Audi UR Quattro Rally Build

6 minute(s) of a 357 minute read

Prepping for Custom Stainless Exhaust and Skid Plat Design

We are honored to have a friend of ours agree to build us an exhaust. It’s going to be 3” stainless steel with one muffler at the rear and as similar looking to the works cars as possible. Of course, that meant we had to build a skid plate! Well, not exactly but we did need to see how much room we would have around it so we mocked one up.

First the rear support bar which spans the chassis rails behind the gearbox. We used some rather flimsy aluminum tube we had lying around which made it really easy to flatten the ends.

Our surrogate 3” exhaust tubing fit through but it might need to be lower.

Next, we turned our attention to the front support. We thought we would see if we could mock up a reasonable facsimile of the works support using PVC conduit, even though that would be a little larger diameter than the steel tube we’d ultimately be using. How hard could it be?

Not bad eh?

Next, we need an actual plate. Fortunately, we are a Corbeau seats dealer and their seat boxes are perfect for mocking up skid plates. Our plan was to try to replicate the molded Kevlar are whatever exotic material this one was made from, but in aluminum plate. This might be a three or even four Hobnob project!

Well, you don’t know until you try so we put the kettle and our thinking caps on and had a Hobnob. First, we made a masking tape mold off of our 1:18 model. Then we put that on the photocopier and hit x18! (no, we didn’t)

As convoluted as the works plate appears, if you study the it carefully you can make out many flat looking facets to it. Most obvious is the center section that is about two feet wide. We realized that if we took a long piece of box this wide and put two bends in it we would have the essential structure down. Moreover, if we weld some 2” wide rims on it might look quite similar. So that’s the plan.

We were pretty happy with this so far and decided that maybe this idea had some legs. We pushed on with mounting the cardboard plate to the PVC support bars so we could remove the box and axles stands. To do this we made some clips out of some thin aluminum sheet and bent them around the bars. They worked rather well unless there’s a slight breeze or somebody sneezes too closely!

So that was the basic structure sorted. Now we just needed to widen it; and form the upturned sides! A bit more Corbeau cardboard and loads of Hobnobs and Yorkshire tea later we had this:

Lovely. Right; what shall we work on next? Mud flaps? First, we’ll have to put the kettle on!