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Discussion Starter · #1 · (Edited)
See page 3 for V2.0 update start

I'm putting this on the first post on all three threads.

The guy that owns Kyle Engineering worked from 2018 to 2020 on the Mercedes F1 team doing aero design. As such:

I have located several 3D 1st gen models of various detail. The best one will cost me a hundred bucks or so.

I've talked with Kyle and he's willing to do CFD work for us!

I've got to have a more in depth conversation with him to add the aero bits I'm working on to the 3D model.



The long anticipated (or dreaded) third part of my aero mods is now underway. This is part three. Part two with a link to part one is here: Updated: Vortex design, installation

11/1/20 - Well, a lot has happened over the past few weeks. I've gotten super sick with my long term condition rearing it's ugly head (good news, I have it under control now) so I haven't been able to drive or test as much as I would like to so instead, I've been re-educating myself on aero aspects, creating a middle of the road downforce and drag reduction plan for the Stealth. Having "Hypertension crisis" blood pressure and "ALERT: Irregular heartbeat detected" isn't exactly the time I want to be crawling about under the Stealth.
 

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Discussion Starter · #2 ·
While I'm sitting around not stressing my heart any more than necessary until I have the ultrasound to see if I need surgery, I've been pretty busy thinking, which is always a bad idea. Especially when you factor in my dubious time in college where I learned just enough to be Bond villan material.

If I take this thread to it's logical conclusion, there will be a massive amount of reading material in the form of documents and videos. I will add associated links at the end of each post.

At first, I thought I'd make me a nice little plastic board diffuser with some fins, slap it on the 'ol Stealth and motor down the road. Uh, no, it ain't happening that way. It's my own fault because of that stupid thing called research. Argh.

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The key to effective (as opposed to pretty) aerodynamics is knowledge and education. Visually pleasing design plays only a small part. Yeah an F1 car (arguably the king of aero bits) does sort of look good. Having a wind tunnel to test would be nice but we'll have to settle for tufts and sport cameras.

This particular thread is about the design and building of a rear diffuser for a Stealth, 1st gen. I cannot say if this design will work on a 3000gt because I take as part of the total package the stock Stealth spoiler which as you know is far different from the spoiler on a 3000gt. As such, I'm keeping in mind three aspects:

1. The banana spoiler messes up the attached airflow off the deck lid. The roof vortex generation:
A. Stabilizes the flow over the spoiler and
B. Keeps the attached flow on the spoiler.

2. The distance of the spoiler from the end of the deck lid produces downforce in a rather balanced way. With the air dam I built for the front to increase front downforce, reduce underbody drag and put more air into the radiator, combined with the forward rear spoiler, my car now needs more downforce in the rear which will (oddly enough) reduce aero drag at the rear of the car.

3. Assuming that I keep the existing spoiler, the main rear downforce falls to the diffuser.

I've been learning about aerodynamics from one of the aero designers of Louis Hamilton's Mercedes. If it's good enough for the Merc, it's good enough for me. I'm taking the knowledge I supposedly learned and putting it to good use and hopefully I can move our platform a little farther forward as far as drag, downforce and fuel mileage go. And I might be able to add a few mph to the top end. Maybe. It all depends on how much aero drag can be removed. There is so, so much to aero on vehicles whether they be on the track or road that it's easy to get lost in the weeds.

The list of aero mods is nearly endless - air dams, side skirts, vortex generators, rear diffusers, dive planes, canards, lips, and spoilers all have an effect on aerodynamics.

MY end goal is twofold: fuel mileage on the highway and downforce at relatively slow speeds (call it 50 mph). You will note that there is a big difference between creating usable downforce and actually feeling the downforce. That is by far the most important thing to take away from street aerodynamics. Just because you don't feel it doesn't mean it isn't doing anything. If you've ever driven a car with good spoilers and air dams at high speed, you'll know what I mean. you can FEEL when the aero really starts to bite the air. But you can generate downforce at low speeds too. Believe me, all them tufts of string on my banana spoiler tells the tale at speeds as low as 30 mph. The thing is if I were to create massive downforce at 30 mph, I'd lose a LOT off the top end by creating massive drag at high speeds. Thus, my goal is both downforce and drag reduction.

