Carl Fausett

Porsche® 928 Competition Chin Splitter

Overview: A lightweight chin splitter for track cars that has inexpensive replaceable panels and a tip-up feature for loading. Wind-tunnel tested and measured for its effectiveness.

Details: Our Competition Chin Splitter will bolt on to the Porsche® 928 frame directly, so the down force generated is correctly loaded right to the frame and suspension. The bottom plate is made from a high-strength composite laminate that is both lightweight and stiff. However, it is designed to break free in the case of an impact or accident so the chin splitter does not cut your front tires or damage the oil pan, etc. during the accident. The bottom plate can be quickly replaced with another one, and the race car can go back out.

You may use our chin splitter as is, or you can build an air dam on top of it for brake ducts or radiator cooling. Several pictures below show how other 928 owners have built various air dam models for themselves.

The composite laminate material is shipped in white as shown. Can be painted in any color you like with any common paint. The composite laminate section weighs 6.4 pounds, 40% less than the same size material in aluminum.

Wind Tunnel Testing: Our wind tunnel tests of this chin splitter (below) show it generated 226 pounds of down force at 85 MPH with a small air dam above it; 330 pounds of down force at 85 MPH with a large air dam above it; and 315 pounds of down force with a large air dam with opening for radiator and intercooler.

Tip-up Feature for Loading: We've solved a problem most of us have experienced with chin splitters; that the race car is hard to load in and out of the trailer without hitting the chin splitter on the ramp. Our chin splitter simply swings up at the front to allow extra clearance for loading without damage. No tools required.

Inexpensive Replacement Panels Available: Race cars hit things. It happens. But when it happens, the composite laminate panel can be inexpensively replaced for just $105. Installs in a manner of minutes. Carry a spare with you!

Kit Includes:
• Pair of lightweight chin splitter mounts
• Lightweight Chin Splitter panel
• All Hardware
• Mounting Instructions

Price: $240 complete. Replacement composite bottom plates, $105.

At my website, I have a number of examples of customer-built air-dams on top of the chin splitter. Those examples can be seen here:
http://www.928motorsports.com/parts/...n_splitter.php

Carl Fausett

These chin splitter mounts have been used and improved over the last 3 years by our team. They have seen Pikes Peak, Bonneville, and Road America - so we know they can handle the forces we have been applying to them.

I've also crashed this chin splitter mount (Road Atlanta) and I still have the smashed mounts - they were good to study to help use make sure that in an accident, the chin splitter mount is not so durable that it damages other parts behind it.

GlenL

How does it work with a stock "S" chin spoiler?

Dean_Fuller

How a bout some pics at a distance...too close to tell what it looks like and what kind of clearance you have. Is it too low for a DD ?

Carl Fausett

In these two pics, you can see a remnant of the stock S chin spoiler on the car. Our chin splitter lays beneath the factory shin spoiler, so that's not a problem.

However, have not tested how it would fit with a full factory chin spoiler in place.
Our mounts reach pretty far forward to support the bottom panel, so I think all you would need is to cut two releif slots into the chin spoiler to allow the chin splitter mounts to pass through.

Speedtoys

It doesnt appear to extend beyond the edges/shadow of the OEM body shape...which for spec/rules based class racing, is a good thing!

Costs...way less than I thought it would...great job!

Carl Fausett

"Why do the 928MS chin splitter mounts reach so far forward?" you may ask...

Because the leading edge of the chin splitter has the greatest downforce on it and it has to be supported, and be able to transfer the downforce to the frame.

We've all seen a row of small turnbuckles used to support the front lip of the chin splitter to the front bumper (like this photo shows). Thats one way to go, but it adds weight and complexity, dirties the aero, and is always in the way if you want to remove the front clip or front bumper for servicing your racer.

So, we made them self-supporting, so the up-straps are not needed.

Carl Fausett

It does not. It is 1/4" inside the profile of the late-model 928 all the way around. Good point - class rules in many groups do not permit the chin splitter to extend further than the nose of the car. And this does not.

Speedtoys

Thats why they dont pay me (as a volunteer) to be a Race Director.

People get bit by the small **** a -lot-.

I'll pick one day a season..and walk around with a string and a plumbweight...



Off topic..the most fun I had was pulling an entire class's spare tires for weight. I just wanted to see WHAT you had to do, within the class rules, to eek out a 50lb spare tire.

Found a lot of water, sand, and concrete that day. The "But this is much safer than bolted down..." welded down spare tires were the more entertaining ones.

Carl Fausett

Pics from a distance per your request.

Height is adjustable by you. There are lot of factors to whether or not you will scrape it during certain movements at the track (curb height, tire diameter, spring rates, sway bar settings, shock absorber compression rate, brake bias, vehicle weight - just to name a few)

BUT... I can say I have had to move mine all over the place to race on gravel, then asphalt, then salt - so I know you too can move it/adjust it as needed.

ALSO: because of the "tip up" design, if you did tap the nose, it swivels up on its mount. If you adjust the drag screw loosely, it will settle back down on its own accord on the next straight. If you adjust the drag screw more snuggly, your chin splitter will remain tipped up until you push it down again. Thats a useful tell-tale for how much dive you are getting on the track.

BEFORE SOMEONE ASKS "What the heck were you guys doing in that first picture (the one with the black tarp behind the car?)?
We were 100 feet away, camera on a tripod, and taking a picture fully zoomed in with a black backdrop (good for a white car) to calculate frontal area.

justaguy

Nice job looks good I'll take a couple of brackets. I'll have to get a price on shipping for the large composite lower piece. May not be worth the shipping.

justaguy

Carl
How many pounds of down force does C -.3 equate to? at say 60, 80, and 100 MPH?

Speedtoys

Send a guy in the truck to go get it Sean..geeeeeez.

928mac

Looks cool but I think it is something that only a track car would require

Carl Fausett

Gretchen is a whiz at international shipping. You might be surprised. Call her at 920-485-0928 and give her your address, or email her at gretchen@928motorsports.com