How would you fab a splitter on my 911?

175K911 · 07-21-2009, 01:04 PM

Need more downforce (or less lift) at higher speeds on the track. Car is fine at most tracks but at a few (VIR, Glen, RA, and probably Barber) I need more front end bite in the high speed 4th and 5th gear turns.

Bumpers are BW Motorsport Ruf Yellowbird replicas from Souk's original GB. I like the look and fit of the bumpers but they really don't allow for a simple splitter under the front valance, it'll be way too high off the ground. I've got the lower rubber lip pretty low but it's not even as wide as the original chin spoiler that the factory fits. And at the moment I've got a plate covering my center oil cooler opening so I don't let extra air under the car.

So I'm thinking of trying to fab some dive planes to attach to both sides of the valance. Either that or figure out a way to redirect more air over the hood rather than under the car. Regardless, even though it's 99% a track car, I still want something that looks good and not something that looks like a 3rd grader made it out of silly putty.

Thoughts?

Zeke · 07-21-2009, 01:09 PM

However, the aerodynamics have not been proven.

Buckterrier · 07-21-2009, 01:29 PM

Quote:

Originally Posted by milt

However, the aerodynamics have not been proven.

And you won't make more

mickey356 · 07-21-2009, 01:36 PM

Where did that front end come from? Holy Crap! That is gorgeous!!!!

Is Marks comment "and you won't make more" implying Milt made it custom? If so, I would really like the how's and where's to make one. It's perfect. It has just enough "old skool" but still enough of the "mod". Just perfect.

Zeke · 07-21-2009, 01:47 PM

Quote:

Originally Posted by mickey356

Where did that front end come from? Holy Crap! That is gorgeous!!!!

Is Marks comment "and you won't make more" implying Milt made it custom? If so, I would really like the how's and where's to make one. It's perfect. It has just enough "old skool" but still enough of the "mod". Just perfect.

It's one hell of a lot of work. It started with a monster like this:

You can see more here: Skunkworks progress....

and here: Why are my bumpers not finished?

blk911 · 07-21-2009, 03:17 PM

Come on Milt, if you won't make more, just make a mold and sell for big $ to your favorite aftermarket manufacturer so they can make them! (you already said you weren't interested in making them a production item, unless you have changed your mind? ;-)

304065 · 07-21-2009, 03:28 PM

C2 Turbo from Getty Design. I don't like the looks of it but the aero is better.

mickey356 · 07-21-2009, 05:36 PM

Jesus Milt, that thing's gonna give me nightmares!!!!

That is quite the jig there. As much as I appreciate the engineering and hard work that went into yours I'm gonna say it'll be awhile before I take that kind of project on.

It's a work of art.

ShakinJoe · 07-21-2009, 07:56 PM

That front is tough to add the splitter as you have indicated. You could do some end wings but I am not sure you would gain that much at lower speeds.

Wyvern · Wyvern's Garage

What about some Cannards (or is that what was refered to as end wings) ?

Cant tell from the photo but do you have a tail ... could that be to much ?

DanielDudley · 07-22-2009, 01:49 AM

I think you would need to fab a piece of aluminum and mount it at the correct angle. Then you would have to fiberglass up the gap. Obviously you would need to rough up the area, and you might make up a form to glass over out of foam.

If you want to play around with it, get some blue masking tape and some cardboard from a bike shop. If you covered the whole bottom of your nose piece with blue duct tape, you could even make a removable splitter that would only be held on by the fasteners. A guy like milt would then probably make a mold and do the whole thing in fiberglass, but you wouldn't have to for a one off. It would probably be lighter though.

175K911 · 07-22-2009, 02:53 AM

Thanks for some of the thoughts. Wish I had the time, talent, etc to try building something like Milt created but adapted for my car. Not looking for a lot more downforce, but just want to make the car feel more comfortable in those top-of-4th gear turns. It's pretty darn good as it is but could always use more. And the front gets to feeling light at 125+ though that's as much a function of -2.75 degrees camber and a touch of toe out as anything.

