CPR

4" is to the edge of bumper

I'll try to see if I can make it another 1/2" or so longer with the current mold....tomorrow night

APKhaos

Patrick,
Can you post a close-up pic of a support arm including its attachment detail?
There's no question that the arms have to go to a structural point on the nose. The splitter itself can be sacrificial, but the nose should survive a splitter impact. The pic will help sort out how best to do that. Looks like you have at least two standard length support rods. Would be good to know their min-max adjustment range, and if other lengths are available.

TonyG

Here...


Go through the bumper skin to connect supports to actual aluminum bumper like so...

TonyG




But I wonder if the actual splitter is strong enough to support itself? The question would be if it would start to buffet at speed and/or fold under. It might be strong enough by itself not to need the supports since it's not a true splitter.

I'll volunteer to be the test mule. I'll mount one with a camera on it and run it around California Speedway at redline in 5th gear. That will tell the story for sure. Of course.. I'd have to have one to test with :-)


TonyG

daigo

Hey Tony, the line up starts back there!

TonyG

no no.... I just took cuts.


TonyG

daigo

BTW, I agree that if possible, following the bumper skin's outline when viewed from above would be ideal. Not just at the nose but the full outline. Having said that CP has been very receptive to my input and I'm very happy to see the closest to what I wanted to design myself.

TonyG

Personally, I'd like to see how low the the thing is to the ground.

The pics don't show enough info, but it looks a little high. That sucker should be no more than 1.5" off the ground on a lowered car. It's got to be low to be effective.


TonyG

daigo

Hmm, I see what you're saying, but in reality even highly developed cars such as the RX8 built by Riley and Scott have the splitter at least 3" off the ground, and it's still extremely effective.

TonyG

Less is more.

3" is on high side to be effective as a splitter. At that height, a lot of air is passing under the car, which limits its effectiveness.

And these cars aren't RX8s with their smooth under body belly.

The 944 has a undercarriage that promotes far more turbulence compared to more modern cars (including the RX8).

That said, the solution is to limit the air under the car. Thus the lower the better. And 3" ain't low enough.

TonyG

333pg333

Tony, The red car in the pictures is standard ride height and no reflection of our lowered cars so I wouldn't worry about the height shown in the pics. In fact my concern would be too low and hitting a gator strip at the wrong angle and inflicting some pretty serious damage?
From what I understand the supports may not even be needed according the CPR Pat? That has yet to be fully substantiated on the track, but he's tested them up to some pretty decent speeds. If that is the case then I'd be inclined to run without just to avoid any knock on effects of a incident with the splitter. If it's not able to run without then I would agree with you on them going through the body work onto the subframe too.

Lorax

It's still an effective air splitter without being that close to the ground. This type would be much much more effective than the AIR type the protrudes further down than out.

TonyG

Effective is measurable in terms of lift, downforce, and drag.

I don't proclaim the AIR unit to be effective.

By the same token, we don't know if this splitter is effective or not.. either.

But I can tell you that to be effective as a splitter, it's got to move air out from under the car. And a 3" column of air is too much to be truly effective on a 944 undercarriage, which is not smooth by today's standards.

TonyG

Lorax

Well, by looking t the design it's obvious that it would force a lot more air over the top of the car... The amount of air the passes under is going to be much much less with a splitter that is forward 5 inches and clears by 3 inches than one that is only clearing 3 inches. It creates a high pressure area at the tip of the splitter because it is forcing any air encountered at a plane higher than that of the lip to go over the car. Normally a significant amount of air that is encountered, even higher up on the bumper, is going to be forced under the car. That high pressure on the top of the splitter is also what creates any actual downforce. I think.

Even if you had a splitter that only cleared 1", you would need serious ground effects on the sides and a diffuser to make use of that, right?

CPR

I go to work for a bit and....damn. All I know is that the handling improved dramatically for me (stock ride height)...especially in the over 60-80mph range (and greater with the speed increase). Where the car used to push in turns at "x" speed, it now did not. The average increase of entry/exit speed was about 10%.

Here is what I can add:

-we found the handling effects to be greatly increased using a mild degree raked splitter, in lieu of a more traditional plane splitter
-the plane splitter redirected @ 13% underneath, the raked version @ 5% underneath
-the unit will not "buckle" under any speed attainable by these cars with or without supports...it is impossible. Yes impossible.
-Technically the sheer point of the hardware would be more relevant than the unit buckling... for arguements sake, calculative measures reflect the unit would reach a viable rate of compromise (mostly be frictional heating) at 436.8821mph.

I'll post some more pics today with better side views.

Animus

Just add me to the top of the list for one. I've been in the original thread and I can't wait to get my hands on one.

List:
1. Animus