That's where all that hypermiling work I did on my Dakota comes in handy. Back in the early 90's, some engineers at GM wanted to see if they could increase the mileage on pickup trucks with aero. So they took two trucks, hung a bunch of cardboard air dams and whatnot on one of them and went for a ride. And that's why Chevy trucks look like they do, because of that testing. With my 2000 Dodge Dakota, peak fuel mileage was 29 mpg on the highway. That is a massive increase in mileage over stock.

Setting aside any drag reduction I'll gain from aero mods, there's the downforce aspect of the whole thing. It's called the coefficient of drag versus the coefficient of negative lift. We want the lowest drag and the highest negative lift (downforce). There's also the CD of the car as we all know BUT the cd means nothing until you factor in the AREA of the front of the car in meters (or feet) squared. For instance a Formula One car has an area of about 1.47. On our cars, it's more like 2 so we need more brute force to move through the air, thus reducing all the OTHER aero drag on the car can only help.

And THEN you have to factor in the density of the air. Which means your downforce varies depending on the density of the air. Believe or not, there's an app for that.

Example:
The psi of air at my altitude is about 14.7 psi
If it's 30 degrees out with 50 percent humidity the density is 0.08094 lb/cu ft
If it's 90 degrees out with 90 percent humidity the density is 0.071144 lb/cu ft

That doesn't mean anything to you or I but on something like an F1 car, it's night and day. This is why teams "miss the setup" when the weather changes between qualifying and race day from an aero aspect.

I'll add to that that that Bernoulli's Principle does not work on cars. Because a low pressure area on a car (like the rear window or after the rear bumper) creates drag, not lift to push the car forward. BECAUSE your low pressure areas are turbulent in nature. There's little eddies in the low pressure messing things up. This is why the vortex generators work so well, they change the airflow (smooth it out) to reduce the turbulence.

So, we move the air around to where it does the most good, using methods that change the air flow to something more usable and thus generate more downforce and less drag.

Downforce means more weight on the tires, creating more grip - whether you feel it or not.

Or for the brainiacs: Downforce = Mass x velocity squared divided by the radius of the corner

Simplified, the variable in the formula is the downforce. The mass will always be the same, the radius of the corner is the same so the VELOCITY will increase as the downforce goes up. This is where vehicle weight comes into play. Not only does the power to weight ratio affect the acceleration, but the mass of the vehicle dictates how effective downforce is. Which is where driving a heavy ass Japanese 90's supercar comes into play.

Testing this? Find a roundabout and start driving. Once you slide, you know your max velocity. Add your bits and try again. Which is my smartass way of saying, learn, learn some more and then use your head and work on your aero. That's why tuft testing is a great way to see what the air is doing around yer car.

The short version is that the actual vortex generators on the car work as expected. The few times I have been well enough to drive recently has the tufts now doing virtually no wiggling around but rather going straight back, as close to perfect airflow as I'm likely to get. Next up is a gurney flap and that part will be done (no taller than 1/16 in).

Now it's time to reduce some drag at the back and add downforce at the same time with a diffuser.

As far as the physical design and building, I'm making the diffuser not out of carbon fiber (simply because I don't want to work with the resin which stinks up the place in the winter), I've ordered 1/8 inch thick 12 in x 12 in ABS plastic panels for the diffuser. About 15 bucks on Amazon. I'll be using the same product for the side skirts when I get around to that part. The neat thing about ABS is that it's rigid and easily formed and molded - usually over 175 F will make it pliable enough to bend and form.

