Jerry Feather

I have had in mind for some time to try to redesign the S4 and later front spoiler. I have had a good used example hanging in my garage for some time that I have been glancing at once in a while with thoughts about how I might replicate it in ABS plastic using one of the forming methods that I am familiar with.

The original spoiler appears to be made by injection molding, probably out of polyurathane, which is closer to rubber than to plastic. I can't use that method or material.

The primary thing that stimulates the flow of my creative juices is my own need. Secondarily is the need of others, perhaps also coupled with some benefit to myself. In this case, in thinking through much of the Radical Custom 928 that I started another thread about, I decided that my redesign of the S4 front spoiler should become part of it. That opened up the flow of juices.

At just about the same time, one of my regular suppliers on eBay posted a somewhat beat-up S4 front spoiler for sale and with numerous pictures in the listing. With those I was able to sit in front of my computer and study the pictures and thus was able to figure out just how the spoiler might be made using the vacu-forming process that I am accustom to.

One conclusion that I had reached about this long ago is that I will need to make this new spoiler in three pieces making it modular. There needs to be two outer pieces and a center section. The main reason for this is because it is otherwise too large to make in one piece in the oven and vacuum table set-up that I have available. The real benefit, however, from this 3-piece requirement is that in a modular format, as damage might occur to it in use, parts can be separately replaced rather than the whole unit. A secondary benefit, to the extent that this becomes merchantable, is that is can be much more easily shipped.

The main difficulty that has had me stumped for some time is that in order to form the end pieces so that they finish with nice formed outer edges rather than raw trimmed edges, they need to be formed around the edge of the forms, and that causes the form to become locked into the plastic formed around it. The solution to this dilemma is to fabricate the forms in separate pieces that can be removed piece-at-a-time thus leaving none of them form locked in.

I was in the middle of cleaning out space in my shop to start the Radical Custom project, but since this spoiler is going to become part of it and since my juices were flowing in this direction, I jumped into the spoiler forms. First I cut one end off of the spare spoiler I had hanging, so I could better work with it rather than wrestling around with the whole thing trying to take measurements and match shapes and curves and such.

Then I began cutting, shaping, and laminating a bunch of various wood products including hardwood faced plywood that I have laying around, and some Poplar boards. After they were laminated with Epoxy, in segments, I screwed them together and began shaping them. Here are some pictures of where I am with this now.

Daniel5691

Amazing Jerry..... amazing.


Dan

SeanR

This should be really interesting. Any interest in making it with a splitter for downforce at the nose?

Jerry Feather

I have some redesign built into this project, but a splitter is not part of it.

One aspect of the redesign that can be readily seen in the pictures is the shape of the brake cooling duct. I have broadened it out at the front from the original design. Another that is not readily apparent is that these outer ends of the spoiler are about roughly half inch shallower; and they are a bit more rounded.

Something else that you can't see in these pictures is that the little protrusion at the outer aft corners of the original spoiler, which I am kind of fond of, are going to be reshaped a bit by making them a bit narrower, from the "thickness" standpoint, and they are going to be extended a bit further up the edge of the wheel opening, perhaps an inch and quarter more than the originals. When the glue cures in what you see now and I can put the corner pieces back on the form I'll take some more pictures so you can see what I am talking about.

Another major redesign that is going to be incorporated in the center section is in relation to the front grill opening. This spoiler actually forms what amounts to the bottom lip of the front grill. It is however fairly far back on the spoiler and fairly close to the grill. Mine is going to be brought forward so it becomes more apparent as the bottom of the grill and it is going to be a bit lower so as to allow for a little larger "gulp" of air through the grill. This too will eliminate the need they apparently found for more air through the bottom of the grill when they started cutting holes in the bottom lip of the original spoiler for the GTS. I think those holes will not be needed in my spoiler design.

Then, to stiffen the center section more I am going to form some inverted ribs in it going front to back. I have quite a bit of the center section form designed, but still in my head.

P.S. Thanks, Dan!

Whitesands

Jerry, you never fail to amaze me.

69gaugeman

Subscribing.

Jerry Feather

Thanks, Ivan.

Your slogan " If a hammer won't fix it, you have an electrical problem" reminds me of a saying when I used to work on the signal gang on the railroad that went "Don't force it! Get a bigger hammer."

jwyatt8171

This will be an interesting thread. Subscribed for sure.

soontobered84

Jerry,
The holes in the front bottom part of the later spoilers were to accommodate the air flow needed for the later S4's and GTS's when the oil cooler was relocated to under the radiator.

The earlier S4 cars can use the later spoiler, but the later S4 cars and the GTS cannot use the earlier spoiler design because of the oil cooler location.

Bill Ball

Probably 80% of S4s have torn spoilers, so there should be a decent market for this, Jerry. However, I wonder how well these might survive if they are ABS plastic. The stock polyethylene ones are somewhat flexible (rubberlike, as you mentioned) and do deform quite a bit on the inevitable curb/parking stop impacts so usually have done pretty well until they are beaten excessively, usually tearing because they have gone completely over a parking space stop and get caught and torn in the process of backing up over the stop.

MjRocket

Very excited and eagerly following your progress Jerry..My hat is off to you my friend.

mark kibort

cool we need to integrate the splitter into it though!

Tom in Austin

Jerry, where do you find time to practice law?

Jerry Feather

I got out of court today a bit earlier than I expected so I got some more forming done on these two forms. I had glued some material on the pieces at the outer corners and today I shaped them to near final shape. Here are some pictures of that process and some more that make these forms a little more descriptive than before.

Jerry Feather

I do most of my sculpting on these forms with this disc sander with a 36 grit sanding disc. I cut the pieces to laminate and fit together with the radial arm saw and the band saw. Here are a few more pictures, in no particular order.