Shakin Joe- Yes, the dive planes I mentioned would be the same thing as a canard. Not sure I need a lot more downforce since the car is fine in most places up to 120 or so. Just gets a bit light coming over the hump on the long back straight at VIR. Plus it would be nice to have more grip up throught the climbing esses, and the esses at the Glen too.

Wyvern- yes have a tail. Similar to the early turbo tail, but with no oil cooler cutout and the tail is 3" longer than the turbo tail was. So it does a pretty good job of negating lift at the back. Maybe too much compared to the front:

Here's a shot comparing my front end with my BIL's stock front valance and lower spoiler. I think I may have actually lost surface area in the front for deflecting air:

spence88mph · 07-22-2009, 02:56 AM

Can you look to the original CTRs for inspiration, going by the Youtube footage they turned very well at high speeds with the same front bumper. Could it be something as simple as ride heights front and rear, getting the front lower than the rear for a little downward attitude?

Mysterytrain · 07-22-2009, 05:59 AM

Geez, Milt I want one! That's a beautiful today as it was the first time you posted that picture!

175K911 · 07-22-2009, 06:22 AM

Quote:

Originally Posted by spence88mph

Can you look to the original CTRs for inspiration, going by the Youtube footage they turned very well at high speeds with the same front bumper. Could it be something as simple as ride heights front and rear, getting the front lower than the rear for a little downward attitude?

I've been running roughly the same stance, alignment and heights for 20+ years, but always with stock Porsche front and rear valances and spoilers. This car is a bit more aggressive suspension wise than in the past; I used to run wither 22/29 or 23/31. And this is the first 911 that has all ER Polybronze and Monoballs everywhere.

I can get up through the VIR climbing esses at either 6500 in 4th or run up there pretty close to flat in 5th and the car works well, but it can always be better can't it? And at places like Mid Ohio, it's fine too. Just the higher speed areas at select tracks. Maybe I'm just hoping for too much with an old car.

mike monde · 07-22-2009, 10:27 AM

Milt,
That front spoiler is beautiful!
Nice job.
Question, are you running a front oil cooler or the air conditioner condenser?
Have you seen improved performance with either?
Long hood lines on a short hood...sweet

84_Carrera · 07-22-2009, 10:33 AM

Quote:

Originally Posted by Buckterrier

And you won't make more

Was that a 'Faux' Pas?

Cory M · 07-22-2009, 10:43 AM

Ed: sent you a PM

aston@ultrasw.c · aston@ultrasw.c's Garage

I have a RUF front on order, now I am having second thoughts!

What if you made the structure out of plywood. Something like a stack of 4 pieces of 1/2" ply cut with a jigsaw. The edges could be rough blended to give the shape you want. The ply could be a cheap grade, C shaped: 3 layers down 1 layer forward.

Then bond together and have the whole lot fiber glassed over by a marine repair shop.

Lots of grinding/filling and sanding to follow.

Then for the lip: aluminum plate or conveyer belting!

Of course I have never done this myself, but I have fabbed all kinds of goodies in the past.

Cory M · 07-22-2009, 02:16 PM

Quote:

Originally Posted by aston@ultrasw.c

I have a RUF front on order, now I am having second thoughts!

What if you made the structure out of plywood. Something like a stack of 4 pieces of 1/2" ply cut with a jigsaw. The edges could be rough blended to give the shape you want. The ply could be a cheap grade, C shaped: 3 layers down 1 layer forward.

Then bond together and have the whole lot fiber glassed over by a marine repair shop.

Lots of grinding/filling and sanding to follow.

Then for the lip: aluminum plate or conveyer belting!

Of course I have never done this myself, but I have fabbed all kinds of goodies in the past.

It would be really heavy with thick plywood and fiberglass. You can buy a material called Alumalite from sign shops, lightweight alumnum honeycomb with plastic sheets bonded to it on both sides. Light and stiff. Splitters tend to be a consumable item, we've made them out of thin (.125-.25") plywood and out of fiberglass sheet, they tend to get very beat up. Best bet is to get a bumper with a splitter built into it, or if you don't want to do that make sure you design your splitter so it is easy and cheap to replace, also make sure it won't cause a lot of damage to your bumper when it gets hit or ripped off.