I have a 93. I'm running the stock twins, non-sequential, with a power FC (not tuned). I have a 3" racing beat turbo back exhaust with a magma flow high flow cat. I want to know what would happen if I took the cat out. Would I blow the engine if I did that before getting it tuned? Do I need a boost controller if I do that?

 

If you take out the cat..The Dog would be Super Jealous! and most likely pee on your bed!

Boost controller would be recommended or just refrain from HARD driving until you get a tune.Boost creep would be the issue here due to a free flowing exhaust.

 

I removed my cat, it's a 94 jdm model so no pre-cat in the down pipe. also a fujitsubo catback. I have a stock intake with a k&n filter, stock ecu, no issues for me. Seems some cars react differently, I have a boost controller on the way just to be safe.

 

With a downpipe, mid-pipe (no main cat) and aftermarket cat back there is some risk of boost creep. How much risk seems to vary between cars and which cat-back. I'm not certain how non-sequential factors in, but my feeling is that it would increase the risk to some degree. Creep is one of those nebulous, unpredictable things. Some guys report never having issues, others have it right away, still others never had a problem until one day under WOT....the planets align, ambient is just right, engine load is just right etc. Creep causes them to run lean, detonate and they just can't figure out why they suddenly a rebuild. And remember, boost controllers control boost spike, but do NOTHING FOR BOOST CREEP. Neither will any tune. The only way to avoid it for certain is to retain enough back-pressure in the system (even a hi-flow cat is typically enough), or port the wastegate on the twins.

The other often overlooked repercussion is that the car will absolutely stink. IMO the stench alone is enough to keep a cat on a streeted car. It'll also makes eyes water and clothes stink and be much louder. I have a friend with a single turbo tracked car that'll make a freight train take a gravel road.

 

The old rule is to not do more than three intake/exhaust mods without either putting some kind of bottleneck in or porting the WG.