clearance to unibody and angling air out past the drip rails, similar to Ferrari example
* Why not cover front subframe also? Is it too low?
* Could use some molded FRP to cover exhaust sections, or front portion if not totally
* Any ideas OP is thinking of integrating?

The last thing this forum needs is more dicks.

Also. We are in 2019, calling someone a school girl is pretty gender insensitive. But I'll stop there before we get into politics haha.

Also, moderators are here to moderate. Not to be dicks. Maybe consider not being a mod if you feel strongly about being a dick.

You're joking right?

I do understand this is a car forum mostly consisting of middle to older aged men haha

You mean real men who don't have a pussy that gets all bloody from being called a little girl over the internet? Then yes, you are correct. ;)

Can we please STOP with all the school girl talk?

https://bigmemes.funnyjunk.com/pictu...45_3613842.jpg

I want to stay above the fray, but I do have a legitimate question since I don't know a lot about undertrays other than what I have read through the years( which is quite little to be honest). It would seem to me using logic that ours cars put out much more heat through our exhaust system than most piston engines, barring true race cars and many high HP street pistons with NO2. If any full undertray traps that much heat between the tray and the car floor and all the intervening components including the trans, drive shaft, U-joints, etc., that cannot be good long term. It would be like putting these things in an oven, particularly in hot climates, and baking them for hours on end. Am I missing something here, if I am please enlighten me.
Mike

You definitely want proper ducting in the engine bay, including the hood. Although I imagine that if you are at speed, enough "cool" air (even if being heated by the radiator and intercooler, but still cooler than the heat coming off the turbos and downpipe) somehow makes it way out of the engine bay through the trans tunnel area (if a flat bottom restricts it to that area.

With or without a flat bottom, a properly ducted system, incorporating a vented hood will help mitigate under hood temps.

I am talking about the entire area from under hood, to the mid body region and all the way on back. It seems to me as an analogy is that if you seal a metal box on all sides and then put a fire in it, the contents get pretty much cooked to a crisp in very short order, i.e. a barbecue but we are not cooking food in this case. I just don't get it.
Mike

It's not really sealed. Air will move through the tranny tunnel to the back of the car. It will also escape other areas. Cabin air temps may increase. If it was really sealed and prevented flow from entering the engine bay, I think you'd feel it when driving.

It's also not insulated like an oven.

That is a common downside to adding a full flat undertray.
You just have to weigh whether it is worth the added stress for lowering the lap times and take care to duct hose from your NACA ducts to the most critical components.
Its also going to be harder to put out a fire from common race situations like transmission rear seal, diff axle seal or even the vent failing and dumping oil onto the exhaust.

Another downside is occasionally cars with full flat bottoms take flight.

I wonder if you just want a set for yourself ;). Just kidding though, you guys should really do it.

Yep.

This. Why do good threads always turn into a pissing match?

Well jokes aside i do want one for myself and i did show my interest above when i said count me in for a set. Not because i cant make them (or design them) but I respect the development from a company/individual who "wasted" their time and money to make a part.
I don't and never will copy someone else's work but if the OP wants to work out a deal i do have the capability and capacity to produce them as a "job-shop" .

As for getting one for my self it will be a major task to ship it half way around the globe :ponder: .. My car is not here in NJ with me lol

Whole thread seems to be a rehash of the Atomic Rex thing from 10 years or more ago.

If you think a flat floor (or the usual japanese diffuser) on a car with road car ride height will make a difference - other than add heat and make access more difficult - you're furiously abusing your old fella!

unfortunately~ but stock braces whole remain.

Id imagine some gussetting in critical areas would be fairly necessary anyway, and could be done in such a way the flat bottom itself lends a fair bit of rigidity to the chassis.
a bit like when building a house with a truss frame roof, the trusses by themselves seem flimsy but as soon as it has the plaster (drywall?) which is also very flimsy, screwed on (let alone the roof sheets) it becomes incredibly stiff and rigid.

hi there~
I don't know if it's okay to advertise here. I'm ready for online sales.
The final mass-production type undertray can be ordered on the following web page.

https://www.wankelgarage.com/product...flat-undertray
https://cimg5.ibsrv.net/gimg/www.rx7...6334b9aa9d.jpg
If you are interested, please visit my homepage.
thanks~

What's the difference between the Type-A and Type-B when you choose "No' Exhaust Line Cutting?

EDIT: Ahhhh - I see. With a set of vents or not near the downpipe.


Also, you say "Applicable only to vehicles with a RE-amemiya rear diffuser" ... RE-A Race or Street? I think you need to specify so people know...

Thank you for your advice. It needs a pro version diffuser.
https://www.rhdjapan.com/re-amemiya-...rbon-fc3s.html

Why not offer the diffuser as well?

Oh my goodness. Whatever happened to your car rulermark