LRSimons
Member
Hi all, I recently (sort of) finished my tuned pipe. It's taken a couple months of intermittent work, but after I got it fitted and somewhat tuned, I made my long standing goal of breaking the 35 mph speed limit on my testing road (and chased down a harley to boot!).
To begin, I cut out trapezoidal shapes out of 18 gauge matching up to Jaguar's dimensions the best I could. By just creating a trapezoid, however, the cone does not come out with square ends, as I found out after the fact. The proper way to do it is to cut arcs instead of square edges on the openings of the cone, which requires more math and fun things like ruining bandsaw blades to cut curves through steel. So, I just squared up the edges of the cones on the belt sander. Actually forming the cones was somewhat difficult, as they never seemed to get completely straight. What seemed to work the best was getting one end somewhat lined up, tacking it, then hammering the next inch into shape and repeating. After the cones were finished, they didn't quite line up, so I just welded in some more metal where there needed to be a bridge. At this point, I was just trying to get a pipe made (it would still work to some degree) rather than stick exactly to dimensions.
Yes, the welds look like garbage. Using whatever machines were available at that moment, I started out with a full size stick welder (terrible), then used the TIG machine (slow), and finally a large MIG machine (which still burned through on the lowest settings but I could do a series of tacks much more quickly and cleaner). The frankenstein part in the middle was a lack of math and planning, as I mentioned above. Feel free to make fun of me now.
Because I wanted to retain my other exhaust (stock with extension and flattened muffler), I made the header and flange as well. At the shop I was working at for this bit, the tubing roller didn't quite have the right dies and therefore was mostly a tubing kinker, not a roller. To get around this, I stuffed the pipe full of sand with both ends welded shut. The tube bent just fine with minimal kinking. I made the flange at home out of some 3/16 flat stock, after I got some better equipment. I just traced the outline of the original flange for a pattern, drilled the holes and cut to shape. To offset the pipe from the engine a bit, I cut two bits of curved pipe and welded them together to end up with a bit of an offset. It was then a matter of attaching the pipe and tuning the header and stinger. As you can see, after I got the pipe attached there was way too much header. I somewhat stupidly decided to remove an inch or two at a time, test, and repeat. This took all day, and I eventually decided to just cut the pipe to about 8", what was recommended from just about everything I read. That was the ticket, and the top speed rocketed up to 35. However, now that the pipe was actually doing something, the AFR needed to be richened up. I didn't really care on my test ride, knowing that something would break from the heat, but I was too exited to finally have something to show for my couple days of tuning and testing. After I hit the top speed and speed matched that poor guy on the harley, pop, magneto failed.
Oh well, glad we still have pedals.
Next step is waiting for a new magneto to arrive, drilling jet (done), and fixing all the stupid stuff I've been putting off in the quest for speed. Now that I can actually reach the speed limit, I'll be able to commute without being run over.
Input welcome.
Logan
To begin, I cut out trapezoidal shapes out of 18 gauge matching up to Jaguar's dimensions the best I could. By just creating a trapezoid, however, the cone does not come out with square ends, as I found out after the fact. The proper way to do it is to cut arcs instead of square edges on the openings of the cone, which requires more math and fun things like ruining bandsaw blades to cut curves through steel. So, I just squared up the edges of the cones on the belt sander. Actually forming the cones was somewhat difficult, as they never seemed to get completely straight. What seemed to work the best was getting one end somewhat lined up, tacking it, then hammering the next inch into shape and repeating. After the cones were finished, they didn't quite line up, so I just welded in some more metal where there needed to be a bridge. At this point, I was just trying to get a pipe made (it would still work to some degree) rather than stick exactly to dimensions.
Yes, the welds look like garbage. Using whatever machines were available at that moment, I started out with a full size stick welder (terrible), then used the TIG machine (slow), and finally a large MIG machine (which still burned through on the lowest settings but I could do a series of tacks much more quickly and cleaner). The frankenstein part in the middle was a lack of math and planning, as I mentioned above. Feel free to make fun of me now.
Because I wanted to retain my other exhaust (stock with extension and flattened muffler), I made the header and flange as well. At the shop I was working at for this bit, the tubing roller didn't quite have the right dies and therefore was mostly a tubing kinker, not a roller. To get around this, I stuffed the pipe full of sand with both ends welded shut. The tube bent just fine with minimal kinking. I made the flange at home out of some 3/16 flat stock, after I got some better equipment. I just traced the outline of the original flange for a pattern, drilled the holes and cut to shape. To offset the pipe from the engine a bit, I cut two bits of curved pipe and welded them together to end up with a bit of an offset. It was then a matter of attaching the pipe and tuning the header and stinger. As you can see, after I got the pipe attached there was way too much header. I somewhat stupidly decided to remove an inch or two at a time, test, and repeat. This took all day, and I eventually decided to just cut the pipe to about 8", what was recommended from just about everything I read. That was the ticket, and the top speed rocketed up to 35. However, now that the pipe was actually doing something, the AFR needed to be richened up. I didn't really care on my test ride, knowing that something would break from the heat, but I was too exited to finally have something to show for my couple days of tuning and testing. After I hit the top speed and speed matched that poor guy on the harley, pop, magneto failed.
Oh well, glad we still have pedals.
Next step is waiting for a new magneto to arrive, drilling jet (done), and fixing all the stupid stuff I've been putting off in the quest for speed. Now that I can actually reach the speed limit, I'll be able to commute without being run over.
Input welcome.
Logan
