New Diffuser For S550

[stoli]

And how does it transfer that downforce to the wheels ? Through crappy looking plastic and tiny bolts ?

Through the venturi effect. Rear diffusers simply guide the air allowing for great pressure differentials on top vs under the car. There is virtually no load on the diffuser itself.

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[Ultimateone]

Looks like another fly by night company that sells bent aluminum and charges a shitload

 

[908ssp]

Amazing thread just proves how little most of you know. If you don't like the looks fine that's your subjective opinion but saying anything about function just proves my initial statement.

 

[Lost Cosmonaut]

Hm, I kind of like it. Anything that keeps air from collecting in the bumper like a giant sail is a good thing, though the design of the S550's rear isn't the worst I've seen, this looks at least like it should separate it a little better.

Diffusers do two things, smooth the airflow across the rear underside of the car which will help it "suck down" to the road and keep air from collecting in the bumper as I mentioned earlier. Most rear bumpers are like giant sails on the rear. The stock diffuser doesn't do much at all since there's a huge open space around the mufflers. Look at the bottom of the GT-R for instance if you want to see good diffuser/undercarriage design. This one looks like it goes far enough forward that it could make a difference, plus it blocks off the exhaust outlets which are an easy place for air to collect.

I've noticed big differences in top speed and downforce with diffusers like the one in the OP, but I run high-speed events where aerodynamics are everything.

 

[Keiferson22]

By "prototype" do they mean proof of concept and hopefully an integrated finished product. At the moment it looks like $hit! Why would you just slap something over the old diffuser and not create a full replacement?

 

[908ssp]

By "prototype" do they mean proof of concept and hopefully an integrated finished product. At the moment it looks like $hit! Why would you just slap something over the old diffuser and not create a full replacement?

Because it isn't necessary or beneficial. The stock "diffuser" is so far away from the ground and so shallow it does nothing good. Putting a proper diffuser on would require it to be closer to the ground and extend as close to the rear sway bar rear suspension as it can reach. Plus for emission reasons it has to go under the evap system. The front edge of the diffuser should be level with the under carriage and the angle up should be around 7 degrees thus from a performance point of view replacing the stock bumper is just a huge waste of money.

 

[i4gains]

By the way, design looks pretty cool and functional, any chance of the ends integrating a bit better with the factory bumper?
veloxmotorsports@ashiftedparadigm - Do we need to pay for membership to post product previews? We can add another component, called a rear spat, which could tie it all together

quote from IG lol, looks like this is obviously a very early stage prototype and they might add another product to make it aesthetic. some of the pics it doesnt look half bad, i have the base bumper so i would just paint that diffuser portion black so the actual diffuser matches

 

[Veloxeric]

Hey guys, figured I'd chime in on here!

We have revised the design slightly from the prototype to better become "part" of the car instead of an addition. Ford didn't make it easy for us but we're doing the best we can . The revision tucks the diffuser further into the bumper. We are also working on rear spats that will help complete the rear end, as well as other aero devices.

Most of the "diffusers" on the market are not functional pieces, and that was our goal with our unit. We hope you like the looks at the end of the day as well, but this is more geared towards reducing drag and lift. That aspect is more important to us than having something look pretty. There are plenty of nice faux diffusers out there, we're not interested in competing with those.

As far as it being weak, it is not weak; and is in fact quite strong. I dropped by Full-Race to show this, (this is still the prototype):

And finally, regarding a "fly by the night" company, we are not that either. We have been in business for a few years now. While we are coming from humble beginnings, we have a very strong foundation in engineering, and we believe that brings a lot to offer to the end user.



Thanks,
Eric

 

[i4gains]

looking good! thank you! cant wait

 

[HoosierDaddy]

How is the belly pan held onto the front of our cars? Or the OEM diffuser on the rear?

The loads on those parts are different. A splitter just reduces the air under the car. A diffuser causes a partial vacuum under them to suck the diffuser (and the car its attached to) down. So a functional diffuser has strong forces trying to pull it off the car while a functional splitter has much less force trying to dislodge it.

 

[c_reber]

I think it would look WAY better on a base car without the factory "diffuser" fins in there. Send me one, and I'll post a bunch of pics to prove it! ;)

 

[SpaceGhost]

I think it would look WAY better on a base car without the factory "diffuser" fins in there. Send me one, and I'll post a bunch of pics to prove it! ;)

This....now i dont need a premium rear bumper.....

 

[rvlyssup]

Looks a lot better now than your first prototype pics. I'd rock it but doubt it'll clear my ROUSH ABs.

 

[CrazedAntelope]

Maybe I'm not understanding something here. I thought the end point of the diffuser should be as high as possible so that the expansion chamber at the back of the car is as large as possible. Increasing the size of the exapnsion chamber forces the air under the car to move even faster, with a lower pressure. Lower pressure under the car equals more downforce.

I'm not really seeing the point of decreasing the height of the rear diffuser. Looks like a smaller expansion chamber and less downforce.

 

[VelossaTech]

Maybe I'm not understanding something here. I thought the end point of the diffuser should be as high as possible so that the expansion chamber at the back of the car is as large as possible. Increasing the size of the exapnsion chamber forces the air under the car to move even faster, with a lower pressure. Lower pressure under the car equals more downforce.

I'm not really seeing the point of decreasing the height of the rear diffuser. Looks like a smaller expansion chamber and less downforce.

Hi I will do the best I can to answer the question. I feel I have relevant information to pass along here. My experience is in multi-physics CFD modeling of turbine diffusers and aerodynamics of turbine blades and vanes. The stuff Velox does is amazing. I am really excited to see them coming out with true engineered components.

That being said, you cannot increase the angle of the diffuser lest you risk flow separation. Flow separation creates a huge pressure drop, unwanted drag and tons of turbulence. The optimal angle for a diffuser is around 7-8 degrees. Any more than that and you blow the boundary layer right off the surface of the diffuser and it will be pointless drag. They are using real aerodynamic approach number 1. by simulating their design using CFD analyses and 2. implementing industry standard practices that have been used for nearly a century in the design of aerospace components.

There are hundreds of research papers written on the topic of flow diffusion. You can google the following term, static pressure recovery ratio. This number is the amount of pressure you can recover from a moving stream by slowing it down into a static stream, the most effective way to do this is with a proper divergence angle, 7 degrees or so. The angle also varies, a very rough surface can actually handle a higher angle 8-9 degrees or more. This is due to the boundary layer thickness, of course you will need to analyze the Reynolds number, verify your Y+ and ensure you are capturing the correct flow at the boundary layer using the correct turbulence model.

I cant speak for velox, but I can assume they are doing it right from what I have seen on their Instagram. I follow them and I really like their approach, true flow simulated engineering and the rigors of aerodynamics are NOT just crunching numbers, it takes experience and R&D, and that is not easy. Props to them.

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