Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Most restrictive part of exhaust system?

As the topic says, which part of the exhaust system is the most restrictive? If I had to guess I'd say the pre cats, but like I said just a guess...

Pre-cats
Stock Y-pipe crush flange
Resonator
STD exhaust pipe diameter
Muffler/mufflers
Stock converter
SVT single pipe diameter

The stock Y-pipe crush flange is so bad there is good arguement it could be the worst.

the heads easily be the most restrictive portion of the exhaust system. factories sometimes
use smaller ports to reduce flow and power and promote better fuel economy.

PS - if you are going with a custom exhaust setup, be sure to use 2.5" piping or thereabouts. anything much larger will kill the backpressure and you will begin to lose torque.

Dude, that's pretty much everything!! I agree with the list, too. The exhaust manifolds really suck. SVT should have stepped up and complained a bit for that. Not to mention the horrible Y-pipe.

WHere exactly are the pre cats?

Right up by the engine exhaust ports. Each is basically an exhaust manifold with a cat canister--one for each cylinder bank.

Yes, I saw mine today....they look like a really
bad idea. It's those dam greenpeacing environmentalists!

You never loose torque. You just shift the peak farther up in the RPM band

too bad we in emmissions controled areas cant even think about touching those damn precats!