how restrictive are factory cats?

[juiced_94gt]

just wondering, i put mine back to smog my car and it fels like its all plugged up now

 

[95opal]

basically its the most resrictive part of the entire system

 

[94MustangGT5.0]

Well, I am not sure which is more restrictive... factory catted h-pipe or crimped factory headers. Either way, getting rid of that stock h-pipe was one of my favorite upgrades yet... it made my exhaust sound AWESOME!! I would definitely get that stock one off there if that's what you are asking this question for, you won't regret it.

 

[Car Nut]

I upgraded to an X pipe with 2 high flow cats and it was way better than the stock H pipe with 4 cats. The stock cats are extremely restrictive. After the upgrade, I could tell a power difference, volume increase, and quicker acceleration through the rpms.

If I started over again, the X pipe would be my first mod and then subs and so on.

 

[302fordracer]

ughh I put on a bbk off road h pipe and whew..breathes way better..louder, faster and more fun...

 

[final5-0]

Without a doubt the 4 cat mid pipe is the greatest choke in the factory exhaust system.

Another thing about that pipe is the older it is the more restrictive it can become.

When I had just a few mods I swithed to a Bassani X with cats and noticed a small gain.

Later
Grady

 

[FastFord]

restrictive restrictive restrictive!!!