Ive read through the exhaust guide and many other exhaust threads and seen that most people agree to get the 94106 converter if ya want a hi flow cat. I have no issue with that.

I have seen that magnaflow has other hi flow cats such as the 94305. The only difference i can see is that the 94106 is 2.5 in/out and the 94305 is 2.25 in/out.

When i get to a point where i can do my exhaust im thinking im going to do 2.25 exhaust piping for better low end (i might go with 2.5 because the job im trying to get is about 40 miles away and this might be a better choice).

So my question is if a person does the 2.25 piping would it be better to do a cat that has 2.25 openings or do you want the 2.5 and why?

Thanks in advance to anyone who can help clear this up.

 

have the cat diameter match your exhaust pipe diameter

 

so then theres no difference between the cats just the inlet outlet sizes?

 

there are different series of cats which are different length/shape/o2 bungs but as long as its the same series as the other it will be fine

 

I appreciate the help clarifying this. Its more because ive never seen anyone really talk about the cats specifically just that the 94106 seems to be the most popular. Like i said since im gonna be doin highway travel i figure 2.5 pipe might end up bein better for me.

 

i would go with the 94105

http://www.magnaflow.com/02catalytic...ER&partnum=941

i just bought 2 94139 because i have a 3" collectors and i need an O2 bung on them

 

Im fairly new to all this but ive looked into a good bit of it. I know im going long tube headers (obx if i can find them) and the magnaflow hi flow cats. So with that being said would it be a better choice to go with the 94136 so i dont have to worry about having it bunged?

And to kinda give ya more to work with im doing that along with the X pipe crossover and magnaflow mufflers. Im looking performance and a good bit of rumble but not drone (Highway driving again)

 

Yes, I would get one with a bung, the headers should have one, then weld thew cat in so the bung on it is after the cat. No extra bungs to be welded in

 

oh cool alright...thanks for the input helps alot

 

The pipe coming off you manifold is 2.5". Keep that 2.5" threw the cats. You can do what ever you want after that. That is why everyone gets the 94106.