Just wondering if any of you have put in a dual exhaust on your motor. I was looking underneath and it is 2 2" pipes going into the cat. If i removed the cat and just ran 2 2inch pipes it seems possible. Only thing is, should i be worried about back pressure?

Has anyone attempted this? if so please let me know how it went, and the steps you did.

 

Dual 2" is usually done - do a search for details. Try "Dual Exhaust"

 

I have seen cat-back duals for this engine in catalogs. If they make them aftermarket, you could do it yourself if you're so inclined.

 

I run a striaght pipe on my 86, but that's single w/ no mufflers or cats, I've had no probs. I think backpressure is an urban legend, as long as you have a full exhaust system at least to in front of the back tire there shouldn't be a prob. Factory manifolds already provide enough back pressure in my book, headers are a differnt story, if I had headers though, I'd still be running striaght pipes out the back. I say go for it and let me know how it sounds. If you're keeping mufflers don't even let backpressure cross your mind.

 

Back pressure thing gets debated over at fordsix every once in a while. The gurus maintain religiously that there is NOTHING to this. What is true is that a lot of folks with carburated engines will notice that the engine runs less well after opening up the exhaust (improving flow = reducing back pressure). That's becuase the better flow of air through the engine has leaned out the carb. The carb will need adjusting. Once you give her more gas, away you go with more power than ever.

Or so the gurus say. I have the stock stuff still. As for EFI machines, I don't know. They eventually adapt, right? But yanking all that polution stuff off might be a problem. I have read that dropping a new cam in an EFI engine creates a problem for a while, which is then compensated and the engine ultimately runs better, but not right away. But I never pay much attention to those posts, as they are not for carbed engines.

 

Free up your exhaust too much, and you'll lose low end power, but you'll still pick up at the high end. course, with a stock exhaust manifold I'd think that it would be hard to have that occur. With headers you're getting better flow. Remember, gases flow faster the hotter they are, and gases are hotter as they are compressed more. This is one reason why you don't want too wide an exhaust. The charts people occasionally post about HP & exhaust pipe diameter (in reference to eachother) with either single or dual really are showing you the proper way. 2" dual exhaust is what I was planning on though, with one cat removed and no mufflers.

Also...remember that the further away the object that creates the backpressure is away from the motor, the less it hurts performance. A muffler right at the back of the exhaust feed will take away less performance than one mounted right behind the catalytic converter. The cats would be mounted further back because of this, but then they would be useless because the gases wouldn't light-off properly.

I'm not an exhaust expert - obviously. This is just information both theoretical and applicable that I have picked up. Please do correct me if my info is off - I'd rather spread truth than myth.

 

Actually I think the reason mufflers are kept closer is so water burns out better, but otherwise a muffler is gonna restrict an engine no matter where it is just about the same. Less pipe behind the muffler will cause it to be less effective, but otherwise think of blowing through a straw, whether you plug the end of the straw or the beginning, it's not gonna be any easier to blow through will it? The only gain w/ the muffler back further is about 1 sec of freedom for the gases until they fill up the volume of the pipe before the muffler. I'm no expert either, so I could be wrong too, I'm just going by my own common sense.