New exhaust for a Z22S

[Ratrod720]

I want to make a new exhaust for my 720 race truck but was wondering about the cat. I know it is illegal to remove a cat from a vehicle equipped with one, but would I get in trouble for taking the cat off my own truck? Is that law just to prevent theft? I want the new exhaust to come straight off the turbo, through a flowmaster muffler and right out the driver side fender. I don't have room for a cat with that setup. And maybe I could just leave the muffler attached to the truck since that technically isn't removing it lol. I don't need it to pass smog by the way.   

[NC85ST]

Don’t worry about a cat in NC with a truck that old. I got rid of the cat on my ‘85 as soon as I didn’t have to get it inspected anymore. Probably could have gotten rid of it sooner.

[powderfinger]

Yep, in NC a vehicle that is 35yrs and older doesn't need to be inspected so no worries.

[Ratrod720]

Thank you! 

[jagman]

Depending on the track, you may have a noise limitation of 108 decibels for the exhaust. 

[Ratrod720]

25 minutes ago, jagman said:

Depending on the track, you may have a noise limitation of 108 decibels for the exhaust. 

I think that should still be below 108 decibels. Once I get it in I'll see. Maybe I'll put a different muffler on it if the flow master don't work.  

[Stoffregen Motorsports]

108 is pretty loud. A straight pipe might make that much noise, but any Datsun with a muffler should be under 100. We learned to install an elbow turned away from the sound meter. Different tracks have their sound meters in different places.

 

Motors tend to make the most power with the muffler as close to the back of the exhaust as you can get it. On a truck, this means after the axle, but there are serious space limitations there.

[datzenmike]

Turbos tend to homogenize the sound pulses also. Obviously sound energy is taken out and used to spin the turbo.