Test car: 1995 Dodge Neon Base Sedan sohc manual
Dyno test: comparison between stock 1995 Neon sohc 2.0 exhaust manifold and 2000-2005 Neon sohc 2.0 exhaust manifold.
The stock cast iron exhaust manifold on the Sohc 1995-1999 Neon works fine for bone stock cars, but the inner diameter of piping is somewhat small, and the primaries have very sharp bends which are restrictive to exhaust flow.
The 00-05 Neon cast iron exhaust manifold has much smoother bends, and slightly larger diameter, which helps improve flow eliminating the header restriction.
When doing this swap, because the 95-99 Neon uses a donut gasket between the header and cat downpipe, whereas the 00-05 Neon uses a four bolt flange, you must use the second gen downpipe as well. The second gen downpipe is too long, so we had to trim a little out of the downpipe for it to fit into the stock Neon exhaust.
Onto the dyno results!
The blue lines are stock 95 sohc manifold and downpipe.
The red lines are 00-05 sohc exhaust manifold and downpipe.
Now, just looking at the peak numbers, the torque gained nicely, but the peak hp number didnt change much. But that is not important, because look at the rest of the graph. Between 4300-5400 rpms we gained anywhere as much as 14 lbs of torque, and 14 hp due to the dip. We also consistently gained 3-4 hp and torque across the rest of the power band.
This same car also had a early 2000 intake manifold and throttle body swapped onto it ,and we gained nice power as well. Check out our other blog post:
Swapped a second gen Neon intake manifold and tb onto a first gen Neon (pics/dyno results)