Pre-modification of J-pipe into 4 tube exhaust set up. Before cutting the three holes for the modification this was a flat plate with a 3 in center pipe that bolted up to a 4 tube into muffler system. Massive restriction. We are chasing a 35 + hp gain.
First a PVC plastic tube was modified to create the shape wanted to create a 4 tube set up out of the single 3 inch J-Pipe.
Then a paper form was created by placing the paper over the plastic piece and cutting it out. This will be place over a metal tube, the shape traced & cut.
This is the metal piece that will be welded to the J-tube
Outline of metal side tube where j-pipe will be have opening cut. The cut was made inside the mark so it fit the plate opening.
Next they were welded to the modified plate. After welding, all the lights were shut off in the shop & a single LED light was placed inside the J-tube to insure there were no possibility of leaks.
J-pipe after welding on side & rear tubes, grinding out the extra metal to smooth the flow of exhaust.
Since the J-pipe & the 4 into muffler are fitted at an angle, a flow spike was added to the 4 in tubes into muffler to guide the exhaust gases in the right direction.
This is how the set up will be bolted to the car. I will post the HP gains after the car is dynoed. The modified system is in a Shelby Cobra replicar with a 347 cu in.