But wait, there's more (of course). You've probably seen diffusers on high end supercars or track cars. You can see them mostly because of the up and down fins which are called strakes. There's a ton of misconception about these strakes. In a pure engineering point of view, strakes really aren't needed. But at the same time, they are.

According to an un-named F1 aero designer, the vortex generated by the diffuser strakes is along the bottom edge of the strakes, not the channels between the strakes. Moreover, the only way that strakes are effective is to have them as close to the tire as possible in order to circumvent what is called "tire squirt." Yeah, your tires squirt. Here's what happens. The air flow of the forward motion of your car causes air to impact the front of the tires. This air flow at the point of the contact patch is squeezed and forced around the tires. On the inside that means that it enters the air flow under your car where it screws with your attached and unattached air flow. So, if you put your strakes as close to the rear tire as possible, it will channel the squirt from the tires harmlessly out the back of the vehicle leaving you with a nice wide unadulterated flow of air to create downforce.

To answer the question that you're probably muttering to yourself, yes, on a road car, at normal driving speeds, all that is meaningless. Depending, of course, on the design of the tire, the contact patch, the width of the tire and the shape of the wheel opening. The safest bet is to assume that tire squirt is going to affect your diffuser, otherwise the diffuser approaches useless pretty parts.

A diffuser comes with several parts and several theories. First is the plate under the car and forms the frame of the diffuser. Tests and research show that right around 10 degrees is the optimum angle. And as luck would have it, there is a sheet metal frame under the gas tank that is just the right size to mount one end of the diffuser and just happens to be between 9 and 11 degrees from the rear bumper fascia to the gas tank.

When you look at rear spoiler - wing style only - the closer the wing is to the surface of the vehicle, the less downforce it produces because the low pressure generated by the wing creates lift which reduces the downforce - like an airplane flying super close to the ground. But, by having the Stealth wing so far forward reduces this effect, AND the vortex generators move the attached airflow farther back onto the trailing surface of the wing thus, nearly eliminating the low pressure under the wing.

Over the past few months, I have been drinking in as much education regarding modern aero on street vehicles. I did a lot on my race car but that was back in the 1970s right after we invented the wheel (we need the wheel to move that other thing we invented, fire) Yes, road racing aero can cross over but there's not enough beer in the world to convince me to put a 3 foot lip or a kitchen counter mounted on broomsticks on my Stealth.

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And I have to say a diffuser in the rain is totally awesome because damn, air blasts out of one.

A nice short summation:

Getting into the nitty gritty, the diffuser does create a vortex. On the BOTTOM edge of the strakes. Having the strakes curved produces a venturi effect. The tires squirt air out the sides as they go over the road which the diffuser also helps with. Sometimes the strakes are super short, sometimes they're super long. Without a wind tunnel and lots of material to sacrifice to the aero gods, I'm going for middle of the road with long strakes on the ends and shorter in the center. There will be 5 strakes in the diffuser. There will also be vortex generators on the diffuser frame as well.




 
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I've actually wondered if TwinZ's diffuser is anything more the looks. I don't think I remember "part 1" of your aero mods or what it entailed, but if you ever get around to doing a splitter Racebred Components supposedly make great splitters. You just trace your bumper and they send you the blade and brackets.
 

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Discussion Starter · #4 ·
I've actually wondered if TwinZ's diffuser is anything more the looks. I don't think I remember "part 1" of your aero mods or what it entailed, but if you ever get around to doing a splitter Racebred Components supposedly make great splitters. You just trace your bumper and they send you the blade and brackets.
My other two threads :
First thread:
Second thread:

. My front air dam sure seems to work well. I styled it after the 3000gt active when it's extended. Yeah, it rubs sometimes but I designed it to be flexible. The last time I went to the cabin, 75 all the way, 21 mpg. So it's doing something under there.

