Finally Getting around to building a new exhaust

[dragon64]

Finally have some time in the shop to fabricate a new exhaust for my car and I just bought a new tool a pipe expander. Actually I'm make 2 different set-ups.The stock 1.8L exhaust doesn't have a short extension between the 2nd cat and the resonator like the 2.4L cars so a slip joint is not possible from the cat back. Since I have to weld onto the 2nd cat anyway decided to fabricate a merge tube from sheetmetal and a short extension to make a slip join possible. The first exhaust system is just your average catback made from re-purposed Yonaka exhaust kit for the mufflers and basic bents and some additional J-U bents and straight pipe. The second exhaust will be a little different. I will be built on the De Laval effect where there is a strong low pressure zone behind a hot high pressure that creates suction in the exhaust as it progresses to the tailpipe. In place of your average everyday glasspack straight through resonator and muffler, I have a S/S Moroso Spiral Muffler. The reason for this is that it has a small diameter velocity tube down the middle keeping exhaust gas velocity high at low rpms but at high RPMs the hot gasses expand release heat and sonic energy creating a vacuum. At the back I'm using a Flowmaster serie 50 Muffler. Again using the muffler as and expansion chamber creating another low pressure zone. On previous cars I have achieved near zero to negative pressure in the exhaust system and at WOT have seen slight positive intake manifold pressure

[vibrologist]

On previous cars I have achieved near zero to negative pressure in the exhaust system and at WOT have seen slight positive intake manifold pressure

Man, that sucks! In a good way.

[dragon64]

Forgot to post this earlier. Did a baseline Dyno run on a friends dyno before chopping out the stock exhaust. My 1.8L/ 5speed my average pulling was a little over 118 whp. We were looking through his database of other cars he has tested and looked up a '12 Scion TC with a 2.4L / Auto and a '10 Corolla XRS also an Auto were only pulling 8 and 10hp more. Waiting for a day when he has free time to do my first "after" dyno runs.

BTW the air box was returned back to stock before the test.