3" testpipe into stock catback...flow restriction?

[Fla240sx]

so I have a 4-2-1 header and a 3" testpipe

I plan on getting 3" catback one day

would it be a restriction to dump a 3" test pipe into the stock catback? or will the air find its way into the smaller pipe... much smaller?

I can just gut out my factory cat for now and put on the testpipe with the catback at a later date....

or do you all think it wouldn't matter one bit?

[deviousKA]

Actually, having a little expansion chamber in somewhere like the cat location, with blunt transition (as in non-taper transition), has some advantageous reversion characteristics.

Not to sound like a broken record, but if your going to stay NA, forget that 3" exhaust. I used to think it wasnt such a big deal, 2.25/2.5" short pipe was pretty good so I figured 3" wouldnt be to bad.

Anyways I sold my s13 to my brother and he was going to do a turbo setup until it turned out his nizzx manifold didnt fit with his turbo. He installed a full stainless 3" turbo catback.

So I buy the car back from him, and all I can say is that 3" cat back is the absolute worst addition the car has ever had. Right now it is setup with Zeitune EFI (map based ECCS) on the stock intake manifold, built NA 2.5l, obx header, 3" cat and 3" cat back.

I thought the engine was finally burnt or I had oil all over my clutch plate during some recent tuning sessions, but all it was, was that damn 3" exhaust. I installed the little ebay restrictor deal in the end of it, and picked up like 30% power across the board (and all of that e-torque that it should have). Im going to put my 2.25" side pipe back on for sure.