What I've learned about diffuser design is overwhelming. I had no idea how much work goes into them. I'd have to see what's under the twin Z. But it's almost simple. The strakes are designed to prevent air from the tire rotation entering the air stream from under the car. Any vortex generation is at the bottom of the strake:
| < strake
^ <vortex

But as far as the strakes go, this is what they do:
  • Strakes don't straighten the flow
  • Strakes aren't vortex generators
  • Tire Squirt and the real reason behind strakes
  • Managing floor vortices
So when you see those diffusers on sites like Carid or Amazon, they're for looks. Unless they're interrupting the air from the tires, they aren't working.

As Kyle has said in his videos, he worked on the Mercedes F1 team and he's run his diffuser information past an "unnamed" F1 aero engineer (I would suppose on the Mercedes team) about what exactly the strakes on the diffuser do and it isn't what I thought at all.

Well, I'm putting this on the first post on all three threads.
The guy that owns Kyle Engineering worked from 2018 to 2020 on the Mercedes F1 team doing aero design. As such:

I have located several 3D 1st gen models of various detail. The best one will cost me a hundred bucks or so.
I've talked with Kyle and he's willing to do CFD work for us!
I've got to have a more in depth conversation with him to add the aero bits I'm working on to the 3D model.
 

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the thing that surprised me about air flow under a car is the speed of the air flow compared to speed of the vehicle.
Gale Banks had a video on cooling the rear differential, and he found that at highway speed, the air flow speed under a 4x4 truck was about 50% of the speed of the 4x4 truck itself.
Jump to minute 20 in this video if you don't care about differential covers :)
 

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Discussion Starter · #6 ·
I have to point out again that this design is by far the most technical I've ever done. I totally wasted my time making the prototype. Argh.

AutoSpeed - Modifying Under-Car Airflow, Part 1

Gale is correct. The way it works is impact with the ground and underbody protrusions cause the air to slow creating drag.

The trick with the diffuser is that the two outboard strakes need to be longer, up to 24 inches long to prevent the tire squirt from entering the flow. This of course affects the ground clearance.

With that in mind, moving the longer strake inboard should block the intrusion.

I've also ordered several larger sheets of ABS for the diffuser. Current cost is still less then $50.

Once the thing is built, I'll add links.
 

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I gotta say, I love your MOXY :)

(I also HAVE to say that I am worried about you physically. You should really be taking it easy. I KNOW, this is your outlet...)

Love you (no ****).

Bob.
 

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Discussion Starter · #9 ·
Why not just go all out and flat bottom the entire car? ;)
I gotta say, I love your MOXY :)

(I also HAVE to say that I am worried about you physically. You should really be taking it easy. I KNOW, this is your outlet...)
Love you (no ****).

Bob.
Well, I've gone out and bought a 4k wifi remote activated controlled from the phone sport camera with about a million different mounts for it which I'm going to be mounting on the car along with a bunch of tufts to look at the air flow. This I am really excited about. I know that spoiler airflow is super nice with the vortex generators so I'm really wanting to see the deck lid and bumper areas.

I'd love to have Kyle run a CFD but his prices start at $1500. I've found a bunch of CFD software that runs on home PCs so I'm going to probably buy one of the 3D Stealth files and use that to do some work.

The underside is already pretty much flat bottom up to the rear suspension. And don't forget I've got that air dam in the front that cuts down on a lot of the front to rear air that's attached to the bottom of the car. I suppose you could put a high angle dam under there but that would be pointless in my opinion. The worry you'd have would be parts hanging down beyond the plane of the slotted panels that I can't remember what they're called. Senior moment.

Also, a street car versus a track car - a street car does one thing more than a track car does and that's the constant changing of the ground height due to suspension travel. That in itself makes it difficult to really tune the underbody areo so really, stopping the tire squirt and increasing the rear downforce with the diffuser is where I'm heading. BUT with the sport mode, a lot of that is negated. So you throw it in sport on the highway (which I do anyway) and get the benefits of a more stable ground clearance.


