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... And, NACA ducts rely on vortices and laminar airflow, so you can't just cut out a NACA silhouette and expect it to move air except like any other fancy hole with a pressure differential.
This project has a lot of potential, and is an impressive effort. But, don't mistake that for real engineering and efficacy. The current design is suspect, at best.
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.
Well, you need to make a few to actually get that testing. Make me a set, and I'll test them at VIR, Watkins Glen, and Summit Point, and I've got lots of data and video of straight speeds with which to compare it.
Great idea and throw some strain gauges on your springs to measure the downforce
Originally Posted by ptrhahn
I didn't get any advance CFD data on my lip spacer, but I can tell you it works like a champ.
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.
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.
I'm planning to add the part as shown in the figure that connects the wheelhouse inner surface to undertray seam-less. NACA duct is attached like this. And appreciate for many comments.
I'm planning to add the part as shown in the figure that connects the wheelhouse inner surface to undertray seam-less. NACA duct is attached like this. And appreciate for many comments.
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.
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 **** 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.
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.
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.
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.
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 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 **** on it. Where are all the custom parts you've made? Where is your engineering degree that justifies the doubt?
Vince
Originally Posted by TwinCharged RX7
+ 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.
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.
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.
Whether or not it works or is functional; it’s bad *** and is way better than something I could do myself. Awesome work OP. I look forward to where this goes!
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.
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?
01-31-19, 01:22 PM
