With the new, more powerful 2.3L street/race motor that’s going in the Squarsche, I needed to upgrade to a full-on performance minded exhaust. So the stock type-4 heat exchangers and off-the-shelf bus 4into1 header was not going to cut it anymore. Since there are not any affordable systems that will work, I opted to make my own so it would fit and incorporate the muffler I wanted to use; a Bischoff S/S Porsche 911 banana can!
So I began by creating a set of stub pipes. I chose to use 1 ½” pipe for the stubs and 1 5/8” for everything else before the collector. I also wanted to try out a new idea that’s been rolling around in my head that would enable me to have leak-free stub to header connections. It involves 2 slip-joints, which cause any exhaust gasses that wish to escape to have to turn 180 degrees, then another 180 degrees and finally another 90 degrees for a total of 450 degrees all in a millisecond; that just isn’t going to happen! So these stubs will be leak-free while being exhaust gasket free too. They were kind of a PITA to make, but they came out exactly as I envisioned and they fit the bill perfectly. I still have some finish welding to do on the flanges and cleaning up on the flanges, but you get the idea. . . Once it's all tacked together, I'll go back and TIG weld every joint.
When building an exhaust, you have an obvious starting point for the system at the heads, but you also need to have an ending point so you can figure out how to get it all to fit. So next I mounted the muffler. Since I had never seen a 911 banana can muffler on a VW engine, I needed to come up with a muffler mount system. You just can’t mount it to the fan shroud since it’s not really made for mounting anything larger than an AC compressor, your mounting options become limited. So I decided to make the mounts attach to the main engine mount bar which is the main load bearing member at the rear and is tied into the body of the car.. The right side mount I made from ¼” steel since it has to bear the full weight on that side and the lions share since that mount is about 1' off center-line.. The left side I made out of 1/8” steel, but tied it into the AC compressor mount holes that already exist in the fan shroud. I cannot tell you for sure just how many times I mounted/dismounted the bar and fan shroud during the build process, but it was at least a couple dozen! Everything was dry fitted, then welded in place to ensure a perfect fit.
Once the bare mounts were made, I needed to make a pair of cradles where the muffler will sit. I chose aluminum for this since it needed to be ¼” thick and steel would just be too ridiculously heavy for this part. All the mock-up was done with the engine sitting on my lift about 10” off the ground with the muffler sitting atop wood bucks that held it at the right position. One of the goals with this exhaust is to not have any part of the system below the bottom of the engine. Ground clearance can be an issue with the car lowered and I got really tired of my exhaust scraping occasionally as I exited a couple parking lots in my town. Plus this car should see a fair amount of track time in the future and I'll be lowering it on those occasions.
Mount holes were drilled through all materials at once so there was no chance of bolts not fitting or fitting loosely. The result is a super-solid mounting that does not rely on the tightness of the bolts to be a tight fit. Here's a few shots of the muffler cradles in place on the mock-up motor:
Here’s some shots of the muffler in place on the new cradle on the mock-up motor:
Strapped on with temporary straps:
I also modified the muffler to exhaust mounting with a V-band coupler so that for track days I can easily remove the muffler and add on a Supertrapp or more basic flow-through muffler/stinger system.
Now that I have a definite beginning point and ending point I needed to locate where the collector would be and begin building to the rest of the header. Stay tuned. . .
I’m also in the process of making my stub pipes and exhaust, so some of these features will be incorporated in since they also use the mount bar, however, I’m not going to be letting that cat out of the bag just yet. . .