Jeez, now we're off topic. Bob.....Moxy? I haven't heard that word in a month of sundays! I think all of us old people should form a Stealth/3k group called the "Geezer Posse" Our emblem would be walkers or canes. We'll get nice chrome emblems made too.

I've had these health problems for nearly 20 years now since I had a run in with a wood spider at our cabin that gave me not only a bacterial infection but naturally occurring Anthrax for which I was on Cipro and have the toxicity disability from it. So that means that I am the actual Spiderman. The big thing is my Vagus nerve is severed in my neck so my heart and brain don't communicate which causes high BP, racing heart, fainting. Plus the Cipro reaction causes all sorts of nerve pain, brain damage, tendon tears. Plus it mimics heart failure so I have the added fun of edema as well. My internist told me several years ago that the problems I have are normally seen in geriatric patients so I'm 62 with an 80 year old body. And the one I'm battling right now, "ascending aortic dilation." This is a 50% mortality condition if it bursts but it can be "replaced" once it gets big enough which brings the mortality down to 15%.


Which is why when someone opens their pie hole and says it could always be worse they wind up waking up looking at the lights (an old hockey term, think Bob Probert. Good friend of mine is Dave Shand, another enforcer. Man, do I have some stories.). Speaking of which, the night the Wings chased old Roy off the ice and he quit the Canadians was the highlight of my life.

 

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Discussion Starter · #10 ·
I should probably tell you guys a secret. Well not really a secret. There was a time before my health issues that I did a lot of videos including two series, one a crime prevention show and the other an alternative energy show wherein I consumed massive quantities of adult beverages and muttered into a camera for a while.

My production company is "A man with too much time on his hands productions." I'll go ahead and wait for comments from abroad (Ohio)

Well, the diffuser design - all the parts are here, still less than $50 - is both back on track and off track at the same time due to something I had not heard of and certainly didn't consider - tire squirt. This is where the air in front of the tire as it goes down the road is forced out at the contact patch, creating a zone or wake of low velocity air which affects the ability of a diffuser to create downforce.

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It boils down to this: Tire squirt has to be accounted for in order for a diffuser to be effective to it's maximum. And since I'm shooting for low speed downforce, I've got to account for it big time.

And so I've wound up reading riveting missives like this: The work of Axerio et al. comprised a comparison of Particle Image Velocimetry (PIV) techniques against two Computational Fluid Dynamics (CFD) methodologies. This work concluded by illustrating how the wake structure of the wheel, particularly the vortex centres of the two lower lobes, oscillate in time.

The one over riding question about the tire squirt subject is this: Does a road tire with treads and a narrower width have less tire squirt than a wider no tread racing tire? Certainly the difference between going down the road at 100 - 150 mph is different than going 200+ full throttle around curves. Even I'm not nuts enough to drive like that.

You might ask well what about a larger wheel, say an 18 inch one. Wouldn't that make it less of a problem? No.

A paper by Atsushi Ogawa on the Honda F1 site shows the difference in the wheel wake with and without a side load on the tire sidewall. It showed nothing more than a more stable wake due to the stiffness of the tire sidewall. A stiffer sidewall means the aerodynamics of the wheel and tire are more consistent.

However, there could be effects from a number of other factors, the sidewall and tread profile with an 18" wheel will be squarer than with a smaller wheel so the separation angle could be different. And then you have to think about tire deformation as the contact patch hits the pavement. Normally, the larger the wheel./ tire, the less the deformation.

The shorter sidewall will mean that the wheel vortex will be closer to the ground and will merge with the lower tire vortex differently. There are some rumors flying around the reason for the flanged wheels in Formula E is to help with this.

And then what I said to myself is "Well, wouldn't a CFD (computerized wind tunnel) help the design?" The obvious answer is no because of the varying compression of the tire as you go down the road and over bumps and such would throw off the model.

Some F1 teams have used the engine exhaust to "seal" off the tire squirt as shown here.

