I have a new to me 88 F250 7.5l. The exhaust system is in pretty bad shape every where and sounds like junk. I was looking to replace the system with headers and dual exhaust. There are currently two tubes running from the catalytic converter back into the engine compartment. One of these tubes is from the front of the cat and the other is from the rear. While I haven't had a chance to study this alot, can someone please tell me what these tubes are doing and what they are connected to? Doesn't seem like I can just toss the whole mess out without problems.

Thanks for the help......

 

This is by no means a scientific nor technical answer, but it should satisfy basic requests, and it is from my own personal experiences, it may vary from your model year (Mine was '85 300I-6): Both of those tubes should be running to your Smog Pump somewhere in the front of the motor. Those hoses provide cool air into the exhaust system (through ports in the extremely hot catalytic converter), which somehow reduces emissions.

Hopefully my post will bring this back to the top, and someone can elaborate on these hoses and the smog pump for you.

Good luck

 

That makes perfectly good sense. Thanks for the reply. I see plenty of anti-smog posts here, so I'm off to do some reading.

 

i am assuming you dont have emissions tests where you live. though i would ask just cause some people get rid of their emissions stuff and then find out they have to get it inspected LOL