Hi-Flow Cat help

[NiNJA]

Hey all,

I just got the APEXi N1 Dual and was wonderin what size hi-flow cat would I use on it? A 2.5inch or 3inch cat? Sorry if this has been posted before, I'm busy installing my Intrax springs and KYB shocks...

            Thanks In Advance

[S14KAT]

To be honest with you I have the Random Tech cat and they don't offer(or at least I don't think they do)different diameters in there cats.  Other manufacturers may be different, but 2.5 inch is the only size that I'm aware of.

[Nismos14]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Quote: from S14KAT on 10:39 pm on Feb. 1, 2002
To be honest with you I have the Random Tech cat and they don't offer(or at least I don't think they do)different diameters in there cats. Other manufacturers may be different, but 2.5 inch is the only size that I'm aware of.</td></tr></table><span id='postcolor'>

did it make a big difference in performance?

[NiNJA]

I think im gonna go with the Carsound cat, it comes in 2, 2.25, 2.5 and 3inch .

[allmotorKA]

You CAN get 3&quot; diameter inlet/outlet cats from Random instead of the 2-1/2&quot; diameter they list for the 240SX. For the 89-97 240SX, Random lists the 2-1/2&quot; diameter cat as part number as 822530...but according to Random, part number 823030 is a 3&quot; diameter cat which was made for the Maxima, but will work for the 240SX as well.

If the N1 dual has a 3&quot; inlet, I would recommend the 3&quot; Random Tech Cat since the Random Cats have slip type flanges. What I mean is that the mounting flange of the cat is free to slide and rotate on the inlet and outlet pipes of the cat. So if you get the 2-1/2&quot; Random Cat, the outlet pipe may be swallowed by the N1 exhaust making it difficult to seal properly without a steel reinforced exhaust gasket.

[NiNJA]

Well to my further research, I think the APEXi N1 Dual is 2.5inch in diameter, and I heard the APEXi N1 Single is 3inch with a 2.5inch converter that you can take off when you go turbo ?? (Not sure on that, if someone can explain for me) ....I'm staying N/A for a while so I'm gonna stick with 2.5inch hi-flow cat...