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Now we're cooking with gas! (an ode to my grandfather) If we could introduce an air stream inside of the tires that would reduce or mitigate the tire squirt. which I'm going to assume is harder than it sounds.

There are astonishingly few technical papers and or studies about this. Everything is geared towards Formula One and other racing cars. However, I think we can assume that tire squirt with a 17 inch wheel, a narrower tire (than a racing tire) and the tread combine with the overhanging bodywork on a road car will lessen the squirt.

There is another little secret to add to the mix. A tiny little spoiler can be added in front of the wheel opening to direct air away from the rear tires. I used these on the front of my truck when I was in my insane "run it on hydrogen" hypermiling days (yes, I had a bunch of hydrogen generators in my truck. Got 29 mpg on the highway with them, so yeah, hydrogen bombs in my truck). People that are serious about hypermiling have flat wheel covers or even extend bodywork right over the rear tires.

Another method I've used are side skirts where the skirt pulls out just before the rear tire, directing air away from them.

There are in fact ways around the issue of tire squirt. What I'll be doing is simpler than that. I'll be using longer strakes next to the tires that curve out from the wheels to help prevent the tire squirt from entering the diffuser.

At this point, the diffuser will look like this:

291210
 
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Discussion Starter · #12 ·
Today the lack of gusty wind and my health both combined to give me the opportunity to do the last aero test before beginning the physical work on the diffuser.

This is an 11 minute video.

This yarn test had two parts. Part one is the rear decklid past the radius. I've included handy lines to describe what the air is doing. It's interesting to note that in the center of the decklid, the yarn sticks straight back. At either end (just before where the tail light begins - starting about 8 inches in), the yarn sticks straight up! There is virtually no downforce or airflow from 8 inches to the edge of the car. I strongly suspect that this is because of the side vents on the C-pillar on the Stealth.

That is staggering to me. Obviously, the loss of that much ( a full 16 inches) airflow to the rear of the car is disturbing in that airflow going straight up is lift. Somehow, this needs to change.

I am hoping to change this with the diffuser as well as a full length Gurney flap on the spoiler.

Part two is a closeup of the 6 inch long 1/4 inch Gurney flap I made and taped on the spoiler. It may or may not be clear but the yarn in front of the Gurney flap does NOT just stick to the flap. The flap makes the air flow straight up and back - this is what the downforce it generates should look like.

 

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Discussion Starter · #13 · (Edited)
Here's an update. As I've mentioned in another thread, I've got a Mercedes F1 aero engineer as a consultant on this project. Here's his video about diffuser design.

Pay attention when he's talking about the strakes and tire squirt and how F1 teams would introduce a high energy stream of air next to the tires @ about 3 minutes. That my friends after the diffuser is my next plan of action.


The issue is that there is a lot of varying information out there about diffusers and how they work. Here's what I can tell you: I'll listen to the guy that got Louis Hamilton 3 world titles when he worked with him.

I've worked out/invented a method to form ABS plastic sheets for the diffuser strakes (the bits that hang down on the diffuser) and have (finally) mocked up the base plates for it. My requirement is that it has to be removable easily which I have achieved.

Total cost for parts is still under $75 US (and parts of Ohio).

Once more, I'm deep into wind tunnel testing of diffuser design with more math involved. This is going to require substantial adult beverages to noodle this out properly. This time, it's a pretty recent study.

"On the Aerodynamics of an Enclosed-Wheel Racing Car: an assessment and proposal of add-on devices for a fourth, high-performance configuration of the DrivAer model"

Applied Aerodynamics Group, Cranfield University, UK

Presented at the World Congress, April 10-12, 2018, Detroit, Michigan

Cooper et al. [13] studied underbody diffusers and highlighted three mechanisms for downforce generation. (I) Upsweep – the inclination of the diffuser resembles that of a wing section and produces downforce by flow deflection. (II) Ground interaction – flow rate increases as the distance between body and ground decreases due to a reduction of the flow cross-section. There is an optimum point for maximum downforce, after which viscosity effects diminishes this gain. (III) Diffuser pumping – an underbody diffuser reduces the pressure behind the car, compared to a baseline case with no diffuser.


