SPEEDHUNTERS: The WELD FR-S!!!

[Ultramaroon]

Don't get me wrong. As others have said, it's beyond craftsmanship. It's a full on work of art!

Would have been nicer for me to lead with that.

[Kiske]

Originally Posted by zooki

I've never understood that whole "3/4's of a fender" thing either...

Just copy/pasting.

No there are not really any performance benefits. The removal of the bottom rear fender is to prevent "aero wash". Air traveling over the front of the wheel arch travels over the fender and over the wheel. The same air hitting the side of the wheel would normally hit or "wash" inwards against the flare. You don't want that in an aero application because it would be unnecessary downforce. To counter-act this, you simply remove the rear of the widened fender so air washes directly rearward. You see similar modifications on rear bumpers/fascias, where they're either removed entirely or vented to prevent the "umbrella" effect of air traveling under the car.

More pictures here: http://www.7tune.com/feature-an-fr-s...-of-this-weld/

Personally, this is what I wanted to see.

[extrashaky]

Originally Posted by Gunman

Helps vent the wheel wells, look at a DTM or JGT car.

I don't think I buy that, but if it does vent the wheel wells I would love to see wind tunnel tests to prove it. Without any kind of intake vents, the airflow looks like it would flow around the front of the wheel well and just create an area of turbulence behind the wheels that would essentially increase drag. I suspect this is purely cosmetic.

[Ultramaroon]

it's so u can see muh ballz

[fatoni]

Originally Posted by Gunman

Helps vent the wheel wells, look at a DTM or JGT car.

Nice to see some real body mods, and not just bolt-ons!

Also expect it to have Weld wheels, based on the name, lol.

that could be the case if this car was about going fast but it clearly isnt the case

[Gunman]

Originally Posted by extrashaky

I don't think I buy that, but if it does vent the wheel wells I would love to see wind tunnel tests to prove it. Without any kind of intake vents, the airflow looks like it would flow around the front of the wheel well and just create an area of turbulence behind the wheels that would essentially increase drag. I suspect this is purely cosmetic.

Dodge Viper GTLM. Look at the front and rear. I've seen the CFD, and wind tunnel data, as I worked on the design of the car. Rules limit the open area to "below the wheel centerline", so that's where we had to stop.

[extrashaky]

Originally Posted by Gunman

Dodge Viper GTLM. Look at the front and rear. I've seen the CFD, and wind tunnel data, as I worked on the design of the car. Rules limit the open area to "below the wheel centerline", so that's where we had to stop.

That Viper has a very obvious NACA duct in front of the rear fender to draw air in. That silly body kit on the FR-S does not. There's no path for the air to enter the wheel well in the FR-S. It would have to go around the side and just circle around behind the wheel, breaking up the airflow and causing drag.

I think all your picture does is prove my point. The FR-S fenders are just cosmetic and have no function at all.

[wheelhaus]

Originally Posted by extrashaky

That Viper has a very obvious NACA duct in front of the rear fender to draw air in. That silly body kit on the FR-S does not. There's no path for the air to enter the wheel well in the FR-S. It would have to go around the side and just circle around behind the wheel, breaking up the airflow and causing drag.

I think all your picture does is prove my point. The FR-S fenders are just cosmetic and have no function at all.

I agree that it doesn't appear to make sense, I'd like to see data showing the fender cutaway has an actual aerodynamic benefit.

However, assuming it actually does provide a benefit, I think you might be stuck on a single point of view that the cutaway is to "vent the wheel well". That naca duct is likely just for the brake duct. Anyways, consider the air flowing around the outside of the car, I think that's where the benefit is believed to be. If the lower edge of the fender is not there, then air flowing past and around the curved carcass of the tire's sidewall cannot be "scooped" up into the fender.

It's like the umbrella effect of a hollow rear bumper with no diffuser. The wheel well might be a little different in practice because you can only get a panel so close to the wheel before you introduce other issues.

Makes sense to me, but I'm still curious how much benefit is actually there, because other race series don't do it, possibly because the rules don't allow.

[Ultramaroon]

I see some nice rock-chip highlights in this car's future.

[Gunman]

It's more about venting the turbulent air created by the rotating tire/wheel, which creates lift on the body. The decision to open up the rear of the fender like that was done long before the location for the rear brake duct was made.

[fatoni]

i think the first point to make is that this isnt a car where they give a shit about performance so i doubt there is any real reason other than aesthetics. second, it really only needs to cutaway about the bottom half of the wheel anyways as the top of it is pushing air the other way right?

[Gunman]

No, if the rules allowed you to vent the top, you'd vent it too. Take a look at the GTD/GT3 spec car, which are allowed front fender vents.


If you look at any LMP1 or P2 car, from before the rules required the "big honking holes", you'd see louvers above the wheel houses, along with venting behind the tire/wheel.

[Pat]

Originally Posted by Ultramaroon

I see some nice rock-chip highlights here.

Isn't that just a reflection?

[Ultramaroon]

Originally Posted by Pat

Isn't that just a reflection?

That's just a preview. Drive it a few months.

My bad... fixed it.