JD's LF fender

[riddle28]

I noticed it at the DTWC, theres a good picture under saturday pre race of the world finals on DoD. He's got a huge wheel well on the LF, it looks odd. whats rumley trying to gain there?

[RaceEngineer]

I noticed it at the DTWC, theres a good picture under saturday pre race of the world finals on DoD. He's got a huge wheel well on the LF, it looks odd. whats rumley trying to gain there?Let air out from under the nose?

[hucktyson]

Good thing he had that huge wheel opening or Bloomquist would have absolutely
Smoked him by 7.2 seconds with several cautions at Charlotte ..... ohhhh wait ....

[Kromulous]

I remember a post a few years ago, about a Rocket car with holes in the LF head light area. It was considered then that was what they were after as well. Interesting thou, that wheel well from that pic you outlined is huge.

[CageFaraday]

I remember a post a few years ago, about a Rocket car with holes in the LF head light area. It was considered then that was what they were after as well. Interesting thou, that wheel well from that pic you outlined is huge.

If the holes were in the headlight, wouldn't that defeat the purpose? I mean you want air "ON" the nose, but you want the air underneath to "GET OUT", so poking holes in the nose up front would decrease the amount of downforce on the nose, because it has a leak... Or am I missing something? I think Mr Rumley can at times be too smart and be looking for the next advantage instead of working on what he's got to improve it and tune it to its full potential. I could see a jumbo wheel opening on LF helping if your in a situation where you have the car really sideways, but if your running more straight ahead it may hurt more than it helps.

[Josh Bayko]

Could be as simple as being prepared for the track being choppy because of the rain.

[RaceEngineer]

If the holes were in the headlight, wouldn't that defeat the purpose? I mean you want air "ON" the nose, but you want the air underneath to "GET OUT", so poking holes in the nose up front would decrease the amount of downforce on the nose, because it has a leak... Or am I missing something? I think Mr Rumley can at times be too smart and be looking for the next advantage instead of working on what he's got to improve it and tune it to its full potential. I could see a jumbo wheel opening on LF helping if your in a situation where you have the car really sideways, but if your running more straight ahead it may hurt more than it helps.The car is never really going straight and the nose wouldn't let air get in that opening anyway, in my estimation.

[CageFaraday]

The car is never really going straight and the nose wouldn't let air get in that opening anyway, in my estimation.

Yes, I know DLM's are technically never straight, but they do incur more yaw at some places. Someone else noted a different car, years before with holes in the "headlight area" and that they were meant to help with down force. I would think any holes in the frontal area, like the head light, would decrease down force instead of helping it. I haven't seen Rumley's big wheel opening myself.

[fast_crew]

What if the holes are meant to let air in, and while passing through the nose and out of the fender well a vacuum effect is created, pulling out more air than what passed through the holes to begin with ...food for thought

[Matt49]

What if the holes are meant to let air in, and while passing through the nose and out of the fender well a vacuum effect is created, pulling out more air than what passed through the holes to begin with ...food for thought

Bingo
Bernoulli's principle

[powerslide]

Why did they go back to the closed off the nose then? I don't see the holes in the nose at the finals. Also if you look at the world finals pics you can see they have a rather large LF wheel opening as well. Its just more noticeable on the JD machine because its white and they took it to the next extreme and stopped it before it went up into the flare

[CageFaraday]

What if the holes are meant to let air in, and while passing through the nose and out of the fender well a vacuum effect is created, pulling out more air than what passed through the holes to begin with ...food for thought


Bingo
Bernoulli's principle

If this were true, why do we close the nose up at all? We use to run good size radiator openings, then we went to zero and use terms like, "sealed off." It just seems to run counter to conventional wisdom on aero principles. Nascar runs as sealed off as they can get without over heating. Since DLM's are about as wide open as you can get underneath, I don't see holes in the headlight being a game changer or at all helpful. But good luck with the spaghetti theory.

[Matt49]

Chill out.
Fast_crew nor I never stated that it was effective in this application.
He explained the theory behind what they were likely after. I then replied because I agreed and named the fluid dynamics principle being described because, you know....maybe, just maybe...some people are on here trying to learn.
You know, there are a lot of people that used to post some really good information on here but that number continues to decline...I wonder why that is.

[Kromulous]

Good post Matt49 !

Agree'd.

[95shaw]

If this were true, why do we close the nose up at all? We use to run good size radiator openings, then we went to zero and use terms like, "sealed off." It just seems to run counter to conventional wisdom on aero principles. Nascar runs as sealed off as they can get without over heating. Since DLM's are about as wide open as you can get underneath, I don't see holes in the headlight being a game changer or at all helpful. But good luck with the spaghetti theory.

Likely meant to keep you looking in this area, while the good stuff is happening somewhere else.

[dirtrace09]

I could see Bernouli's principle being used by many teams that have access to a wind tunnel. Elite modifieds used one a few years ago and had a very different looking deck arrangement. It is a simple principle that could have a major change to downforce.

[Kromulous]

The Elite's wasnt it them that had the exhaust exiting out the decking? raised a big stink down in Florida if i remember right?

[dirtrace09]

Yes that was one of the things that he had on them. Along with a few other things that ump made them change.