Another aspect of the design is the ground clearance in as there ain't a lot of that under there. From the bottom of the gas tank to the ground is just 8 inches which would give me a 6 inch clearance with the strakes installed (the strakes are 2 inches at the front, 4 inches at the bumper). Before I go any further, I need to check the minimum clearance which handily is the end of my steep driveway (the front air dam drags if I back in the garage - no worries, I designed it to flex) so all I have to do is roll on down the driveway and put a tape on it.

In terms of driving stability, the car would be oversteering at higher ride heights and understeering otherwise by an acceptable margin. However, this range of aerodynamic balance is a significant improvement when compared to the baseline version. Note that the baseline has most of the net downforce applied at the front axle, and its balance is shifted even outside the wheelbase as the ride height increases and the rear axle become under lifting load.

Yet another aspect of this is tire squirt and creating a strake to redirect that. Whether the limited ground clearance will come into play remains to be seen. I may have to build a diffuser in front of the rear wheels, ala an F1 car. As I say, it's pretty tight under there.

While I'm working on the video, here's some photos to hopefully whet the interest. These are of the mockup as it exists today held together with the best invention since we invented the wheel when I was a kid to carry around that other invention, fire which is Gorilla tape.

This is the slot that the diffuser frame fits into under the gas tank.

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Here is the base of the frame fitted into the slot.

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Here is one of the strakes before final trimming after it's been molded.

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And as a bonus, here's the gurney flap I'm working on. I still have to shape it a bit more and then put some paint on it.

291443
 

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Discussion Starter · #14 ·
Well, I've gotten up of my keester and set about hanging yarn on the base of the diffuser, mounting it with the ever popular best invention ever, Gorilla tape and mounted one of the cameras under there so I can so some testing.

Once I've done this base test, I'll be forming the ABS for the full frame that goes from exhaust to exhaust tip and doing another test and then get the formula 1 consultant on the job to look at the results and help me determine where to mount the strakes before I unleash the vortex generators on him.

Now this is an angle I bet you've never seen before!


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Discussion Starter · #15 ·
Despite the weather not being ideal and the camera not wanting to play wifi tag with the phone, I was able to shoot video of the center frame of the diffuser from speeds of 25 to 50 mph. 3:25 starts the 50 mph run and show the most activity of the tufts.


The next step will be forming the rest of the frame and tuft testing that at speeds up to 80 mph.
 

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Loving this "bored old man" energy. I gotta ask though, what is your actual overall goal with this? Just giving yourself something to do and being able to say you have the only proven functional diffuser? Or do you actually plan to make and sell these, or sell the design? Honestly I'd love to have a functional diffuser, because I doubt the only one available on the market(TwinZ) is actually functional.
 

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Discussion Starter · #17 ·
Loving this "bored old man" energy. I gotta ask though, what is your actual overall goal with this? Just giving yourself something to do and being able to say you have the only proven functional diffuser? Or do you actually plan to make and sell these, or sell the design? Honestly I'd love to have a functional diffuser, because I doubt the only one available on the market(TwinZ) is actually functional.
Old man energy? Dude, you should see me trying to stumble around these days. Spoiler: I've got Fluoroquinolone toxicity syndrome. You can research that yourself but it ain't pretty. I'm hoping to try Hyperbaric oxygen therapy in a couple of weeks.

I'd be a lot less optimistic if I didn't have an F1 aero engineer working with me. Most of Kyle's information is in his videos but this diffuser is something else altogether. And a spoiler: My brother in law does 3D cad work so he can take a 3D model and add my aero changes to it for CFD testing, I just have to find the most accurate one out of the dozen or so out there. I'm figuring I can get this squared away for less than the cost of a 60k maintenance.

Check out the one on a formula E car.

f1 diffuser.jpg

There's plenty of effective diffuser designs.

f1 diffuser2.jpg

I've always loved aero work. Since I took my first hydrodynamics classes, it's like I can see the way air flows over objects. 9 times out of 10 I'm right. Don't forget I also have very functional vortex generators that makes my banana wing actually work because holy crap do those tufts stand straight up under the wing now - low pressure baby. And I've got the front air dam that throws more air into the radiator and keeps a lot of the aero drag from entering the underside of the car. The smallest changes can produce big differences. The thing with these cars is they were designed with 1980s technology. So they probably put it in a wind tunnel for a bit and sent it on it's way. But here in the 21st century, we can do so, so much better with aero design and improvements. The more downforce, the better high speed handling is (I'm shooting for 50 mph and above) and the less drag the less fuel used, the less stress on the drivetrain, yada, yada.

Unless those commercial diverters were actually tested during design, I would doubt their positive effect. Remember most of the work a diverter does is keep the tire squirt from affecting the flow out the rear. That's why you see tall strakes on diffusers. Any vortex is produced at the bottom edge of the strakes, not within the body of it. I'd love to see the actual diffuser on Hamilton's car. Plus three words: rain rooster tail. And another aspect of the underside of your car: The lower the body is to the ground, the worse your aero drag unless you use ground effects. I'm going to show how to do that too.

The whole package when it's done will aid fuel mileage, top end and handling. Future plans include dive planes, better engine compartment evacuation (the open blisters help a lot but it can be better), and doing something about that damned fake vents behind the doors. I'll also be adding diverters to prevent any aero drag on the tires as well. Don't get me started on the intercoolers and those openings. That deal needs some attention which is what the splitter will help.

Back when I had my Dakota, it had a 4.7 liter hemi style engine. Taking my trip to our cabin, 250 miles, would use 7/8 of a tank and if you've ever driven a truck in a heavy crosswind, oh my. Once I got the air dam, vortex generators and hard bed cover I was down to 3/4 of a tank. For two years, I also had a bunch of hydrogen generators too and that got me down to 1/2 a tank, or 10 gallons to go 250 miles. I'll show you those things when I shoot the first diffuser video this weekend.
 

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I meant "old man energy" in a good way, like "I got nothing better to do, so gonna focus entirely on this one random specific thing". And if you come out of this thing with an actual functional, "easy" to produce diffuser I'm definitely interested. I plan to start tracking next year and the street classes allow for only a wing or a diffuser, and I'm not trying to lose my working rear AA.
 

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Discussion Starter · #19 ·
I meant "old man energy" in a good way, like "I got nothing better to do, so gonna focus entirely on this one random specific thing". And if you come out of this thing with an actual functional, "easy" to produce diffuser I'm definitely interested. I plan to start tracking next year and the street classes allow for only a wing or a diffuser, and I'm not trying to lose my working rear AA.
Well you guys, I had two online shows before I got sick. CSI Saline (crime prevention) and This Old Shack which was an alternative energy show.

My production company is in fact "A man with too much time on his hands"

I'll try and locate some old copies. Never put them on YouTube.
 

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Discussion Starter · #20 ·
I meant "old man energy" in a good way, like "I got nothing better to do, so gonna focus entirely on this one random specific thing". And if you come out of this thing with an actual functional, "easy" to produce diffuser I'm definitely interested. I plan to start tracking next year and the street classes allow for only a wing or a diffuser, and I'm not trying to lose my working rear AA.
Now that I actually read what you posted, your active aero. Gurney flap. Wouldn't go over quarter inch tho. If you have either the lap time or ability to measure the downforce, I'd think make several a foot long each and attach them one at a time until lap time starts rising.

I'll start shooting tomorrow for sure. Multi parts however cause I know you kids got the attention span of a gnat. :ROFLMAO:
 
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